tentativo di bruciarsi la retina. | retinal burn attempt.

 

taken in Roma, Italy.

 

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My thanks to Carol and Jim Dory whom I met on flickr! :-)

 

Carol and Jim introduced me to many of the local community of Nome, a town which reminds me of my own childhood small town. Wonderful.

 

The owner of the local Skidoo-snowmobile, all-terrain-vehicle shop (a big business in Nome) had a 16 foot custom made skiff that took us out to seldom-visited Sledge Island.

 

The place is right out of an adventure story. It’s an island that’s 5 miles off of the coast, that even the locals never go to. Big mistake. I heard rumors that it had a puffin rookery. Wow. It was right out of a science fiction novel. It was right out of Survivors. It was the most amazing thing I’ve ever seen in my life. It was simply awesome.

 

Razor sharp rocks, literally, on this weird island with towering spires and no place to come near, teeming with thousands of birds on the cliff, nesting and defending any flat space on these needles or cliffs.

 

I was speechless (except for saying “holy cow”, and “awesome” about every 5 seconds). Sometimes when the boat came near the cliffs HUNDREDS of murres would take off all around us. Arctic foxes, ravens stealing sky blue eggs, nesting kittiwakes, dizzying heights of rugged beauty.

 

And then I saw puffins. PUFFINS. Both kinds (the tufted was a lifer). In breeding plumage. In flight. In love. In everything..... I had died and went to heaven.

 

This shot unfortunately isn’t that good. I took 2000 shots from a rocking boat with my giant lens hand held. Most were really, really, blurry cause the boat was rocking so much. It wasn’t so much a matter of aim, as it was just hope the birds in the frame when you take the shot...Blind squirrel hunting for acorns...

 

This was the only one of two or three lucky shots I was happy with. It was taken near midnight - but being near the solstice, the sun never went down - it just stayed wonderfully low. One of the wonderful things about shooting in the arctic is it doubles or triples the amount of time in the day for good light :-)

 

Next year, the pribolofs, where apparently you can get so close to the puffins that you can do retinal scans.

A study of the effects of high voltage and household cleaning products on instant pull apart color film.

 

Materials: Fujifilm FP100-45C Instant Color Film, various household cleaning products (bleach, vinegar, baking soda, hydrogen peroxide, salt, rubbing alcohol), 15,000 volt neon tube ballast.

 

By Phillip Stearns

Barry McGee

The common kingfisher (Alcedo atthis), also known as the Eurasian kingfisher and river kingfisher, is a small kingfisher with seven subspecies recognized within its wide distribution across Eurasia and North Africa. It is resident in much of its range, but migrates from areas where rivers freeze in winter.

 

This sparrow-sized bird has the typical short-tailed, large-headed kingfisher profile; it has blue upperparts, orange underparts and a long bill. It feeds mainly on fish, caught by diving, and has special visual adaptations to enable it to see prey under water. The glossy white eggs are laid in a nest at the end of a burrow in a riverbank.

 

This species has the typical short-tailed, dumpy-bodied, large-headed, and long-billed kingfisher shape. The adult male of the western European subspecies, A. a. ispida has green-blue upperparts with pale azure-blue back and rump, a rufous patch by the bill base, and a rufous ear-patch. It has a green-blue neck stripe, white neck blaze and throat, rufous underparts, and a black bill with some red at the base. The legs and feet are bright red. It is about 16 centimetres (6.3 in) long with a wingspan of 25 cm (9.8 in), and weighs 34–46 grams (1.2–1.6 oz). The female is identical in appearance to the male except that her lower mandible is orange-red with a black tip. The juvenile is similar to the adult, but with duller and greener upperparts and paler underparts. Its bill is black, and the legs are also initially black. Feathers are moulted gradually between July and November with the main flight feathers taking 90–100 days to moult and regrow. Some that moult late may suspend their moult during cold winter weather.

 

The flight of the kingfisher is fast, direct and usually low over water. The short, rounded wings whirr rapidly, and a bird flying away shows an electric-blue "flash" down its back.

 

In North Africa, Europe and Asia north of the Himalayas, this is the only small blue kingfisher. In south and southeast Asia, it can be confused with six other small blue-and-rufous kingfishers, but the rufous ear patches distinguish it from all but juvenile blue-eared kingfishers; details of the head pattern may be necessary to differentiate the two species where both occur.

 

The common kingfisher has no song. The flight call is a short, sharp whistle chee repeated two or three times. Anxious birds emit a harsh, shrit-it-it and nestlings call for food with a churring noise.

 

The common kingfisher is widely distributed over Europe, Asia, and North Africa, mainly south of 60°N. It is a common breeding species over much of its vast Eurasian range, but in North Africa it is mainly a winter visitor, although it is a scarce breeding resident in coastal Morocco and Tunisia. In temperate regions, this kingfisher inhabits clear, slow-flowing streams and rivers, and lakes with well-vegetated banks. It frequents scrubs and bushes with overhanging branches close to shallow open water in which it hunts. In winter it is more coastal, often feeding in estuaries or harbors and along rocky seashores. Tropical populations are found by slow-flowing rivers, in mangrove creeks and in swamps.

 

Common kingfishers are important members of ecosystems and good indicators of freshwater community health. The highest densities of breeding birds are found in habitats with clear water, which permits optimal prey visibility, and trees or shrubs on the banks. These habitats have also the highest quality of water, so the presence of this bird confirms the standard of the water. Measures to improve water flow can disrupt this habitat, and in particular, the replacement of natural banks by artificial confinement greatly reduces the populations of fish, amphibians and aquatic reptiles, and waterside birds are lost. It can tolerate a certain degree of urbanization, provided the water remains clean.

 

This species is resident in areas where the climate is mild year-round, but must migrate after breeding from regions with prolonged freezing conditions in winter. Most birds winter within the southern parts of the breeding range, but smaller numbers cross the Mediterranean into Africa or travel over the mountains of Malaysia into Southeast Asia. Kingfishers migrate mainly at night, and some Siberian breeders must travel at least 3,000 km (1,900 mi) between the breeding sites and the wintering areas.

 

The common kingfisher hunts from a perch 1–2 m (3.3–6.6 ft) above the water, on a branch, post or riverbank, bill pointing down as it searches for prey. It bobs its head when food is detected to gauge the distance and plunges steeply down to seize its prey usually no deeper than 25 cm (9.8 in) below the surface. The wings are opened underwater and the open eyes are protected by the transparent third eyelid. The bird rises beak-first from the surface and flies back to its perch. At the perch the fish is adjusted until it is held near its tail and beaten against the perch several times. Once dead, the fish is positioned lengthways and swallowed head-first. A few times each day, a small greyish pellet of fish bones and other indigestible remains is regurgitated.

 

The food is mainly fish up to 12.5 cm (4.9 in) long, but the average size is 2.3 cm (0.91 in). In Central Europe, 97% of the diet was found to be composed of fish ranging in size from 2 to 10 cm with an average of 6.5 cm (body mass range from 10 g, average 3 g). Minnows, sticklebacks, small roach and trout are typical prey. About 60% of food items are fish, but this kingfisher also catches aquatic insects such as dragonfly larvae and water beetles, and, in winter, crustaceans including freshwater shrimps. In Central Europe, however, fish represented 99.9% of the diet (data from rivers, streams, and reservoirs from years 1999 to 2013). Common kingfishers have also been observed to catch lamprey. One study found that food provisioning rate increased with brood size, from 1498 g (505 fishes for four nestlings) to 2968 g (894 fishes for eight nestlings). During the fledging period each chick consumed on average 334 g of fish, which resulted in an estimated daily food intake of 37% of the chick's body mass (average over the entire nestling period). The average daily energy intake was 73.5 kJ per chick (i.e., 1837 kJ per 25 days of the fledging period).

 

A challenge for any diving bird is the change in refraction between air and water. The eyes of many birds have two foveae (the fovea is the area of the retina with the greatest density of light receptors), and a kingfisher can switch from the main central fovea to the auxiliary fovea when it enters water; a retinal streak of high receptor density which connects the two foveae allows the image to swing temporally as the bird drops onto the prey. The egg-shaped lens of the eye points towards the auxiliary fovea, enabling the bird to maintain visual acuity underwater. Because of the positions of the foveae, the kingfisher has monocular vision in air, and binocular vision in water. The underwater vision is not as a sharp as in air, but the ability to judge the distance of moving prey is more important than the sharpness of the image.

 

Each cone cell of a bird's retina contains an oil droplet that may contain carotenoid pigments. These droplets enhance color vision and reduce glare. Aquatic kingfishers have high numbers of red pigments in their oil droplets; the reason red droplets predominate is not understood, but the droplets may help with the glare or the dispersion of light from particulate matter in the water.

 

For more information, please visit en.wikipedia.org/wiki/Common_kingfisher

The octopus (plural octopuses) is a soft-bodied, eight-limbed mollusc of the order Octopoda (/ɒkˈtɒpədə/, ok-TO-pə-də). Around 300 species are recognised, and the order is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like other cephalopods, the octopus is bilaterally symmetric with two eyes and a beak, with its mouth at the center point of the eight limbs.[a] The soft body can rapidly alter its shape, enabling octopuses to squeeze through small gaps. They trail their eight appendages behind them as they swim. The siphon is used both for respiration and for locomotion, by expelling a jet of water. Octopuses have a complex nervous system and excellent sight, and are among the most intelligent and behaviourally diverse of all invertebrates.

 

Octopuses inhabit various regions of the ocean, including coral reefs, pelagic waters, and the seabed; some live in the intertidal zone and others at abyssal depths. Most species grow quickly, mature early, and are short-lived. In most species, the male uses a specially adapted arm to deliver a bundle of sperm directly into the female's mantle cavity, after which he becomes senescent and dies, while the female deposits fertilised eggs in a den and cares for them until they hatch, after which she also dies. Strategies to defend themselves against predators include the expulsion of ink, the use of camouflage and threat displays, the ability to jet quickly through the water and hide, and even deceit. All octopuses are venomous, but only the blue-ringed octopuses are known to be deadly to humans.

 

Octopuses appear in mythology as sea monsters like the Kraken of Norway and the Akkorokamui of the Ainu, and probably the Gorgon of ancient Greece. A battle with an octopus appears in Victor Hugo's book Toilers of the Sea, inspiring other works such as Ian Fleming's Octopussy. Octopuses appear in Japanese erotic art, shunga. They are eaten and considered a delicacy by humans in many parts of the world, especially the Mediterranean and the Asian seas.

 

ETYMOLOGY AND PLURALISATION

The scientific Latin term octopus was derived from Ancient Greek ὀκτώπους, a compound form of ὀκτώ (oktō, "eight") and πούς (pous, "foot"), itself a variant form of ὀκτάπους, a word used for example by Alexander of Tralles (c. 525–605) for the common octopus. The standard pluralised form of "octopus" in English is "octopuses"; the Ancient Greek plural ὀκτώποδες, "octopodes" (/ɒkˈtɒpədiːz/), has also been used historically. The alternative plural "octopi" is considered grammatically incorrect because it wrongly assumes that octopus is a Latin second declension "-us" noun or adjective when, in either Greek or Latin, it is a third declension noun.

 

Fowler's Modern English Usage states that the only acceptable plural in English is "octopuses", that "octopi" is misconceived, and "octopodes" pedantic; the latter is nonetheless used frequently enough to be acknowledged by the descriptivist Merriam-Webster 11th Collegiate Dictionary and Webster's New World College Dictionary. The Oxford English Dictionary lists "octopuses", "octopi", and "octopodes", in that order, reflecting frequency of use, calling "octopodes" rare and noting that "octopi" is based on a misunderstanding. The New Oxford American Dictionary (3rd Edition, 2010) lists "octopuses" as the only acceptable pluralisation, and indicates that "octopodes" is still occasionally used, but that "octopi" is incorrect.

 

ANATOMY AND PHYSIOLOGY

SIZE

The giant Pacific octopus (Enteroctopus dofleini) is often cited as the largest known octopus species. Adults usually weigh around 15 kg, with an arm span of up to 4.3 m. The largest specimen of this species to be scientifically documented was an animal with a live mass of 71 kg. Much larger sizes have been claimed for the giant Pacific octopus: one specimen was recorded as 272 kg with an arm span of 9 m. A carcass of the seven-arm octopus, Haliphron atlanticus, weighed 61 kg and was estimated to have had a live mass of 75 kg. The smallest species is Octopus wolfi, which is around 2.5 cm and weighs less than 1 g.

 

EXTERNAL CHARACTERISTICS

The octopus is bilaterally symmetrical along its dorso-ventral axis; the head and foot are at one end of an elongated body and function as the anterior (front) of the animal. The head includes the mouth and brain. The foot has evolved into a set of flexible, prehensile appendages, known as "arms", that surround the mouth and are attached to each other near their base by a webbed structure. The arms can be described based on side and sequence position (such as L1, R1, L2, R2) and divided into four pairs. The two rear appendages are generally used to walk on the sea floor, while the other six are used to forage for food; hence some biologists refer to the animals as having six "arms" and two "legs". The bulbous and hollow mantle is fused to the back of the head and is known as the visceral hump; it contains most of the vital organs. The mantle cavity has muscular walls and contains the gills; it is connected to the exterior by a funnel or siphon. The mouth of an octopus, located underneath the arms, has a sharp hard beak.

 

The skin consists of a thin outer epidermis with mucous cells and sensory cells, and a connective tissue dermis consisting largely of collagen fibres and various cells allowing colour change. Most of the body is made of soft tissue allowing it to lengthen, contract, and contort itself. The octopus can squeeze through tiny gaps; even the larger species can pass through an opening close to 2.5 cm in diameter. Lacking skeletal support, the arms work as muscular hydrostats and contain longitudinal, transverse and circular muscles around a central axial nerve. They can extend and contract, twist to left or right, bend at any place in any direction or be held rigid.

 

The interior surfaces of the arms are covered with circular, adhesive suckers. The suckers allow the octopus to anchor itself or to manipulate objects. Each sucker is usually circular and bowl-like and has two distinct parts: an outer shallow cavity called an infundibulum and a central hollow cavity called an acetabulum, both of which are thick muscles covered in a protective chitinous cuticle. When a sucker attaches to a surface, the orifice between the two structures is sealed. The infundibulum provides adhesion while the acetabulum remains free, and muscle contractions allow for attachment and detachment.

The eyes of the octopus are large and are at the top of the head. They are similar in structure to those of a fish and are enclosed in a cartilaginous capsule fused to the cranium. The cornea is formed from a translucent epidermal layer and the slit-shaped pupil forms a hole in the iris and lies just behind. The lens is suspended behind the pupil and photoreceptive retinal cells cover the back of the eye. The pupil can be adjusted in size and a retinal pigment screens incident light in bright conditions.Some species differ in form from the typical octopus body shape. Basal species, the Cirrina, have stout gelatinous bodies with webbing that reaches near the tip of their arms, and two large fins above the eyes, supported by an internal shell. Fleshy papillae or cirri are found along the bottom of the arms, and the eyes are more developed.

 

CIRCULATORY SYSTEM

Octopuses have a closed circulatory system, in which the blood remains inside blood vessels. Octopuses have three hearts; a systemic heart that circulates blood around the body and two branchial hearts that pump it through each of the two gills. The systemic heart is inactive when the animal is swimming and thus it tires quickly and prefers to crawl. Octopus blood contains the copper-rich protein haemocyanin to transport oxygen. This makes the blood very viscous and it requires considerable pressure to pump it around the body; octopuses' blood pressures can exceed 75 mmHg. In cold conditions with low oxygen levels, haemocyanin transports oxygen more efficiently than haemoglobin. The haemocyanin is dissolved in the plasma instead of being carried within blood cells, and gives the blood a bluish colour.

 

The systemic heart has muscular contractile walls and consists of a single ventricle and two atria, one for each side of the body. The blood vessels consist of arteries, capillaries and veins and are lined with a cellular endothelium which is quite unlike that of most other invertebrates. The blood circulates through the aorta and capillary system, to the vena cavae, after which the blood is pumped through the gills by the auxiliary hearts and back to the main heart. Much of the venous system is contractile, which helps circulate the blood.

 

RESPIRATION

Respiration involves drawing water into the mantle cavity through an aperture, passing it through the gills, and expelling it through the siphon. The ingress of water is achieved by contraction of radial muscles in the mantle wall, and flapper valves shut when strong circular muscles force the water out through the siphon. Extensive connective tissue lattices support the respiratory muscles and allow them to expand the respiratory chamber. The lamella structure of the gills allows for a high oxygen uptake, up to 65% in water at 20 °C. Water flow over the gills correlates with locomotion, and an octopus can propel its body when it expels water out of its siphon.

 

The thin skin of the octopus absorbs additional oxygen. When resting, around 41% of an octopus's oxygen absorption is through the skin. This decreases to 33% when it swims, as more water flows over the gills; skin oxygen uptake also increases. When it is resting after a meal, absorption through the skin can drop to 3% of its total oxygen uptake.

 

DIGESTION AND EXCRETION

The digestive system of the octopus begins with the buccal mass which consists of the mouth with its chitinous beak, the pharynx, radula and salivary glands. The radula is a spiked, muscular tongue-like organ with multiple rows of tiny teeth. Food is broken down and is forced into the oesophagus by two lateral extensions of the esophageal side walls in addition to the radula. From there it is transferred to the gastrointestinal tract, which is mostly suspended from the roof of the mantle cavity by numerous membranes. The tract consists of a crop, where the food is stored; a stomach, where food is ground down; a caecum where the now sludgy food is sorted into fluids and particles and which plays an important role in absorption; the digestive gland, where liver cells break down and absorb the fluid and become "brown bodies"; and the intestine, where the accumulated waste is turned into faecal ropes by secretions and blown out of the funnel via the rectum.

 

During osmoregulation, fluid is added to the pericardia of the branchial hearts. The octopus has two nephridia (equivalent to vertebrate kidneys) which are associated with the branchial hearts; these and their associated ducts connect the pericardial cavities with the mantle cavity. Before reaching the branchial heart, each branch of the vena cava expands to form renal appendages which are in direct contact with the thin-walled nephridium. The urine is first formed in the pericardial cavity, and is modified by excretion, chiefly of ammonia, and selective absorption from the renal appendages, as it is passed along the associated duct and through the nephridiopore into the mantle cavity.

 

NERVOUS SYSTEM AND SENSES

The octopus (along with cuttlefish) has the highest brain-to-body mass ratios of all invertebrates; it is also greater than that of many vertebrates. It has a highly complex nervous system, only part of which is localised in its brain, which is contained in a cartilaginous capsule. Two-thirds of an octopus's neurons are found in the nerve cords of its arms, which show a variety of complex reflex actions that persist even when they have no input from the brain. Unlike vertebrates, the complex motor skills of octopuses are not organised in their brain via an internal somatotopic map of its body, instead using a nonsomatotopic system unique to large-brained invertebrates.

 

Like other cephalopods, octopuses can distinguish the polarisation of light. Colour vision appears to vary from species to species, for example being present in O. aegina but absent in O. vulgaris. Researchers believe that opsins in the skin can sense different wavelengths of light and help the creatures choose a coloration that camouflages them, in addition to light input from the eyes. Other researchers hypothesise that cephalopod eyes in species which only have a single photoreceptor protein may use chromatic aberration to turn monochromatic vision into colour vision, though this sacrifices image quality. This would explain pupils shaped like the letter U, the letter W, or a dumbbell, as well as explaining the need for colourful mating displays.

 

Attached to the brain are two special organs called statocysts (sac-like structures containing a mineralised mass and sensitive hairs), that allow the octopus to sense the orientation of its body. They provide information on the position of the body relative to gravity and can detect angular acceleration. An autonomic response keeps the octopus's eyes oriented so that the pupil is always horizontal. Octopuses may also use the statocyst to hear sound. The common octopus can hear sounds between 400 Hz and 1000 Hz, and hears best at 600 Hz.

 

Octopuses also have an excellent sense of touch. The octopus's suction cups are equipped with chemoreceptors so the octopus can taste what it touches. Octopus arms do not become tangled or stuck to each other because the sensors recognise octopus skin and prevent self-attachment.

 

The arms contain tension sensors so the octopus knows whether its arms are stretched out, but this is not sufficient for the brain to determine the position of the octopus's body or arms. As a result, the octopus does not possess stereognosis; that is, it does not form a mental image of the overall shape of the object it is handling. It can detect local texture variations, but cannot integrate the information into a larger picture. The neurological autonomy of the arms means the octopus has great difficulty learning about the detailed effects of its motions. It has a poor proprioceptive sense, and it knows what exact motions were made only by observing the arms visually.

Ink sac

 

The ink sac of an octopus is located under the digestive gland. A gland attached to the sac produces the ink, and the sac stores it. The sac is close enough to the funnel for the octopus to shoot out the ink with a water jet. Before it leaves the funnel, the ink passes through glands which mix it with mucus, creating a thick, dark blob which allows the animal to escape from a predator. The main pigment in the ink is melanin, which gives it its black colour. Cirrate octopuses lack the ink sac.

 

LIFECYCLE

REPRODUCTION

Octopuses are gonochoric and have a single, posteriorly-located gonad which is associated with the coelom. The testis in males and the ovary in females bulges into the gonocoel and the gametes are released here. The gonocoel is connected by the gonoduct to the mantle cavity, which it enters at the gonopore. An optic gland creates hormones that cause the octopus to mature and age and stimulate gamete production. The gland may be triggered by environmental conditions such as temperature, light and nutrition, which thus control the timing of reproduction and lifespan.

 

When octopuses reproduce, the male uses a specialised arm called a hectocotylus to transfer spermatophores (packets of sperm) from the terminal organ of the reproductive tract (the cephalopod "penis") into the female's mantle cavity. The hectocotylus in benthic octopuses is usually the third right arm, which has a spoon-shaped depression and modified suckers near the tip. In most species, fertilisation occurs in the mantle cavity.

 

The reproduction of octopuses has been studied in only a few species. One such species is the giant Pacific octopus, in which courtship is accompanied, especially in the male, by changes in skin texture and colour. The male may cling to the top or side of the female or position himself beside her. There is some speculation that he may first use his hectocotylus to remove any spermatophore or sperm already present in the female. He picks up a spermatophore from his spermatophoric sac with the hectocotylus, inserts it into the female's mantle cavity, and deposits it in the correct location for the species, which in the giant Pacific octopus is the opening of the oviduct. Two spermatophores are transferred in this way; these are about one metre (yard) long, and the empty ends may protrude from the female's mantle. A complex hydraulic mechanism releases the sperm from the spermatophore, and it is stored internally by the female.

 

About forty days after mating, the female giant Pacific octopus attaches strings of small fertilised eggs (10,000 to 70,000 in total) to rocks in a crevice or under an overhang. Here she guards and cares for them for about five months (160 days) until they hatch. In colder waters, such as those off of Alaska, it may take as much as 10 months for the eggs to completely develop. The female aerates the eggs and keeps them clean; if left untended, many eggs will not hatch. She does not feed during this time and dies soon afterwards. Males become senescent and die a few weeks after mating.

 

The eggs have large yolks; cleavage (division) is superficial and a germinal disc develops at the pole. During gastrulation, the margins of this grow down and surround the yolk, forming a yolk sac, which eventually forms part of the gut. The dorsal side of the disc grows upwards and forms the embryo, with a shell gland on its dorsal surface, gills, mantle and eyes. The arms and funnel develop as part of the foot on the ventral side of the disc. The arms later migrate upwards, coming to form a ring around the funnel and mouth. The yolk is gradually absorbed as the embryo develops.

Most young octopuses hatch as paralarvae and are planktonic for weeks to months, depending on the species and water temperature. They feed on copepods, arthropod larvae and other zooplankton, eventually settling on the ocean floor and developing directly into adults with no distinct metamorphoses that are present in other groups of mollusc larvae. Octopus species that produce larger eggs – including the southern blue-ringed, Caribbean reef, California two-spot, Eledone moschata and deep sea octopuses – do not have a paralarval stage, but hatch as benthic animals similar to the adults.In the argonaut (paper nautilus), the female secretes a fine, fluted, papery shell in which the eggs are deposited and in which she also resides while floating in mid-ocean. In this she broods the young, and it also serves as a buoyancy aid allowing her to adjust her depth. The male argonaut is minute by comparison and has no shell.

 

LIFESPAN

Octopuses have a relatively short life expectancy; some species live for as little as six months. The giant Pacific octopus, one of the two largest species of octopus, may live for as much as five years. Octopus lifespan is limited by reproduction: males can live for only a few months after mating, and females die shortly after their eggs hatch. The larger Pacific striped octopus is an exception, as it can reproduce multiple times over a life of around two years. Octopus reproductive organs mature due to the hormonal influence of the optic gland but result in the inactivation of their digestive glands, typically causing the octopus to die from starvation. Experimental removal of both optic glands after spawning was found to result in the cessation of broodiness, the resumption of feeding, increased growth, and greatly extended lifespans. It has been proposed that the naturally short lifespan may be functional to prevent rapid overpopulation.

 

DISTRIBUTION AND HABITAT

Octopuses live in every ocean, and different species have adapted to different marine habitats. As juveniles, common octopuses inhabit shallow tide pools. The Hawaiian day octopus (Octopus cyanea) lives on coral reefs; argonauts drift in pelagic waters. Abdopus aculeatus mostly lives in near-shore seagrass beds. Some species are adapted to the cold, ocean depths. The spoon-armed octopus (Bathypolypus arcticus) is found at depths of 1,000 m, and Vulcanoctopus hydrothermalis lives near hydrothermal vents at 2,000 m. The cirrate species are often free-swimming and live in deep-water habitats. Although several species are known to live at bathyal and abyssal depths, there is only a single indisputable record of an octopus in the hadal zone; a species of Grimpoteuthis (dumbo octopus) photographed at 6,957 m. No species are known to live in fresh water.

 

BEHAVIOUR AND ECOLOGY

Most species are solitary when not mating, though a few are known to occur in high densities and with frequent interactions, signaling, mate defending and eviction of individuals from dens. This is likely the result of abundant food supplies combined with limited den sites. The larger Pacific striped octopus however is social, living in groups of up to 40 individuals that share dens. Octopuses hide in dens, which are typically crevices in rocky outcrops or other hard structures, though some species burrow into sand or mud. Octopuses are not territorial but generally remain in a home range; they may leave the area in search of food. They can use navigation skills to return to a den without having to retrace their outward route. They are not known to be migratory.

 

Octopuses bring captured prey back to the den where they can eat it safely. Sometimes the octopus catches more prey than it can eat, and the den is often surrounded by a midden of dead and uneaten food items. Other creatures, such as fish, crabs, molluscs and echinoderms, often share the den with the octopus, either because they have arrived as scavengers, or because they have survived capture. Octopuses rarely engage in interspecific cooperative hunting with fish as their partners. They regulate the species composition of the hunting group - and the behavior of their partners - by punching them.

 

FEEDING

Nearly all octopuses are predatory; bottom-dwelling octopuses eat mainly crustaceans, polychaete worms, and other molluscs such as whelks and clams; open-ocean octopuses eat mainly prawns, fish and other cephalopods. Major items in the diet of the giant Pacific octopus include bivalve molluscs such as the cockle Clinocardium nuttallii, clams and scallops and crustaceans such as crabs and spider crabs. Prey that it is likely to reject include moon snails because they are too large and limpets, rock scallops, chitons and abalone, because they are too securely fixed to the rock.

 

A benthic (bottom-dwelling) octopus typically moves among the rocks and feels through the crevices. The creature may make a jet-propelled pounce on prey and pull it towards the mouth with its arms, the suckers restraining it. Small prey may be completely trapped by the webbed structure. Octopuses usually inject crustaceans like crabs with a paralysing saliva then dismember them with their beaks. Octopuses feed on shelled molluscs either by forcing the valves apart, or by drilling a hole in the shell to inject a nerve toxin. It used to be thought that the hole was drilled by the radula, but it has now been shown that minute teeth at the tip of the salivary papilla are involved, and an enzyme in the toxic saliva is used to dissolve the calcium carbonate of the shell. It takes about three hours for O. vulgaris to create a 0.6 mm hole. Once the shell is penetrated, the prey dies almost instantaneously, its muscles relax, and the soft tissues are easy for the octopus to remove. Crabs may also be treated in this way; tough-shelled species are more likely to be drilled, and soft-shelled crabs are torn apart.

 

Some species have other modes of feeding. Grimpoteuthis has a reduced or non-existent radula and swallows prey whole. In the deep-sea genus Stauroteuthis, some of the muscle cells that control the suckers in most species have been replaced with photophores which are believed to fool prey by directing them towards the mouth, making them one of the few bioluminescent octopuses.

 

LOCOMOTION

Octopuses mainly move about by relatively slow crawling with some swimming in a head-first position. Jet propulsion or backwards swimming, is their fastest means of locomotion, followed by swimming and crawling. When in no hurry, they usually crawl on either solid or soft surfaces. Several arms are extended forwards, some of the suckers adhere to the substrate and the animal hauls itself forwards with its powerful arm muscles, while other arms may push rather than pull. As progress is made, other arms move ahead to repeat these actions and the original suckers detach. During crawling, the heart rate nearly doubles, and the animal requires ten or fifteen minutes to recover from relatively minor exercise.

 

Most octopuses swim by expelling a jet of water from the mantle through the siphon into the sea. The physical principle behind this is that the force required to accelerate the water through the orifice produces a reaction that propels the octopus in the opposite direction. The direction of travel depends on the orientation of the siphon. When swimming, the head is at the front and the siphon is pointed backwards, but when jetting, the visceral hump leads, the siphon points towards the head and the arms trail behind, with the animal presenting a fusiform appearance. In an alternative method of swimming, some species flatten themselves dorso-ventrally, and swim with the arms held out sideways, and this may provide lift and be faster than normal swimming. Jetting is used to escape from danger, but is physiologically inefficient, requiring a mantle pressure so high as to stop the heart from beating, resulting in a progressive oxygen deficit.

 

Cirrate octopuses cannot produce jet propulsion and rely on their fins for swimming. They have neutral buoyancy and drift through the water with the fins extended. They can also contract their arms and surrounding web to make sudden moves known as "take-offs". Another form of locomotion is "pumping", which involves symmetrical contractions of muscles in their webs producing peristaltic waves. This moves the body slowly.

 

In 2005, Adopus aculeatus and veined octopus (Amphioctopus marginatus) were found to walk on two arms, while at the same time mimicking plant matter. This form of locomotion allows these octopuses to move quickly away from a potential predator without being recognised. A study of this behaviour led to the suggestion that the two rearmost appendages may be more accurately termed "legs" rather than "arms". Some species of octopus can crawl out of the water briefly, which they may do between tide pools while hunting crustaceans or gastropods or to escape predators. "Stilt walking" is used by the veined octopus when carrying stacked coconut shells. The octopus carries the shells underneath it with two arms, and progresses with an ungainly gait supported by its remaining arms held rigid.

 

INTELLIGENCE

Octopuses are highly intelligent; the extent of their intelligence and learning capability are not well defined. Maze and problem-solving experiments have shown evidence of a memory system that can store both short- and long-term memory. It is not known precisely what contribution learning makes to adult octopus behaviour. Young octopuses learn nothing from their parents, as adults provide no parental care beyond tending to their eggs until the young octopuses hatch.

 

In laboratory experiments, octopuses can be readily trained to distinguish between different shapes and patterns. They have been reported to practise observational learning, although the validity of these findings is contested. Octopuses have also been observed in what has been described as play: repeatedly releasing bottles or toys into a circular current in their aquariums and then catching them. Octopuses often break out of their aquariums and sometimes into others in search of food. They have even boarded fishing boats and opened holds to eat crabs. The veined octopus collects discarded coconut shells, then uses them to build a shelter, an example of tool use.

 

CAMOUFLAGE AND COLOUR CHANGE

Octopuses use camouflage when hunting and to avoid predators. To do this they use specialised skin cells which change the appearance of the skin by adjusting its colour, opacity, or reflectivity. Chromatophores contain yellow, orange, red, brown, or black pigments; most species have three of these colours, while some have two or four. Other colour-changing cells are reflective iridophores and white leucophores. This colour-changing ability is also used to communicate with or warn other octopuses.

 

Octopuses can create distracting patterns with waves of dark coloration across the body, a display known as the "passing cloud". Muscles in the skin change the texture of the mantle to achieve greater camouflage. In some species, the mantle can take on the spiky appearance of algae; in others, skin anatomy is limited to relatively uniform shades of one colour with limited skin texture. Octopuses that are diurnal and live in shallow water have evolved more complex skin than their nocturnal and deep-sea counterparts.

 

A "moving rock" trick involves the octopus mimicking a rock and then inching across the open space with a speed matching the movement in the surrounding water, allowing it to move in plain sight of a predator.

 

DEFENCE

Aside from humans, octopuses may be preyed on by fishes, seabirds, sea otters, pinnipeds, cetaceans, and other cephalopods. Octopuses typically hide or disguise themselves by camouflage and mimicry; some have conspicuous warning coloration (aposematism) or deimatic behaviour. An octopus may spend 40% of its time hidden away in its den. When the octopus is approached, it may extend an arm to investigate. 66% of Enteroctopus dofleini in one study had scars, with 50% having amputated arms. The blue rings of the highly venomous blue-ringed octopus are hidden in muscular skin folds which contract when the animal is threatened, exposing the iridescent warning. The Atlantic white-spotted octopus (Callistoctopus macropus) turns bright brownish red with oval white spots all over in a high contrast display. Displays are often reinforced by stretching out the animal's arms, fins or web to make it look as big and threatening as possible.

 

Once they have been seen by a predator, they commonly try to escape but can also use distraction with an ink cloud ejected from the ink sac. The ink is thought to reduce the efficiency of olfactory organs, which would aid evasion from predators that employ smell for hunting, such as sharks. Ink clouds of some species might act as pseudomorphs, or decoys that the predator attacks instead.

 

When under attack, some octopuses can perform arm autotomy, in a manner similar to the way skinks and other lizards detach their tails. The crawling arm may distract would-be predators. Such severed arms remain sensitive to stimuli and move away from unpleasant sensations. Octopuses can replace lost limbs.

 

Some octopuses, such as the mimic octopus, can combine their highly flexible bodies with their colour-changing ability to mimic other, more dangerous animals, such as lionfish, sea snakes, and eels.

 

PATHOGENS AND PARASITES

The diseases and parasites that affect octopuses have been little studied, but cephalopods are known to be the intermediate or final hosts of various parasitic cestodes, nematodes and copepods; 150 species of protistan and metazoan parasites have been recognised. The Dicyemidae are a family of tiny worms that are found in the renal appendages of many species; it is unclear whether they are parasitic or are endosymbionts. Coccidians in the genus Aggregata living in the gut cause severe disease to the host. Octopuses have an innate immune system, and the haemocytes respond to infection by phagocytosis, encapsulation, infiltration or cytotoxic activities to destroy or isolate the pathogens. The haemocytes play an important role in the recognition and elimination of foreign bodies and wound repair. Captive animals have been found to be more susceptible to pathogens than wild ones. A gram-negative bacterium, Vibrio lentus, has been found to cause skin lesions, exposure of muscle and death of octopuses in extreme cases.

 

EVOLUTION

The scientific name Octopoda was first coined and given as the order of octopuses in 1818 by English biologist William Elford Leach, who classified them as Octopoida the previous year. The Octopoda consists of around 300 known species and were historically divided into two suborders, the Incirrina and the Cirrina. However, more recent evidence suggests that Cirrina are merely the most basal species and are not a unique clade. The incirrate octopuses (the majority of species) lack the cirri and paired swimming fins of the cirrates. In addition, the internal shell of incirrates is either present as a pair of stylets or absent altogether.

 

FOSSIL HISTORY AND PHYLOGENY

Cephalopods have existed for 500 million years and octopus ancestors were in the Carboniferous seas 300 million years ago. The oldest known octopus fossil is Pohlsepia, which lived 296 million years ago. Researchers have identified impressions of eight arms, two eyes, and possibly an ink sac. Octopuses are mostly soft tissue, and so fossils are relatively rare. Octopuses, squids and cuttlefish belong to the clade Coleoidea. They are known as "soft-bodied" cephalopods, lacking the external shell of most molluscs and other cephalopods like the nautiloids and the extinct Ammonoidea. Octopuses have eight limbs like other coleoids but lack the extra specialised feeding appendages known as tentacles which are longer and thinner with suckers only at their club-like ends. The vampire squid (Vampyroteuthis) also lacks tentacles but has sensory filaments.

 

The cladograms are based on Sanchez et al., 2018, who created a molecular phylogeny based on mitochondrial and nuclear DNA marker sequences.

 

RNA EDITING

Octopuses and other coleoid cephalopods are capable of greater RNA editing (which involves changes to the nucleic acid sequence of the primary transcript of RNA molecules) than any other organisms. Editing is concentrated in the nervous system and affects proteins involved in neural excitability and neuronal morphology. More than 60% of RNA transcripts for coleoid brains are recoded by editing, compared to less than 1% for a human or fruit fly. Coleoids rely mostly on ADAR enzymes for RNA editing, which requires large double-stranded RNA structures to flank the editing sites. Both the structures and editing sites are conserved in the coleoid genome and the mutation rates for the sites are severely hampered. Hence, greater transcriptome plasticity has come at the cost of slower genome evolution. High levels of RNA editing do not appear to be present in more basal cephalopods or other molluscs.

 

RELATIONSHIP TO HUMANS

CULTURAL REFERENCES

Ancient seafaring people were aware of the octopus, as evidenced by certain artworks and designs. For example, a stone carving found in the archaeological recovery from Bronze Age Minoan Crete at Knossos (1900–1100 BC) has a depiction of a fisherman carrying an octopus. The terrifyingly powerful Gorgon of Greek mythology has been thought to have been inspired by the octopus or squid, the octopus itself representing the severed head of Medusa, the beak as the protruding tongue and fangs, and its tentacles as the snakes. The Kraken are legendary sea monsters of giant proportions said to dwell off the coasts of Norway and Greenland, usually portrayed in art as a giant octopus attacking ships. Linnaeus included it in the first edition of his 1735 Systema Naturae. One translation of the Hawaiian creation myth the Kumulipo suggests that the octopus is the lone survivor of a previous age. The Akkorokamui is a gigantic octopus-like monster from Ainu folklore.

 

A battle with an octopus plays a significant role in Victor Hugo's book Travailleurs de la mer (Toilers of the Sea), relating to his time in exile on Guernsey. Ian Fleming's 1966 short story collection Octopussy and The Living Daylights, and the 1983 James Bond film were partly inspired by Hugo's book.

 

Japanese erotic art, shunga, includes ukiyo-e woodblock prints such as Katsushika Hokusai's 1814 print Tako to ama (The Dream of the Fisherman's Wife), in which an ama diver is sexually intertwined with a large and a small octopus. The print is a forerunner of tentacle erotica. The biologist P. Z. Myers noted in his science blog, Pharyngula, that octopuses appear in "extraordinary" graphic illustrations involving women, tentacles, and bare breasts.

 

Since it has numerous arms emanating from a common centre, the octopus is often used as a symbol for a powerful and manipulative organisation, company, or country.

 

DANGER

Octopuses generally avoid humans, but incidents have been verified. For example, a 2.4-metre Pacific octopus, said to be nearly perfectly camouflaged, "lunged" at a diver and "wrangled" over his camera before it let go. Another diver recorded the encounter on video.

 

All species are venomous, but only blue-ringed octopuses have venom that is lethal to humans. Bites are reported each year across the animals' range from Australia to the eastern Indo-Pacific Ocean. They bite only when provoked or accidentally stepped upon; bites are small and usually painless. The venom appears to be able to penetrate the skin without a puncture, given prolonged contact. It contains tetrodotoxin, which causes paralysis by blocking the transmission of nerve impulses to the muscles. This causes death by respiratory failure leading to cerebral anoxia. No antidote is known, but if breathing can be kept going artificially, patients recover within 24 hours. Bites have been recorded from captive octopuses of other species; they leave swellings which disappear in a day or two.

 

FISHERIES AND CUISINE

Octopus fisheries exist around the world with total catches varying between 245,320 and 322,999 metric tons from 1986 to 1995. The world catch peaked in 2007 at 380,000 tons, and fell by a tenth by 2012. Methods to capture octopuses include pots, traps, trawls, snares, drift fishing, spearing, hooking and hand collection. Octopus is eaten in many cultures and is a common food on the Mediterranean and Asian coasts. The arms and sometimes other body parts are prepared in various ways, often varying by species or geography. Live octopuses are eaten in several countries around the world, including the US. Animal welfare groups have objected to this practice on the basis that octopuses can experience pain. Octopuses have a food conversion efficiency greater than that of chickens, making octopus aquaculture a possibility.

 

IN SCIENCE AND TECHNOLOGY

In classical Greece, Aristotle (384–322 BC) commented on the colour-changing abilities of the octopus, both for camouflage and for signalling, in his Historia animalium: "The octopus ... seeks its prey by so changing its colour as to render it like the colour of the stones adjacent to it; it does so also when alarmed." Aristotle noted that the octopus had a hectocotyl arm and suggested it might be used in sexual reproduction. This claim was widely disbelieved until the 19th century. It was described in 1829 by the French zoologist Georges Cuvier, who supposed it to be a parasitic worm, naming it as a new species, Hectocotylus octopodis. Other zoologists thought it a spermatophore; the German zoologist Heinrich Müller believed it was "designed" to detach during copulation. In 1856 the Danish zoologist Japetus Steenstrup demonstrated that it is used to transfer sperm, and only rarely detaches.

 

Octopuses offer many possibilities in biological research, including their ability to regenerate limbs, change the colour of their skin, behave intelligently with a distributed nervous system, and make use of 168 kinds of protocadherins (humans have 58), the proteins that guide the connections neurons make with each other. The California two-spot octopus has had its genome sequenced, allowing exploration of its molecular adaptations. Having independently evolved mammal-like intelligence, octopuses have been compared to hypothetical intelligent extraterrestrials. Their problem-solving skills, along with their mobility and lack of rigid structure enable them to escape from supposedly secure tanks in laboratories and public aquariums.

 

Due to their intelligence, octopuses are listed in some countries as experimental animals on which surgery may not be performed without anesthesia, a protection usually extended only to vertebrates. In the UK from 1993 to 2012, the common octopus (Octopus vulgaris) was the only invertebrate protected under the Animals (Scientific Procedures) Act 1986. In 2012, this legislation was extended to include all cephalopods in accordance with a general EU directive.

 

Some robotics research is exploring biomimicry of octopus features. Octopus arms can move and sense largely autonomously without intervention from the animal's central nervous system. In 2015 a team in Italy built soft-bodied robots able to crawl and swim, requiring only minimal computation. In 2017 a German company made an arm with a soft pneumatically controlled silicone gripper fitted with two rows of suckers. It is able to grasp objects such as a metal tube, a magazine, or a ball, and to fill a glass by pouring water from a bottle.

 

WIKIPEDIA

Owls are birds from the order Strigiformes, which includes about 200 species of mostly solitary and nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp talons, and feathers adapted for silent flight. Exceptions include the diurnal northern hawk-owl and the gregarious burrowing owl.

 

Owls hunt mostly small mammals, insects, and other birds, although a few species specialize in hunting fish. They are found in all regions of the Earth except Antarctica and some remote islands.

 

Owls are divided into two families: the Strigidae family of true (or typical) owls; and the Tytonidae family of barn-owls.

 

ANATOMY

Owls possess large, forward-facing eyes and ear-holes, a hawk-like beak, a flat face, and usually a conspicuous circle of feathers, a facial disc, around each eye. The feathers making up this disc can be adjusted to sharply focus sounds from varying distances onto the owls' asymmetrically placed ear cavities. Most birds of prey have eyes on the sides of their heads, but the stereoscopic nature of the owl's forward-facing eyes permits the greater sense of depth perception necessary for low-light hunting. Although owls have binocular vision, their large eyes are fixed in their sockets - as are those of most other birds - so they must turn their entire heads to change views. As owls are farsighted, they are unable to clearly see anything within a few centimeters of their eyes. Caught prey can be felt by owls with the use of filoplumes - hairlike feathers on the beak and feet that act as "feelers". Their far vision, particularly in low light, is exceptionally good.

 

Owls can rotate their heads and necks as much as 270°. Owls have 14 neck vertebrae compared to seven in humans, which makes their necks more flexible. They also have adaptations to their circulatory systems, permitting rotation without cutting off blood to the brain: the foramina in their vertebrae through which the vertebral arteries pass are about 10 times the diameter of the artery, instead of about the same size as the artery as in humans; the vertebral arteries enter the cervical vertebrae higher than in other birds, giving the vessels some slack, and the carotid arteries unite in a very large anastomosis or junction, the largest of any bird's, preventing blood supply from being cut off while they rotate their necks. Other anastomoses between the carotid and vertebral arteries support this effect.

 

The smallest owl—weighing as little as 31 g and measuring some 13.5 cm - is the elf owl (Micrathene whitneyi). Around the same diminutive length, although slightly heavier, are the lesser known long-whiskered owlet (Xenoglaux loweryi) and Tamaulipas pygmy owl (Glaucidium sanchezi). The largest owl by length is the great grey owl (Strix nebulosa), which measures about 70 cm on average and can attain a length of 84 cm). However, the heaviest (and largest winged) owls are two similarly sized eagle owls; the Eurasian eagle-owl (Bubo bubo) and Blakiston's fish owl (B. blakistoni). These two species, which are on average about 2.53 cm shorter in length than the great grey, can both attain a wingspan of 2 m and a weight of 4.5 kg in the largest females.

 

Different species of owls produce different sounds; this distribution of calls aids owls in finding mates or announcing their presence to potential competitors, and also aids ornithologists and birders in locating these birds and distinguishing species. As noted above, their facial discs help owls to funnel the sound of prey to their ears. In many species, these discs are placed asymmetrically, for better directional location.

 

Owl plumage is generally cryptic, although several species have facial and head markings, including face masks, ear tufts, and brightly coloured irises. These markings are generally more common in species inhabiting open habitats, and are thought to be used in signaling with other owls in low-light conditions.

 

SEXUAL DIMORPHISM

Sexual dimorphism is a physical difference between males and females of a species. Reverse sexual dimorphism, when females are larger than males, has been observed across multiple owl species. The degree of size dimorphism varies across multiple populations and species, and is measured through various traits, such as wing span and body mass. Overall, female owls tend to be slightly larger than males. The exact explanation for this development in owls is unknown. However, several theories explain the development of sexual dimorphism in owls.

 

One theory suggests that selection has led males to be smaller because it allows them to be efficient foragers. The ability to obtain more food is advantageous during breeding season. In some species, female owls stay at their nest with their eggs while it is the responsibility of the male to bring back food to the nest. However, if food is scarce, the male first feeds himself before feeding the female. Small birds, which are agile, are an important source of food for owls. Male burrowing owls have been observed to have longer wing chords than females, despite being smaller than females. Furthermore, owls have been observed to be roughly the same size as their prey. This has also been observed in other predatory birds, which suggests that owls with smaller bodies and long wing chords have been selected for because of the increased agility and speed that allows them to catch their prey.

 

Another popular theory suggests that females have not been selected to be smaller like male owls because of their sexual roles. In many species, female owls may not leave the nest. Therefore, females may have a larger mass to allow them to go for a longer period of time without starving. For example, one hypothesized sexual role is that larger females are more capable of dismembering prey and feeding it to their young, hence female owls are larger than their male counterparts.

 

A different theory suggests that the size difference between male and females is due to sexual selection: since large females can choose their mate and may violently reject a male's sexual advances, smaller male owls that have the ability to escape unreceptive females are more likely to have been selected.

 

ADAPTATIONS AND HUNTING

All owls are carnivorous birds of prey and live mainly on a diet of insects and small rodents such as mice, rats, and hares. Some owls are also specifically adapted to hunt fish. They are very adept in hunting in their respective environments. Since owls can be found in nearly all parts of the world and across a multitude of ecosystems, their hunting skills and characteristics vary slightly from species to species, though most characteristics are shared among all species.

 

FLIGHT AND FEATHERS

Most owls share an innate ability to fly almost silently and also more slowly in comparison to other birds of prey. Most owls live a mainly nocturnal lifestyle and being able to fly without making any noise gives them a strong advantage over their prey that are listening for the slightest sound in the night. A silent, slow flight is not as necessary for diurnal and crepuscular owls given that prey can usually see an owl approaching. While the morphological and biological mechanisms of this silent flight are more or less unknown, the structure of the feather has been heavily studied and accredited to a large portion of why they have this ability. Owls’ feathers are generally larger than the average birds’ feathers, have fewer radiates, longer pennulum, and achieve smooth edges with different rachis structures. Serrated edges along the owl’s remiges bring the flapping of the wing down to a nearly silent mechanism. The serrations are more likely reducing aerodynamic disturbances, rather than simply reducing noise. The surface of the flight feathers is covered with a velvety structure that absorbs the sound of the wing moving. These unique structures reduce noise frequencies above 2 kHz, making the sound level emitted drop below the typical hearing spectrum of the owl’s usual prey and also within the owl’s own best hearing range. This optimizes the owl’s ability to silently fly to capture prey without the prey hearing the owl first as it flies in. It also allows the owl to monitor the sound output from its flight pattern.

 

The feather adaption that allows silent flight means that barn owl feathers are not waterproof. To retain the softness and silent flight, the barn owl cannot use the preen oil or powder dust that other species use for waterproofing. In wet weather, they cannot hunt and this may be disastrous during the breeding season. Barn owls are frequently found drowned in cattle drinking troughs, since they land to drink and bathe, but are unable to climb out. Owls can struggle to keep warm, because of their lack of waterproofing, so large numbers of downy feathers help them to retain body heat.

 

VISION

Eyesight is a particular characteristic of the owl that aids in nocturnal prey capture. Owls are part of a small group of birds that live nocturnally, but do not use echolocation to guide them in flight in low-light situations. Owls are known for their disproportionally large eyes in comparison to their skulls. An apparent consequence of the evolution of an absolutely large eye in a relatively small skull is that the eye of the owl has become tubular in shape. This shape is found in other so-called nocturnal eyes, such as the eyes of strepsirrhine primates and bathypelagic fishes. Since the eyes are fixed into these sclerotic tubes, they are unable to move the eyes in any direction. Instead of moving their eyes, owls swivel their heads to view their surroundings. Owls' heads are capable of swiveling through an angle of roughly 270°, easily enabling them to see behind them without relocating the torso. This ability keeps bodily movement at a minimum, thus reduces the amount of sound the owl makes as it waits for its prey. Owls are regarded as having the most frontally placed eyes among all avian groups, which gives them some of the largest binocular fields of vision. However, owls are farsighted and cannot focus on objects within a few centimeters of their eyes. While owls are commonly believed to have great nocturnal vision due to their large (thus very light-gathering) eyes and pupils and/or extremely sensitive rod receptors, the true cause for their ability to see in the night is due to neural mechanisms which mediate the extraction of spatial information gathered from the retinal image throughout the nocturnal luminance range. These mechanisms are only able to function due to the large-sized retinal image. Thus, the primary nocturnal function in the vision of the owl is due to its large posterior nodal distance; retinal image brightness is only maximized to the owl within secondary neural functions. These attributes of the owl cause its nocturnal eyesight to be far superior to that of its average prey.

 

HEARING

Owls exhibit specialized hearing functions and ear shapes that also aid in hunting. They are noted for asymmetrical ear placements on the skull in some genera. Owls can have either internal or external ears, both of which are asymmetrical. Asymmetry has not been reported to extend to the middle or internal ear of the owl. Asymmetrical ear placement on the skull allows the owl to pinpoint the location of its prey. This is especially true for strictly nocturnal species such as the barn owls Tyto or Tengmalm's owl. With ears set at different places on its skull, an owl is able to determine the direction from which the sound is coming by the minute difference in time that it takes for the sound waves to penetrate the left and right ears.[citation needed] The owl turns its head until the sound reaches both ears at the same time, at which point it is directly facing the source of the sound. This time difference between ears is a matter of about 0.00003 seconds, or 30 millionths of a second. Behind the ear openings are modified, dense feathers, densely packed to form a facial ruff, which creates an anterior-facing, concave wall that cups the sound into the ear structure. This facial ruff is poorly defined in some species, and prominent, nearly encircling the face, in other species. The facial disk also acts to direct sound into the ears, and a downward-facing, sharply triangular beak minimizes sound reflection away from the face. The shape of the facial disk is adjustable at will to focus sounds more effectively.

 

The prominences above a great horned owl's head are commonly mistaken as its ears. This is not the case; they are merely feather tufts. The ears are on the sides of the head in the usual location (in two different locations as described above).

 

TALONS

While the auditory and visual capabilities of the owl allow it to locate and pursue its prey, the talons and beak of the owl do the final work. The owl kills its prey using these talons to crush the skull and knead the body. The crushing power of an owl’s talons varies according to prey size and type, and by the size of the owl. The burrowing owl (Athene cunicularia), a small, partly insectivorous owl, has a release force of only 5 N. The larger barn owl (Tyto alba) needs a force of 30 N to release its prey, and one of the largest owls, the great horned owl (Bubo virginianus) needs a force over 130 N to release prey in its talons. An owl’s talons, like those of most birds of prey, can seem massive in comparison to the body size outside of flight. The masked owl has some of the proportionally longest talons of any bird of prey; they appear enormous in comparison to the body when fully extended to grasp prey. An owl’s claws are sharp and curved. The family Tytonidae has inner and central toes of about equal length, while the family Strigidae has an inner toe that is distinctly shorter than the central one. These different morphologies allow efficiency in capturing prey specific to the different environments they inhabit.

 

BEAK

The beak of the owl is short, curved, and downward-facing, and typically hooked at the tip for gripping and tearing its prey. Once prey is captured, the scissor motion of the top and lower bill is used to tear the tissue and kill. The sharp lower edge of the upper bill works in coordination with the sharp upper edge of the lower bill to deliver this motion. The downward-facing beak allows the owl’s field of vision to be clear, as well as directing sound into the ears without deflecting sound waves away from the face.

 

CAMOUFLAGE

The coloration of the owl’s plumage plays a key role in its ability to sit still and blend into the environment, making it nearly invisible to prey. Owls tend to mimic the colorations and sometimes even the texture patterns of their surroundings, the common barn owl being an exception. Nyctea scandiaca, or the snowy owl, appears nearly bleach-white in color with a few flecks of black, mimicking their snowy surroundings perfectly. Likewise, the mottled wood-owl (Strix ocellata) displays shades of brown, tan, and black, making the owl nearly invisible in the surrounding trees, especially from behind. Usually, the only tell-tale sign of a perched owl is its vocalizations or its vividly colored eyes.

 

BEHAVIOR

The serrations on the leading edge of an owl's flight feathers reduce noise

 

Most owls are nocturnal, actively hunting their prey in darkness. Several types of owls, however, are crepuscular - active during the twilight hours of dawn and dusk; one example is the pygmy owl (Glaucidium). A few owls are active during the day, also; examples are the burrowing owl (Speotyto cunicularia) and the short-eared owl (Asio flammeus).

 

Much of the owls' hunting strategy depends on stealth and surprise. Owls have at least two adaptations that aid them in achieving stealth. First, the dull coloration of their feathers can render them almost invisible under certain conditions. Secondly, serrated edges on the leading edge of owls' remiges muffle an owl's wing beats, allowing an owl's flight to be practically silent. Some fish-eating owls, for which silence has no evolutionary advantage, lack this adaptation.

 

An owl's sharp beak and powerful talons allow it to kill its prey before swallowing it whole (if it is not too big). Scientists studying the diets of owls are helped by their habit of regurgitating the indigestible parts of their prey (such as bones, scales, and fur) in the form of pellets. These "owl pellets" are plentiful and easy to interpret, and are often sold by companies to schools for dissection by students as a lesson in biology and ecology.

 

BREEDING AND REPRODUCTION

Owl eggs typically have a white colour and an almost spherical shape, and range in number from a few to a dozen, depending on species and the particular season; for most, three or four is the more common number. In at least one species, female owls do not mate with the same male for a lifetime. Female burrowing owls commonly travel and find other mates, while the male stays in his territory and mates with other females.

 

EVOLUTION AND SYSTEMATICS

The systematic placement of owls is disputed. For example, the Sibley-Ahlquist taxonomy finds that, based on DNA-DNA hybridization, owls are more closely related to the nightjars and their allies (Caprimulgiformes) than to the diurnal predators in the order Falconiformes; consequently, the Caprimulgiformes are placed in the Strigiformes, and the owls in general become a family, the Strigidae. A recent study indicates that the drastic rearrangement of the genome of the accipitrids may have obscured any close relationship of theirs with groups such as the owls. In any case, the relationships of the Caprimulgiformes, the owls, the falcons, and the accipitrid raptors are not resolved to satisfaction; currently, a trend to consider each group (with the possible exception of the accipitrids) as a distinct order is increasing.

 

Some 220 to 225 extant species of owls are known, subdivided into two families: typical owls (Strigidae) and barn-owls (Tytonidae). Some entirely extinct families have also been erected based on fossil remains; these differ much from modern owls in being less specialized or specialized in a very different way (such as the terrestrial Sophiornithidae). The Paleocene genera Berruornis and Ogygoptynx show that owls were already present as a distinct lineage some 60–57 million years ago (Mya), hence, possibly also some 5 million years earlier, at the extinction of the nonavian dinosaurs. This makes them one of the oldest known groups of non-Galloanserae landbirds. The supposed "Cretaceous owls" Bradycneme and Heptasteornis are apparently nonavialan maniraptors.

 

During the Paleogene, the Strigiformes radiated into ecological niches now mostly filled by other groups of birds.[clarification needed] The owls as known today, though, evolved their characteristic morphology and adaptations during that time, too. By the early Neogene, the other lineages had been displaced by other bird orders, leaving only barn-owls and typical owls. The latter at that time were usually a fairly generic type of (probably earless) owls similar to today's North American spotted owl or the European tawny owl; the diversity in size and ecology found in typical owls today developed only subsequently.

 

Around the Paleogene-Neogene boundary (some 25 Mya), barn-owls were the dominant group of owls in southern Europe and adjacent Asia at least; the distribution of fossil and present-day owl lineages indicates that their decline is contemporary with the evolution of the different major lineages of typical owls, which for the most part seems to have taken place in Eurasia. In the Americas, rather an expansion of immigrant lineages of ancestral typical owls occurred.

The supposed fossil herons "Ardea" perplexa (Middle Miocene of Sansan, France) and "Ardea" lignitum (Late Pliocene of Germany) were more probably owls; the latter was apparently close to the modern genus Bubo. Judging from this, the Late Miocene remains from France described as "Ardea" aureliensis should also be restudied. The Messelasturidae, some of which were initially believed to be basal Strigiformes, are now generally accepted to be diurnal birds of prey showing some convergent evolution towards owls. The taxa often united under Strigogyps were formerly placed in part with the owls, specifically the Sophiornithidae; they appear to be Ameghinornithidae instead.

 

SYMBOLISM AND MYTHOLOGY

AFRICAN CULTURES

Among the Kikuyu of Kenya, it was believed that owls were harbingers of death. If one saw an owl or heard its hoot, someone was going to die. In general, owls are viewed as harbingers of bad luck, ill health, or death. The belief is widespread even today.

 

ANCIENT EUROPEAN AND MODERN WESTERN CULTURE

The modern West generally associates owls with wisdom. This link goes back at least as far as Ancient Greece, where Athens, noted for art and scholarship, and Athena, Athens' patron goddess and the goddess of wisdom, had the owl as a symbol.[34] Marija Gimbutas traces veneration of the owl as a goddess, among other birds, to the culture of Old Europe, long pre-dating Indo-European cultures.

 

T. F. Thiselton-Dyer in his Folk-lore of Shakespeare says that "from the earliest period it has been considered a bird of ill-omen," and Pliny tells us how, on one occasion, even Rome itself underwent a lustration, because one of them strayed into the Capitol. He represents it also as a funereal bird, a monster of the night, the very abomination of human kind. Virgil describes its death-howl from the top of the temple by night, a circumstance introduced as a precursor of Dido's death. Ovid, too, constantly speaks of this bird's presence as an evil omen; and indeed the same notions respecting it may be found among the writings of most of the ancient poets." A list of "omens drear" in John Keats' Hyperion includes the "gloom-bird's hated screech." Pliny the Elder reports that owl's eggs were commonly used as a hangover cure.

 

HINDUISM

In Hinduism, an owl is the vahana, mount, of the Goddess Lakshmi.

 

NATIVE AMERICAN CULTURES

People often allude to the reputation of owls as bearers of supernatural danger when they tell misbehaving children, "the owls will get you", and in most Native American folklore, owls are a symbol of death. For example:

 

According to Apache and Seminole tribes, hearing owls hooting is considered the subject of numerous "bogeyman" stories told to warn children to remain indoors at night or not cry too much, otherwise the owl may carry them away. In some tribal legends, owls are associated with spirits of the dead, and the bony circles around an owl's eyes are said to comprise the fingernails of apparitional humans. Sometimes owls are said to carry messages from beyond the grave or deliver supernatural warnings to people who have broken tribal taboos.

The Aztecs and Maya, along with other natives of Mesoamerica, considered the owl a symbol of death and destruction. In fact, the Aztec god of death, Mictlantecuhtli, was often depicted with owls. There is an old saying in Mexico that is still in use: Cuando el tecolote canta, el indio muere ("When the owl cries/sings, the Indian dies"). The Popol Vuh, a Mayan religious text, describes owls as messengers of Xibalba (the Mayan "Place of Fright").

The belief that owls are messengers and harbingers of the dark powers is also found among the Hočągara (Winnebago) of Wisconsin.[46] When in earlier days the Hočągara committed the sin of killing enemies while they were within the sanctuary of the chief's lodge, an owl appeared and spoke to them in the voice of a human, saying, "From now on the Hočągara will have no luck." This marked the beginning of the decline of their tribe. An owl appeared to Glory of the Morning, the only female chief of the Hočąk nation, and uttered her name. Soon afterwards she died.

According to the culture of the Hopi, a Uto-Aztec tribe, taboos surround owls, which are associated with sorcery and other evils.

Ojibwe tribes, as well as their Aboriginal Canadian counterparts, used an owl as a symbol for both evil and death. In addition, they used owls as a symbol of very high status of spiritual leaders of their spirituality.

Pawnee tribes viewed owls as the symbol of protection from any danger within their realms.

Pueblo people associated owls with Skeleton Man, the god of death and spirit of fertility.

Yakama tribes use an owl as a powerful totem. Such taboos or totems often guide where and how forests and natural resources are useful with management, even to this day and even with the proliferation of "scientific" forestry on reservations.

 

Use as rodent control

A purpose-built owl-house or owlery at a farm near Morton on the Hill, England (2006)

 

Encouraging natural predators to control rodent population is a natural form of pest control, along with excluding food sources for rodents. Placing a nest box for owls on a property can help control rodent populations (one family of hungry barn owls can consume more than 3,000 rodents in a nesting season) while maintaining the naturally balanced food chain

 

ATTACKS ON HUMANS

Although humans and owls frequently live together in harmony, there have been incidents when owls have attacked humans. In January 2013, a man from Inverness, Scotland suffered heavy bleeding and went into shock after being attacked by an owl, which was likely a 50-cm tall eagle owl.[52] The photographer Eric Hosking lost his left eye after attempting to photograph a tawny owl, which inspired the title of his 1970 autobiography, An Eye for a Bird.

 

CONSERVATION ISSUES

All owls are listed in Appendix II of the international CITES treaty (the Convention on Illegal Trade in Endangered Species of Wild Fauna and Flora). Although owls have long been hunted, a 2008 news story from Malaysia indicates that the magnitude of owl poaching may be on the rise. In November 2008, TRAFFIC reported the seizure of 900 plucked and "oven-ready" owls in Peninsular Malaysia. Said Chris Shepherd, Senior Programme Officer for TRAFFIC's Southeast Asia office, "This is the first time we know of where 'ready-prepared' owls have been seized in Malaysia, and it may mark the start of a new trend in wild meat from the region. We will be monitoring developments closely." TRAFFIC commended the Department of Wildlife and National Parks in Malaysia for the raid that exposed the huge haul of owls. Included in the seizure were dead and plucked barn owls, spotted wood owls, crested serpent eagles, barred eagles, and brown wood owls, as well as 7,000 live lizards.

 

WIKIPEDIA

A study of the effects of high voltage and household cleaning products on instant pull apart color film.

 

Materials: Fujifilm FP100-45C Instant Color Film, various household cleaning products (bleach, vinegar, baking soda, hydrogen peroxide, salt, rubbing alcohol), 15,000 volt neon tube ballast.

 

By Phillip Stearns

No really, look INTO my eye!

 

Folks, this is the back of my EYEBALL!

 

Story:

I was fixing a computer that processes medical optical shots. I look over at the equipment and notice there's a Canon 40D attached to this odd contraption that is essentially a very specialized lens! After I fixed the computer, I asked the nurse if I could do some test shots of my eyes.

 

So! They place your chin on a little rest, eye looking into a soft padded lens, at a single green dot. All the lights are off so your pupil fully dialates. 3...2...1 BOOF!

 

And Voila! A picture of the inside of my eye. The blackish spot is where my pupil was, and the light spot is the reflection of the green dot. (?) It also marks the spot where all the optical nerves gather to go out the back of the eyeball.

 

Looks like an alien planet to me.

 

License For Use?

 

Connect: Facebook | Twitter | Instagram | Wedding Photography

 

___

Cant sleep so took a few close ups of my eyeball, held the flash off camera to the side while having a finger on the shutter and looking at the swivel screen with the other eye to see the focus. multitasking with insomnia. :)

 

Hit the L key to view larger on black. Scroll Down to see closer in.

it was a sunny, beautiful morning and odin came into the bedroom.

 

"poppi, i see spots. i think i'm getting sick."

 

and so, that's how an otherwise normal day started. at first i thought he might be playing a game, but he was pretty specific and consistent with the details about the spots in terms of size and color and number.

 

i suddenly found myself attempting to not freak out as i recalled that the sudden appearance of floaters could be sign of retina detaching and, of course, most of you know he's at a higher risk for retinal detachment thanks to his history of retinopathy of prematurity.

 

so, after debating whether or not we were being alarmist, we scheduled an emergency eye exam and i found myself having a surreal lunch with co-workers about the odds of odin having a detached retina.

 

a few short hours later and we're in the doctor's office and odin is going through the pupil dilation routine and time is slowing down to a halt. dilation drops go in both eyes. and left eye checks out fine. right eye didn't dilate properly. doc thinks the nurse didn't put drops in, but i'm sure she did.

 

something feels wrong.

 

the doc looks into odin's right eye after putting more drops in and waiting 10 more minutes, pauses, covers his odin's left eye and asks him to identify the shape on the wall.

 

"i can't see it," odin responded.

 

time is slowing down more. odin is smiling, happy to be sitting in the cool eye doctor chair as i hear the doc say, "we have a problem," followed by phrases strung together loosely.

 

"detached retina"

 

"essentially no vision in the right eye"

 

"emergency surgery at the mayo clinic".

 

we won't know much about prognosis or probable outcomes until he gets evaluated by the experts. we expect that we'll hear bright and early tomorrow from the mayo about when he'll go in for evaluation and surgery.

 

needless to say, coming less than 2 weeks away from his fourth birthday, we're feeling a little sucker-punched.

 

it's been almost 1,400 days since rop surgery and i was really starting to hold out hope that we had finally escaped its grasp.

Dr. R. Kim (right), Chief Medical Officer, Aravind Eye Hospital, Madurai, India, performs a peripheral retinal examination on M. Kaliappan's, 75, left eye using an indirect ophthalmoscope (not pictured) and a 20 diopter viewing lens in the eye examination room, Friday, Nov. 16, 2018. Mr. Kaliappan who had undergone retinal detachment surgery in his left eye 10 years back had come for a routine follow-up. Apart from his regular clinical work, Dr. Kim is involved in driving innovation in the organisation. "People ask me, 'How can you let a machine screen a patient?' I tell them, 'Why not when they can trust a driverless vehicle while traveling?'"

 

WSJ Story

 

Outtakes

Riparian Thicket, Yosemite Valley, Yosemite National Park, California. February 13, 2015. © Copyright 2015 G Dan Mitchell - all rights reserved.

 

Hazy afternoon winter light in a thicket of trees along the banks of the Merced River, Yosemite Valley

 

A shorter than usual post today, as I'm dealing (successfully!) with an unexpected eye problem, and one effect of the treatment is that I need to minimize computer/reading/writing time for a few days. (The short story is that I had retinal detachment, we caught it right away, were able to treat it on an out-patient basis, I'm home, and the results look fine. In short, what looked scary at first appears to be heading towards an excellent outcome.) So, briefly...

 

A week ago I was in Yosemite Valley for about two hours between visits to a couple of other places, and I had time to photograph around one of the large meadows late in the day, as the afternoon sun was dropping toward the tops of the cliffs and the hazy air became luminous. I wandered over to a section of the Merced River where I like to photograph cottonwood trees in spring and fall, and looking down the river I saw this little vignette in the backlight.

  

G Dan Mitchell is a California photographer and visual opportunist whose subjects include the Pacific coast, redwood forests, central California oak/grasslands, the Sierra Nevada, California deserts, urban landscapes, night photography, and more.

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Text, photographs, and other media are © Copyright G Dan Mitchell (or others when indicated) and are not in the public domain and may not be used on websites, blogs, or in other media without advance permission from G Dan Mitchell.

The common kingfisher (Alcedo atthis), also known as the Eurasian kingfisher and river kingfisher, is a small kingfisher with seven subspecies recognized within its wide distribution across Eurasia and North Africa. It is resident in much of its range, but migrates from areas where rivers freeze in winter.

 

This sparrow-sized bird has the typical short-tailed, large-headed kingfisher profile; it has blue upperparts, orange underparts and a long bill. It feeds mainly on fish, caught by diving, and has special visual adaptations to enable it to see prey under water. The glossy white eggs are laid in a nest at the end of a burrow in a riverbank.

 

This species has the typical short-tailed, dumpy-bodied, large-headed, and long-billed kingfisher shape. The adult male of the western European subspecies, A. a. ispida has green-blue upperparts with pale azure-blue back and rump, a rufous patch by the bill base, and a rufous ear-patch. It has a green-blue neck stripe, white neck blaze and throat, rufous underparts, and a black bill with some red at the base. The legs and feet are bright red. It is about 16 centimetres (6.3 in) long with a wingspan of 25 cm (9.8 in), and weighs 34–46 grams (1.2–1.6 oz). The female is identical in appearance to the male except that her lower mandible is orange-red with a black tip. The juvenile is similar to the adult, but with duller and greener upperparts and paler underparts. Its bill is black, and the legs are also initially black. Feathers are moulted gradually between July and November with the main flight feathers taking 90–100 days to moult and regrow. Some that moult late may suspend their moult during cold winter weather.

 

The flight of the kingfisher is fast, direct and usually low over water. The short, rounded wings whirr rapidly, and a bird flying away shows an electric-blue "flash" down its back.

 

In North Africa, Europe and Asia north of the Himalayas, this is the only small blue kingfisher. In south and southeast Asia, it can be confused with six other small blue-and-rufous kingfishers, but the rufous ear patches distinguish it from all but juvenile blue-eared kingfishers; details of the head pattern may be necessary to differentiate the two species where both occur.

 

The common kingfisher has no song. The flight call is a short, sharp whistle chee repeated two or three times. Anxious birds emit a harsh, shrit-it-it and nestlings call for food with a churring noise.

 

The common kingfisher is widely distributed over Europe, Asia, and North Africa, mainly south of 60°N. It is a common breeding species over much of its vast Eurasian range, but in North Africa it is mainly a winter visitor, although it is a scarce breeding resident in coastal Morocco and Tunisia. In temperate regions, this kingfisher inhabits clear, slow-flowing streams and rivers, and lakes with well-vegetated banks. It frequents scrubs and bushes with overhanging branches close to shallow open water in which it hunts. In winter it is more coastal, often feeding in estuaries or harbors and along rocky seashores. Tropical populations are found by slow-flowing rivers, in mangrove creeks and in swamps.

 

Common kingfishers are important members of ecosystems and good indicators of freshwater community health. The highest densities of breeding birds are found in habitats with clear water, which permits optimal prey visibility, and trees or shrubs on the banks. These habitats have also the highest quality of water, so the presence of this bird confirms the standard of the water. Measures to improve water flow can disrupt this habitat, and in particular, the replacement of natural banks by artificial confinement greatly reduces the populations of fish, amphibians and aquatic reptiles, and waterside birds are lost. It can tolerate a certain degree of urbanization, provided the water remains clean.

 

This species is resident in areas where the climate is mild year-round, but must migrate after breeding from regions with prolonged freezing conditions in winter. Most birds winter within the southern parts of the breeding range, but smaller numbers cross the Mediterranean into Africa or travel over the mountains of Malaysia into Southeast Asia. Kingfishers migrate mainly at night, and some Siberian breeders must travel at least 3,000 km (1,900 mi) between the breeding sites and the wintering areas.

 

The common kingfisher hunts from a perch 1–2 m (3.3–6.6 ft) above the water, on a branch, post or riverbank, bill pointing down as it searches for prey. It bobs its head when food is detected to gauge the distance and plunges steeply down to seize its prey usually no deeper than 25 cm (9.8 in) below the surface. The wings are opened underwater and the open eyes are protected by the transparent third eyelid. The bird rises beak-first from the surface and flies back to its perch. At the perch the fish is adjusted until it is held near its tail and beaten against the perch several times. Once dead, the fish is positioned lengthways and swallowed head-first. A few times each day, a small greyish pellet of fish bones and other indigestible remains is regurgitated.

 

The food is mainly fish up to 12.5 cm (4.9 in) long, but the average size is 2.3 cm (0.91 in). In Central Europe, 97% of the diet was found to be composed of fish ranging in size from 2 to 10 cm with an average of 6.5 cm (body mass range from 10 g, average 3 g). Minnows, sticklebacks, small roach and trout are typical prey. About 60% of food items are fish, but this kingfisher also catches aquatic insects such as dragonfly larvae and water beetles, and, in winter, crustaceans including freshwater shrimps. In Central Europe, however, fish represented 99.9% of the diet (data from rivers, streams, and reservoirs from years 1999 to 2013). Common kingfishers have also been observed to catch lamprey. One study found that food provisioning rate increased with brood size, from 1498 g (505 fishes for four nestlings) to 2968 g (894 fishes for eight nestlings). During the fledging period each chick consumed on average 334 g of fish, which resulted in an estimated daily food intake of 37% of the chick's body mass (average over the entire nestling period). The average daily energy intake was 73.5 kJ per chick (i.e., 1837 kJ per 25 days of the fledging period).

 

A challenge for any diving bird is the change in refraction between air and water. The eyes of many birds have two foveae (the fovea is the area of the retina with the greatest density of light receptors), and a kingfisher can switch from the main central fovea to the auxiliary fovea when it enters water; a retinal streak of high receptor density which connects the two foveae allows the image to swing temporally as the bird drops onto the prey. The egg-shaped lens of the eye points towards the auxiliary fovea, enabling the bird to maintain visual acuity underwater. Because of the positions of the foveae, the kingfisher has monocular vision in air, and binocular vision in water. The underwater vision is not as a sharp as in air, but the ability to judge the distance of moving prey is more important than the sharpness of the image.

 

Each cone cell of a bird's retina contains an oil droplet that may contain carotenoid pigments. These droplets enhance color vision and reduce glare. Aquatic kingfishers have high numbers of red pigments in their oil droplets; the reason red droplets predominate is not understood, but the droplets may help with the glare or the dispersion of light from particulate matter in the water.

 

For more information, please visit en.wikipedia.org/wiki/Common_kingfisher

A study of the effects of high voltage and household cleaning products on instant pull apart color film.

 

Materials: Fujifilm FP100-45C Instant Color Film, various household cleaning products (bleach, vinegar, baking soda, hydrogen peroxide, salt, rubbing alcohol), 15,000 volt neon tube ballast.

 

By Phillip Stearns

Thank you to Retinal Fedish for letting me use her photo to paint this in

watercolor 11 X 14

Jellyfish, also known sea jellies, are the medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria.

 

Jellyfish are mainly free-swimming marine animals with umbrella-shaped bells and trailing tentacles, although a few are anchored to the seabed by stalks rather than being mobile. The bell can pulsate to provide propulsion for highly efficient locomotion. The tentacles are armed with stinging cells and may be used to capture prey and defend against predators. Jellyfish have a complex life cycle. The medusa is normally the sexual phase, which produces planula larvae; these then disperse widely and enter a sedentary polyp phase, before reaching sexual maturity.

 

Jellyfish are found all over the world, from surface waters to the deep sea. Scyphozoans (the "true jellyfish") are exclusively marine, but some hydrozoans with a similar appearance live in freshwater. Large, often colorful, jellyfish are common in coastal zones worldwide. The medusae of most species are fast-growing, and mature within a few months then die soon after breeding, but the polyp stage, attached to the seabed, may be much more long-lived. Jellyfish have been in existence for at least 500 million years,[1] and possibly 700 million years or more, making them the oldest multi-organ animal group.[2]

 

Jellyfish are eaten by humans in certain cultures. They are considered a delicacy in some Asian countries, where species in the Rhizostomeae order are pressed and salted to remove excess water. Australian researchers have described them as a "perfect food": sustainable and protein-rich but relatively low in food energy.[3]

 

They are also used in research, where the green fluorescent protein used by some species to cause bioluminescence has been adapted as a fluorescent marker for genes inserted into other cells or organisms.

 

The stinging cells used by jellyfish to subdue their prey can injure humans. Thousands of swimmers worldwide are stung every year, with effects ranging from mild discomfort to serious injury or even death. When conditions are favourable, jellyfish can form vast swarms, which can be responsible for damage to fishing gear by filling fishing nets, and sometimes clog the cooling systems of power and desalination plants which draw their water from the sea.

  

Names

The name jellyfish, in use since 1796,[4] has traditionally been applied to medusae and all similar animals including the comb jellies (ctenophores, another phylum).[5][6] The term jellies or sea jellies is more recent, having been introduced by public aquaria in an effort to avoid use of the word "fish" with its modern connotation of an animal with a backbone, though shellfish, cuttlefish and starfish are not vertebrates either.[7][8] In scientific literature, "jelly" and "jellyfish" have been used interchangeably.[9][10] Many sources refer to only scyphozoans as "true jellyfish".[11]

 

A group of jellyfish is called a "smack"[12] or a "smuck".[13]

 

Mapping to taxonomic groups

 

A purple-striped jellyfish at the Monterey Bay Aquarium

Phylogeny

Definition

The term jellyfish broadly corresponds to medusae,[4] that is, a life-cycle stage in the Medusozoa. The American evolutionary biologist Paulyn Cartwright gives the following general definition:

 

Typically, medusozoan cnidarians have a pelagic, predatory jellyfish stage in their life cycle; staurozoans are the exceptions [as they are stalked].[14]

 

The Merriam-Webster dictionary defines jellyfish as follows:

 

A free-swimming marine coelenterate that is the sexually reproducing form of a hydrozoan or scyphozoan and has a nearly transparent saucer-shaped body and extensible marginal tentacles studded with stinging cells.[15]

 

Given that jellyfish is a common name, its mapping to biological groups is inexact. Some authorities have called the comb jellies[16] and certain salps[16] jellyfish, though other authorities state that neither of these are jellyfish, which they consider should be limited to certain groups within the medusozoa.[17][18]

 

The non-medusozoan clades called jellyfish by some but not all authorities (both agreeing and disagreeing citations are given in each case) are indicated with "???" on the following cladogram of the animal kingdom:

 

Animalia

Porifera

 

Ctenophora (comb jellies)[16] ???[17]

 

Cnidaria (includes jellyfish and other jellies)

 

Bilateria

Protostomia

 

Deuterostomia

Ambulacraria

 

Chordata

Tunicata (includes salps)[16] ???[18]

 

Vertebrata

 

Medusozoan jellyfish

Jellyfish are not a clade, as they include most of the Medusozoa, barring some of the Hydrozoa.[19][20] The medusozoan groups included by authorities are indicated on the following phylogenetic tree by the presence of citations. Names of included jellyfish, in English where possible, are shown in boldface; the presence of a named and cited example indicates that at least that species within its group has been called a jellyfish.

 

Cnidaria

Anthozoa (corals)

 

Polypodiozoa and Myxozoa (parasitic cnidarians)

 

Medusozoa

Acraspeda

Staurozoa (stalked jellyfish)[21]

 

Rhopaliophora

Cubozoa (box jellyfish)[16]

 

Scyphozoa

Discomedusae[16]

 

Coronatae (crown jellyfish)[22]

 

(true jellyfish[19])

Hydrozoa

Aplanulata

 

Siphonophorae

 

Some Leptothecata[16] e.g. crystal jelly

 

Filifera[16] e.g. red paper lantern jellyfish[23]

 

Trachylinae

Limnomedusae, e.g. flower hat jelly[16]

 

Narcomedusae, e.g. cosmic jellyfish[24]

 

Taxonomy

The subphylum Medusozoa includes all cnidarians with a medusa stage in their life cycle. The basic cycle is egg, planula larva, polyp, medusa, with the medusa being the sexual stage. The polyp stage is sometimes secondarily lost. The subphylum include the major taxa, Scyphozoa (large jellyfish), Cubozoa (box jellyfish) and Hydrozoa (small jellyfish), and excludes Anthozoa (corals and sea anemones).[25] This suggests that the medusa form evolved after the polyps.[26] Medusozoans have tetramerous symmetry, with parts in fours or multiples of four.[25]

 

The four major classes of medusozoan Cnidaria are:

 

Scyphozoa are sometimes called true jellyfish, though they are no more truly jellyfish than the others listed here. They have tetra-radial symmetry. Most have tentacles around the outer margin of the bowl-shaped bell, and long, oral arms around the mouth in the center of the subumbrella.[25]

Cubozoa (box jellyfish) have a (rounded) box-shaped bell, and their velarium assists them to swim more quickly. Box jellyfish may be related more closely to scyphozoan jellyfish than either are to the Hydrozoa.[26]

Hydrozoa medusae also have tetra-radial symmetry, nearly always have a velum (diaphragm used in swimming) attached just inside the bell margin, do not have oral arms, but a much smaller central stalk-like structure, the manubrium, with terminal mouth opening, and are distinguished by the absence of cells in the mesoglea. Hydrozoa show great diversity of lifestyle; some species maintain the polyp form for their entire life and do not form medusae at all (such as Hydra, which is hence not considered a jellyfish), and a few are entirely medusal and have no polyp form.[25]

Staurozoa (stalked jellyfish) are characterized by a medusa form that is generally sessile, oriented upside down and with a stalk emerging from the apex of the "calyx" (bell), which attaches to the substrate. At least some Staurozoa also have a polyp form that alternates with the medusoid portion of the life cycle. Until recently, Staurozoa were classified within the Scyphozoa.[25]

There are over 200 species of Scyphozoa, about 50 species of Staurozoa, about 50 species of Cubozoa, and the Hydrozoa includes about 1000–1500 species that produce medusae, but many more species that do not.[27][28]

 

Fossil history

 

Fossil jellyfish, Rhizostomites lithographicus, one of the Scypho-medusae, from the Kimmeridgian (late Jurassic, 157 to 152 mya) of Solnhofen, Germany

 

Stranded scyphozoans on a Cambrian tidal flat at Blackberry Hill, Wisconsin

 

The conulariid Conularia milwaukeensis from the Middle Devonian of Wisconsin

Since jellyfish have no hard parts, fossils are rare. The oldest unambiguous fossil of a free-swimming medusa is Burgessomedusa from the mid Cambrian Burgess Shale of Canada, which is likely either a stem group of box jellyfish (Cubozoa) or Acraspeda (the clade including Staurozoa, Cubozoa, and Scyphozoa). Other claimed records from the Cambrian of China and Utah in the United States are uncertain, and possibly represent ctenophores instead.[29]

 

Anatomy

 

Labelled cross section of a jellyfish

The main feature of a true jellyfish is the umbrella-shaped bell. This is a hollow structure consisting of a mass of transparent jelly-like matter known as mesoglea, which forms the hydrostatic skeleton of the animal.[25] 95% or more of the mesogloea consists of water,[30] but it also contains collagen and other fibrous proteins, as well as wandering amoebocytes which can engulf debris and bacteria. The mesogloea is bordered by the epidermis on the outside and the gastrodermis on the inside. The edge of the bell is often divided into rounded lobes known as lappets, which allow the bell to flex. In the gaps or niches between the lappets are dangling rudimentary sense organs known as rhopalia, and the margin of the bell often bears tentacles.[25]

  

Anatomy of a scyphozoan jellyfish

On the underside of the bell is the manubrium, a stalk-like structure hanging down from the centre, with the mouth, which also functions as the anus, at its tip. There are often four oral arms connected to the manubrium, streaming away into the water below.[31] The mouth opens into the gastrovascular cavity, where digestion takes place and nutrients are absorbed. This is subdivided by four thick septa into a central stomach and four gastric pockets. The four pairs of gonads are attached to the septa, and close to them four septal funnels open to the exterior, perhaps supplying good oxygenation to the gonads. Near the free edges of the septa, gastric filaments extend into the gastric cavity; these are armed with nematocysts and enzyme-producing cells and play a role in subduing and digesting the prey. In some scyphozoans, the gastric cavity is joined to radial canals which branch extensively and may join a marginal ring canal. Cilia in these canals circulate the fluid in a regular direction.[25]

  

Discharge mechanism of a nematocyst

The box jellyfish is largely similar in structure. It has a squarish, box-like bell. A short pedalium or stalk hangs from each of the four lower corners. One or more long, slender tentacles are attached to each pedalium.[32] The rim of the bell is folded inwards to form a shelf known as a velarium which restricts the bell's aperture and creates a powerful jet when the bell pulsates, allowing box jellyfish to swim faster than true jellyfish.[25] Hydrozoans are also similar, usually with just four tentacles at the edge of the bell, although many hydrozoans are colonial and may not have a free-living medusal stage. In some species, a non-detachable bud known as a gonophore is formed that contains a gonad but is missing many other medusal features such as tentacles and rhopalia.[25] Stalked jellyfish are attached to a solid surface by a basal disk, and resemble a polyp, the oral end of which has partially developed into a medusa with tentacle-bearing lobes and a central manubrium with four-sided mouth.[25]

 

Most jellyfish do not have specialized systems for osmoregulation, respiration and circulation, and do not have a central nervous system. Nematocysts, which deliver the sting, are located mostly on the tentacles; true jellyfish also have them around the mouth and stomach.[33] Jellyfish do not need a respiratory system because sufficient oxygen diffuses through the epidermis. They have limited control over their movement, but can navigate with the pulsations of the bell-like body; some species are active swimmers most of the time, while others largely drift.[34] The rhopalia contain rudimentary sense organs which are able to detect light, water-borne vibrations, odour and orientation.[25] A loose network of nerves called a "nerve net" is located in the epidermis.[35][36] Although traditionally thought not to have a central nervous system, nerve net concentration and ganglion-like structures could be considered to constitute one in most species.[37] A jellyfish detects stimuli, and transmits impulses both throughout the nerve net and around a circular nerve ring, to other nerve cells. The rhopalial ganglia contain pacemaker neurones which control swimming rate and direction.[25]

 

In many species of jellyfish, the rhopalia include ocelli, light-sensitive organs able to tell light from dark. These are generally pigment spot ocelli, which have some of their cells pigmented. The rhopalia are suspended on stalks with heavy crystals at one end, acting like gyroscopes to orient the eyes skyward. Certain jellyfish look upward at the mangrove canopy while making a daily migration from mangrove swamps into the open lagoon, where they feed, and back again.[2]

 

Box jellyfish have more advanced vision than the other groups. Each individual has 24 eyes, two of which are capable of seeing colour, and four parallel information processing areas that act in competition,[38] supposedly making them one of the few kinds of animal to have a 360-degree view of its environment.[39]

 

Box jellyfish eye

The study of jellyfish eye evolution is an intermediary to a better understanding of how visual systems evolved on Earth.[40] Jellyfish exhibit immense variation in visual systems ranging from photoreceptive cell patches seen in simple photoreceptive systems to more derived complex eyes seen in box jellyfish.[40] Major topics of jellyfish visual system research (with an emphasis on box jellyfish) include: the evolution of jellyfish vision from simple to complex visual systems), the eye morphology and molecular structures of box jellyfish (including comparisons to vertebrate eyes), and various uses of vision including task-guided behaviors and niche specialization.

 

Evolution

Experimental evidence for photosensitivity and photoreception in cnidarians antecedes the mid 1900s, and a rich body of research has since covered evolution of visual systems in jellyfish.[41] Jellyfish visual systems range from simple photoreceptive cells to complex image-forming eyes. More ancestral visual systems incorporate extraocular vision (vision without eyes) that encompass numerous receptors dedicated to single-function behaviors. More derived visual systems comprise perception that is capable of multiple task-guided behaviors.

 

Although they lack a true brain, cnidarian jellyfish have a "ring" nervous system that plays a significant role in motor and sensory activity. This net of nerves is responsible for muscle contraction and movement and culminates the emergence of photosensitive structures.[40] Across Cnidaria, there is large variation in the systems that underlie photosensitivity. Photosensitive structures range from non-specialized groups of cells, to more "conventional" eyes similar to those of vertebrates.[41] The general evolutionary steps to develop complex vision include (from more ancestral to more derived states): non-directional photoreception, directional photoreception, low-resolution vision, and high-resolution vision.[40] Increased habitat and task complexity has favored the high-resolution visual systems common in derived cnidarians such as box jellyfish.[40]

 

Basal visual systems observed in various cnidarians exhibit photosensitivity representative of a single task or behavior. Extraocular photoreception (a form of non-directional photoreception), is the most basic form of light sensitivity and guides a variety of behaviors among cnidarians. It can function to regulate circadian rhythm (as seen in eyeless hydrozoans) and other light-guided behaviors responsive to the intensity and spectrum of light. Extraocular photoreception can function additionally in positive phototaxis (in planula larvae of hydrozoans),[41] as well as in avoiding harmful amounts of UV radiation via negative phototaxis. Directional photoreception (the ability to perceive direction of incoming light) allows for more complex phototactic responses to light, and likely evolved by means of membrane stacking.[40] The resulting behavioral responses can range from guided spawning events timed by moonlight to shadow responses for potential predator avoidance.[41][42] Light-guided behaviors are observed in numerous scyphozoans including the common moon jelly, Aurelia aurita, which migrates in response to changes in ambient light and solar position even though they lack proper eyes.[41]

 

The low-resolution visual system of box jellyfish is more derived than directional photoreception, and thus box jellyfish vision represents the most basic form of true vision in which multiple directional photoreceptors combine to create the first imaging and spatial resolution. This is different from the high-resolution vision that is observed in camera or compound eyes of vertebrates and cephalopods that rely on focusing optics.[41] Critically, the visual systems of box jellyfish are responsible for guiding multiple tasks or behaviors in contrast to less derived visual systems in other jellyfish that guide single behavioral functions. These behaviors include phototaxis based on sunlight (positive) or shadows (negative), obstacle avoidance, and control of swim-pulse rate.[43]

 

Box jellyfish possess "proper eyes" (similar to vertebrates) that allow them to inhabit environments that lesser derived medusae cannot. In fact, they are considered the only class in the clade Medusozoa that have behaviors necessitating spatial resolution and genuine vision.[41] However, the lens in their eyes are more functionally similar to cup-eyes exhibited in low-resolution organisms, and have very little to no focusing capability.[44][43] The lack of the ability to focus is due to the focal length exceeding the distance to the retina, thus generating unfocused images and limiting spatial resolution.[41] The visual system is still sufficient for box jellyfish to produce an image to help with tasks such as object avoidance.

 

Utility as a model organism

Box jellyfish eyes are a visual system that is sophisticated in numerous ways. These intricacies include the considerable variation within the morphology of box jellyfishes' eyes (including their task/behavior specification), and the molecular makeup of their eyes including: photoreceptors, opsins, lenses, and synapses.[41] The comparison of these attributes to more derived visual systems can allow for a further understanding of how the evolution of more derived visual systems may have occurred, and puts into perspective how box jellyfish can play the role as an evolutionary/developmental model for all visual systems.[45]

 

Characteristics

Box jellyfish visual systems are both diverse and complex, comprising multiple photosystems.[41] There is likely considerable variation in visual properties between species of box jellyfish given the significant inter-species morphological and physiological variation. Eyes tend to differ in size and shape, along with number of receptors (including opsins), and physiology across species of box jellyfish.[41]

 

Box jellyfish have a series of intricate lensed eyes that are similar to those of more derived multicellular organisms such as vertebrates. Their 24 eyes fit into four different morphological categories.[46] These categories consist of two large, morphologically different medial eyes (a lower and upper lensed eye) containing spherical lenses, a lateral pair of pigment slit eyes, and a lateral pair of pigment pit eyes.[43] The eyes are situated on rhopalia (small sensory structures) which serve sensory functions of the box jellyfish and arise from the cavities of the exumbrella (the surface of the body) on the side of the bells of the jellyfish.[41] The two large eyes are located on the mid-line of the club and are considered complex because they contain lenses. The four remaining eyes lie laterally on either side of each rhopalia and are considered simple. The simple eyes are observed as small invaginated cups of epithelium that have developed pigmentation.[47] The larger of the complex eyes contains a cellular cornea created by a mono ciliated epithelium, cellular lens, homogenous capsule to the lens, vitreous body with prismatic elements, and a retina of pigmented cells. The smaller of the complex eyes is said to be slightly less complex given that it lacks a capsule but otherwise contains the same structure as the larger eye.[47]

 

Box jellyfish have multiple photosystems that comprise different sets of eyes.[41] Evidence includes immunocytochemical and molecular data that show photopigment differences among the different morphological eye types, and physiological experiments done on box jellyfish to suggest behavioral differences among photosystems. Each individual eye type constitutes photosystems that work collectively to control visually guided behaviors.[41]

 

Box jellyfish eyes primarily use c-PRCs (ciliary photoreceptor cells) similar to that of vertebrate eyes. These cells undergo phototransduction cascades (process of light absorption by photoreceptors) that are triggered by c-opsins.[48] Available opsin sequences suggest that there are two types of opsins possessed by all cnidarians including an ancient phylogenetic opsin, and a sister ciliary opsin to the c-opsins group. Box jellyfish could have both ciliary and cnidops (cnidarian opsins), which is something not previously believed to appear in the same retina.[41] Nevertheless, it is not entirely evident whether cnidarians possess multiple opsins that are capable of having distinctive spectral sensitivities.[41]

 

Comparison with other organisms

Comparative research on genetic and molecular makeup of box jellyfishes' eyes versus more derived eyes seen in vertebrates and cephalopods focuses on: lenses and crystallin composition, synapses, and Pax genes and their implied evidence for shared primordial (ancestral) genes in eye evolution.[49]

 

Box jellyfish eyes are said to be an evolutionary/developmental model of all eyes based on their evolutionary recruitment of crystallins and Pax genes.[45] Research done on box jellyfish including Tripedalia cystophora has suggested that they possess a single Pax gene, PaxB. PaxB functions by binding to crystallin promoters and activating them. PaxB in situ hybridization resulted in PaxB expression in the lens, retina, and statocysts.[45] These results and the rejection of the prior hypothesis that Pax6 was an ancestral Pax gene in eyes has led to the conclusion that PaxB was a primordial gene in eye evolution, and that the eyes of all organisms likely share a common ancestor.[45]

 

The lens structure of box jellyfish appears very similar to those of other organisms, but the crystallins are distinct in both function and appearance.[49] Weak reactions were seen within the sera and there were very weak sequence similarities within the crystallins among vertebrate and invertebrate lenses.[49] This is likely due to differences in lower molecular weight proteins and the subsequent lack of immunological reactions with antisera that other organisms' lenses exhibit.[49]

 

All four of the visual systems of box jellyfish species investigated with detail (Carybdea marsupialis, Chiropsalmus quadrumanus, Tamoya haplonema and Tripedalia cystophora) have invaginated synapses, but only in the upper and lower lensed eyes. Different densities were found between the upper and lower lenses, and between species.[46] Four types of chemical synapses have been discovered within the rhopalia which could help in understanding neural organization including: clear unidirectional, dense-core unidirectional, clear bidirectional, and clear and dense-core bidirectional. The synapses of the lensed eyes could be useful as markers to learn more about the neural circuit in box jellyfish retinal areas.[46]

 

Evolution as a response to natural stimuli

The primary adaptive responses to environmental variation observed in box jellyfish eyes include pupillary constriction speeds in response to light environments, as well as photoreceptor tuning and lens adaptations to better respond to shifts between light environments and darkness. Interestingly, some box jellyfish species' eyes appear to have evolved more focused vision in response to their habitat.[50]

 

Pupillary contraction appears to have evolved in response to variation in the light environment across ecological niches across three species of box jellyfish (Chironex fleckeri, Chiropsella bronzie, and Carukia barnesi). Behavioral studies suggest that faster pupil contraction rates allow for greater object avoidance,[50] and in fact, species with more complex habitats exhibit faster rates. Ch. bronzie inhabit shallow beach fronts that have low visibility and very few obstacles, thus, faster pupil contraction in response to objects in their environment is not important. Ca. barnesi and Ch. fleckeri are found in more three-dimensionally complex environments like mangroves with an abundance of natural obstacles, where faster pupil contraction is more adaptive.[50] Behavioral studies support the idea that faster pupillary contraction rates assist with obstacle avoidance as well as depth adjustments in response to differing light intensities.

 

Light/dark adaptation via pupillary light reflexes is an additional form of an evolutionary response to the light environment. This relates to the pupil's response to shifts between light intensity (generally from sunlight to darkness). In the process of light/dark adaptation, the upper and lower lens eyes of different box jellyfish species vary in specific function.[43] The lower lens-eyes contain pigmented photoreceptors and long pigment cells with dark pigments that migrate on light/dark adaptation, while the upper-lens eyes play a concentrated role in light direction and phototaxis given that they face upward towards the water surface (towards the sun or moon).[43] The upper lens of Ch. bronzie does not exhibit any considerable optical power while Tr. cystophora (a box jellyfish species that tends to live in mangroves) does. The ability to use light to visually guide behavior is not of as much importance to Ch. bronzie as it is to species in more obstacle-filled environments.[43] Differences in visually guided behavior serve as evidence that species that share the same number and structure of eyes can exhibit differences in how they control behavior.

 

Largest and smallest

Jellyfish range from about one millimeter in bell height and diameter,[51] to nearly 2 metres (6+1⁄2 ft) in bell height and diameter; the tentacles and mouth parts usually extend beyond this bell dimension.[25]

 

The smallest jellyfish are the peculiar creeping jellyfish in the genera Staurocladia and Eleutheria, which have bell disks from 0.5 millimetres (1⁄32 in) to a few millimeters in diameter, with short tentacles that extend out beyond this, which these jellyfish use to move across the surface of seaweed or the bottoms of rocky pools;[51] many of these tiny creeping jellyfish cannot be seen in the field without a hand lens or microscope. They can reproduce asexually by fission (splitting in half). Other very small jellyfish, which have bells about one millimeter, are the hydromedusae of many species that have just been released from their parent polyps;[52] some of these live only a few minutes before shedding their gametes in the plankton and then dying, while others will grow in the plankton for weeks or months. The hydromedusae Cladonema radiatum and Cladonema californicum are also very small, living for months, yet never growing beyond a few mm in bell height and diameter.[53]

  

The lion's mane jellyfish (Cyanea capillata) is one of the largest species.

The lion's mane jellyfish, Cyanea capillata, was long-cited as the largest jellyfish, and arguably the longest animal in the world, with fine, thread-like tentacles that may extend up to 36.5 m (119 ft 9 in) long (though most are nowhere near that large).[54][55] They have a moderately painful, but rarely fatal, sting.[56] The increasingly common giant Nomura's jellyfish, Nemopilema nomurai, found in some, but not all years in the waters of Japan, Korea and China in summer and autumn is another candidate for "largest jellyfish", in terms of diameter and weight, since the largest Nomura's jellyfish in late autumn can reach 2 m (6 ft 7 in) in bell (body) diameter and about 200 kg (440 lb) in weight, with average specimens frequently reaching 0.9 m (2 ft 11 in) in bell diameter and about 150 kg (330 lb) in weight.[57][58] The large bell mass of the giant Nomura's jellyfish[59] can dwarf a diver and is nearly always much greater than the Lion's Mane, whose bell diameter can reach 1 m (3 ft 3 in).[60]

 

The rarely encountered deep-sea jellyfish Stygiomedusa gigantea is another candidate for "largest jellyfish", with its thick, massive bell up to 100 cm (3 ft 3 in) wide, and four thick, "strap-like" oral arms extending up to 6 m (19+1⁄2 ft) in length, very different from the typical fine, threadlike tentacles that rim the umbrella of more-typical-looking jellyfish, including the Lion's Mane.[61]

 

Desmonema glaciale, which lives in the Antarctic region, can reach a very large size (several meters).[62][63] Purple-striped jelly (Chrysaora colorata) can also be extremely long (up to 15 feet).[64]

 

Life history and behavior

See also: Biological life cycle and Developmental biology

Illustration of two life stages of seven jelly species

The developmental stages of scyphozoan jellyfish's life cycle:

1–3 Larva searches for site

4–8 Polyp grows

9–11 Polyp strobilates

12–14 Medusa grows

Life cycle

Jellyfish have a complex life cycle which includes both sexual and asexual phases, with the medusa being the sexual stage in most instances. Sperm fertilize eggs, which develop into larval planulae, become polyps, bud into ephyrae and then transform into adult medusae. In some species certain stages may be skipped.[65]

 

Upon reaching adult size, jellyfish spawn regularly if there is a sufficient supply of food. In most species, spawning is controlled by light, with all individuals spawning at about the same time of day; in many instances this is at dawn or dusk.[66] Jellyfish are usually either male or female (with occasional hermaphrodites). In most cases, adults release sperm and eggs into the surrounding water, where the unprotected eggs are fertilized and develop into larvae. In a few species, the sperm swim into the female's mouth, fertilizing the eggs within her body, where they remain during early development stages. In moon jellies, the eggs lodge in pits on the oral arms, which form a temporary brood chamber for the developing planula larvae.[67]

 

The planula is a small larva covered with cilia. When sufficiently developed, it settles onto a firm surface and develops into a polyp. The polyp generally consists of a small stalk topped by a mouth that is ringed by upward-facing tentacles. The polyps resemble those of closely related anthozoans, such as sea anemones and corals. The jellyfish polyp may be sessile, living on the bottom, boat hulls or other substrates, or it may be free-floating or attached to tiny bits of free-living plankton[68] or rarely, fish[69][70] or other invertebrates. Polyps may be solitary or colonial.[71] Most polyps are only millimetres in diameter and feed continuously. The polyp stage may last for years.[25]

 

After an interval and stimulated by seasonal or hormonal changes, the polyp may begin reproducing asexually by budding and, in the Scyphozoa, is called a segmenting polyp, or a scyphistoma. Budding produces more scyphistomae and also ephyrae.[25] Budding sites vary by species; from the tentacle bulbs, the manubrium (above the mouth), or the gonads of hydromedusae.[68] In a process known as strobilation, the polyp's tentacles are reabsorbed and the body starts to narrow, forming transverse constrictions, in several places near the upper extremity of the polyp. These deepen as the constriction sites migrate down the body, and separate segments known as ephyra detach. These are free-swimming precursors of the adult medusa stage, which is the life stage that is typically identified as a jellyfish.[25][72] The ephyrae, usually only a millimeter or two across initially, swim away from the polyp and grow. Limnomedusae polyps can asexually produce a creeping frustule larval form, which crawls away before developing into another polyp.[25] A few species can produce new medusae by budding directly from the medusan stage. Some hydromedusae reproduce by fission.[68]

 

Lifespan

Little is known of the life histories of many jellyfish as the places on the seabed where the benthic forms of those species live have not been found. However, an asexually reproducing strobila form can sometimes live for several years, producing new medusae (ephyra larvae) each year.[73]

 

An unusual species, Turritopsis dohrnii, formerly classified as Turritopsis nutricula,[74] might be effectively immortal because of its ability under certain circumstances to transform from medusa back to the polyp stage, thereby escaping the death that typically awaits medusae post-reproduction if they have not otherwise been eaten by some other organism. So far this reversal has been observed only in the laboratory.[75]

 

Locomotion

 

Jellyfish locomotion is highly efficient. Muscles in the jellylike bell contract, setting up a start vortex and propelling the animal. When the contraction ends, the bell recoils elastically, creating a stop vortex with no extra energy input.

Using the moon jelly Aurelia aurita as an example, jellyfish have been shown to be the most energy-efficient swimmers of all animals.[76] They move through the water by radially expanding and contracting their bell-shaped bodies to push water behind them. They pause between the contraction and expansion phases to create two vortex rings. Muscles are used for the contraction of the body, which creates the first vortex and pushes the animal forward, but the mesoglea is so elastic that the expansion is powered exclusively by relaxing the bell, which releases the energy stored from the contraction. Meanwhile, the second vortex ring starts to spin faster, sucking water into the bell and pushing against the centre of the body, giving a secondary and "free" boost forward. The mechanism, called passive energy recapture, only works in relatively small jellyfish moving at low speeds, allowing the animal to travel 30 percent farther on each swimming cycle. Jellyfish achieved a 48 percent lower cost of transport (food and oxygen intake versus energy spent in movement) than other animals in similar studies. One reason for this is that most of the gelatinous tissue of the bell is inactive, using no energy during swimming.[77]

 

Ecology

Diet

Jellyfish are, like other cnidarians, generally carnivorous (or parasitic),[78] feeding on planktonic organisms, crustaceans, small fish, fish eggs and larvae, and other jellyfish, ingesting food and voiding undigested waste through the mouth. They hunt passively using their tentacles as drift lines, or sink through the water with their tentacles spread widely; the tentacles, which contain nematocysts to stun or kill the prey, may then flex to help bring it to the mouth.[25] Their swimming technique also helps them to capture prey; when their bell expands it sucks in water which brings more potential prey within reach of the tentacles.[79]

 

A few species such as Aglaura hemistoma are omnivorous, feeding on microplankton which is a mixture of zooplankton and phytoplankton (microscopic plants) such as dinoflagellates.[80] Others harbour mutualistic algae (Zooxanthellae) in their tissues;[25] the spotted jellyfish (Mastigias papua) is typical of these, deriving part of its nutrition from the products of photosynthesis, and part from captured zooplankton.[81][82] The upside-down jellyfish (Cassiopea andromeda) also has a symbiotic relationship with microalgae, but captures tiny animals to supplement their diet. This is done by releasing tiny balls of living cells composed of mesoglea. These use cilia to drive them through water and stinging cells which stun the prey. The blobs also seems to have digestive capabilities.[83]

 

Predation

Other species of jellyfish are among the most common and important jellyfish predators. Sea anemones may eat jellyfish that drift into their range. Other predators include tunas, sharks, swordfish, sea turtles and penguins.[84][85] Jellyfish washed up on the beach are consumed by foxes, other terrestrial mammals and birds.[86] In general however, few animals prey on jellyfish; they can broadly be considered to be top predators in the food chain. Once jellyfish have become dominant in an ecosystem, for example through overfishing which removes predators of jellyfish larvae, there may be no obvious way for the previous balance to be restored: they eat fish eggs and juvenile fish, and compete with fish for food, preventing fish stocks from recovering.[87]

 

Symbiosis

Some small fish are immune to the stings of the jellyfish and live among the tentacles, serving as bait in a fish trap; they are safe from potential predators and are able to share the fish caught by the jellyfish.[88] The cannonball jellyfish has a symbiotic relationship with ten different species of fish, and with the longnose spider crab, which lives inside the bell, sharing the jellyfish's food and nibbling its tissues.[89]

 

Blooms

Main article: Jellyfish bloom

 

Map of population trends of native and invasive jellyfish.[90]

Circles represent data records; larger circles denote higher certainty of findings.

Increase (high certainty)

Increase (low certainty)

Stable/variable

Decrease

No data

Jellyfish form large masses or blooms in certain environmental conditions of ocean currents, nutrients, sunshine, temperature, season, prey availability, reduced predation and oxygen concentration. Currents collect jellyfish together, especially in years with unusually high populations. Jellyfish can detect marine currents and swim against the current to congregate in blooms.[91][92] Jellyfish are better able to survive in nutrient-rich, oxygen-poor water than competitors, and thus can feast on plankton without competition. Jellyfish may also benefit from saltier waters, as saltier waters contain more iodine, which is necessary for polyps to turn into jellyfish. Rising sea temperatures caused by climate change may also contribute to jellyfish blooms, because many species of jellyfish are able to survive in warmer waters.[93] Increased nutrients from agricultural or urban runoff with nutrients including nitrogen and phosphorus compounds increase the growth of phytoplankton, causing eutrophication and algal blooms. When the phytoplankton die, they may create dead zones, so-called because they are hypoxic (low in oxygen). This in turn kills fish and other animals, but not jellyfish,[94] allowing them to bloom.[95][96] Jellyfish populations may be expanding globally as a result of land runoff and overfishing of their natural predators.[97][98] Jellyfish are well placed to benefit from disturbance of marine ecosystems. They reproduce rapidly; they prey upon many species, while few species prey on them; and they feed via touch rather than visually, so they can feed effectively at night and in turbid waters.[99][100] It may be difficult for fish stocks to re-establish themselves in marine ecosystems once they have become dominated by jellyfish, because jellyfish feed on plankton, which includes fish eggs and larvae.[101][102][96]

  

Moon jellyfishes can live in northern hemisphere seas,[103][104] such as the Baltic Sea.[105][106]

As suspected at the turn of this century, [107][108] jellyfish blooms are increasing in frequency. Between 2013 and 2020 the Mediterranean Science Commission monitored on a weekly basis the frequency of such outbreaks in coastal waters from Morocco to the Black Sea, revealing a relatively high frequency of these blooms nearly all year round, with peaks observed from March to July and often again in the autumn. The blooms are caused by different jellyfish species, depending on their localisation within the Basin: one observes a clear dominance of Pelagia noctiluca and Velella velella outbreaks in the western Mediterranean, of Rhizostoma pulmo and Rhopilema nomadica outbreaks in the eastern Mediterranean, and of Aurelia aurita and Mnemiopsis leidyi outbreaks in the Black Sea.[109]

 

Some jellyfish populations that have shown clear increases in the past few decades are invasive species, newly arrived from other habitats: examples include the Black Sea, Caspian Sea, Baltic Sea, central and eastern Mediterranean, Hawaii, and tropical and subtropical parts of the West Atlantic (including the Caribbean, Gulf of Mexico and Brazil).[105][106]

 

Jellyfish blooms can have significant impact on community structure. Some carnivorous jellyfish species prey on zooplankton while others graze on primary producers.[110] Reductions in zooplankton and ichthyoplankton due to a jellyfish bloom can ripple through the trophic levels. High-density jellyfish populations can outcompete other predators and reduce fish recruitment.[111] Increased grazing on primary producers by jellyfish can also interrupt energy transfer to higher trophic levels.[112]

 

During blooms, jellyfish significantly alter the nutrient availability in their environment. Blooms require large amounts of available organic nutrients in the water column to grow, limiting availability for other organisms.[113] Some jellyfish have a symbiotic relationship with single-celled dinoflagellates, allowing them to assimilate inorganic carbon, phosphorus, and nitrogen creating competition for phytoplankton.[113] Their large biomass makes them an important source of dissolved and particulate organic matter for microbial communities through excretion, mucus production, and decomposition.[90][114] The microbes break down the organic matter into inorganic ammonium and phosphate. However, the low carbon availability shifts the process from production to respiration creating low oxygen areas making the dissolved inorganic nitrogen and phosphorus largely unavailable for primary production.

 

These blooms have very real impacts on industries. Jellyfish can outcompete fish by utilizing open niches in over-fished fisheries.[115] Catch of jellyfish can strain fishing gear and lead to expenses relating to damaged gear. Power plants have been shut down due to jellyfish blocking the flow of cooling water.[116] Blooms have also been harmful for tourism, causing a rise in stings and sometimes the closure of beaches.[117]

 

Jellyfish form a component of jelly-falls, events where gelatinous zooplankton fall to the seafloor, providing food for the benthic organisms there.[118] In temperate and subpolar regions, jelly-falls usually follow immediately after a bloom.[119]

 

Habitats

 

A common Scyphozoan jellyfish seen near beaches in the Florida Panhandle

Most jellyfish are marine animals, although a few hydromedusae inhabit freshwater. The best known freshwater example is the cosmopolitan hydrozoan jellyfish, Craspedacusta sowerbii. It is less than an inch (2.5 cm) in diameter, colorless and does not sting.[120] Some jellyfish populations have become restricted to coastal saltwater lakes, such as Jellyfish Lake in Palau.[121] Jellyfish Lake is a marine lake where millions of golden jellyfish (Mastigias spp.) migrate horizontally across the lake daily.[82]

 

Although most jellyfish live well off the ocean floor and form part of the plankton, a few species are closely associated with the bottom for much of their lives and can be considered benthic. The upside-down jellyfish in the genus Cassiopea typically lie on the bottom of shallow lagoons where they sometimes pulsate gently with their umbrella top facing down. Even some deep-sea species of hydromedusae and scyphomedusae are usually collected on or near the bottom. All of the stauromedusae are found attached to either seaweed or rocky or other firm material on the bottom.[122]

 

Some species explicitly adapt to tidal flux. In Roscoe Bay, jellyfish ride the current at ebb tide until they hit a gravel bar, and then descend below the current. They remain in still waters until the tide rises, ascending and allowing it to sweep them back into the bay. They also actively avoid fresh water from mountain snowmelt, diving until they find enough salt.

  

Parasites

Jellyfish are hosts to a wide variety of parasitic organisms. They act as intermediate hosts of endoparasitic helminths, with the infection being transferred to the definitive host fish after predation. Some digenean trematodes, especially species in the family Lepocreadiidae, use jellyfish as their second intermediate hosts. Fish become infected by the trematodes when they feed on infected jellyfish.

 

Relation to humans

Jellyfish have long been eaten in some parts of the world. Fisheries have begun harvesting the American cannonball jellyfish, Stomolophus meleagris, along the southern Atlantic coast of the United States and in the Gulf of Mexico for export to Asia.

 

Jellyfish are also harvested for their collagen, which is being investigated for use in a variety of applications including the treatment of rheumatoid arthritis.

 

Aquaculture and fisheries of other species often suffer severe losses – and so losses of productivity – due to jellyfish.

 

Products

Main article: Jellyfish as food

In some countries, including China, Japan, and Korea, jellyfish are a delicacy. The jellyfish is dried to prevent spoiling. Only some 12 species of scyphozoan jellyfish belonging to the order Rhizostomeae are harvested for food, mostly in southeast Asia. Rhizostomes, especially Rhopilema esculentum in China (海蜇 hǎizhé, 'sea stingers') and Stomolophus meleagris (cannonball jellyfish) in the United States, are favored because of their larger and more rigid bodies and because their toxins are harmless to humans.

 

Traditional processing methods, carried out by a jellyfish master, involve a 20- to 40-day multi-phase procedure in which, after removing the gonads and mucous membranes, the umbrella and oral arms are treated with a mixture of table salt and alum, and compressed. Processing makes the jellyfish drier and more acidic, producing a crisp texture. Jellyfish prepared this way retain 7–10% of their original weight, and the processed product consists of approximately 94% water and 6% protein. Freshly processed jellyfish has a white, creamy color and turns yellow or brown during prolonged storage.

 

In China, processed jellyfish are desalted by soaking in water overnight and eaten cooked or raw. The dish is often served shredded with a dressing of oil, soy sauce, vinegar and sugar, or as a salad with vegetables. In Japan, cured jellyfish are rinsed, cut into strips and served with vinegar as an appetizer. Desalted, ready-to-eat products are also available.

 

Biotechnology

The hydromedusa Aequorea victoria was the source of green fluorescent protein, studied for its role in bioluminescence and later for use as a marker in genetic engineering.

Pliny the Elder reported in his Natural History that the slime of the jellyfish "Pulmo marinus" produced light when rubbed on a walking stick.

 

In 1961, Osamu Shimomura extracted green fluorescent protein (GFP) and another bioluminescent protein, called aequorin, from the large and abundant hydromedusa Aequorea victoria, while studying photoproteins that cause bioluminescence in this species. Three decades later, Douglas Prasher sequenced and cloned the gene for GFP. Martin Chalfie figured out how to use GFP as a fluorescent marker of genes inserted into other cells or organisms. Roger Tsien later chemically manipulated GFP to produce other fluorescent colors to use as markers. In 2008, Shimomura, Chalfie and Tsien won the Nobel Prize in Chemistry for their work with GFP. Man-made GFP became widely used as a fluorescent tag to show which cells or tissues express specific genes. The genetic engineering technique fuses the gene of interest to the GFP gene. The fused DNA is then put into a cell, to generate either a cell line or (via IVF techniques) an entire animal bearing the gene. In the cell or animal, the artificial gene turns on in the same tissues and the same time as the normal gene, making a fusion of the normal protein with GFP attached to the end, illuminating the animal or cell reveals what tissues express that protein—or at what stage of development. The fluorescence shows where the gene is expressed.

 

Aquarium display

Jellyfish are displayed in many public aquariums. Often the tank's background is blue and the animals are illuminated by side light, increasing the contrast between the animal and the background. In natural conditions, many jellies are so transparent that they are nearly invisible. Jellyfish are not adapted to closed spaces. They depend on currents to transport them from place to place. Professional exhibits as in the Monterey Bay Aquarium feature precise water flows, typically in circular tanks to avoid trapping specimens in corners. The outflow is spread out over a large surface area and the inflow enters as a sheet of water in front of the outflow, so the jellyfish do not get sucked into it. As of 2009, jellyfish were becoming popular in home aquariums, where they require similar equipment.

 

Stings

Jellyfish are armed with nematocysts, a type of specialized stinging cell. Contact with a jellyfish tentacle can trigger millions of nematocysts to pierce the skin and inject venom, but only some species' venom causes an adverse reaction in humans. In a study published in Communications Biology, researchers found a jellyfish species called Cassiopea xamachana which when triggered will release tiny balls of cells that swim around the jellyfish stinging everything in their path. Researchers described these as "self-propelling microscopic grenades" and named them cassiosomes.

 

The effects of stings range from mild discomfort to extreme pain and death. Most jellyfish stings are not deadly, but stings of some box jellyfish (Irukandji jellyfish), such as the sea wasp, can be deadly. Stings may cause anaphylaxis (a form of shock), which can be fatal. Jellyfish kill 20 to 40 people a year in the Philippines alone. In 2006 the Spanish Red Cross treated 19,000 stung swimmers along the Costa Brava.

 

Vinegar (3–10% aqueous acetic acid) may help with box jellyfish stings but not the stings of the Portuguese man o' war. Clearing the area of jelly and tentacles reduces nematocyst firing. Scraping the affected skin, such as with the edge of a credit card, may remove remaining nematocysts. Once the skin has been cleaned of nematocysts, hydrocortisone cream applied locally reduces pain and inflammation. Antihistamines may help to control itching. Immunobased antivenins are used for serious box jellyfish stings.

 

In Elba Island and Corsica dittrichia viscosa is now used by residents and tourists to heal stings from jellyfish, bees and wasps pressing fresh leaves on the skin with quick results.

 

Mechanical issues

Jellyfish in large quantities can fill and split fishing nets and crush captured fish. They can clog cooling equipment, having disabled power stations in several countries; jellyfish caused a cascading blackout in the Philippines in 1999, as well as damaging the Diablo Canyon Power Plant in California in 2008. They can also stop desalination plants and ships' engines.

The Horror is coming,

in the form of a Fest.

Do you have what it takes,

to awake from your rest?

 

Crawl from your graves,

haunt not that doll,

polish up the broom,

there is to be a Ball!

 

We ask all Nightmares,

be you big or small,

get ready for Horrorfest,

for we wish to see you all!

 

horrorfest.thedarkcollective.com/?p=91

 

October 18th is fast approaching! With over 120+ designers, a Hunt, Gachas, Limited Editions, Unique Charity Items, The Grande Sepia Ball as well as other added Horrors, this is an event you don’t want to miss.

 

This years charity is The Epilepsy Therapy Project. We have a team page so people can track our progress in meeting our goal of at least $2,000.00.

 

You can find out more HERE.

 

All donations and charity proceeds will be sent to our bank alt ‘Horrorfest Resident’ whose account records will be completely transparent, and who is not used for anything at all apart from Guild of Gloom events. Approximately 1 week after Horrorfest is over, details of transactions from SL to the charity will be documented on the Horrorfest blog (This may be later, depending on cashing out times which are a bit borked right now).

 

Please have a read of The Epilepsy Therapy Project’s website. It’s a wonderful cause and seriously underfunded. This is our chance to give them a presence in the virtual world.

 

That is all for now, I look forward to see you all very soon!

 

Credits

 

Hair – Underscore

Shape – External Appearance Shapes

Skin – Tableau Vivant

Eyes – Avatar Bizarre – Retinal Polish in White/Glow Version @ Horrorfest

Eyelashes – La Sylphide

Makeup(Bloody Lips) – Corvus

Full Avatar Outfit – Avatar Bizarre – Harker Tux in Black @ Horrorfest

 

I’ll be showing these suits from Avatar Bizarre in more detail at a later date, I just wanted to do a artistic shot for this first post of many.

What do you see, Merc, when you look up with those warm, brown eyes?

 

Today, Merc visited an ophthalmology specialist, Dr. David Canton, DVM, DACVO. Merc suffers from Nyctalopia which is a fancy way of saying he doesn't see well in the dark. We went because some standard poodles can sometimes get Progressive Retinal Atrophy (PRA), a progressive deterioration of the retinal cells that leads to blindness. Nyctalopia is a symptom of the disease. So far, there was nothing conclusive in the exam. That means that visually, the specialist couldn't find anything to indicate Merc has the disease. We're to go back in six months to see if Merc's retinas show any signs of degeneration. Updates to his eye status are below in comments.

 

Am I guilty of looking without seeing? Not today. Until the spring comes, I'll be watching out for you. When it's dark, stick by me, and we'll walk together.

 

I love you Merc.

  

'XD Retinal, Writings about the Obscenity of Teeth' by Francesca Pennini, performed by Collettivo Cinetico (Italy) during the 1st European Festival of Contemporary Dance - Kraków/Bytom. Teatr PWST, Kraków, Poland

it's art in the street. The Philadelphia Museum of Art has a very famous toilet by Duchamp. Yea, just a real urinal signed by Duchamp.

He had a seminal influence on the development of conceptual art. By World War I, he had rejected the work of many of his fellow artists (such as Henri Matisse) as "retinal" art, intended only to please the eye. Instead, Duchamp wanted to use art to serve the mind.

Jellyfish, also known sea jellies, are the medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria.

 

Jellyfish are mainly free-swimming marine animals with umbrella-shaped bells and trailing tentacles, although a few are anchored to the seabed by stalks rather than being mobile. The bell can pulsate to provide propulsion for highly efficient locomotion. The tentacles are armed with stinging cells and may be used to capture prey and defend against predators. Jellyfish have a complex life cycle. The medusa is normally the sexual phase, which produces planula larvae; these then disperse widely and enter a sedentary polyp phase, before reaching sexual maturity.

 

Jellyfish are found all over the world, from surface waters to the deep sea. Scyphozoans (the "true jellyfish") are exclusively marine, but some hydrozoans with a similar appearance live in freshwater. Large, often colorful, jellyfish are common in coastal zones worldwide. The medusae of most species are fast-growing, and mature within a few months then die soon after breeding, but the polyp stage, attached to the seabed, may be much more long-lived. Jellyfish have been in existence for at least 500 million years, and possibly 700 million years or more, making them the oldest multi-organ animal group.

 

Jellyfish are eaten by humans in certain cultures. They are considered a delicacy in some Asian countries, where species in the Rhizostomeae order are pressed and salted to remove excess water. Australian researchers have described them as a "perfect food": sustainable and protein-rich but relatively low in food energy.

 

They are also used in research, where the green fluorescent protein used by some species to cause bioluminescence has been adapted as a fluorescent marker for genes inserted into other cells or organisms.

 

The stinging cells used by jellyfish to subdue their prey can injure humans. Thousands of swimmers worldwide are stung every year, with effects ranging from mild discomfort to serious injury or even death. When conditions are favourable, jellyfish can form vast swarms, which can be responsible for damage to fishing gear by filling fishing nets, and sometimes clog the cooling systems of power and desalination plants which draw their water from the sea.

  

Names

The name jellyfish, in use since 1796, has traditionally been applied to medusae and all similar animals including the comb jellies (ctenophores, another phylum). The term jellies or sea jellies is more recent, having been introduced by public aquaria in an effort to avoid use of the word "fish" with its modern connotation of an animal with a backbone, though shellfish, cuttlefish and starfish are not vertebrates either. In scientific literature, "jelly" and "jellyfish" have been used interchangeably. Many sources refer to only scyphozoans as "true jellyfish".

 

A group of jellyfish is called a "smack" or a "smuck".

 

Definition

The term jellyfish broadly corresponds to medusae, that is, a life-cycle stage in the Medusozoa. The American evolutionary biologist Paulyn Cartwright gives the following general definition:

 

Typically, medusozoan cnidarians have a pelagic, predatory jellyfish stage in their life cycle; staurozoans are the exceptions [as they are stalked].

 

The Merriam-Webster dictionary defines jellyfish as follows:

 

A free-swimming marine coelenterate that is the sexually reproducing form of a hydrozoan or scyphozoan and has a nearly transparent saucer-shaped body and extensible marginal tentacles studded with stinging cells.

 

Given that jellyfish is a common name, its mapping to biological groups is inexact. Some authorities have called the comb jellies and certain salps jellyfish, though other authorities state that neither of these are jellyfish, which they consider should be limited to certain groups within the medusozoa.

 

The non-medusozoan clades called jellyfish by some but not all authorities (both agreeing and disagreeing citations are given in each case) are indicated with on the following cladogram of the animal kingdom:

 

Jellyfish are not a clade, as they include most of the Medusozoa, barring some of the Hydrozoa. The medusozoan groups included by authorities are indicated on the following phylogenetic tree by the presence of citations. Names of included jellyfish, in English where possible, are shown in boldface; the presence of a named and cited example indicates that at least that species within its group has been called a jellyfish.

 

Taxonomy

The subphylum Medusozoa includes all cnidarians with a medusa stage in their life cycle. The basic cycle is egg, planula larva, polyp, medusa, with the medusa being the sexual stage. The polyp stage is sometimes secondarily lost. The subphylum include the major taxa, Scyphozoa (large jellyfish), Cubozoa (box jellyfish) and Hydrozoa (small jellyfish), and excludes Anthozoa (corals and sea anemones). This suggests that the medusa form evolved after the polyps. Medusozoans have tetramerous symmetry, with parts in fours or multiples of four.

 

The four major classes of medusozoan Cnidaria are:

Scyphozoa are sometimes called true jellyfish, though they are no more truly jellyfish than the others listed here. They have tetra-radial symmetry. Most have tentacles around the outer margin of the bowl-shaped bell, and long, oral arms around the mouth in the center of the subumbrella.

Cubozoa (box jellyfish) have a (rounded) box-shaped bell, and their velarium assists them to swim more quickly. Box jellyfish may be related more closely to scyphozoan jellyfish than either are to the Hydrozoa.

Hydrozoa medusae also have tetra-radial symmetry, nearly always have a velum (diaphragm used in swimming) attached just inside the bell margin, do not have oral arms, but a much smaller central stalk-like structure, the manubrium, with terminal mouth opening, and are distinguished by the absence of cells in the mesoglea. Hydrozoa show great diversity of lifestyle; some species maintain the polyp form for their entire life and do not form medusae at all (such as Hydra, which is hence not considered a jellyfish), and a few are entirely medusal and have no polyp form.

Staurozoa (stalked jellyfish) are characterized by a medusa form that is generally sessile, oriented upside down and with a stalk emerging from the apex of the "calyx" (bell), which attaches to the substrate. At least some Staurozoa also have a polyp form that alternates with the medusoid portion of the life cycle. Until recently, Staurozoa were classified within the Scyphozoa.

There are over 200 species of Scyphozoa, about 50 species of Staurozoa, about 50 species of Cubozoa, and the Hydrozoa includes about 1000–1500 species that produce medusae, but many more species that do not.

 

Fossil history

Since jellyfish have no hard parts, fossils are rare. The oldest unambiguous fossil of a free-swimming medusa is Burgessomedusa from the mid Cambrian Burgess Shale of Canada, which is likely either a stem group of box jellyfish (Cubozoa) or Acraspeda (the clade including Staurozoa, Cubozoa, and Scyphozoa). Other claimed records from the Cambrian of China and Utah in the United States are uncertain, and possibly represent ctenophores instead.

 

Anatomy

The main feature of a true jellyfish is the umbrella-shaped bell. This is a hollow structure consisting of a mass of transparent jelly-like matter known as mesoglea, which forms the hydrostatic skeleton of the animal. 95% or more of the mesogloea consists of water, but it also contains collagen and other fibrous proteins, as well as wandering amoebocytes which can engulf debris and bacteria. The mesogloea is bordered by the epidermis on the outside and the gastrodermis on the inside. The edge of the bell is often divided into rounded lobes known as lappets, which allow the bell to flex. In the gaps or niches between the lappets are dangling rudimentary sense organs known as rhopalia, and the margin of the bell often bears tentacles.

  

Anatomy of a scyphozoan jellyfish

On the underside of the bell is the manubrium, a stalk-like structure hanging down from the centre, with the mouth, which also functions as the anus, at its tip. There are often four oral arms connected to the manubrium, streaming away into the water below. The mouth opens into the gastrovascular cavity, where digestion takes place and nutrients are absorbed. This is subdivided by four thick septa into a central stomach and four gastric pockets. The four pairs of gonads are attached to the septa, and close to them four septal funnels open to the exterior, perhaps supplying good oxygenation to the gonads. Near the free edges of the septa, gastric filaments extend into the gastric cavity; these are armed with nematocysts and enzyme-producing cells and play a role in subduing and digesting the prey. In some scyphozoans, the gastric cavity is joined to radial canals which branch extensively and may join a marginal ring canal. Cilia in these canals circulate the fluid in a regular direction.

  

Discharge mechanism of a nematocyst

The box jellyfish is largely similar in structure. It has a squarish, box-like bell. A short pedalium or stalk hangs from each of the four lower corners. One or more long, slender tentacles are attached to each pedalium. The rim of the bell is folded inwards to form a shelf known as a velarium which restricts the bell's aperture and creates a powerful jet when the bell pulsates, allowing box jellyfish to swim faster than true jellyfish. Hydrozoans are also similar, usually with just four tentacles at the edge of the bell, although many hydrozoans are colonial and may not have a free-living medusal stage. In some species, a non-detachable bud known as a gonophore is formed that contains a gonad but is missing many other medusal features such as tentacles and rhopalia. Stalked jellyfish are attached to a solid surface by a basal disk, and resemble a polyp, the oral end of which has partially developed into a medusa with tentacle-bearing lobes and a central manubrium with four-sided mouth.

 

Most jellyfish do not have specialized systems for osmoregulation, respiration and circulation, and do not have a central nervous system. Nematocysts, which deliver the sting, are located mostly on the tentacles; true jellyfish also have them around the mouth and stomach. Jellyfish do not need a respiratory system because sufficient oxygen diffuses through the epidermis. They have limited control over their movement, but can navigate with the pulsations of the bell-like body; some species are active swimmers most of the time, while others largely drift. The rhopalia contain rudimentary sense organs which are able to detect light, water-borne vibrations, odour and orientation. A loose network of nerves called a "nerve net" is located in the epidermis. Although traditionally thought not to have a central nervous system, nerve net concentration and ganglion-like structures could be considered to constitute one in most species. A jellyfish detects stimuli, and transmits impulses both throughout the nerve net and around a circular nerve ring, to other nerve cells. The rhopalial ganglia contain pacemaker neurones which control swimming rate and direction.

 

In many species of jellyfish, the rhopalia include ocelli, light-sensitive organs able to tell light from dark. These are generally pigment spot ocelli, which have some of their cells pigmented. The rhopalia are suspended on stalks with heavy crystals at one end, acting like gyroscopes to orient the eyes skyward. Certain jellyfish look upward at the mangrove canopy while making a daily migration from mangrove swamps into the open lagoon, where they feed, and back again.

 

Box jellyfish have more advanced vision than the other groups. Each individual has 24 eyes, two of which are capable of seeing colour, and four parallel information processing areas that act in competition, supposedly making them one of the few kinds of animal to have a 360-degree view of its environment.

 

Box jellyfish eye

The study of jellyfish eye evolution is an intermediary to a better understanding of how visual systems evolved on Earth. Jellyfish exhibit immense variation in visual systems ranging from photoreceptive cell patches seen in simple photoreceptive systems to more derived complex eyes seen in box jellyfish. Major topics of jellyfish visual system research (with an emphasis on box jellyfish) include: the evolution of jellyfish vision from simple to complex visual systems), the eye morphology and molecular structures of box jellyfish (including comparisons to vertebrate eyes), and various uses of vision including task-guided behaviors and niche specialization.

 

Evolution

Experimental evidence for photosensitivity and photoreception in cnidarians antecedes the mid 1900s, and a rich body of research has since covered evolution of visual systems in jellyfish. Jellyfish visual systems range from simple photoreceptive cells to complex image-forming eyes. More ancestral visual systems incorporate extraocular vision (vision without eyes) that encompass numerous receptors dedicated to single-function behaviors. More derived visual systems comprise perception that is capable of multiple task-guided behaviors.

 

Although they lack a true brain, cnidarian jellyfish have a "ring" nervous system that plays a significant role in motor and sensory activity. This net of nerves is responsible for muscle contraction and movement and culminates the emergence of photosensitive structures. Across Cnidaria, there is large variation in the systems that underlie photosensitivity. Photosensitive structures range from non-specialized groups of cells, to more "conventional" eyes similar to those of vertebrates. The general evolutionary steps to develop complex vision include (from more ancestral to more derived states): non-directional photoreception, directional photoreception, low-resolution vision, and high-resolution vision. Increased habitat and task complexity has favored the high-resolution visual systems common in derived cnidarians such as box jellyfish.

 

Basal visual systems observed in various cnidarians exhibit photosensitivity representative of a single task or behavior. Extraocular photoreception (a form of non-directional photoreception), is the most basic form of light sensitivity and guides a variety of behaviors among cnidarians. It can function to regulate circadian rhythm (as seen in eyeless hydrozoans) and other light-guided behaviors responsive to the intensity and spectrum of light. Extraocular photoreception can function additionally in positive phototaxis (in planula larvae of hydrozoans), as well as in avoiding harmful amounts of UV radiation via negative phototaxis. Directional photoreception (the ability to perceive direction of incoming light) allows for more complex phototactic responses to light, and likely evolved by means of membrane stacking. The resulting behavioral responses can range from guided spawning events timed by moonlight to shadow responses for potential predator avoidance. Light-guided behaviors are observed in numerous scyphozoans including the common moon jelly, Aurelia aurita, which migrates in response to changes in ambient light and solar position even though they lack proper eyes.

 

The low-resolution visual system of box jellyfish is more derived than directional photoreception, and thus box jellyfish vision represents the most basic form of true vision in which multiple directional photoreceptors combine to create the first imaging and spatial resolution. This is different from the high-resolution vision that is observed in camera or compound eyes of vertebrates and cephalopods that rely on focusing optics. Critically, the visual systems of box jellyfish are responsible for guiding multiple tasks or behaviors in contrast to less derived visual systems in other jellyfish that guide single behavioral functions. These behaviors include phototaxis based on sunlight (positive) or shadows (negative), obstacle avoidance, and control of swim-pulse rate.

 

Box jellyfish possess "proper eyes" (similar to vertebrates) that allow them to inhabit environments that lesser derived medusae cannot. In fact, they are considered the only class in the clade Medusozoa that have behaviors necessitating spatial resolution and genuine vision. However, the lens in their eyes are more functionally similar to cup-eyes exhibited in low-resolution organisms, and have very little to no focusing capability. The lack of the ability to focus is due to the focal length exceeding the distance to the retina, thus generating unfocused images and limiting spatial resolution. The visual system is still sufficient for box jellyfish to produce an image to help with tasks such as object avoidance.

 

Utility as a model organism

Box jellyfish eyes are a visual system that is sophisticated in numerous ways. These intricacies include the considerable variation within the morphology of box jellyfishes' eyes (including their task/behavior specification), and the molecular makeup of their eyes including: photoreceptors, opsins, lenses, and synapses. The comparison of these attributes to more derived visual systems can allow for a further understanding of how the evolution of more derived visual systems may have occurred, and puts into perspective how box jellyfish can play the role as an evolutionary/developmental model for all visual systems.

 

Characteristics

Box jellyfish visual systems are both diverse and complex, comprising multiple photosystems. There is likely considerable variation in visual properties between species of box jellyfish given the significant inter-species morphological and physiological variation. Eyes tend to differ in size and shape, along with number of receptors (including opsins), and physiology across species of box jellyfish.

 

Box jellyfish have a series of intricate lensed eyes that are similar to those of more derived multicellular organisms such as vertebrates. Their 24 eyes fit into four different morphological categories. These categories consist of two large, morphologically different medial eyes (a lower and upper lensed eye) containing spherical lenses, a lateral pair of pigment slit eyes, and a lateral pair of pigment pit eyes. The eyes are situated on rhopalia (small sensory structures) which serve sensory functions of the box jellyfish and arise from the cavities of the exumbrella (the surface of the body) on the side of the bells of the jellyfish. The two large eyes are located on the mid-line of the club and are considered complex because they contain lenses. The four remaining eyes lie laterally on either side of each rhopalia and are considered simple. The simple eyes are observed as small invaginated cups of epithelium that have developed pigmentation. The larger of the complex eyes contains a cellular cornea created by a mono ciliated epithelium, cellular lens, homogenous capsule to the lens, vitreous body with prismatic elements, and a retina of pigmented cells. The smaller of the complex eyes is said to be slightly less complex given that it lacks a capsule but otherwise contains the same structure as the larger eye.

 

Box jellyfish have multiple photosystems that comprise different sets of eyes. Evidence includes immunocytochemical and molecular data that show photopigment differences among the different morphological eye types, and physiological experiments done on box jellyfish to suggest behavioral differences among photosystems. Each individual eye type constitutes photosystems that work collectively to control visually guided behaviors.

 

Box jellyfish eyes primarily use c-PRCs (ciliary photoreceptor cells) similar to that of vertebrate eyes. These cells undergo phototransduction cascades (process of light absorption by photoreceptors) that are triggered by c-opsins. Available opsin sequences suggest that there are two types of opsins possessed by all cnidarians including an ancient phylogenetic opsin, and a sister ciliary opsin to the c-opsins group. Box jellyfish could have both ciliary and cnidops (cnidarian opsins), which is something not previously believed to appear in the same retina. Nevertheless, it is not entirely evident whether cnidarians possess multiple opsins that are capable of having distinctive spectral sensitivities.

 

Comparison with other organisms

Comparative research on genetic and molecular makeup of box jellyfishes' eyes versus more derived eyes seen in vertebrates and cephalopods focuses on: lenses and crystallin composition, synapses, and Pax genes and their implied evidence for shared primordial (ancestral) genes in eye evolution.

 

Box jellyfish eyes are said to be an evolutionary/developmental model of all eyes based on their evolutionary recruitment of crystallins and Pax genes. Research done on box jellyfish including Tripedalia cystophora has suggested that they possess a single Pax gene, PaxB. PaxB functions by binding to crystallin promoters and activating them. PaxB in situ hybridization resulted in PaxB expression in the lens, retina, and statocysts. These results and the rejection of the prior hypothesis that Pax6 was an ancestral Pax gene in eyes has led to the conclusion that PaxB was a primordial gene in eye evolution, and that the eyes of all organisms likely share a common ancestor.

 

The lens structure of box jellyfish appears very similar to those of other organisms, but the crystallins are distinct in both function and appearance. Weak reactions were seen within the sera and there were very weak sequence similarities within the crystallins among vertebrate and invertebrate lenses. This is likely due to differences in lower molecular weight proteins and the subsequent lack of immunological reactions with antisera that other organisms' lenses exhibit.

 

All four of the visual systems of box jellyfish species investigated with detail (Carybdea marsupialis, Chiropsalmus quadrumanus, Tamoya haplonema and Tripedalia cystophora) have invaginated synapses, but only in the upper and lower lensed eyes. Different densities were found between the upper and lower lenses, and between species. Four types of chemical synapses have been discovered within the rhopalia which could help in understanding neural organization including: clear unidirectional, dense-core unidirectional, clear bidirectional, and clear and dense-core bidirectional. The synapses of the lensed eyes could be useful as markers to learn more about the neural circuit in box jellyfish retinal areas.

 

Evolution as a response to natural stimuli

The primary adaptive responses to environmental variation observed in box jellyfish eyes include pupillary constriction speeds in response to light environments, as well as photoreceptor tuning and lens adaptations to better respond to shifts between light environments and darkness. Interestingly, some box jellyfish species' eyes appear to have evolved more focused vision in response to their habitat.

 

Pupillary contraction appears to have evolved in response to variation in the light environment across ecological niches across three species of box jellyfish (Chironex fleckeri, Chiropsella bronzie, and Carukia barnesi). Behavioral studies suggest that faster pupil contraction rates allow for greater object avoidance, and in fact, species with more complex habitats exhibit faster rates. Ch. bronzie inhabit shallow beach fronts that have low visibility and very few obstacles, thus, faster pupil contraction in response to objects in their environment is not important. Ca. barnesi and Ch. fleckeri are found in more three-dimensionally complex environments like mangroves with an abundance of natural obstacles, where faster pupil contraction is more adaptive. Behavioral studies support the idea that faster pupillary contraction rates assist with obstacle avoidance as well as depth adjustments in response to differing light intensities.

 

Light/dark adaptation via pupillary light reflexes is an additional form of an evolutionary response to the light environment. This relates to the pupil's response to shifts between light intensity (generally from sunlight to darkness). In the process of light/dark adaptation, the upper and lower lens eyes of different box jellyfish species vary in specific function. The lower lens-eyes contain pigmented photoreceptors and long pigment cells with dark pigments that migrate on light/dark adaptation, while the upper-lens eyes play a concentrated role in light direction and phototaxis given that they face upward towards the water surface (towards the sun or moon). The upper lens of Ch. bronzie does not exhibit any considerable optical power while Tr. cystophora (a box jellyfish species that tends to live in mangroves) does. The ability to use light to visually guide behavior is not of as much importance to Ch. bronzie as it is to species in more obstacle-filled environments. Differences in visually guided behavior serve as evidence that species that share the same number and structure of eyes can exhibit differences in how they control behavior.

 

Largest and smallest

Jellyfish range from about one millimeter in bell height and diameter, to nearly 2 metres (6+1⁄2 ft) in bell height and diameter; the tentacles and mouth parts usually extend beyond this bell dimension.

 

The smallest jellyfish are the peculiar creeping jellyfish in the genera Staurocladia and Eleutheria, which have bell disks from 0.5 millimetres (1⁄32 in) to a few millimeters in diameter, with short tentacles that extend out beyond this, which these jellyfish use to move across the surface of seaweed or the bottoms of rocky pools; many of these tiny creeping jellyfish cannot be seen in the field without a hand lens or microscope. They can reproduce asexually by fission (splitting in half). Other very small jellyfish, which have bells about one millimeter, are the hydromedusae of many species that have just been released from their parent polyps; some of these live only a few minutes before shedding their gametes in the plankton and then dying, while others will grow in the plankton for weeks or months. The hydromedusae Cladonema radiatum and Cladonema californicum are also very small, living for months, yet never growing beyond a few mm in bell height and diameter.

 

The lion's mane jellyfish, Cyanea capillata, was long-cited as the largest jellyfish, and arguably the longest animal in the world, with fine, thread-like tentacles that may extend up to 36.5 m (119 ft 9 in) long (though most are nowhere near that large). They have a moderately painful, but rarely fatal, sting. The increasingly common giant Nomura's jellyfish, Nemopilema nomurai, found in some, but not all years in the waters of Japan, Korea and China in summer and autumn is another candidate for "largest jellyfish", in terms of diameter and weight, since the largest Nomura's jellyfish in late autumn can reach 2 m (6 ft 7 in) in bell (body) diameter and about 200 kg (440 lb) in weight, with average specimens frequently reaching 0.9 m (2 ft 11 in) in bell diameter and about 150 kg (330 lb) in weight. The large bell mass of the giant Nomura's jellyfish can dwarf a diver and is nearly always much greater than the Lion's Mane, whose bell diameter can reach 1 m (3 ft 3 in).

 

The rarely encountered deep-sea jellyfish Stygiomedusa gigantea is another candidate for "largest jellyfish", with its thick, massive bell up to 100 cm (3 ft 3 in) wide, and four thick, "strap-like" oral arms extending up to 6 m (19+1⁄2 ft) in length, very different from the typical fine, threadlike tentacles that rim the umbrella of more-typical-looking jellyfish, including the Lion's Mane.

 

Desmonema glaciale, which lives in the Antarctic region, can reach a very large size (several meters). Purple-striped jelly (Chrysaora colorata) can also be extremely long (up to 15 feet).

 

Life history and behavior

Life cycle

Jellyfish have a complex life cycle which includes both sexual and asexual phases, with the medusa being the sexual stage in most instances. Sperm fertilize eggs, which develop into larval planulae, become polyps, bud into ephyrae and then transform into adult medusae. In some species certain stages may be skipped.

 

Upon reaching adult size, jellyfish spawn regularly if there is a sufficient supply of food. In most species, spawning is controlled by light, with all individuals spawning at about the same time of day; in many instances this is at dawn or dusk. Jellyfish are usually either male or female (with occasional hermaphrodites). In most cases, adults release sperm and eggs into the surrounding water, where the unprotected eggs are fertilized and develop into larvae. In a few species, the sperm swim into the female's mouth, fertilizing the eggs within her body, where they remain during early development stages. In moon jellies, the eggs lodge in pits on the oral arms, which form a temporary brood chamber for the developing planula larvae.

 

The planula is a small larva covered with cilia. When sufficiently developed, it settles onto a firm surface and develops into a polyp. The polyp generally consists of a small stalk topped by a mouth that is ringed by upward-facing tentacles. The polyps resemble those of closely related anthozoans, such as sea anemones and corals. The jellyfish polyp may be sessile, living on the bottom, boat hulls or other substrates, or it may be free-floating or attached to tiny bits of free-living plankton or rarely, fish or other invertebrates. Polyps may be solitary or colonial. Most polyps are only millimetres in diameter and feed continuously. The polyp stage may last for years.

 

After an interval and stimulated by seasonal or hormonal changes, the polyp may begin reproducing asexually by budding and, in the Scyphozoa, is called a segmenting polyp, or a scyphistoma. Budding produces more scyphistomae and also ephyrae. Budding sites vary by species; from the tentacle bulbs, the manubrium (above the mouth), or the gonads of hydromedusae. In a process known as strobilation, the polyp's tentacles are reabsorbed and the body starts to narrow, forming transverse constrictions, in several places near the upper extremity of the polyp. These deepen as the constriction sites migrate down the body, and separate segments known as ephyra detach. These are free-swimming precursors of the adult medusa stage, which is the life stage that is typically identified as a jellyfish. The ephyrae, usually only a millimeter or two across initially, swim away from the polyp and grow. Limnomedusae polyps can asexually produce a creeping frustule larval form, which crawls away before developing into another polyp. A few species can produce new medusae by budding directly from the medusan stage. Some hydromedusae reproduce by fission.

 

Lifespan

Little is known of the life histories of many jellyfish as the places on the seabed where the benthic forms of those species live have not been found. However, an asexually reproducing strobila form can sometimes live for several years, producing new medusae (ephyra larvae) each year.

 

An unusual species, Turritopsis dohrnii, formerly classified as Turritopsis nutricula, might be effectively immortal because of its ability under certain circumstances to transform from medusa back to the polyp stage, thereby escaping the death that typically awaits medusae post-reproduction if they have not otherwise been eaten by some other organism. So far this reversal has been observed only in the laboratory.

 

Locomotion

Jellyfish locomotion is highly efficient. Muscles in the jellylike bell contract, setting up a start vortex and propelling the animal. When the contraction ends, the bell recoils elastically, creating a stop vortex with no extra energy input.

Using the moon jelly Aurelia aurita as an example, jellyfish have been shown to be the most energy-efficient swimmers of all animals. They move through the water by radially expanding and contracting their bell-shaped bodies to push water behind them. They pause between the contraction and expansion phases to create two vortex rings. Muscles are used for the contraction of the body, which creates the first vortex and pushes the animal forward, but the mesoglea is so elastic that the expansion is powered exclusively by relaxing the bell, which releases the energy stored from the contraction. Meanwhile, the second vortex ring starts to spin faster, sucking water into the bell and pushing against the centre of the body, giving a secondary and "free" boost forward. The mechanism, called passive energy recapture, only works in relatively small jellyfish moving at low speeds, allowing the animal to travel 30 percent farther on each swimming cycle. Jellyfish achieved a 48 percent lower cost of transport (food and oxygen intake versus energy spent in movement) than other animals in similar studies. One reason for this is that most of the gelatinous tissue of the bell is inactive, using no energy during swimming.

 

Ecology

Diet

Jellyfish are, like other cnidarians, generally carnivorous (or parasitic), feeding on planktonic organisms, crustaceans, small fish, fish eggs and larvae, and other jellyfish, ingesting food and voiding undigested waste through the mouth. They hunt passively using their tentacles as drift lines, or sink through the water with their tentacles spread widely; the tentacles, which contain nematocysts to stun or kill the prey, may then flex to help bring it to the mouth. Their swimming technique also helps them to capture prey; when their bell expands it sucks in water which brings more potential prey within reach of the tentacles.

 

A few species such as Aglaura hemistoma are omnivorous, feeding on microplankton which is a mixture of zooplankton and phytoplankton (microscopic plants) such as dinoflagellates. Others harbour mutualistic algae (Zooxanthellae) in their tissues; the spotted jellyfish (Mastigias papua) is typical of these, deriving part of its nutrition from the products of photosynthesis, and part from captured zooplankton. The upside-down jellyfish (Cassiopea andromeda) also has a symbiotic relationship with microalgae, but captures tiny animals to supplement their diet. This is done by releasing tiny balls of living cells composed of mesoglea. These use cilia to drive them through water and stinging cells which stun the prey. The blobs also seems to have digestive capabilities.

 

Predation

Other species of jellyfish are among the most common and important jellyfish predators. Sea anemones may eat jellyfish that drift into their range. Other predators include tunas, sharks, swordfish, sea turtles and penguins. Jellyfish washed up on the beach are consumed by foxes, other terrestrial mammals and birds. In general however, few animals prey on jellyfish; they can broadly be considered to be top predators in the food chain. Once jellyfish have become dominant in an ecosystem, for example through overfishing which removes predators of jellyfish larvae, there may be no obvious way for the previous balance to be restored: they eat fish eggs and juvenile fish, and compete with fish for food, preventing fish stocks from recovering.

 

Symbiosis

Some small fish are immune to the stings of the jellyfish and live among the tentacles, serving as bait in a fish trap; they are safe from potential predators and are able to share the fish caught by the jellyfish. The cannonball jellyfish has a symbiotic relationship with ten different species of fish, and with the longnose spider crab, which lives inside the bell, sharing the jellyfish's food and nibbling its tissues.

 

Main article: Jellyfish bloom

Jellyfish form large masses or blooms in certain environmental conditions of ocean currents, nutrients, sunshine, temperature, season, prey availability, reduced predation and oxygen concentration. Currents collect jellyfish together, especially in years with unusually high populations. Jellyfish can detect marine currents and swim against the current to congregate in blooms. Jellyfish are better able to survive in nutrient-rich, oxygen-poor water than competitors, and thus can feast on plankton without competition. Jellyfish may also benefit from saltier waters, as saltier waters contain more iodine, which is necessary for polyps to turn into jellyfish. Rising sea temperatures caused by climate change may also contribute to jellyfish blooms, because many species of jellyfish are able to survive in warmer waters. Increased nutrients from agricultural or urban runoff with nutrients including nitrogen and phosphorus compounds increase the growth of phytoplankton, causing eutrophication and algal blooms. When the phytoplankton die, they may create dead zones, so-called because they are hypoxic (low in oxygen). This in turn kills fish and other animals, but not jellyfish, allowing them to bloom. Jellyfish populations may be expanding globally as a result of land runoff and overfishing of their natural predators. Jellyfish are well placed to benefit from disturbance of marine ecosystems. They reproduce rapidly; they prey upon many species, while few species prey on them; and they feed via touch rather than visually, so they can feed effectively at night and in turbid waters. It may be difficult for fish stocks to re-establish themselves in marine ecosystems once they have become dominated by jellyfish, because jellyfish feed on plankton, which includes fish eggs and larvae.

 

As suspected at the turn of this century, jellyfish blooms are increasing in frequency. Between 2013 and 2020 the Mediterranean Science Commission monitored on a weekly basis the frequency of such outbreaks in coastal waters from Morocco to the Black Sea, revealing a relatively high frequency of these blooms nearly all year round, with peaks observed from March to July and often again in the autumn. The blooms are caused by different jellyfish species, depending on their localisation within the Basin: one observes a clear dominance of Pelagia noctiluca and Velella velella outbreaks in the western Mediterranean, of Rhizostoma pulmo and Rhopilema nomadica outbreaks in the eastern Mediterranean, and of Aurelia aurita and Mnemiopsis leidyi outbreaks in the Black Sea.

 

Some jellyfish populations that have shown clear increases in the past few decades are invasive species, newly arrived from other habitats: examples include the Black Sea, Caspian Sea, Baltic Sea, central and eastern Mediterranean, Hawaii, and tropical and subtropical parts of the West Atlantic (including the Caribbean, Gulf of Mexico and Brazil).

 

Jellyfish blooms can have significant impact on community structure. Some carnivorous jellyfish species prey on zooplankton while others graze on primary producers. Reductions in zooplankton and ichthyoplankton due to a jellyfish bloom can ripple through the trophic levels. High-density jellyfish populations can outcompete other predators and reduce fish recruitment. Increased grazing on primary producers by jellyfish can also interrupt energy transfer to higher trophic levels.

 

During blooms, jellyfish significantly alter the nutrient availability in their environment. Blooms require large amounts of available organic nutrients in the water column to grow, limiting availability for other organisms. Some jellyfish have a symbiotic relationship with single-celled dinoflagellates, allowing them to assimilate inorganic carbon, phosphorus, and nitrogen creating competition for phytoplankton. Their large biomass makes them an important source of dissolved and particulate organic matter for microbial communities through excretion, mucus production, and decomposition. The microbes break down the organic matter into inorganic ammonium and phosphate. However, the low carbon availability shifts the process from production to respiration creating low oxygen areas making the dissolved inorganic nitrogen and phosphorus largely unavailable for primary production.

 

These blooms have very real impacts on industries. Jellyfish can outcompete fish by utilizing open niches in over-fished fisheries. Catch of jellyfish can strain fishing gear and lead to expenses relating to damaged gear. Power plants have been shut down due to jellyfish blocking the flow of cooling water. Blooms have also been harmful for tourism, causing a rise in stings and sometimes the closure of beaches.

 

Jellyfish form a component of jelly-falls, events where gelatinous zooplankton fall to the seafloor, providing food for the benthic organisms there. In temperate and subpolar regions, jelly-falls usually follow immediately after a bloom.

 

Habitats

Most jellyfish are marine animals, although a few hydromedusae inhabit freshwater. The best known freshwater example is the cosmopolitan hydrozoan jellyfish, Craspedacusta sowerbii. It is less than an inch (2.5 cm) in diameter, colorless and does not sting. Some jellyfish populations have become restricted to coastal saltwater lakes, such as Jellyfish Lake in Palau. Jellyfish Lake is a marine lake where millions of golden jellyfish (Mastigias spp.) migrate horizontally across the lake daily.

 

Although most jellyfish live well off the ocean floor and form part of the plankton, a few species are closely associated with the bottom for much of their lives and can be considered benthic. The upside-down jellyfish in the genus Cassiopea typically lie on the bottom of shallow lagoons where they sometimes pulsate gently with their umbrella top facing down. Even some deep-sea species of hydromedusae and scyphomedusae are usually collected on or near the bottom. All of the stauromedusae are found attached to either seaweed or rocky or other firm material on the bottom.

 

Some species explicitly adapt to tidal flux. In Roscoe Bay, jellyfish ride the current at ebb tide until they hit a gravel bar, and then descend below the current. They remain in still waters until the tide rises, ascending and allowing it to sweep them back into the bay. They also actively avoid fresh water from mountain snowmelt, diving until they find enough salt.

  

Parasites

Jellyfish are hosts to a wide variety of parasitic organisms. They act as intermediate hosts of endoparasitic helminths, with the infection being transferred to the definitive host fish after predation. Some digenean trematodes, especially species in the family Lepocreadiidae, use jellyfish as their second intermediate hosts. Fish become infected by the trematodes when they feed on infected jellyfish.

 

Relation to humans

Jellyfish have long been eaten in some parts of the world. Fisheries have begun harvesting the American cannonball jellyfish, Stomolophus meleagris, along the southern Atlantic coast of the United States and in the Gulf of Mexico for export to Asia.

 

Jellyfish are also harvested for their collagen, which is being investigated for use in a variety of applications including the treatment of rheumatoid arthritis.

 

Aquaculture and fisheries of other species often suffer severe losses – and so losses of productivity – due to jellyfish.

 

Products

Main article: Jellyfish as food

In some countries, including China, Japan, and Korea, jellyfish are a delicacy. The jellyfish is dried to prevent spoiling. Only some 12 species of scyphozoan jellyfish belonging to the order Rhizostomeae are harvested for food, mostly in southeast Asia. Rhizostomes, especially Rhopilema esculentum in China (海蜇 hǎizhé, 'sea stingers') and Stomolophus meleagris (cannonball jellyfish) in the United States, are favored because of their larger and more rigid bodies and because their toxins are harmless to humans.

 

Traditional processing methods, carried out by a jellyfish master, involve a 20- to 40-day multi-phase procedure in which, after removing the gonads and mucous membranes, the umbrella and oral arms are treated with a mixture of table salt and alum, and compressed. Processing makes the jellyfish drier and more acidic, producing a crisp texture. Jellyfish prepared this way retain 7–10% of their original weight, and the processed product consists of approximately 94% water and 6% protein. Freshly processed jellyfish has a white, creamy color and turns yellow or brown during prolonged storage.

 

In China, processed jellyfish are desalted by soaking in water overnight and eaten cooked or raw. The dish is often served shredded with a dressing of oil, soy sauce, vinegar and sugar, or as a salad with vegetables. In Japan, cured jellyfish are rinsed, cut into strips and served with vinegar as an appetizer. Desalted, ready-to-eat products are also available.

 

Biotechnology

The hydromedusa Aequorea victoria was the source of green fluorescent protein, studied for its role in bioluminescence and later for use as a marker in genetic engineering.

Pliny the Elder reported in his Natural History that the slime of the jellyfish "Pulmo marinus" produced light when rubbed on a walking stick.

 

In 1961, Osamu Shimomura extracted green fluorescent protein (GFP) and another bioluminescent protein, called aequorin, from the large and abundant hydromedusa Aequorea victoria, while studying photoproteins that cause bioluminescence in this species. Three decades later, Douglas Prasher sequenced and cloned the gene for GFP. Martin Chalfie figured out how to use GFP as a fluorescent marker of genes inserted into other cells or organisms. Roger Tsien later chemically manipulated GFP to produce other fluorescent colors to use as markers. In 2008, Shimomura, Chalfie and Tsien won the Nobel Prize in Chemistry for their work with GFP. Man-made GFP became widely used as a fluorescent tag to show which cells or tissues express specific genes. The genetic engineering technique fuses the gene of interest to the GFP gene. The fused DNA is then put into a cell, to generate either a cell line or (via IVF techniques) an entire animal bearing the gene. In the cell or animal, the artificial gene turns on in the same tissues and the same time as the normal gene, making a fusion of the normal protein with GFP attached to the end, illuminating the animal or cell reveals what tissues express that protein—or at what stage of development. The fluorescence shows where the gene is expressed.

 

Aquarium display

Jellyfish are displayed in many public aquariums. Often the tank's background is blue and the animals are illuminated by side light, increasing the contrast between the animal and the background. In natural conditions, many jellies are so transparent that they are nearly invisible. Jellyfish are not adapted to closed spaces. They depend on currents to transport them from place to place. Professional exhibits as in the Monterey Bay Aquarium feature precise water flows, typically in circular tanks to avoid trapping specimens in corners. The outflow is spread out over a large surface area and the inflow enters as a sheet of water in front of the outflow, so the jellyfish do not get sucked into it. As of 2009, jellyfish were becoming popular in home aquariums, where they require similar equipment.

 

Stings

Jellyfish are armed with nematocysts, a type of specialized stinging cell. Contact with a jellyfish tentacle can trigger millions of nematocysts to pierce the skin and inject venom, but only some species' venom causes an adverse reaction in humans. In a study published in Communications Biology, researchers found a jellyfish species called Cassiopea xamachana which when triggered will release tiny balls of cells that swim around the jellyfish stinging everything in their path. Researchers described these as "self-propelling microscopic grenades" and named them cassiosomes.

 

The effects of stings range from mild discomfort to extreme pain and death. Most jellyfish stings are not deadly, but stings of some box jellyfish (Irukandji jellyfish), such as the sea wasp, can be deadly. Stings may cause anaphylaxis (a form of shock), which can be fatal. Jellyfish kill 20 to 40 people a year in the Philippines alone. In 2006 the Spanish Red Cross treated 19,000 stung swimmers along the Costa Brava.

 

Vinegar (3–10% aqueous acetic acid) may help with box jellyfish stings but not the stings of the Portuguese man o' war. Clearing the area of jelly and tentacles reduces nematocyst firing. Scraping the affected skin, such as with the edge of a credit card, may remove remaining nematocysts. Once the skin has been cleaned of nematocysts, hydrocortisone cream applied locally reduces pain and inflammation. Antihistamines may help to control itching. Immunobased antivenins are used for serious box jellyfish stings.

 

In Elba Island and Corsica dittrichia viscosa is now used by residents and tourists to heal stings from jellyfish, bees and wasps pressing fresh leaves on the skin with quick results.

 

Mechanical issues

Jellyfish in large quantities can fill and split fishing nets and crush captured fish. They can clog cooling equipment, having disabled power stations in several countries; jellyfish caused a cascading blackout in the Philippines in 1999, as well as damaging the Diablo Canyon Power Plant in California in 2008. They can also stop desalination plants and ships' engines.

ANAGLYPH, made from original tissue stereoview in my collection:

"Le Tribunal De Satan"

 

This image views in 3D when wearing RED/CYAN 3D glasses.

 

The original stereoview is here: www.flickr.com/photos/depthandtime/5455128918/

 

There is a fair amount of retinal rivalry going on from the pin pricking done to the original. The original is made of multiple layers of tissue paper with hand coloring applied to the layer behind the front photographic layer. These images are meant to be viewed with backlight as transparencies. The pinpricking of the eyes in these images is usually accompanied by some red coloring to make the eyes appear as though they are glowing red......neat for anything but an anaglyph:)

The domestic turkey (Meleagris gallopavo domesticus) is a large fowl, one of the two species in the genus Meleagris and the same species as the wild turkey. Although turkey domestication was thought to have occurred in central Mesoamerica at least 2,000 years ago, recent research suggests a possible second domestication event in the area that is now the southwestern United States between 200 BC and 500 AD. However, all of the main domestic turkey varieties today descend from the turkey raised in central Mexico that was subsequently imported into Europe by the Spanish in the 16th century.

 

The domestic turkey is a popular form of poultry, and it is raised throughout temperate parts of the world, partially because industrialized farming has made it very cheap for the amount of meat it produces. Female domestic turkeys are called hens, and the chicks are poults or turkeylings. In Canada and the United States, male turkeys are called toms; in the United Kingdom and Ireland, they are stags.

 

The great majority of domestic turkeys are bred to have white feathers because their pin feathers are less visible when the carcass is dressed, although brown or bronze-feathered varieties are also raised. The fleshy protuberance atop the beak is the snood, and the one attached to the underside of the beak is known as a wattle.

 

The English-language name for this species results from an early misidentification of the bird with an unrelated species which was imported to Europe through the country of Turkey. The Latin species name gallopāvō means "chicken peacock".

 

History

The modern domestic turkey is descended from the South Mexican subspecies (the nominate subspecies M. g. gallopavo) of wild turkey, found in Central Mexico in a region bounded by the present Mexican states of Jalisco to the northwest, Guerrero to the southwest, and Veracruz to the east. Ancient Mesoamericans domesticated this subspecies, using its meat and eggs as major sources of protein and employing its feathers extensively for decorative purposes. The Aztecs associated the turkey with their trickster god Tezcatlipoca, perhaps because of its perceived humorous behavior.

 

Domestic turkeys were taken to Europe by the Spanish. Many distinct breeds were developed in Europe (e.g. Spanish Black, Royal Palm). In the early 20th century, many advances were made in the breeding of turkeys, resulting in breeds such as the Beltsville Small White.

  

Black Spanish turkeys

The 16th-century English navigator William Strickland is generally credited with introducing the turkey into England.[6] His family coat of arms – showing a turkey cock as the family crest – is among the earliest known European depictions of a turkey. English farmer Thomas Tusser notes the turkey being among farmer's fare at Christmas in 1573. The domestic turkey was sent from England to Jamestown, Virginia in 1608. A document written in 1584 lists supplies to be furnished to future colonies in the New World; "turkies, male and female".

 

Prior to the late 19th century, turkey was something of a luxury in the UK, with goose or beef a more common Christmas dinner among the working classes. In Charles Dickens' A Christmas Carol (1843), Bob Cratchit had a goose before Scrooge bought him a turkey.

 

Turkey production in the UK was centered in East Anglia, using two breeds, the Norfolk Black and the Norfolk Bronze (also known as Cambridge Bronze). These would be driven as flocks, after shoeing, down to markets in London from the 17th century onwards – the breeds having arrived in the early 16th century via Spain.

 

Intensive farming of turkeys from the late 1940s dramatically cut the price, making it more affordable for the working classes. With the availability of refrigeration, whole turkeys could be shipped frozen to distant markets. Later advances in disease control increased production even more. Advances in shipping, changing consumer preferences and the proliferation of commercial poultry plants has made fresh turkey inexpensive as well as readily available.

 

Recent genome analysis has provided researchers with the opportunity to determine the evolutionary history of domestic turkeys, and their relationship to other domestic fowl.

 

Behaviour

Young domestic turkeys readily fly short distances, perch and roost. These behaviours become less frequent as the birds mature, but adults will readily climb on objects such as bales of straw. Young birds perform spontaneous, frivolous running ('frolicking') which has all the appearance of play. Commercial turkeys show a wide diversity of behaviours including 'comfort' behaviours such as wing-flapping, feather ruffling, leg stretching and dust-bathing. Turkeys are highly social and become very distressed when isolated. Many of their behaviours are socially facilitated; i.e., expression of a behaviour by one animal increases the tendency for this behaviour to be performed by others. Adults can recognise 'strangers' and placing any alien turkey into an established group will almost certainly result in that individual being attacked, sometimes fatally. Turkeys are highly vocal, and 'social tension' within the group can be monitored by the birds' vocalisations. A high-pitched trill indicates the birds are becoming aggressive which can develop into intense sparring where opponents leap at each other with the large, sharp talons, and try to peck or grasp the head of each other. Aggression increases in frequency and severity as the birds mature.

 

Maturing males spend a considerable proportion of their time sexually displaying. This is very similar to that of the wild turkey and involves fanning the tail feathers, drooping the wings and erecting all body feathers, including the 'beard' (a tuft of black, modified hair-like feathers on the centre of the breast). The skin of the head, neck and caruncles (fleshy nodules) becomes bright blue and red, and the snood (an erectile appendage on the forehead) elongates, the birds 'sneeze' at regular intervals, followed by a rapid vibration of their tail feathers. Throughout, the birds strut slowly about, with the neck arched backward, their breasts thrust forward and emitting their characteristic 'gobbling' call.

 

Size and weight

The domestic turkey is the eighth largest living bird species in terms of maximum mass at 39 kg (86 lbs).[citation needed] Due to their extreme size differences, domestic turkeys are semi-flightless, as younger or smaller specimens are still capable of short-distance flight, whereas the largest individuals are completely flightless and terrestrial.

 

Turkey breeds

The Broad Breasted White is the commercial turkey of choice for large scale industrial turkey farms, and consequently is the most consumed variety of the bird. Usually the turkey to receive a "presidential pardon", a U.S. custom, is a Broad Breasted White.

The Broad Breasted Bronze is another commercially developed strain of table bird.

The Standard Bronze looks much like the Broad Breasted Bronze, except that it is single breasted, and can naturally breed.

The Bourbon Red turkey is a smaller, non-commercial breed with dark reddish feathers with white markings.

Slate, or Blue Slate, turkeys are a very rare breed with gray-blue feathers.

The Black ("Spanish Black", "Norfolk Black") has very dark plumage with a green sheen.

The Narragansett Turkey is a popular heritage breed named after Narraganset Bay in New England.

The Chocolate is a rarer heritage breed with markings similar to a Black Spanish, but light brown instead of black in color. Common in the Southern U.S. and France before the Civil War.

The Beltsville Small White is a small heritage breed, whose development started in 1934. The breed was introduced in 1941 and was admitted to the APA Standard in 1951. Although slightly bigger and broader than the Midget White, both are often mislabeled.

The Midget White is a smaller heritage breed.

Commercial production

In commercial production, breeder farms supply eggs to hatcheries. After 28 days of incubation, the hatched poults are sexed and delivered to the grow-out farms; hens are raised separately from toms because of different growth rates.

 

In the UK, it is common to rear chicks in the following way. Between one and seven days of age, chicks are placed into small 2.5 m (8 ft) circular brooding pens to ensure they encounter food and water. To encourage feeding, they may be kept under constant light for the first 48 hours. To assist thermoregulation, air temperature is maintained at 35 °C (95 °F) for the first three days, then lowered by approximately 3 °C (5.4 °F) every two days to 18 °C (64 °F) at 37 days of age, and infrared heaters are usually provided for the first few days. Whilst in the pens, feed is made widely accessible by scattering it on sheets of paper in addition to being available in feeders. After several days, the pens are removed, allowing the birds access to the entire rearing shed, which may contain tens of thousands of birds. The birds remain there for several weeks, after which they are transported to another unit.

 

The vast majority of turkeys are reared indoors in purpose-built or modified buildings of which there are many types. Some types have slatted walls to allow ventilation, but many have solid walls and no windows to allow artificial lighting manipulations to optimise production. The buildings can be very large (converted aircraft hangars are sometimes used) and may contain tens of thousands of birds as a single flock. The floor substrate is usually deep-litter, e.g. wood shavings, which relies upon the controlled build-up of a microbial flora requiring skilful management. Ambient temperatures for adult domestic turkeys are usually maintained between 18 and 21 °C (64 and 70 °F). High temperatures should be avoided because the high metabolic rate of turkeys (up to 69 W/bird) makes them susceptible to heat stress, exacerbated by high stocking densities. Commercial turkeys are kept under a variety of lighting schedules, e.g. continuous light, long photoperiods (23 h), or intermittent lighting, to encourage feeding and accelerate growth. Light intensity is usually low (e.g. less than one lux) to reduce feather pecking.

 

Rations generally include corn and soybean meal, with added vitamins and minerals, and is adjusted for protein, carbohydrate and fat based on the age and nutrient requirements. Hens are slaughtered at about 14–16 weeks and toms at about 18–20 weeks of age when they can weigh over 20 kg (44 lb) compared to a mature male wild turkey which weighs approximately 10.8 kg (24 lb).

 

Welfare concerns

Stocking density is an issue in the welfare of commercial turkeys and high densities are a major animal welfare concern. Permitted stocking densities for turkeys reared indoors vary according to geography and animal welfare farm assurance schemes. For example, in Germany, there is a voluntary maximum of 52 kg/m2 and 58 kg/m2 for males and females respectively. In the UK, the RSPCA Freedom Foods assurance scheme reduces permissible stocking density to 25 kg/m2 for turkeys reared indoors. Turkeys maintained at commercial stocking densities (8 birds/m2; 61 kg/m2) exhibit increased welfare problems such as increases in gait abnormalities, hip and foot lesions, and bird disturbances, and decreased bodyweight compared with lower stocking densities. Turkeys reared at 8 birds/m2 have a higher incidence of hip lesions and foot pad dermatitis than those reared at 6.5 or 5.0 birds/m2. Insufficient space may lead to an increased risk for injuries such as broken wings caused by hitting the pen walls or other turkeys during aggressive encounters and can also lead to heat stress. The problems of small space allowance are exacerbated by the major influence of social facilitation on the behaviour of turkeys. If turkeys are to feed, drink, dust-bathe, etc., simultaneously, then to avoid causing frustration, resources and space must be available in large quantities.

 

Lighting manipulations used to optimise production can compromise welfare. Long photoperiods combined with low light intensity can result in blindness from buphthalmia (distortions of the eye morphology) or retinal detachment.

 

Feather pecking occurs frequently amongst commercially reared turkeys and can begin at 1 day of age. This behaviour is considered to be re-directed foraging behaviour, caused by providing poultry with an impoverished foraging environment. To reduce feather pecking, turkeys are often beak-trimmed. Ultraviolet-reflective markings appear on young birds at the same time as feather pecking becomes targeted toward these areas, indicating a possible link. Commercially reared turkeys also perform head-pecking, which becomes more frequent as they sexually mature. When this occurs in small enclosures or environments with few opportunities to escape, the outcome is often fatal and rapid. Frequent monitoring is therefore essential, particularly of males approaching maturity. Injuries to the head receive considerable attention from other birds, and head-pecking often occurs after a relatively minor injury has been received during a fight or when a lying bird has been trodden upon and scratched by another. Individuals being re-introduced after separation are often immediately attacked again. Fatal head-pecking can occur even in small (10 birds), stable groups. Commercial turkeys are normally reared in single-sex flocks. If a male is inadvertently placed in a female flock, he may be aggressively victimised (hence the term 'henpecked'). Females in male groups will be repeatedly mated, during which it is highly likely she will be injured from being trampled upon.

 

Breeding and companies

The dominant commercial breed is the Broad-Breasted Whites (similar to the "White Holland", but a separate breed), which have been selected for size and amount of meat. Mature toms are too large to achieve natural fertilization without injuring the hens, so their semen is collected, and hens are inseminated artificially. Several hens can be inseminated from each collection, so fewer toms are needed. The eggs of some turkey breeds are able to develop without fertilization, in a process called parthenogenesis. Breeders' meat is too tough for roasting, and is mostly used to make processed meats.

 

Waste products

Approximately two billion to four billion pounds (900,000 to 1,800,000 t) of poultry feathers are produced every year by the poultry industry. Most are ground into a protein source for ruminant animal feed, which are able to digest the protein keratin of which feathers are composed. Researchers at the United States Department of Agriculture (USDA) have patented a method of removing the stiff quill from the fibers which make up the feather.[citation needed] As this is a potential supply of natural fibers, research has been conducted at Philadelphia University's School of Engineering and Textiles to determine textile applications for feather fibers. Turkey feather fibers have been blended with nylon and spun into yarn, and then used for knitting. The yarns were tested for strength while the fabrics were evaluated as insulation materials. In the case of the yarns, as the percentage of turkey feather fibers increased, the strength decreased. In fabric form, as the percentage of turkey feather fibers increased, the heat retention capability of the fabric increased.

 

Turkeys as food

Turkey, breast, meat only, raw

Nutritional value per 100 g (3.5 oz)

Energy465 kJ (111 kcal)

Carbohydrates

0 g

Sugars0 g

Dietary fiber0 g

Fat

0.7 g

Protein

24.6 g

VitaminsQuantity%DV†

Thiamine (B1)0%0 mg

Riboflavin (B2)8%0.1 mg

Niacin (B3)44%6.6 mg

Pantothenic acid (B5)14%0.7 mg

Vitamin B646%0.6 mg

Folate (B9)2%8 μg

Vitamin C0%0 mg

MineralsQuantity%DV†

Calcium1%10 mg

Iron9%1.2 mg

Magnesium8%28 mg

Phosphorus29%206 mg

Potassium6%293 mg

Sodium3%49 mg

Zinc13%1.2 mg

Units

μg = micrograms • mg = milligrams

IU = International units

†Percentages are roughly approximated using US recommendations for adults.

 

Source: USDA Nutrient Database

Approximately 620 million turkeys are slaughtered each year for meat worldwide. Turkeys are traditionally eaten as the main course of Christmas feasts in much of the English-speaking world (stuffed turkey) since appearing in England in the 16th century, as well as for Thanksgiving in the United States and Canada. While eating turkey was once mainly restricted to special occasions such as these, turkey is now eaten year-round and forms a regular part of many diets.

 

Turkeys are sold sliced and ground, as well as "whole" in a manner similar to chicken with the head, feet, and feathers removed. Frozen whole turkeys remain popular. Sliced turkey is frequently used as a sandwich meat or served as cold cuts; in some cases, where recipes call for chicken, turkey can be used as a substitute. Additionally, ground turkey is frequently marketed as a healthy ground beef substitute. Without careful preparation, cooked turkey may end up less moist than other poultry meats, such as chicken or duck. The breast of the turkey can be dipped in breadcrumbs as an alternative to chicken nuggets.

 

Wild turkeys, while technically the same species as domestic turkeys, have a very different taste from farm-raised turkeys. In contrast to domestic turkeys, almost all wild turkey meat is "dark" (even the breast) and more intensely flavored. The flavor can also vary seasonally with changes in available forage, often leaving wild turkey meat with a gamier flavor in late summer due to the greater number of insects in its diet over the preceding months. Wild turkeys that have fed predominantly on grass and grain have a milder flavor. Older heritage breeds also differ in flavor.

 

Unlike chicken, duck, and quail eggs, turkey eggs are not commonly sold as food due to the high demand for whole turkeys and the lower output of turkey eggs as compared with other fowl. The value of a single turkey egg is estimated to be about US$3.50 on the open market, substantially more than a single carton of one dozen chicken eggs.

 

White turkey meat is often considered healthier than dark meat because of its lower fat content, but the nutritional differences are small. Although turkey is reputed to cause sleepiness, holiday dinners are commonly large meals served with carbohydrates, fats, and alcohol in a relaxed atmosphere, all of which are bigger contributors to post-meal sleepiness than the tryptophan in turkey.

 

Cooking

Both fresh and frozen turkeys are used for cooking; as with most foods, fresh turkeys are generally preferred, although they cost more. Around holiday seasons, high demand for fresh turkeys often makes them difficult to purchase without ordering in advance. For the frozen variety, the large size of the turkeys typically used for consumption makes defrosting them a major endeavor: a typically sized turkey will take several days to properly defrost.

 

Turkeys are usually baked or roasted in an oven for several hours, often while the cook prepares the remainder of the meal. Sometimes, a turkey is brined before roasting to enhance flavor and moisture content. This is necessary because the dark meat requires a higher temperature to denature all of the myoglobin pigment than the white meat (which is very low in myoglobin), so that fully cooking the dark meat tends to dry out the breast. Brining makes it possible to fully cook the dark meat without drying the breast meat. Turkeys are sometimes decorated with turkey frills prior to serving.

 

In some areas, particularly the American South, turkeys may also be deep fried in hot oil (often peanut oil) for 30 to 45 minutes by using a turkey fryer. Deep frying turkey has become something of a fad, with hazardous consequences for those unprepared to safely handle the large quantities of hot oil required.

 

Turkey litter for fuel

Although most commonly used as fertilizer, turkey litter (droppings mixed with bedding material, usually wood chips) has been used as a fuel source in electric power plants. One such plant in western Minnesota provided 55 megawatts of power using 500,000 tons of litter per year. The plant, known as Fibrominn, operated from 2007 to 2018.

 

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Exploding sun? Retinal detachment?

Bees are flying insects closely related to wasps and ants, known for their role in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyletic lineage within the superfamily Apoidea. They are presently considered a clade, called Anthophila. There are over 16,000 known species of bees in seven recognized biological families. Some species – including honey bees, bumblebees, and stingless bees – live socially in colonies while some species – including mason bees, carpenter bees, leafcutter bees, and sweat bees – are solitary.

 

Bees are found on every continent except for Antarctica, in every habitat on the planet that contains insect-pollinated flowering plants. The most common bees in the Northern Hemisphere are the Halictidae, or sweat bees, but they are small and often mistaken for wasps or flies. Bees range in size from tiny stingless bee species, whose workers are less than 2 millimetres long, to Megachile pluto, the largest species of leafcutter bee, whose females can attain a length of 39 millimetres.

 

Bees feed on nectar and pollen, the former primarily as an energy source and the latter primarily for protein and other nutrients. Most pollen is used as food for their larvae. Vertebrate predators of bees include birds such as bee-eaters; insect predators include beewolves and dragonflies.

 

Bee pollination is important both ecologically and commercially, and the decline in wild bees has increased the value of pollination by commercially managed hives of honey bees. The analysis of 353 wild bee and hoverfly species across Britain from 1980 to 2013 found the insects have been lost from a quarter of the places they inhabited in 1980.

 

Human beekeeping or apiculture has been practised for millennia, since at least the times of Ancient Egypt and Ancient Greece. Bees have appeared in mythology and folklore, through all phases of art and literature from ancient times to the present day, although primarily focused in the Northern Hemisphere where beekeeping is far more common.

 

EVOLUTION

The ancestors of bees were wasps in the family Crabronidae, which were predators of other insects. The switch from insect prey to pollen may have resulted from the consumption of prey insects which were flower visitors and were partially covered with pollen when they were fed to the wasp larvae. This same evolutionary scenario may have occurred within the vespoid wasps, where the pollen wasps evolved from predatory ancestors. Until recently, the oldest non-compression bee fossil had been found in New Jersey amber, Cretotrigona prisca of Cretaceous age, a corbiculate bee. A bee fossil from the early Cretaceous (~100 mya), Melittosphex burmensis, is considered "an extinct lineage of pollen-collecting Apoidea sister to the modern bees". Derived features of its morphology (apomorphies) place it clearly within the bees, but it retains two unmodified ancestral traits (plesiomorphies) of the legs (two mid-tibial spurs, and a slender hind basitarsus), showing its transitional status. By the Eocene (~45 mya) there was already considerable diversity among eusocial bee lineages.

 

The highly eusocial corbiculate Apidae appeared roughly 87 Mya, and the Allodapini (within the Apidae) around 53 Mya. The Colletidae appear as fossils only from the late Oligocene (~25 Mya) to early Miocene. The Melittidae are known from Palaeomacropis eocenicus in the Early Eocene. The Megachilidae are known from trace fossils (characteristic leaf cuttings) from the Middle Eocene. The Andrenidae are known from the Eocene-Oligocene boundary, around 34 Mya, of the Florissant shale. The Halictidae first appear in the Early Eocene with species found in amber. The Stenotritidae are known from fossil brood cells of Pleistocene age.

 

COEVOLUTION

The earliest animal-pollinated flowers were shallow, cup-shaped blooms pollinated by insects such as beetles, so the syndrome of insect pollination was well established before the first appearance of bees. The novelty is that bees are specialized as pollination agents, with behavioral and physical modifications that specifically enhance pollination, and are the most efficient pollinating insects. In a process of coevolution, flowers developed floral rewards such as nectar and longer tubes, and bees developed longer tongues to extract the nectar. Bees also developed structures known as scopal hairs and pollen baskets to collect and carry pollen. The location and type differ among and between groups of bees. Most species have scopal hairs on their hind legs or on the underside of their abdomens. Some species in the family Apidae have pollen baskets on their hind legs, while very few lack these and instead collect pollen in their crops. The appearance of these structures drove the adaptive radiation of the angiosperms, and, in turn, bees themselves. Bees coevolved not only with flowers but it is believed that some species coevolved with mites. Some provide tufts of hairs called acarinaria that appear to provide lodgings for mites; in return, it is believed that mites eat fungi that attack pollen, so the relationship in this case may be mutualistc.

 

CHARACTERISTICS

Bees differ from closely related groups such as wasps by having branched or plume-like setae (hairs), combs on the forelimbs for cleaning their antennae, small anatomical differences in limb structure, and the venation of the hind wings; and in females, by having the seventh dorsal abdominal plate divided into two half-plates.

 

Bees have the following characteristics:

 

A pair of large compound eyes which cover much of the surface of the head. Between and above these are three small simple eyes (ocelli) which provide information on light intensity.

The antennae usually have 13 segments in males and 12 in females, and are geniculate, having an elbow joint part way along. They house large numbers of sense organs that can detect touch (mechanoreceptors), smell and taste; and small, hairlike mechanoreceptors that can detect air movement so as to "hear" sounds.

The mouthparts are adapted for both chewing and sucking by having both a pair of mandibles and a long proboscis for sucking up nectar.

The thorax has three segments, each with a pair of robust legs, and a pair of membranous wings on the hind two segments. The front legs of corbiculate bees bear combs for cleaning the antennae, and in many species the hind legs bear pollen baskets, flattened sections with incurving hairs to secure the collected pollen. The wings are synchronised in flight, and the somewhat smaller hind wings connect to the forewings by a row of hooks along their margin which connect to a groove in the forewing.

The abdomen has nine segments, the hindermost three being modified into the sting.

 

The largest species of bee is thought to be Wallace's giant bee Megachile pluto, whose females can attain a length of 39 millimetres. The smallest species may be dwarf stingless bees in the tribe Meliponini whose workers are less than 2 millimetres in length.

 

SOCIALITY

HAPLODIPLOID BREEDING SYSTEM

According to inclusive fitness theory, organisms can gain fitness not just through increasing their own reproductive output, but also that of close relatives. In evolutionary terms, individuals should help relatives when Cost < Relatedness * Benefit. The requirements for eusociality are more easily fulfilled by haplodiploid species such as bees because of their unusual relatedness structure.

 

In haplodiploid species, females develop from fertilized eggs and males from unfertilized eggs. Because a male is haploid (has only one copy of each gene), his daughters (which are diploid, with two copies of each gene) share 100% of his genes and 50% of their mother's. Therefore, they share 75% of their genes with each other. This mechanism of sex determination gives rise to what W. D. Hamilton termed "supersisters", more closely related to their sisters than they would be to their own offspring. Workers often do not reproduce, but they can pass on more of their genes by helping to raise their sisters (as queens) than they would by having their own offspring (each of which would only have 50% of their genes), assuming they would produce similar numbers. This unusual situation has been proposed as an explanation of the multiple (at least 9) evolutions of eusociality within Hymenoptera.

Haplodiploidy is neither necessary nor sufficient for eusociality. Some eusocial species such as termites are not haplodiploid. Conversely, all bees are haplodiploid but not all are eusocial, and among eusocial species many queens mate with multiple males, creating half-sisters that share only 25% of each-other's genes. But, monogamy (queens mating singly) is the ancestral state for all eusocial species so far investigated, so it is likely that haplodiploidy contributed to the evolution of eusociality in bees.

 

EUSOCIALIT

Bees may be solitary or may live in various types of communities. Eusociality appears to have originated from at least three independent origins in halictid bees. The most advanced of these are species with eusocial colonies; these are characterised by cooperative brood care and a division of labour into reproductive and non-reproductive adults, plus overlapping generations. This division of labour creates specialized groups within eusocial societies which are called castes. In some species, groups of cohabiting females may be sisters, and if there is a division of labour within the group, they are considered semisocial. The group is called eusocial if, in addition, the group consists of a mother (the queen) and her daughters (workers). When the castes are purely behavioural alternatives, with no morphological differentiation other than size, the system is considered primitively eusocial, as in many paper wasps; when the castes are morphologically discrete, the system is considered highly eusocial.True honey bees (genus Apis, of which seven species are currently recognized) are highly eusocial, and are among the best known insects. Their colonies are established by swarms, consisting of a queen and several hundred workers. There are 29 subspecies of one of these species, Apis mellifera, native to Europe, the Middle East, and Africa. Africanized bees are a hybrid strain of A. mellifera that escaped from experiments involving crossing European and African subspecies; they are extremely defensive.[Stingless bees are also highly eusocial. They practise mass provisioning, with complex nest architecture and perennial colonies also established via swarming.

 

Many bumblebees are eusocial, similar to the eusocial Vespidae such as hornets in that the queen initiates a nest on her own rather than by swarming. Bumblebee colonies typically have from 50 to 200 bees at peak population, which occurs in mid to late summer. Nest architecture is simple, limited by the size of the pre-existing nest cavity, and colonies rarely last more than a year. In 2011, the International Union for Conservation of Nature set up the Bumblebee Specialist Group to review the threat status of all bumblebee species worldwide using the IUCN Red List criteria.

 

There are many more species of primitively eusocial than highly eusocial bees, but they have been studied less often. Most are in the family Halictidae, or "sweat bees". Colonies are typically small, with a dozen or fewer workers, on average. Queens and workers differ only in size, if at all. Most species have a single season colony cycle, even in the tropics, and only mated females hibernate. A few species have long active seasons and attain colony sizes in the hundreds, such as Halictus hesperus. Some species are eusocial in parts of their range and solitary in others, or have a mix of eusocial and solitary nests in the same population. The orchid bees (Apidae) include some primitively eusocial species with similar biology. Some allodapine bees (Apidae) form primitively eusocial colonies, with progressive provisioning: a larva's food is supplied gradually as it develops, as is the case in honey bees and some bumblebees.

 

SOLITARY AND COMMUNAL BEES

Most other bees, including familiar insects such as carpenter bees, leafcutter bees and mason bees are solitary in the sense that every female is fertile, and typically inhabits a nest she constructs herself. There is no division of labor so these nests lack queens and worker bees for these species. Solitary bees typically produce neither honey nor beeswax. Bees collect pollen to feed their young, and have the necessary adaptations to do this. However, certain wasp species such as pollen wasps have similar behaviours, and a few species of bee scavenge from carcases to feed their offspring. Solitary bees are important pollinators; they gather pollen to provision their nests with food for their brood. Often it is mixed with nectar to form a paste-like consistency. Some solitary bees have advanced types of pollen-carrying structures on their bodies. Very few species of solitary bee are being cultured for commercial pollination. Most of these species belong to a distinct set of genera which are commonly known by their nesting behavior or preferences, namely: carpenter bees, sweat bees, mason bees, plasterer bees, squash bees, dwarf carpenter bees, leafcutter bees, alkali bees and digger bees.Most solitary bees nest in the ground in a variety of soil textures and conditions while others create nests in hollow reeds or twigs, holes in wood. The female typically creates a compartment (a "cell") with an egg and some provisions for the resulting larva, then seals it off. A nest may consist of numerous cells. When the nest is in wood, usually the last (those closer to the entrance) contain eggs that will become males. The adult does not provide care for the brood once the egg is laid, and usually dies after making one or more nests. The males typically emerge first and are ready for mating when the females emerge. Solitary bees are either stingless or very unlikely to sting (only in self-defense, if ever). While solitary, females each make individual nests. Some species, such as the European mason bee Hoplitis anthocopoides, and the Dawson's Burrowing bee, Amegilla dawsoni, are gregarious, preferring to make nests near others of the same species, and giving the appearance of being social. Large groups of solitary bee nests are called aggregations, to distinguish them from colonies. In some species, multiple females share a common nest, but each makes and provisions her own cells independently. This type of group is called "communal" and is not uncommon. The primary advantage appears to be that a nest entrance is easier to defend from predators and parasites when multiple females use that same entrance regularly

 

BIOLOGY

LIFE CYCLE

The life cycle of a bee, be it a solitary or social species, involves the laying of an egg, the development through several moults of a legless larva, a pupation stage during which the insect undergoes complete metamorphosis, followed by the emergence of a winged adult. Most solitary bees and bumble bees in temperate climates overwinter as adults or pupae and emerge in spring when increasing numbers of flowering plants come into bloom. The males usually emerge first and search for females with which to mate. The sex of a bee is determined by whether or not the egg is fertilised; after mating, a female stores the sperm, and determines which sex is required at the time each individual egg is laid, fertilised eggs producing female offspring and unfertilised eggs, males. Tropical bees may have several generations in a year and no diapause stage.

 

The egg is generally oblong, slightly curved and tapering at one end. Solitary bees, lay each egg in a separate cell with a supply of mixed pollen and nectar next to it. This may be rolled into a pellet or placed in a pile and is known as mass provisioning. Social bee species provision progressively, that is, they feed the larva regularly while it grows. The nest varies from a hole in the ground or in wood, in solitary bees, to a substantial structure with wax combs in bumblebees and honey bees.

 

In most species, larvae are whitish grubs, roughly oval and bluntly-pointed at both ends. They have 15 segments and spiracles in each segment for breathing. They have no legs but move within the cell, helped by tubercles on their sides. They have short horns on the head, jaws for chewing food and an appendage on either side of the mouth tipped with a bristle. There is a gland under the mouth that secretes a viscous liquid which solidifies into the silk they use to produce a cocoon. The cocoon is semi-transparent and the pupa can be seen through it. Over the course of a few days, the larva undergoes metamorphosis into a winged adult. When ready to emerge, the adult splits its skin dorsally and climbs out of the exuviae and breaks out of the cell.

 

FLIGHT

Antoine Magnan's 1934 book Le vol des insectes, says that he and André Sainte-Laguë had applied the equations of air resistance to insects and found that their flight could not be explained by fixed-wing calculations, but that "One shouldn't be surprised that the results of the calculations don't square with reality". This has led to a common misconception that bees "violate aerodynamic theory". In fact it merely confirms that bees do not engage in fixed-wing flight, and that their flight is explained by other mechanics, such as those used by helicopters. In 1996 it was shown that vortices created by many insects' wings helped to provide lift. High-speed cinematography and robotic mock-up of a bee wing showed that lift was generated by "the unconventional combination of short, choppy wing strokes, a rapid rotation of the wing as it flops over and reverses direction, and a very fast wing-beat frequency". Wing-beat frequency normally increases as size decreases, but as the bee's wing beat covers such a small arc, it flaps approximately 230 times per second, faster than a fruitfly (200 times per second) which is 80 times smaller.

 

NAVIGATION, COMMUNICATION AND FINDING FOOD

The ethologist Karl von Frisch studied navigation in the honey bee. He showed that honey bees communicate by the waggle dance, in which a worker indicates the location of a food source to other workers in the hive. He demonstrated that bees can recognize a desired compass direction in three different ways: by the sun, by the polarization pattern of the blue sky, and by the earth's magnetic field. He showed that the sun is the preferred or main compass; the other mechanisms are used under cloudy skies or inside a dark beehive. Bees navigate using spatial memory with a "rich, map-like organization".

 

DIGESTION

The gut of bees is relatively simple, but multiple metabolic strategies exist in the gut microbiota. Pollinating bees consume nectar and pollen, which require different digestion strategies by somewhat specialized bacteria. While nectar is a liquid of mostly monosaccharide sugars and so easily absorbed, pollen contains complex polysaccharides: branching pectin and hemicellulose. Approximately five groups of bacteria are involved in digestion. Three groups specialize in simple sugars (Snodgrassella and two groups of Lactobacillus), and two other groups in complex sugars (Gilliamella and Bifidobacterium). Digestion of pectin and hemicellulose is dominated by bacterial clades Gilliamella and Bifidobacterium respectively. Bacteria that cannot digest polysaccharides obtain enzymes from their neighbors, and bacteria that lack certain amino acids do the same, creating multiple ecological niches.

 

Although most bee species are nectarivorous and palynivorous, some are not. Particularly unusual are vulture bees in the genus Trigona, which consume carrion and wasp brood, turning meat into a honey-like substance.

 

ECOLOGY

FLORAL RELATIONSHIPS

Most bees are polylectic (generalist) meaning they collect pollen from a range of flowering plants, but some are oligoleges (specialists), in that they only gather pollen from one or a few species or genera of closely related plants. Specialist pollinators also include bee species which gather floral oils instead of pollen, and male orchid bees, which gather aromatic compounds from orchids (one of the few cases where male bees are effective pollinators). Bees are able to sense the presence of desirable flowers through ultraviolet patterning on flowers, floral odors, and even electromagnetic fields. Once landed, a bee then uses nectar quality and pollen taste to determine whether to continue visiting similar flowers.

 

In rare cases, a plant species may only be effectively pollinated by a single bee species, and some plants are endangered at least in part because their pollinator is also threatened. But, there is a pronounced tendency for oligolectic bees to be associated with common, widespread plants visited by multiple pollinator species. For example, the creosote bush in the arid parts of the United States southwest is associated with some 40 oligoleges.

 

AS MIMICS AND MODELS

Many bees are aposematically coloured, typically orange and black, warning of their ability to defend themselves with a powerful sting. As such they are models for Batesian mimicry by non-stinging insects such as bee-flies, robber flies and hoverflies, all of which gain a measure of protection by superficially looking and behaving like bees.

 

Bees are themselves Müllerian mimics of other aposematic insects with the same colour scheme, including wasps, lycid and other beetles, and many butterflies and moths (Lepidoptera) which are themselves distasteful, often through acquiring bitter and poisonous chemicals from their plant food. All the Müllerian mimics, including bees, benefit from the reduced risk of predation that results from their easily recognised warning coloration.

 

Bees are also mimicked by plants such as the bee orchid which imitates both the appearance and the scent of a female bee; male bees attempt to mate (pseudocopulation) with the furry lip of the flower, thus pollinating it

 

AS BROOD PARASITES

Brood parasites occur in several bee families including the apid subfamily Nomadinae. Females of these species lack pollen collecting structures (the scopa) and do not construct their own nests. They typically enter the nests of pollen collecting species, and lay their eggs in cells provisioned by the host bee. When the "cuckoo" bee larva hatches, it consumes the host larva's pollen ball, and often the host egg also. In particular, the Arctic bee species, Bombus hyperboreus is an aggressive species that attacks and enslaves other bees of the same subgenus. However, unlike many other bee brood parasites, they have pollen baskets and often collect pollen.

 

In Southern Africa, hives of African honeybees (A. mellifera scutellata) are being destroyed by parasitic workers of the Cape honeybee, A. m. capensis. These lay diploid eggs ("thelytoky"), escaping normal worker policing, leading to the colony's destruction; the parasites can then move to other hives.

 

The cuckoo bees in the Bombus subgenus Psithyrus are closely related to, and resemble, their hosts in looks and size. This common pattern gave rise to the ecological principle "Emery's rule". Others parasitize bees in different families, like Townsendiella, a nomadine apid, two species of which are cleptoparasites of the dasypodaid genus Hesperapis, while the other species in the same genus attacks halictid bees.

 

NOCTURNAL BEES

Four bee families (Andrenidae, Colletidae, Halictidae, and Apidae) contain some species that are crepuscular. Most are tropical or subtropical, but some live in arid regions at higher latitudes. These bees have greatly enlarged ocelli, which are extremely sensitive to light and dark, though incapable of forming images. Some have refracting superposition compound eyes: these combine the output of many elements of their compound eyes to provide enough light for each retinal photoreceptor. Their ability to fly by night enables them to avoid many predators, and to exploit flowers that produce nectar only or also at night.

 

PREDATORS, PARASITES AND PATHOGENS

Vertebrate predators of bees include bee-eaters, shrikes and flycatchers, which make short sallies to catch insects in flight. Swifts and swallows fly almost continually, catching insects as they go. The honey buzzard attacks bees' nests and eats the larvae. The greater honeyguide interacts with humans by guiding them to the nests of wild bees. The humans break open the nests and take the honey and the bird feeds on the larvae and the wax. Among mammals, predators such as the badger dig up bumblebee nests and eat both the larvae and any stored food.Specialist ambush predators of visitors to flowers include crab spiders, which wait on flowering plants for pollinating insects; predatory bugs, and praying mantises, some of which (the flower mantises of the tropics) wait motionless, aggressive mimics camouflaged as flowers. Beewolves are large wasps that habitually attack bees; the ethologist Niko Tinbergen estimated that a single colony of the beewolf Philanthus triangulum might kill several thousand honeybees in a day: all the prey he observed were honeybees. Other predatory insects that sometimes catch bees include robber flies and dragonflies. Honey bees are affected by parasites including acarine and Varroa mites. However, some bees are believed to have a mutualistic relationship with mites.

 

RELATIONSHIP WITH HUMANS

IN MYTHOLOGY AND FOLKLORE

Homer's Hymn to Hermes describes three bee-maidens with the power of divination and thus speaking truth, and identifies the food of the gods as honey. Sources associated the bee maidens with Apollo and, until the 1980s, scholars followed Gottfried Hermann (1806) in incorrectly identifying the bee-maidens with the Thriae. Honey, according to a Greek myth, was discovered by a nymph called Melissa ("Bee"); and honey was offered to the Greek gods from Mycenean times. Bees were also associated with the Delphic oracle and the prophetess was sometimes called a bee.

 

The image of a community of honey bees has been used from ancient to modern times, in Aristotle and Plato; in Virgil and Seneca; in Erasmus and Shakespeare; Tolstoy, and by political and social theorists such as Bernard Mandeville and Karl Marx as a model for human society. In English folklore, bees would be told of important events in the household, in a custom known as "Telling the bees".

 

IN ART AND LITERATURE

Some of the oldest examples of bees in art are rock paintings in Spain which have been dated to 15,000 BC.

 

W. B. Yeats's poem The Lake Isle of Innisfree (1888) contains the couplet "Nine bean rows will I have there, a hive for the honey bee, / And live alone in the bee loud glade." At the time he was living in Bedford Park in the West of London. Beatrix Potter's illustrated book The Tale of Mrs Tittlemouse (1910) features Babbity Bumble and her brood (pictured). Kit Williams' treasure hunt book The Bee on the Comb (1984) uses bees and beekeeping as part of its story and puzzle. Sue Monk Kidd's The Secret Life of Bees (2004), and the 2009 film starring Dakota Fanning, tells the story of a girl who escapes her abusive home and finds her way to live with a family of beekeepers, the Boatwrights.

 

The humorous 2007 animated film Bee Movie used Jerry Seinfeld's first script and was his first work for children; he starred as a bee named Barry B. Benson, alongside Renée Zellweger. Critics found its premise awkward and its delivery tame. Dave Goulson's A Sting in the Tale (2014) describes his efforts to save bumblebees in Britain, as well as much about their biology. The playwright Laline Paull's fantasy The Bees (2015) tells the tale of a hive bee named Flora 717 from hatching onwards.

 

BEEKEEPING

Humans have kept honey bee colonies, commonly in hives, for millennia. Beekeepers collect honey, beeswax, propolis, pollen, and royal jelly from hives; bees are also kept to pollinate crops and to produce bees for sale to other beekeepers.

 

Depictions of humans collecting honey from wild bees date to 15,000 years ago; efforts to domesticate them are shown in Egyptian art around 4,500 years ago. Simple hives and smoke were used; jars of honey were found in the tombs of pharaohs such as Tutankhamun. From the 18th century, European understanding of the colonies and biology of bees allowed the construction of the moveable comb hive so that honey could be harvested without destroying the colony. Among Classical Era authors, beekeeping with the use of smoke is described in Aristotle's History of Animals Book 9. The account mentions that bees die after stinging; that workers remove corpses from the hive, and guard it; castes including workers and non-working drones, but "kings" rather than queens; predators including toads and bee-eaters; and the waggle dance, with the "irresistible suggestion" of άpοσειονται ("aroseiontai", it waggles) and παρακολουθούσιν ("parakolouthousin", they watch).

 

Beekeeping is described in detail by Virgil in his Georgics; it is also mentioned in his Aeneid, and in Pliny's Natural History.

 

AS COMMERCIAL POLLINATORS

Bees play an important role in pollinating flowering plants, and are the major type of pollinator in many ecosystems that contain flowering plants. It is estimated that one third of the human food supply depends on pollination by insects, birds and bats, most of which is accomplished by bees, whether wild or domesticated. Over the last half century, there has been a general decline in the species richness of wild bees and other pollinators, probably attributable to stress from increased parasites and disease, the use of pesticides, and a general decrease in the number of wild flowers. Climate change probably exacerbates the problem.

 

Contract pollination has overtaken the role of honey production for beekeepers in many countries. After the introduction of Varroa mites, feral honey bees declined dramatically in the US, though their numbers have since recovered. The number of colonies kept by beekeepers declined slightly, through urbanization, systematic pesticide use, tracheal and Varroa mites, and the closure of beekeeping businesses. In 2006 and 2007 the rate of attrition increased, and was described as colony collapse disorder. In 2010 invertebrate iridescent virus and the fungus Nosema ceranae were shown to be in every killed colony, and deadly in combination. Winter losses increased to about 1/3. Varroa mites were thought to be responsible for about half the losses.

 

Apart from colony collapse disorder, losses outside the US have been attributed to causes including pesticide seed dressings, using neonicotinoids such as Clothianidin, Imidacloprid and Thiamethoxam. From 2013 the European Union restricted some pesticides to stop bee populations from declining further. In 2014 the Intergovernmental Panel on Climate Change report warned that bees faced increased risk of extinction because of global warming. In 2018 the European Union decided to ban field use of all three major neonicotinoids; they remain permitted in veterinary, greenhouse, and vehicle transport usage.

 

Farmers have focused on alternative solutions to mitigate these problems. By raising native plants, they provide food for native bee pollinators like Lasioglossum vierecki and L. leucozonium, leading to less reliance on honey bee populations.

 

AS FOOD PRODUCERS

Honey is a natural product produced by bees and stored for their own use, but its sweetness has always appealed to humans. Before domestication of bees was even attempted, humans were raiding their nests for their honey. Smoke was often used to subdue the bees and such activities are depicted in rock paintings in Spain dated to 15,000 BC.

 

Honey bees are used commercially to produce honey. They also produce some substances used as dietary supplements with possible health benefits, pollen, propolis, and royal jelly, though all of these can also cause allergic reactions.

 

AS FOOD (BE BROOD)

Bees are partly considered edible insects. Indigenous people in many countries eat insects, including the larvae and pupae of bees, mostly stingless species. They also gather larvae, pupae and surrounding cells, known as bee brood, for consumption. In the Indonesian dish botok tawon from Central and East Java, bee larvae are eaten as a companion to rice, after being mixed with shredded coconut, wrapped in banana leaves, and steamed.

 

Bee brood (pupae and larvae) although low in calcium, has been found to be high in protein and carbohydrate, and a useful source of phosphorus, magnesium, potassium, and trace minerals iron, zinc, copper, and selenium. In addition, while bee brood was high in fat, it contained no fat soluble vitamins (such as A, D, and E) but it was a good source of most of the water-soluble B-vitamins including choline as well as vitamin C. The fat was composed mostly of saturated and monounsaturated fatty acids with 2.0% being polyunsaturated fatty acids.

 

AS ALTERNATIVE MEDICINE

Apitherapy is a branch of alternative medicine that uses honey bee products, including raw honey, royal jelly, pollen, propolis, beeswax and apitoxin (Bee venom). The claim that apitherapy treats cancer, which some proponents of apitherapy make, remains unsupported by evidence-based medicine.

 

STINGS

The painful stings of bees are mostly associated with the poison gland and the Dufour's gland which are abdominal exocrine glands containing various chemicals. In Lasioglossum leucozonium, the Dufour's Gland mostly contains octadecanolide as well as some eicosanolide. There is also evidence of n-triscosane, n-heptacosane, and 22-docosanolide. However, the secretions of these glands could also be used for nest construction.

 

WIKIPEDIA

This little girl was afraid of dogs. Thankfully her mom was extremely cool and allowed me to hand her Blue's leash. In 2 minutes her fear was transformed into adoration. Blue has never known anything but to completely trust everyone and everything around her. Blind and mostly deaf now, allowing a complete stranger to lead her. I am ashamed that I have somehow been unable to assimilate any of her grace.

A Leucistic Sandhill Crane at the Monte Vista crane festival. I've been to lots of crane festivals and seen thousands of cranes but this is the first leucistic I've ever seen.

 

Information from Wikipedia on Leucism.

Leucism (occasionally spelled leukism) is a general term for the phenotype resulting from defects in pigment cell differentiation and/or migration from the neural crest to skin, hair, or feathers during development. This results in either the entire surface (if all pigment cells fail to develop) or patches of body surface (if only a subset are defective) having a lack of cells capable of making pigment.

 

Since all pigment cell-types differentiate from the same multipotent precursor cell-type, leucism can cause the reduction in all types of pigment. This is in contrast to albinism, for which leucism is often mistaken. Albinism results in the reduction of melanin production only, though the melanocyte (or melanophore) is still present. Thus in species that have other pigment cell-types, for example xanthophores, albinos are not entirely white, but instead display a pale yellow colour.

 

More common than a complete absence of pigment cells is localized or incomplete hypopigmentation, resulting in irregular patches of white on an animal that otherwise has normal colouring and patterning. This partial leucism is known as a "pied" or "piebald" effect; and the ratio of white to normal-coloured skin can vary considerably not only between generations, but between different offspring from the same parents, and even between members of the same litter. This is notable in horses, cows, cats, dogs, the urban crow and the ball python but is also found in many other species.

 

A further difference between albinism and leucism is in eye colour. Due to the lack of melanin production in both the retinal pigmented epithelium (RPE) and iris, albinos typically have red eyes due to the underlying blood vessels showing through. In contrast, most leucistic animals have normally coloured eyes. This is because the melanocytes of the RPE are not derived from the neural crest, instead an outpouching of the neural tube generates the optic cup which, in turn, forms the retina. As these cells are from an independent developmental origin, they are typically unaffected by the genetic cause of leucism.

 

Genes that, when mutated, can cause leucism include, c-kit,[4] mitf[5] and EDNRB.[6]

 

Edited to remove retinal reflections.

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Finally got around to taking a few proper new photos today. I've been wanting to work on food shots for a while now, expect more of these in the near future :)

 

I explained earlier that I've been super busy setting up my photo business.

We've also been having a medical issue and have been in and out of the hospital for a large portion of the past week. Poor Wil needed eye surgery Friday (retinal detachment; he lost 75% of his right eye's field of vision on Wednesday). He's doing well, and we're joking around - basically using laughter to stay positive because while he will be fine, he won't be able to work or drive for a while - while working hard to get his eye to heal :) It's going to take a while, but it should all heal up fine while his retina fixes itself onto its proper place again.

 

© 2011 Karin E. Lips - do not use without my written permission. If you want to use this image or other photos, please contact me first :)

I appreciate your comments and faves, so much, but please do not post any group images in my comments, I will delete them because I like to keep everything nice and organized..! Thank you!

You can find links to my sites, FB pages, Twitter etc on my flickr profile - please check it out! :)

Go to the Book with image in the Internet Archive

Title: United States Naval Medical Bulletin Vol. 3, Nos. 1-4, 1909

Creator: U.S. Navy. Bureau of Medicine and Surgery

Publisher:

Sponsor:

Contributor:

Date: 1909

Language: eng

  

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Table of Contents</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Preface vii</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Special articles 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The artificial illumination of naval vessels (a study in naval

hygiene), by J. D. Gatewood 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A simple operation for hemorrhoids, by H. F. Hull 22</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Suggested devices 25</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A metal suspensory, by W. B. Grove 25</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A short and accurate method of calculating the age in years and months,

by E. M. Brown 25</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Card for index system to be used in preparing smooth quarterly form

"X" at recruiting stations, etc., by C. R. Keen 27</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Clinical notes 29</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of angina Ludovici, by W. S. Pugh 29</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of Vincent's angina, by G. F. Clark 31</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Rupture of the iris; two cases, by R. K. Riggs 32</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Wood alcohol poisoning; 13 cases, 3 deaths, by R. A. Baehmann 33</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of virulent chancroids, by D. C. Gather 36</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of septicemia successfully treated with Steam's streptolytic

serum by M. F. Gates . 39</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">An unusual case of undescended testicle, by E. M. Brown 39</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Current comment 41</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">United States Pharmacopeial Convention 41</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Concerning extracts or abstracts for publication 4l</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Measuring the height of recruits 43</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Suggestions for the study of heat exhaustion 44</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Perfected routine of dosage, etc., in the treatment of tuberculosis by

the administration of mercury, by B. L. Wright 46</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Has the chemical examination of water practical value to the military medical

officer? by P. '.T'. Waldner 47</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">An aid in throat and laryngeal examinations, by E. M. Brown 50</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Progress in medical sciences 51</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Laboratory —An anatomical peculiarity noted in specimens of hook worm

from Culebra 51</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Preliminary note on the lesions of anchylostomiasis in the intestines of

dogs, by O. J. Mink 51</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Preliminary note on nematode found in the liver of a wild rat, by O.

J.Mink 52</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Chemistry and pharmacy — Note on the disintegration of tablets;

influence of benzoic acid and benzoates on digestion and health: address on the

clinical examination of urine, with especial reference to estimation of urea;

determination of pepsin by the edestin test, E. W. Brown and P. J. Waldner 52</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery —Review of advances; the operative treatment of recent

fractures of the femoral shaft; the treatment of fractures by mobilization and massage;

has surgical treatment lessened mortality from appendicitis; when to operate

for appendicitis; diffuse septic peritonitis, due to appendicitis; local

anesthesia of a limb by venous transfusion after expulsion of blood; on

narcosis under an artificially restricted circulation; the correlation of

glands with internal secretion; improved technique for the detection of

tubercle bacilli in the urine; relief of the wounded during battle, H. C. Curl

and H. W. Smith 54</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Pathology and bacteriology —On the so-called fatty degeneration of the adrenals;

three cases of squamous celled carcinoma of the gall bladder; the practical

value of the demonstration of spirochaeta pallida in the early diagnosis of

syphilis; C. 8. Butler and O. J. Mink 65</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Medical zoology — Plague in ground squirrels (a review); the prevalence

and distribution of the animal parasites of man in the Philippine Islands, with

a consideration of their possible influence on the public'</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">health; preliminary note on a protozoan in yaws; the intestinal protozoa

of man, R. C. Holcomb • 67</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tropical medicine — Ankylostomiasis in the Tropics; bilharziasis among women

and girls in Egypt; a report of several cases with unusual symptoms caused by

contact with some unknown variety of jellyfish; the diagnosis of latent

malaria; haemolysins and antihaemolytic substances in the blood of malarial

patients, E. R. Stitt 73</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine —The direct inspection of the gastric mucous membrane;

toxemia from the standpoint of perverted metabolism; a rapid method of

test-meal removal, lavage, and inflation; the therapeutics of diseases which

involve the internal secretions (mercury in the treatment of tuberculosis — its

mode of action —a warning); Flexner's serum in the treatment of epidemic

cerebrospinal meningitis; vascular crises; the curative influence of extracts

of leucocytes upon infections in animals, R. M. Kennedy 77</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hygiene and sanitation —Koch's standpoint with reference to the

question of the relation between human and bovine tuberculosis; the prevention of

tuberculosis; tropical lands and white races; sanitary report of the operations

of the naval expeditionary corps (German) in southwest Africa and in east

Africa; growth and naval military service; a study in measurements of cadets at

the naval school; on growth in height of youths serving their time in the army;

the value of fencing as a sport from hygienic and ethical point* of view; on-

the significance of the ophthalmo-reaction for the army; hematuria caused by a

parasite akin to bilharzia; the complex nature of typhoid etiology and the role

played by animals and man in the spread of the typhoid group of diseases; amoebae

carriers, H. G. Beyer 90</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Reports and letters 195</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Annual meeting of the American Pharmaceutical Association, Alrik Hammar,

delegate 105</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of an epidemic of typhoid on the U.S.S. Maine, by M. S.

Elliott.<span>  </span>106</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of an epidemic of grippe on the U. S. S. Charleston, by M. F.

Gates. 109</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 2</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Preface vii</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Special articles 111</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The treatment of tuberculosis and the results observed during the year 1908

(at the United States Naval Hospital, Las Animas, Colo.), by B. L. Wright 111</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Laboratory studies and observations during the year 1908 (at the United

States Naval Hospital, Las Animas, Colo.), by A. B. Clifford 114</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tonsillar hypertrophy; a menace to the service, by B. F. Jenness 120</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The ice bag in the treatment of typhoid fever, by G. Tucker Smith 122</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Treatment of typhoid fever by colon irrigations, by the late C. G.

Alderman 124</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Suggested devices 129</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Description of a pit incinerator furnace, by R. C. Holcomb 129</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Clinical notes 131</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of a case of malignant endocarditis, following chancroid, by I.

Franklin Cohn 131</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of multiple infected wounds from bear bite, by C. C. Grieve 132</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case presenting successive liver abscesses, by H. C. Curl and H. W. Smith

134</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Cerebro-spinal fever, by J. G. Field 135</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Current comment 141</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Gangosa in Haiti 141</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hookworm disease in recruits from the Southern States 141</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Care of ears and eyes in the Japanese navy<span>  </span><span> </span>142</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The question of ear protection in the British navy 142</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report relative to a series of experiments conducted on board the U. S.

S. Ohio during target practice, with "Plasticine" for the protection

of the ear drums during heavy gun fire, by W. M. Garton 142</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hygienic rules, with particular reference to venereal prophylaxis, in

the Austro-Hungarian navy 144</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Experiments with gonococcic vaccine, by W. M. Garton 145</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Thyroidal enlargement among applicants for enlistment in the Northwest,

by W. A. Angwin 147</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Progress in medical sciences 148</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Laboratory — Sterilization of catgut, by H. W. Smith 148</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Chemistry and pharmacy — Fluidglycerates, pharmaceutical and physiological

aspect; the importance and significance of the chemical examination of the

gastric contents after a test meal, with a new method for estimating the

ferment activity of the gastric contents; demonstrations of enzymes and

antienzymes; studies on the chemistry of anaphylaxis; the clinical value of

viscosity determination; the viscosity of the blood; the detection and

quantitative determination of B-oxybutyric acid in the urine; a new method for

the quantitative estimation of albumin in the urine; concerning the diagnostic

value of Cammidge crystals in pancreatic diseases, E. W. Brown and P. J.

Waldner 150</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery — Review of advances; cerebral decompression; operative treatment

of acute gonorrheal epididymitis; appendectomy in diffuse septic peritonitis;

concerning technique of skin grafting; treatment of hypertrophy of the prostate

by injections of alien blood; the value of the Cammidge reaction in the diagnosis

of pancreatic disease; the Cammidge reaction in experimental pancreatitis; the

syphilis case sheet; the thymus in Basedow's disease; the effect of mammalian

pituitary on tetany after parathyreoidectomy, and upon the pupil; hemorrhage in

jaundice controlled by blood transfusion; on the haematogenic origin of

purulent nephritis through the staphylococcus; the snapping hip; three cases of

liver abscess treated by aspiration and injection of quinine, H. C. Curl and H.

\V. Smith: 156</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Pathology and bacteriology — <span> </span>Widal’s

reaction with sterilized cultures; a new medium for typhoid work; report on a

further series of blood cultures from seventy-four cases of typhoid and

paratyphoid fever; the histology of liver tissue regeneration; typhoid bacilli

and gall bladder; the occurrence and distribution of the spirochaeta pallida in

congenital syphilis; experiments on the differentiation of cholera and

cholera-like vitrios by complement fixation;<span> 

</span>C. S. Butler and O. J. Mink 166</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Medical zoology —What is "schistosoma mansoni;" pulmonary

bilharziasis; filariasis and elephantiasis in southern Luzon; the diagnosis of African

tick fever from the examination of the blood; the parasite of</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Kula Azar and allied organisms; a new human nematode-strongylus gibsoni;

report of the Permanent Commission for the Suppression of Uncinariasis; on the

supposed occurrence of the filaria immitis in man, R. C. Holcomb 174</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tropical medicine —An inquiry concerning the etiology of beriberi; have

trypanosomes an ultramicroscopical stage in their life history?; atoxyl as a

curative agent in malaria, E. R. Stitt 179</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine —The treatment of acute inflammatory conditions by

Bier's hypertemia; treatment of tetanus with subarachnoid injections of

magnesium sulphate; the serum diagnosis of syphilis; tubercle bacilli in the

sputum; a summary of the most recently published work on the doctrine of

opsonins; experimental investigation on "simple continued fever," H.

M. Kennedy 182</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hygiene and sanitation —On the application of heat for the purification

of water with troops in the field; catarrhal icterus of eberthian origin; the epidemic

of typhoid fever on H. M. S. Regina Elena; the treatment of sweat-foot in the

army; a contribution to our knowledge of the spread of cerebro-spinal

meningitis; on book disinfection on the large scale; the etiology of impetigo

contagiosa; tuberculosis in the British army and its prevention; symptoms that

may be attributed to soldering with the oxyhydrogen</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">flame; tactics and the health of the army, H. G. Beyer 189</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Reports and letters 203</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Seventeenth annual meeting of the Association of Military Surgeons,

Manley H. Simons, delegate 203</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report and recommendations of a board of officers, convened at the navy-yard,

Mare Island, Cal., on the precautionary methods <span> </span>to be taken to prevent the invasion of bubonic

plague at that station 205</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 3</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Preface VII</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Special articles 211</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Notes on the treatment of elephantiasis by the internal administration

of tinctuia ferri cbloridi, by P. S. Rossiter 211</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A few notes on syphilis, by W. J. Zalesky 215</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A note on the pathology of epidemic asthma, by O. J. Mink 222</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report on sixteen cases of heat prostration, with remarks on etiology,

by A. G. Grunwell 223</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Reviews 231</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Liver abscess from the point of view of etiology and prophylaxis; pathology

and differential diagnosis; and treatment (3 papers), by G. B. Crow,, J. A. B.

Sinclair, and J. F. Cottle 231</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Suggested devices 245</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Appliances improvised on sick bay bunks, by C. M. De Valin 245</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Clinical notes 247</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of fracture of patella, with operation at sea, by N. J.

Blackwood.. 247</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of n current nasal hemorrhage, by Raymond Spear 250</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of traumatic pneumonia, by C. F. Sterne 252</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of liver abscess, by M. A. Stuart 254</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Current comment 255</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hospital corps efficiency report 255</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Physical defects found on reexamination of recruits 255</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Some observations on the berthing of enlisted men of the navy, with suggestions

for improvement, by L. W. Curtis 256</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The value of a chemical examination of water, by E. R. Noyes 257</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Progress in medical sciences 267</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Laboratory —A method for the preparation of flat worms for study, by O.

J. Mink and A. H. Ebeling .. 267</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The formalin method for the clinical estimation of ammonia in the

urine, by E. W. Brown 269</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Bang's method for estimation of sugar in the urine; the Edestin method for

the estimation of pepsin in stomach contents 273</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Chemistry and pharmacy — Concerning the fractional precipitation of

albumin in the spinal fluid of normal cases luetics, functional and organic nervous

diseases and their bearing upon the differential diagnosis of dementia

paralytica, tabes dorsalis, tertiary and late syphilis; quantitative determination

of several sugars in the presence of each other in diabetic urines; the butyric

reaction for syphilis in man and in the monkey; excretion of amino acids in

pregnancy and after parturition; the relation between the protein content of

the blood serum and that of serous fluids; the further separation of antitoxin

from its associated proteins in horse serum, E. W. Brown and P. J. Waldner...276-279</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery —The Hodgen splint; surgical anemia and resuscitation; mechanism

underlying artificial respiration; a new theory of surgical shock; carbon

dioxide snow in the treatment of augioma; bursitis subacromialis, or

periarthritis of the shoulder joint; report on the local anesthetics recommended

as substitutes for cocaine; further researches on the etiology of endemic

goiter; auto- and iso-transplantation, in dogs, of the parathyroid glandules;

partial, progressive, and complete occlusion of the aorta and other large

arteries in the dog by means of the metal band; C. F. Stokes, R. Spear, and H.

W. Smith 279-289</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Pathology and bacteriology —A simple method for the diagnosis of

syphilis; differential methods for detecting the typhoid bacilli in infected

water and milk; a peculiar intralobular cirrhosis of the liver produced by the protozoal

parasite of kala azar; the pathological anatomy of atoxyl poisoning; an

observation on the fate of B. Bulgaricus in the digestive tract of a monkey; a

contribution to the pathology of the spleen; a note, on the histology of a caue

of myelomatosis with Bence-Jones protein in</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">the urine; a new method for the recognition of indol in media; the rapid

diagnosis of rabies (a new stain for negri bodies); C. S. Butler and O. J. Mink

289-297</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Medical zoology —Anew intestinal trematodeof man; some applications of the

precipitin reaction in the diagnosis of hydatid disease; bilharzia, hematobia,

and circumcision; trichocephaliasis; R. C. Holcomb ...... 297-306</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tropical medicine — Rice and beriberi; on the etiology of ulcerative

granuloma of the pudenda; amaebic dysentery with abscess of the liver in a patient

who had never been out of England; E. R. Stitt 306-308</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine —The dietetic treatment of diabetes; artificial

hyperemia in the treatment of pulmonary tuberculosis; remarks on the treatment of

gastric ulcer by immediate feeding; present status of the tuberculin tests; T.

W. Richards S0S-315</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hygiene and sanitation — On 'a new and practical method of securing bodily

cleanliness for our men on board ship; on the heat-conducting power of linoleum

as compared to that of floors made of wood or of</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">betone; on the discrimination of unrecognized diseases and on a disease

of overcrowding in ships, <span> </span>especially at

Malta; H. G. Beyer 315-320</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Reports and letters 321</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Guam; reports on health and sanitation for the years 1907 and 1908, by F.

E. McCullough and G. L. Angeny. 321</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 4</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Preface vii</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Special articles 335</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The hospital camp at Norfolk, Va., by P. A. Lovering 335</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The teaching of tropical medicine outside of the Tropics, by E. R.

Stitt 308</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Ethyl chloride as a general anaesthetic, by L. W. Johnson 344</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Chronic nephritis in recruits, by B. F. Jenness 347</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Supplementary report on the investigation of Samoan conjunctivitis, by P.

S. Rossiter 349</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Points on embalming practicable on board ship, by C. Schaffer 351</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Reviews 355</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgical shock; a review of recent literature, by H. W. Smith 355</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Suggested devices 365</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Installation of an X-ray apparatus on the U. S. S. Maryland, by A.

Farenholt 365</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Method of fumigation of vessels at Hamburg 368</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">An oxygen apparatus 370</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">An easily constructed bunk tray, by C. M. Oman 371</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Clinical notes 373</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Operations upon the kidney. United States naval hospital, New York, by G.

T. Smith 373</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A report on two cases of dentigerous cysts, by D. N. Carpenter 374</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of mammary development in the male, by E. M. Brown 376</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Operative treatment of epididymitis, by W. S. Pugh, Jr 376</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Two cases from report of U. S. S. Hancock—1908: (1) Retinal hemorrhage,

(2) myocarditis with rupture, by P. Leach 377</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of fracture of the skull; operation and recovery, by F. W. F.

Wieber. 378</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Carron oil in the treatment of otitis media suppurativa (acuta), by R.

E. Riggs 379</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Fracture of skull and gunshot wound of lung, with recovery, by W. S.

Pugh, Jr ..... 381</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Two unusual appendix cases, by R. R. Richardson 382</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Proctoclysis in typhoid fever, by C. F. Stokes 384</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Current comment 385</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Subscription price of the Bulletin 385</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Note on New York Post-Graduate Medical School 385</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Note on contributions to the Bulletin 385</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Note on annual meeting of American Medical Association on revision of pharmacopeia

386</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Note on inquiry concerning clothing in the Tropics 386</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Note on publicity concerning venereal disease in California 387</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Review of Gatewood's Naval Hygiene 387</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Note on the work at Tay Tay 388</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Medical examination of army recruits, by A. E. Peck 389</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Notes on the treatment of syphilis, by W. S. Hoen 391</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Views on the treatment of typhoid fever, by H. A. May 393</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Progress in medical sciences 397</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Laboratory —Benedict's method for the estimation of glucose in the

urine; estimation of uric acid in the urine, Folin-Schaffer; clinical method

for the estimation of uric acid, modification of the Folin-Schaffer process; test

for blood in the urine; two methods for the estimation of albumin in the urine,

by O. J. Mink and E. W. Brown 397</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Chemistry and pharmacy —The excretion in urine of sugars other than

glucose; experiments and experiences, pharmacological and clinical, with

digitalis, squill, and strophanthus; a reagent for the detection of reducing

sugars; on the antagonism of alcohol to carbolic acid ; the antitoxic activity

of iodine in tuberculosis; new experiments on the physiological action of

sulphuric ether; contribution to the physiology of the glands —further

contributions on the function of the spleen as an organ of iron metabolism;

modifications in the chemical composition of the blood serum in victims of

carbon dioxide poisoning, by P. J. Waldnerand C. Schaffer 402</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Pathology and bacteriology —Studies on typhoid fever; chloroform

poisoning — liver necrosis and repair; the importance of blood cultures in the

study of infections of otitic origin; the cultivation of the spirocheeta

pallidum; the cultivation of the bacillus leprae; the chemistry of the liver in

chloroform necrosis; the present status of the whooping-cough question; the

conveyance of whooping cough from man to animals by direct experiment; serology

of syphilis, by C. S. Butler and O. J. Mink 407</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Medical zoology — Schistosomiasis at Bahia; contribution to the study

of schistosomiasis in Bahia, Brazil; notes on malaria and kala-azar; endemic

amoebic dysentery in New York, with a review of its <span> </span>istribution in North America; filaria

(microfilaria) philippinensis; the distribution of filaria in the Philippine

Islands; acariens and cancers—acariens and leprosy; necator americanus in

Ceylon; anaemia due to trichocephalus dispar; study of the protozoa of J. H.

Wright in sixteen cases of Aleppo boil, by R. C. Holcomb 411</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tropical medicine — Infantile kala-azar; on the identity of beri-beri

and epidemic dropsy; Malta fever in South Africa; leprosy in the Philippine

Islands and its treatment; the various types of plague and their clinical

manifestations, by C. S. Butler 417</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hygiene and sanitation —The means by which infectious diseases are

transmitted; a critical study of the value of the measurements of chest expansion

and lung capacity; notes on the sanitation of yellow fever and malaria; the

house fly as a disease carrier, by H. G. Beyer 419</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine —A study of the aural and laryngeal complications of

typhoid fever, especially as observed in hospital practice; the problem of

cancer considered from the standpoint of immunity; nine cases of typhoid fever

treated with an antiendotoxic serum, by T. W. Richards 425</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery —Some practical points in the application of the bismuth paste

in chronic suppurative diseases; the sequence of the pathological changes in appendiceal

peritonitis; direct blood transfusion by means of paraffin-coated glass tubes;

the use of animal membrane in producing mobility in ankylosed joints, by C. F.

Stokes and R. Spear 431</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Reports and letters 489</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">American Medical Association, by M. F. Gates 439</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report on the Second International Conference for Revision of Nomenclature

of Diseases and Causes of Death, by F. L. Pleadwell 445</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report upon medical relief measures at Messina, Sicily, by M. Donelson.

. 449</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Reports of medical relief measures at Adana, Turkey, by J. T. Miller

and L. W. McGuire 452</p>

  

If you have questions concerning reproductions, please contact the Contributing Library.

 

Note: The colors, contrast and appearance of these illustrations are unlikely to be true to life. They are derived from scanned images that have been enhanced for machine interpretation and have been altered from their originals.

 

Read/Download from the Internet Archive

 

See all images from this book

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A study of the effects of high voltage and household cleaning products on instant pull apart color film.

 

Materials: Fujifilm FP100-45C Instant Color Film, various household cleaning products (bleach, vinegar, baking soda, hydrogen peroxide, salt, rubbing alcohol), 15,000 volt neon tube ballast.

 

By Phillip Stearns

As you know, pro-vitamin A carotenoids can be cleaved to produce retinal. This is a very rare shot (which is why it's in a frame). It was taken at the exact moment the chop occurred and what you see is a 9-cis-isomer of retinoic acid. At least we think so.

     

The German Shorthaired Pointer is a breed of medium-sized pointing dog developed in nineteenth century Germany. It is energetic and powerful, with strong legs and great endurance. It is a versatile all-purpose gun dog suitable for hunting and retrieving on both land and water, with a strong drive to find and chase game. It may also be kept as a companion dog, though as a high-energy sporting dog, it requires significant amounts of exercise.

 

German Shorthaired Pointers have a short coat that comes in various combinations, generally a mix of liver and white. They have moderately long floppy ears set high on the head. Longer, broad, and strong, muzzles allow retrieval of heavier game. The dog's profile should be straight or strongly Roman nosed; any dished appearance to the profile is incorrect according to breed standards. Their eyes are generally brown, with darker ones being desirable; yellow or "bird of prey" eyes are a fault. The tail is commonly docked, although that is now prohibited in some countries. In competition, they are penalized if the tail is curved either up or down while the dog is moving. When the GSP is in classic point stance, the tail should be held straight out from the body, forming a line with the pointing head and body. Like all German pointers, GSPs have webbed feet, and are known for going after waterfowl in the water.

 

The German Shorthaired Pointer is a member of the Sporting Group. In 2016, CJ, a three-year-old German Shorthaired Pointer, won the Best in Show award at the 140th Westminster Kennel Club Dog Show.

 

Appearance

The German Shorthaired Pointer's coat is short and flat with a dense undercoat protected by stiff guard hairs, making the coat water resistant and allowing the dog to stay warm in cold weather. That allows the dog to be an agile hunter, with high performance in both field and water. The coat can be a dark brown with some lighter brown colors, referred to as "liver" (incorrectly as "chocolate" or "chestnut"), black (although any area of black is cause for disqualification in American Kennel Club-sanctioned shows), white, liver roan, or liver and white.

 

Health

Most German Shorthaired Pointers are tough, healthy dogs, but the breed can be subject to a number of hereditary disorders due to their breeding. Some of these health disorders include, hypothyroidism, hip dysplasia, osteochondrosis dissecans (OCD), pannus, progressive retinal atrophy (PRA), epilepsy, skin disorders and cancerous lesions in the mouth, on the skin and other areas of the body. As with other breeds, un-spayed female GSPs are prone to breast cancer. This risk is reduced if they are spayed.

 

A genetic form of lupus, termed exfoliative cutaneous lupus erythematosus (ECLE) has also been recognized in German shorthaired pointer dogs.

 

Care

The GSP has a median lifespan of 9 years in a Danish survey and 12 years in a UK survey. In the UK survey about 1 in 8 lived to >15 years with the longest lived dog living to 17 years.

 

History

German hunters spent generations crossing different breeds until the GSP came during the 1800s. They were successful to the point that the GSP is among the top-winning breeds in competitive hunting events. According to the American Kennel Club, it is likely that the GSP is descended from a breed known as the German Bird Dog, which itself is related to the Old Spanish Pointer, introduced to Germany in the 17th century. It is also likely that various German hound and tracking dogs, as well as the English Pointer and the Arkwright Pointer also contributed to the development of the breed. However, as the first studbook was not created until 1870, it is impossible to identify all of the dogs that went into creating this breed. The breed was officially recognized by the American Kennel Club in 1930. World War II affected the breeding of GSP. Toward the end of the war many of the breeders hid their gold, diamonds, their GSPs and more. Then the best dogs were sent to Yugoslavia for safe keeping. Today the GSP ranks 19th among the 155 breeds and it varieties recognized by the AKC.

 

Current uses

Like the other German pointers (the German Wirehaired Pointer and the less well-known German Longhaired Pointer), the GSP can perform virtually all gun dog roles. It is a pointer and retriever, an upland bird dog, and water dog. The GSP can be used for hunting larger and more dangerous game. It is an excellent swimmer but also works well in rough terrain. It is tenacious, tireless, hardy, and reliable. German Shorthaired Pointers are proficient with many different types of game and sport, including trailing, retrieving, and pointing pheasant, quail, grouse, waterfowl, raccoons, opossum, and even deer.

  

A GSP after a successful hunt for stubble quail

German Shorthaired Pointers are still currently used as versatile hunting and gun dogs. With their high intelligence and athleticism the German Shorthaired Pointer performs well in many AKC sports such as Agility, Dock Diving, and Obedience. German Shorthaired Pointers are also used in law enforcement for nosework such as the detection of illicit substances.

As Suley says, what it might look like right after a nuclear bomb

White Tiger or Bengal Tiger (Panthera tigris)

 

The white tiger is a pigmentation variant of the Bengal tiger, which is reported in the wild from time to time in States of India like Assam, Bengal, Bihar,Sunderbans and especially in the former State of Rewa.

  

Variation

 

The White Bengal tigers are distinctive for their color fur. According to the website, “Animal Corner,” the correct term to name the white tiger is Chinchilla albinistic. The white fur is due to the lack of pheomelanin pigment, which is found in Bengal tigers with orange color fur. When compared to Bengal tigers, the white Bengal tigers tend to grow faster and heavier than the orange Bengal tiger. They also tend to be somewhat bigger at birth, and as fully grown adults. White Bengal tigers are fully grown when they are 2–3 years of age. White male tigers reach weights of 200 to 230 kilograms and up to 3 meters in length. Similar to zebras, the white Bengal tiger’s stripes are like fingerprints, no two tigers have the same. Also, the stripes of the tiger are a pigmentation of the skin.

 

For a white Bengal tiger to be born, both parents must carry the unusual gene for white colouring, which, according to the website “Animal Corner,” only happens naturally about once in 10,000 births. As stated by Kailash Sankhala, the director of the New Delhi Zoo in the 1960s, “one of the functions of the white gene tiger may have been to keep a size gene in the population, in case it's ever needed." Dark-striped white individuals are well-documented in the Bengal tiger subspecies, also known as the Royal Bengal or Indian tiger (Panthera tigris tigris or P. t. bengalensis), and may also have occurred in captive Siberian tigers (Panthera tigris altaica)[citation needed], as well as having been reported historically in several other subspecies.

 

Currently, several hundred white tigers are in captivity worldwide, with about one hundred being found in India. Nevertheless, their population is on the increase. Nandankanan in the state of Odisha, India, is the host zoo for white tigers. In 1980, the first litter of white tigers were born to Deepak and Ganga, two normal tawny tigers. Subsequent litters of white tigers have been distributed to zoos both at home and abroad. Currently, Nandankanan is home to over 34 white tigers. Their unique white color fur has made them popular in entertainment showcasing exotic animals, and at zoos. German-American magicians Siegfried & Roy became famous for breeding and training two white tigers for their performances, referring to them as "royal white tigers," the white tiger's association with the Maharaja of Rewa. The first white Bengal tiger was found in India by royalty Maharaja Shri Martand Singh of Rewa. According to the website, “Animal Corner”, in 1948, Maharaja killed the white tigress leaving four cubs behind. Later, the cubs of the dead tigress were shot except for the white cub. It is believed that all white Bengal tigers are descendants of this cub.

  

White Siberian tigers

 

The existence of white Siberian tigers has not been scientifically documented, despite occasional unsubstantiated reports of sightings of white tigers in the regions where wild Siberian tigers live. It may be that the white mutation does not exist in the wild Siberian tiger population: no white Siberian tigers have been born in captivity, despite the fact that the subspecies has been extensively bred during the last few decades (with much outbreeding between the different Siberian lineages for purposes of conservation genetics); a recessive allele should occasionally turn up in a homozygous state during such breeding, and in this particular case yield white tigers from normally-colored parents, but no such animals have been reported.

 

The famous white Siberian tigers found in captivity are actually not pure Siberian tigers. They are instead the result of Siberian tigers breeding with Bengal tigers. The gene for white coating is quite common among Bengal tigers, but the natural birth of a white Bengal tiger is still a very rare occasion in the wild, where white tigers are not bred selectively.

 

The white tiger is not considered a tiger subspecies, but rather a hybrid mutant variant of the existing tiger subspecies. If a pure white Siberian tiger were to be born, it would therefore not be selectively bred within the tiger conservation programs. It would, however, probably still be selectively bred outside the program in an effort to create more white Siberian tigers. Due to the popularity of white tigers, they are used to attract visitors to zoos. White tigers are found in zoos in China commonly. White Tigers are very large. They can weigh up to 300 kg and reach more than 4 meters of length.

  

Stripeless white tigers and golden tabby tiger

 

An additional genetic condition can remove most of the striping of a white tiger, making the animal almost pure white. One such specimen was exhibited at Exeter Change in England in 1820, and described by Georges Cuvier as "A white variety of Tiger is sometimes seen, with the stripes very opaque, and not to be observed except in certain angles of light." Naturalist Richard Lydekker said that, "a white tiger, in which the fur was of a creamy tint, with the usual stripes faintly visible in certain parts, was exhibited at the old menagerie at Exeter Change about the year 1820." Hamilton Smith said, "A wholly white tiger, with the stripe-pattern visible only under reflected light, like the pattern of a white tabby cat, was exhibited in the Exeter Change Menagerie in 1820.", and John George Wood stated that, "a creamy white, with the ordinary tigerine stripes so faintly marked that they were only visible in certain lights." Edwin Henry Landseer also drew this tigress in 1824.

 

The modern strain of snow white tigers came from repeated brother–sister matings of Bhim and Sumita at Cincinnati Zoo. The gene involved may have come from a Siberian tiger, via their part-Siberian ancestor Tony. Continued inbreeding appears to have caused a recessive gene for stripelessness to show up. About one fourth of Bhim and Sumita's offspring were stripeless. Their striped white offspring, which have been sold to zoos around the world, may also carry the stripeless gene. Because Tony's genome is present in many white tiger pedigrees, the gene may also be present in other captive white tigers. As a result, stripeless white tigers have appeared in zoos as far afield as the Czech Republic (Liberec), Spain and Mexico. Stage magicians Siegfried & Roy were the first to attempt to selectively breed tigers for stripelessness; they owned snow-white Bengal tigers taken from Cincinnati Zoo (Tsumura, Mantra, Mirage and Akbar-Kabul) and Guadalajara, Mexico (Vishnu and Jahan), as well as a stripeless Siberian tiger called Apollo.

 

In 2004, a blue-eyed, stripeless white tiger was born in a wildlife refuge in Alicante, Spain. Its parents are normal orange Bengals. The cub was named Artico ("Arctic").

Stripeless white tigers were thought to be sterile until Siegfried & Roy's stripeless white tigress Sitarra, a daughter of Bhim and Sumita, gave birth. Another variation which came out of the white strains were unusually light-orange tigers called "golden tabby tigers". These are probably orange tigers which carry the stripeless white gene as a recessive. Some white tigers in India are very dark, between white and orange.

  

Genetics

 

A white tiger's pale coloration is due to the lack of the red and yellow pigments that normally produce the orange color. This had long been thought to be due to a mutation in the gene for the tyrosinase enzyme. A knockout mutation in this gene results in albinism, the inability to make either pheomelanin or eumelanin, while the consequence of a less severe mutation in the same gene is the cause of a selective loss of pheomelanin, the so-called Chinchilla trait. The white phenotype in tigers had been attributed to this Chinchilla mutation in tyrosinase, and some publications prior to the 1980s refer to it as an albino gene for this reason.[citation needed] However, genomic analysis has demonstrated instead that a mutation in the SLC45A2 gene is responsible. The resultant single amino acid substitution in this transport protein, by a mechanism yet to be determined, causes the elimination of pheomelanin expression seen in the white tiger. This is a recessive trait, meaning that it is only seen in individuals that are homozygous for this mutation. Inbreeding promotes recessive traits and has been used as a strategy to produce white tigers in captivity.

 

The stripe color varies due to the influence and interaction of other genes. Another genetic characteristic makes the stripes of the tiger very pale; white tigers of this type are called snow-white or "pure white". White tigers, Siamese cats, and Himalayan rabbits have enzymes in their fur which react to temperature, causing them to grow darker in the cold. A white tiger named Mohini was whiter than her relatives in the Bristol Zoo, who showed more cream tones. This may have been because she spent less time outdoors in the winter. White tigers produce a mutated form of tyrosinase, an enzyme used in the production of melanin, which only functions at certain temperatures, below 37 °C (99 °F). This is why Siamese cats and Himalayan rabbits are darker on their faces, ears, legs, and tails (the color points), where the cold penetrates more easily. This is called acromelanism, and other cats breeds derived from the Siamese, such as the Himalayan and the snowshoe cat, also exhibit the condition. Kailash Sankhala observed that white tigers were always whiter in Rewa State, even when they were born in New Delhi and returned there. "In spite of living in a dusty courtyard, they were always snow white." A weakened immune system is directly linked to reduced pigmentation in white tigers.

  

Genetic defects

 

Outside of India, inbred white tigers have been prone to crossed eyes, a condition known as strabismus, an example of which is "Clarence the cross-eyed lion", due to incorrectly routed visual pathways in the brains of white tigers. When stressed or confused, all white tigers cross their eyes. Strabismus is associated with white tigers of mixed Bengal x Siberian ancestry. The only pure-Bengal white tiger reported to be cross-eyed was Mohini's daughter Rewati. Strabismus is directly linked to the white gene and is not a separate consequence of inbreeding. The orange litter-mates of white tigers are not prone to strabismus. Siamese cats and albinos of every species which have been studied all exhibit the same visual pathway abnormality found in white tigers. Siamese cats are also sometimes cross-eyed, as are some albino ferrets. The visual pathway abnormality was first documented in white tigers in the brain of a white tiger called Moni after he died, although his eyes were of normal alignment. The abnormality is that there is a disruption in the optic chiasm. The examination of Moni's brain suggested the disruption is less severe in white tigers than it is in Siamese cats. Because of the visual pathway abnormality, by which some optic nerves are routed to the wrong side of the brain, white tigers have a problem with spatial orientation, and bump into things until they learn to compensate. Some tigers compensate by crossing their eyes. When the neurons pass from the retina to the brain and reach the optic chiasma, some cross and some do not, so that visual images are projected to the wrong hemisphere of the brain. White tigers cannot see as well as normal tigers and suffer from photophobia, like albinos.

 

Other genetic problems include shortened tendons of the forelegs, club foot, kidney problems, arched or crooked backbone and twisted neck. Reduced fertility and miscarriages, noted by ”tiger man” Kailash Sankhala in pure-Bengal white tigers were attributed to inbreeding depression. A condition known as "star-gazing" (the head and neck are raised almost straight up, as if the affected animal is gazing at the stars), which is associated with inbreeding in big cats, has also been reported in white tigers. Some white tigers born to North American lines have bulldog faces with a snub nose, jutting jaw, domed head and wide-set eyes with an indentation between the eyes. However, some of these traits may be linked to poor diet rather than inbreeding.

There was a 450 lb (200 kg) male cross-eyed white tiger at the Pana'ewa Rainforest Zoo in Hawaii, which was donated to the zoo by Las Vegas magician Dirk Arthur. There is a picture of a white tiger which appears to be cross-eyed on just one side in Siegfried & Roy's book Mastering The Impossible. A white tiger, named Scarlett O'Hara, who was Tony's sister, was cross-eyed only on the right side.

 

A male white tiger named Cheytan, a son of Bhim and Sumita born at the Cincinnati Zoo, died at the San Antonio Zoo in 1992 from anaesthesia complications during root canal therapy. It appears that white tigers also react strangely to anaesthesia. The best drug for immobilizing a tiger is CI 744, but a few tigers, white ones in particular, undergo a re-sedation effect 24–36 hours later. This is due to their inability to produce normal tyrosinase, a trait they share with albinos, according to zoo veterinarian David Taylor. He treated a pair of white tigers from the Cincinnati Zoo at Fritz Wurm's safari park in Stukenbrock, Germany, for salmonella poisoning, which reacted strangely to the anaesthesia.

 

Mohini was checked for Chédiak-Higashi syndrome in 1960, but the results were inconclusive. This condition is similar to albino mutations and causes bluish lightening of the fur color, crossed eyes, and prolonged bleeding after surgery. Also, in the event of an injury, the blood is slow to coagulate. This condition has been observed in domestic cats, but there has never been a case of a white tiger having Chédiak-Higashi syndrome. There has been a single case of a white tiger having central retinal degeneration, reported from the Milwaukee County Zoo, which could be related to reduced pigmentation in the eye. The white tiger in question was a male named Mota on loan from the Cincinnati Zoo.

 

There is a myth that white tigers have an 80% infant mortality rate. However, the infant mortality rate for white tigers is no higher than it is for normal orange tigers bred in captivity. Cincinnati Zoo director Ed Maruska said: "We have not experienced premature death among our white tigers. Forty-two animals born in our collection are still alive. Mohan, a large white tiger, died just short of his 20th birthday, an enviable age for a male of any subspecies, since most males live shorter captive lives. Premature deaths in other collections may be artifacts of captive environmental conditions...in 52 births we had four stillbirths, one of which was an unexplained loss. We lost two additional cubs from viral pneumonia, which is not excessive. Without data from non-inbred tiger lines, it is difficult to determine whether this number is high or low with any degree of accuracy."Ed Maruska also addressed the issue of deformities: "Other than a case of hip dysplasia that occurred in a male white tiger, we have not encountered any other body deformities or any physiological or neurological disorders. Some of these reported maladies in mutant tigers in other collections may be a direct result of inbreeding or improper rearing management of tigers generally."

  

Inbreeding and outcrossing

 

Because of the extreme rarity of the white tiger allele in the wild,[9] the breeding pool was limited to the small number of white tigers in captivity. According to Kailash Sankhala, the last white tiger ever seen in the wild was shot in 1958. Today there is a large number of white tigers in captivity. A white Amur tiger may have been born at Center Hill and has given rise to a strain of white Amur tigers. A man named Robert Baudy realized that his tigers had white genes when a tiger he sold to Marwell Zoo in England developed white spots, and bred them accordingly. The Lowry Park Zoo in Tampa Bay has four of these white Amur tigers, descended from Robert Baudy's stock.

It has also been possible to expand the white-gene pool by outcrossing white tigers with unrelated orange tigers and then using the cubs to produce more white tigers. The white tigers Ranjit, Bharat, Priya and Bhim were all outcrossed, in some instances to more than one tiger. Bharat was bred to an unrelated orange tiger named Jack from the San Francisco Zoo and had an orange daughter named Kanchana. Bharat and Priya were also bred with an unrelated orange tiger from Knoxville Zoo, and Ranjit was bred to this tiger's sister, also from Knoxville Zoo. Bhim fathered several litters with an unrelated orange tigress named Kimanthi at the Cincinnati Zoo. ankam Ranjeeth had several mates at the Omaha Zoo.

 

The last descendants of Bristol Zoo's white tigers were a group of orange tigers from outcrosses which were bought by a Pakistani senator and shipped to Pakistan. Rajiv, Pretoria Zoo's white tiger, who was born in the Cincinnati Zoo, was also outcrossed and sired at least two litters of orange cubs at Pretoria Zoo. Outcrossing is not necessarily done with the intent of producing more white cubs by resuming inbreeding further down the line.

 

Outcrossing is a way of bringing fresh blood into the white strain. The New Delhi Zoo loaned out white tigers to some of India's better zoos for outcrossing, and the government had to impose a whip to force zoos to return either the white tigers or their orange offspring.

 

Siegfried & Roy performed at least one outcross. In the mid-1980s they offered to work with the Indian government in the creation of a healthier strain of white tigers. The Indian government reportedly considered the offer; however, India had a moratorium on breeding white tigers after cubs were born at New Delhi Zoo with arched backs and clubbed feet, necessitating euthanasia. Siegfried & Roy have bred white tigers in collaboration with the Nashville Zoo.

 

Because of the inbreeding and resulting genetic defects the Association of Zoos and Aquariums barred member zoos from breeding white tigers, white lions and king cheetahs in a white paper adopted by the board of directors in July 2011. It is noteworthy that the first person to speak out against the displaying of white tigers was William G. Conway, General Director of the New York Zoological Society, which later became known as the Wildlife Conservation Society when he said, "White tigers are freaks. It's not the role of a zoo to show two headed calves and white tigers." He warned AZA in 1983 of the harm to the zoo's credibility in catering to the public's fascination with freaks, but went unheeded until 2008 when AZA issued a request to their members to stop breeding white tigers and then later in July 2011 when the AZA formally adopted that stance as policy. Conway was attacked by Ed Maruska of the Cincinnati Zoo for his observation, but in the end Conway's belief was validated.

 

A complete scan of the genome led to the discovery that the white tiger’s distinguishing characteristic arises from a single naturally occurring mutation, the substitution of one amino acid for another—valine for alanine—in the protein identified as SLC45A2. The implication of this discovery means that white tigers can be bred from any colored Bengal tiger pair possessing the unique but naturally occurring recessive gene.

  

Popular culture

 

White tigers appear frequently in literature, video games, television, and comic books. Such examples include the Swedish rock band Kent, which featured a white tiger on the cover of their best-selling album Vapen & ammunition in 2002. This was a tribute to the band's home town Eskilstuna, as the local zoo in town had white tigers from the Hawthorn Circus as its main attraction. The white tiger has also been featured in the video for the song "Human" by the popular American synth-rock band The Killers. White Tiger is also the name of an American glam metal band from the 1980s.

 

In the live action version of Disney's 101 Dalmatians, Cruella de Vil kills a white tiger for its fur.

 

- Seto Bagh (or White tiger in English) is a Nepali language novel by Diamond - Shumsher Rana about an encounter with a white tiger.

 

- Aravind Adiga's novel The White Tiger won the Man Booker Prize in 2008. The central character and narrator refers to himself as "The White Tiger". It was a nickname given to him as a child to denote that he was unique in the "jungle" (his hometown), that he was smarter than the others.

 

- Video games including white tigers include Zoo Tycoon, the Warcraft universe, and Perfect World International. White Tigers are featured as a wild, tamable "pet" companion in Guild Wars Factions. White tigers are also seen in Heroes of Might and Magic IV. The protector of the mystical world of Shangri-La in Far Cry 4 is a white tiger that allies with the protagonist to defeat demons.

  

- Both the Power Rangers and the Japanese Super Sentai series from which the Power Rangers series is based on, have used White Tiger themed mecha. A trained white tiger from the Bowmanville Zoo in Ontario, Canada, was used in the Animorphs TV series. A superhero named White Tiger appears in "The Justice Friends" on Dexter's Laboratory.

 

- Marvel Comics also publishes several superheroes who go by the name White Tiger. A white tiger named White Blaze is frequently shown in the anime Ronin Warriors.

 

- Tigatron from the animated TV series Transformers: Beast Wars is based on the white tiger. There have been at least 4 heroes in Marvel comics called "The White Tiger": two gained powers from a group of three mystic amulets that they possessed, one was actually a tigress evolved by the High Evolutionary, and one was given an artificial version of the "Black Panther's Heart Shaped Herb".

 

- Kylie Chan's 'Dark Heavens' series incorporates the four winds of Chinese mythology – including The White Tiger.

 

- In Hayate the Combat Butler, Tama; Nagi Sanzenin's pet tiger is a white tiger.

In 2013, a white tiger used for election campaign in Lahore, Pakistan died of dehydration

  

In Captivity

 

India

 

Nandankanan, in the Indian state of Odisha hosts 34 white tigers. White tigers were born to normal coloured parents in 1980, a unique event in the world. A unique white tiger safari was established in this Zoological Park on 1 October 1991.

 

Algeria

 

Parc de Ben Aknoun, is a zoo in the city of Algiers, which houses white tigers of a rare breed. Two females and a male, were brought on a flight from Gabon, in July 2014.

 

Portugal

 

Jardim Zoológico de Lisboa (the Zoologic Garden of Lisbon) is home to five white tigers, a male and female along with their cubs (one male and two females), all born in the zoo.

 

Trinidad

 

The Emperor Valley Zoo houses a male and female white tiger. On 9 January 2015 the female white bengal tiger named Rajasi gave birth to two cubs at the Emperor Valley Zoo.

 

Hungary

 

Two Bengal White Tigers where born in a zoo in January of 2015, in a zoo in Gyor.

  

[Credit: en.wikipedia.org/]

Natural history of universe history // // // human history, world history --- Research Overview

  

Chronology of World History (Natural universe, the earth, the human world, life) // New geological new astronomical - chronological universe

  

Historical records and research according to the World, World History, the history of world civilization, chronicle world events, as well as natural history, earth history, history of the universe, geological history, biological history and the like.

World History books have a lot of authority, the United States, Britain, Russia, Europe, middle country have similar universal history masterpiece. Scroll a few million words, it is worth intensive reading. Shanfanjiujian this article, a brief description of some of the problems, as superficial academic exchanges.

  

Chronology of World History

About 300,400 million years ago: humans appeared on earth.

About 200,300 --1 million years ago: Palaeolithic humans. Chipped stone popular, has been the use of fire

Collection industry, descent and family matriarchal commune produced.

 

BC 3 - 1 million years ago: the primitive religion appears.

About 12,000 BC - 4000 BC: Stone Age humans. Invention and using a bow, fine stone widely used hunting industry.

From about 8000 BC - Former 2000: mankind has entered the Neolithic Age. Popular burnishing stone, there have been primitive agriculture and animal husbandry

. Matriarchal commune prosperity.

6000 BC: Asia Minor appeared linen and wool fabrics.

Circa 6000 - 1000 BC: ancient Mesopotamia, Asia Minor, Greece, Rome, Persia, India and other places were primitive and ancient religions

Teach prevalent.

       

BC 4000 - 3000 BC: Ancient Egypt, Southwest Asia, Southern Europe, Central Europe and China and other places have started to use copper ore.

3500 BC - 3100 years ago: in ancient Mesopotamia Uruk period. It appears pottery wheel pottery and ziggurat building, creating a cuneiform. Gouy

And national (Nome) is formed. It appeared hieroglyphics.

3500 BC - 3000 BC: Ancient Mesopotamia residents began to use wheeled transport. The ancient Egyptians used in agriculture plow, harrow

And fertilization.

  

3100 years ago: the rulers of ancient Egypt conquered Lower Egypt Menes, the initial formation of national unity. Egypt started the Early Dynastic Period.

3000 BC: Ancient Mesopotamia Sumerian city-state area appeared slavery.

3000 BC: Ancient Egyptian appear paddle and sail boats. The ancient Egyptians used bronze mirrors. Ancient Indians invented the stamp characters.

 

Before 2686 - before 2181: the Egyptian Old Kingdom. Complete national unity, large-scale construction of the pyramid.

Before the 27th century: the heroic epic of ancient Mesopotamia Sumerian era of the "Epic of Gilgamesh" is formed.

26th century BC: the famous ancient Egyptian Sphinx completed.

  

Europe appears knitting machine.

   

Chronology of World History "World History, World History." Long and complicated history of the world, some historical facts will inevitably have questions or inaccurate too, need to continue to identify and correct them later modified to restore the original appearance of history.

About 300,400 million years ago: humans appeared on earth.

About 200,300 --1 million years ago: Palaeolithic humans. Chipped stone popular, it has been the use of fire, late extensive use of bone, horn device. Hunting.

Collection industry, descent and family matriarchal commune produced.

About 170 million years ago: Yuanmou Yuanmou Chinese people living in this area, has been able to manufacture and use of stone tools.

{[(See World History, encyclopedias Stavros reason Oceanus: "Global History" McNeil "Rise of the West - the history of the human community" and "World History", as well as W · H.. McNeil's "World History" (1967), Stavrianos "global History" and so on.}

1

BC 3 - 1 million years ago: the primitive religion appears.

About 12,000 BC - 4000 BC: Stone Age humans. Invention and using a bow, fine stone widely used hunting industry.

From about 8000 BC - Former 2000: mankind has entered the Neolithic Age. Burnishing stone popular, there have been primitive agriculture and animal husbandry.

. Matriarchal commune prosperity.

6000 BC: Asia Minor appeared linen and wool fabrics.

Circa 6000 - 1000 BC: ancient Mesopotamia, Asia Minor, Greece, Rome, Persia, India and other places were primitive and ancient religions

Teach prevalent.

Circa 5000: Start with a cold forging method and processing of natural copper southwest Asia and Central Asia. Ancient Egypt has been used and other arms balance scale, the most known

Weighing early.

From about 5000 BC - Former 4000: In ancient Egypt, the sun and moon appear as regular calendar.

 

BC 4000 - 3000 BC: Ancient Egypt, Southwest Asia, Southern Europe, Central Europe and China and other places have started to use copper ore.

3760 years ago: the first year of the ancient Jewish calendar.

3500 BC - 3100 years ago: in ancient Mesopotamia Uruk period. It appears pottery wheel pottery and ziggurat building, creating a cuneiform. Gouy

And national (Nome) is formed. It appeared hieroglyphics.

3500 BC - 3000 BC: Ancient Mesopotamia residents began to use wheeled transport. The ancient Egyptians used in agriculture plow, harrow

And fertilization.

{5ooo BC before}

Before 2686 - before 2181: the Egyptian Old Kingdom. Complete national unity, large-scale construction of the pyramid.

 

26th century BC: the famous ancient Egyptian Sphinx completed.

2,500 years ago: the ancient Sumerian Medicine found that mineral water has healing properties, the ancient Sumerians used oil lamps, learn to bake bread and brew beer

liqueur. Europe appears knitting machine.

Circa 2500 - 1500 BC: Xiyaguya said period

Before the 25th century - before the 23 century: in Ancient Babylonians invention of pottery carved on the map.

Before 2378 - before 2371: the ancient Sumerian king of Lagash Urukagina reign,

Before 2371 - before 2154: the ancient Mesopotamian Akkadian Kingdom.

From about 2300 BC - Former 1750: Ancient Indian Harappa culture period.

Before 2181 - before 2040: First Intermediate Period of Ancient Egypt.

  

Before 2017 - before 1595: the era of ancient Mesopotamia Ancient Babylon

Before 2000: - Aegean Mycenaean civilization appears. Ancient Egypt appear library, mummification.

Before 1900-- before 1600: the ancient Greek text appears linear, bronze widely used.

   

Walsh (William H.Walsh, 1913-1986), British philosopher>

Before 1792 - before 1750: Ancient Mesopotamia Ancient Babylon 6th generation reign of King Hammurabi, will be "Code of Hammurabi"

Before 1786 - before 1567: the Second Intermediate Period of ancient Egypt. Hyksos invasion of Egypt ruled over a hundred years.

Before the 18th century: ancient Babylon occurred farmers almanac, including irrigation, cultivation and harvesting, as the earliest known farmers almanac.

 

Before 1567 - before 1085: New Kingdom of ancient Egypt.

  

The ancient Babylonians created a well-developed mathematics and astronomy. Horses start for vehicle transport. UK Salisbury and Wiltshire areas built

Build Stonehenge. Ancient Egyptians used mercury.

About 14 centuries ago: Chinese Pan Geng moved to Yin from Om generate Oracle.

The first 14 - Former 12th century: the ancient Hittite Empire in West Asia.

The mid-14th century BC - 11th century ago: the ancient Xiyaguya said Empire.

About 13 centuries ago: Chinese Shang bronzes heyday. Late Shang Si Mu Wu Ding is the largest remaining bronze.

Former 11-- 9th century BC: the ancient Greek Homeric.

 

1000 BC - Former 600 years: The ancient Indian Vedic period. Aryan state formation, Brahmanism spread.

10th century - 612 years ago: the ancient Assyrian West New Empire. Iron appeared and widely used.

Top 10 - Top 5 Century: Ancient Indian earliest philosophical writings, Brahmanism classic "Upanishads" formation.

841 years ago

9 century ago: the ancient Greek Sparta state formation.

8th century: the ancient Greek epic "Iliad", "Odyssey" is formed, transfer to Homer. Pergamum invented parchment people in the Middle East.

 

Ancient Greek first Olympic Games held in Olympia.

 

BC 700 - 600 years ago: the ancient Phoenicians with suet and mountain ash into soap.

Before 8 - 6th century BC: the Roman monarchy era.

Before 626 BC - 539 years: the ancient Mesopotamia the Neo-Babylonian Kingdom.

Before 624 BC - 547 years: the ancient Greek philosopher Thales alive, the creation of Miletus school.

 

Before 610 BC - 546 years: the ancient Greek philosopher Anaximander alive.

About 7 centuries ago: the Babylonians found eclipses recurring Saros.

Before 604 BC - 561 years: the ancient Mesopotamia the Neo-Babylonian king Nebuchadnezzar II reign, the construction of the Hanging Gardens, destroy the Jewish state.

594 years ago: the ancient Greek Athenian Solon implement political and economic reform, issued the "Code of Attica."

From about 580 BC - 500 years ago: the ancient Greek mathematician and philosopher Pythagoras was alive, the creation of the Pythagoreans.

 

About 563 years ago - 483 years ago: Sakyamuni, founder of Buddhism alive.

Before 558 BC - 330 years: the ancient Persian Empire and West Asia.

551 BC - 479 BC: Confucius alive, the creation of the Confucian school of thought, the first private school, presided over the compilation of ancient culture finishing. Existing "The Analects

"

.

About the first 500-- 449 years ago: Persian War.

Before 485 BC - 425 years: the ancient Greek historian Herodotus alive.

  

Before 469 BC - 399 years: the ancient Greek philosopher Socrates alive.

Before about 460 BC - 401 years: the ancient Greek historian Thucydides alive, author of "History of the Peloponnesian War."

About the first 460-- 370 years ago: the ancient Greek philosopher Democritus alive.

432 years ago: the ancient Greek Parthenon, built by the sculptor Phidias decorative design.

Former 431-- 404 years ago: the occurrence of the Peloponnesian War. World military history.

Before 427 BC - 348 years / 347 years ago: the ancient Greek philosopher Plato alive.

  

Before 334 BC - 324 years: the Macedonian king Alexander the Great led his army conquests of Persia, Central Asia and India, travel thousands of miles, the world's ancient history

The famous military expedition. .

Before 330 BC - 275 years: the ancient Greek mathematician Euclid alive, the "Geometry."

323 BC - 187 years ago: the ancient Indian kingdom of Magadha Mauryan period.

 

4th century BC - AD 3,4 century: the ancient Indian epic "Mahabharata" is formed.

 

Before 287 BC - 212 years: the ancient Greek mathematician and physicist Archimedes alive.

About 280 years ago: the ancient port city of Alexandria, Egypt built the Pharos lighthouse, one of the seven wonders of the ancient world.

About 269 years ago - 232 years ago: the ancient Indian kingdom of Magadha Mauryan king Ashoka reign of the Mauryan entered its peak phase.

  

7 years ago or four years ago: According to legend, the founder of the birth of Jesus Christ.

1st century: Greek sculptor Ndiaye Sandra Ross, Nuoduoluosi, 波利佐罗斯 three carved marble statue of "Laocoon."

1st century AD the Roman Empire began

395 years of Christianity

476 years of the Roman Empire split

  

Early 7th century Frankish kingdom established

622 years of the rise of Islam

  

676 Japanese Taika Reforms begin

8 mid-century Silla unified the Korean Peninsula most

In the early 9th century Arab empire become

843 formed the Kingdom of the English.

Charlie is not the 12th century division of the empire, France, Germany, and Italy produce prototype

Japan entered the 14-16 century during the reign of the Shogunate

1453 Renaissance in Europe

1453 Byzantine Empire

1492 Dias voyage along the southern coast of Africa

1497--1498, Columbus reached America / Columbus discovered the New World

1519-1522 Voyage Vasco da Gama India

1640 Magellan sailed round the world fleet

1688 English bourgeois revolution began

1760s British coup, the new bourgeoisie and the establishment of the rule of Guizhou

1775--1783 British industrial revolution began

July 4, 1776 North American War of Independence

North American Continental Congress issued a "Declaration of Independence", the United States declared independence

Power 1785 Watt improved the steam engine is made to start a textile machine used / technological revolution, industrial

  

1848--1849 European revolution

1861 Russian serfdom reform

1861 --1865 US Civil War

Japan's Meiji Restoration began in 1868

Finalize the unification of Italy in 1870

1871 completed the unification of Germany, the German Empire was established

     

1939.9 Second World War broke out

1

1943.12.1, the United States, Britain issued the Cairo Declaration <>

  

The United Nations established 1945.10

   

The former Soviet Union.

  

1993 establishing the European Union

      

World History events

Create ancient Egyptian civilization

  

Old Babylonian kingdom

  

"Code of Hammurabi" development

  

Trojan War

  

Solon

  

Darius Battle

  

Battle of Marathon

  

The birth of Ancient Greek Philosophy / human history, cultural heritage, European civilization

/

  

Olympic Games / World Sports Events

  

[Many major events in world history, important people, it is difficult to accurately include all of them. There are various versions of the General History of the World, it is difficult consensus.]

  

Rise and Fall of the Roman Empire

  

Establishment and spread of Christianity

  

"Justinian Code" handed down

  

Germanic peoples migration

  

Founding and demise of the Mayan civilization

  

Collisions of European civilization

  

The collapse of the Byzantine Empire

  

The rise of the Ottoman Empire

  

Hundred Years War

  

Renaissance

  

Shakespeare Drama Creation

  

Opening of new routes

  

The European Reformation

  

Copernicus presented heliocentric

  

Newton discovered gravity

  

English bourgeois revolution

  

Faraday invention motor

  

Enlightenment

  

Reform of Peter I / Russia

  

The first industrial revolution

  

American Revolutionary

  

The French Revolution

  

The rise and fall of Napoleon

  

Latin American War of Independence

  

1848 European Revolution

  

Darwin's Theory of Evolution

  

the Meiji Reform

  

The establishment of the first international

  

second industrial revolution

  

Telephone and radio technology invention

  

Wright brothers and the birth of the aircraft

  

Birth car

  

Krstic invention Train

  

World War I

  

Establishment of an international coalition

  

Einstein theory of relativity

  

Second World War

The former Soviet Union / the end of the Cold War.

The establishment of the United Nations

  

New Changes in the third technological revolution the international political and economic new pattern of new trends

  

Modern society / world economy and world politics / World Military / World Culture / World Religion / World Population, etc.

Globalization - new opportunities, new challenges, new world and evolution

  

Man on the moon / cosmic revolution, the revolutionary planet, the planet began to society

  

{{ "The Outline of History" (English) Hz with Joe Wells.

"The Outline of History: Biological and concise history of mankind" (English) Hz with Joe Wells.

 

"History of Western civilization," [US] · E · Robert Lerner waited. This is a very influential book in North America, three co-historian. The former Soviet Academy of Sciences Editor: World History

 

"World history of civilization," [US] Philip Lee Ralph waited. 4 co-historian.

    

"World history of civilization," the Weierdulan. An amazing work. }}

  

Appears cloning / modern biological technology

  

Create ancient Egyptian civilization

  

Old Babylonian kingdom

  

Trojan War

  

Solon

  

Darius Battle

  

Battle of Marathon

  

Establishment and spread of Christianity

  

"Justinian Code" handed down

  

Germanic peoples migration

  

Founding and demise of the Mayan civilization

  

The collapse of the Byzantine Empire

  

The rise of the Ottoman Empire

  

Hundred Years War

  

Renaissance

  

Opening of new routes

  

The European Reformation

  

Copernicus presented heliocentric

  

Newton discovered gravity

  

English bourgeois revolution

  

NYSE / capitalist development

  

Faraday invention motor

  

Reform of Peter I

  

The first industrial revolution

  

American Revolutionary

  

The French Revolution

  

The rise and fall of Napoleon

  

1848 European Revolution

  

Darwin's Theory of Evolution

  

Telephone and radio technology invention

  

{{Main part of world history events, individual controversial history of the world can be found in general history, world history and civilization classics Encyclopedia of network resources, the world's three encyclopedia}}.

  

Third technological revolution

  

After the Cold War new world-changing. Competitive countries in the world, the rapid development of modern science and technology productivity.

  

Genetic engineering, aerospace engineering, computer and information network engineering, materials engineering, energy engineering, mechatronics, biomedical engineering, agricultural engineering, intelligent robotics, marine technology, military engineering and technology applied to human society greatly.

  

Competition and conflict in various new challenges, new conflicts, civilization, religion, nationality, culture, etc. followed, the world order is facing change and innovation, a serious challenge to the consolidation and development of the turmoil in the world order - Transformation ago Row.

  

Humans - primates

  

Primates - physiological characteristics {evolutionary / biological human primate evolution, comparative study}

  

Primates primate skull

In primates inhabit trees common features, there are many differences. Including the holding force needed collarbone in the chest ribs, all angles to ensure freedom of movement of the shoulder, in front of the fingers, nails, touch sensitive finger (toe) end, the tendency smell degradation, the number of teeth is relatively degraded, complex visual system (visual sensitivity and color sense), and trunk disproportionate brain, the cerebral cortex expanded pairs of mammary gland, a common child, a longer gestation period and the like.

  

Usually highly social primates, and there is hierarchy. Pliocene period began monogamous primates, and form a stable patriarchal society.

  

Primate head has two eyes forward: This binocular can provide an accurate sense of distance. There are towering above the orbital brow.

  

There is a huge dome on primate skull - skull, which was unusual in its class. Skull protects the brain following the same difference. Human cranial cavity volume (space inside the skull) than non-human primates should be three times the largest cranial cavity, which show that humans have larger brains. The average human cranial volume is 1201 cubic centimeters, while gorillas are 469 cm3, 400 cm3 chimps, orangutans is 397 cubic centimeters. The primary direction of primate evolution is the brain, especially the neocortex. According to anthropologists and geneticists concluded that the evolution and mutation of the human brain in a few tens of thousand years after part of evolution, part may be degraded. to genetic variation, mutation, cells, enzymes, proteins and the like.

  

Primates generally have five toes on each forelimb (finger), the end of each toe has horny toenails. Hand, foot and toes very sensitive skin, constitute a well-developed sense of touch systems. Most primates are suitable for the thumb grip objects (opposable thumbs), which is characterized by iconic primates, but not unique. For example opossum there so fingers. For primates, such as finger nails is accompanied by short walk between the ancient trees of the product. Many methods thus developed upper limb walking out.

Primate of all ring-shaped neck sternum very obvious

Snout primates (lower jaw) showed shrinking trend. Technically speaking, the Old World and New World monkeys distinction lies in the structure of the nose, and the difference between the Old World monkeys and apes in the arrangement of the teeth. New World monkeys nostrils facing side, and old world monkeys are toward the lower nostril. Primates with a variety of teeth arranged manner. Hominid molar tip (the last tip) is in the early history of primates evolved, and this corresponds to the original lower molars tip (lower front tip) will disappear. Prosimians has its unique fixed upper lip, wet nose and lower front teeth inward.

  

Primate evolution and vision compared to most mammals was unusual. Primate ancestors developed trichromatic vision (can see three colors function), and nocturnal animals, warm-blooded animals and other mammals in the dinosaur ancestors of the period is lost in one third of the retinal cones.

  

Movement primates varied and useful arms, feet, jumping, arboreal, and walk on all fours on land, knuckles and other reptiles. Many of the original monkeys suborder animals vertical jumping and attached to trees, shrubs, including many monkeys, all indri. Humans are the only primates to fully upright.

  

Female migration system - born females leave the group. Male remained in the original population, while females and the collective is not closely linked.

  

Male exchange system - females remain in the original group and the males in adulthood Relocate. Allow polygamy society will fall into this category. Such social groups usually slightly larger, common in the ring-tailed lemurs, capuchin monkeys.

  

Monogamy - a male and a female stable structure, sometimes accompanied by heirs. Family care and social services (such as territorial defense) the work is divided into two sides. Parents will leave the territory after adult children. Such a society is more typical gibbon groups. However, where monogamy is not faithful representation of life.

  

Lonely type (for female) - together with the male will protect their territory, and which will include several female areas of activity. Such structures are found in apes.

  

Primates

  

Primate slower growth than other mammals. In addition to humans, primates cubs all rely on breastfeeding transfer of nutrients by the mother to protect, guide and support. Some species are also males, particularly his father, in charge of children's activities and safety. Other family members. encyclopedia site Wikipedia, Encyclopedia Britannica, Encyclopedia Americana and other information sites.]>

  

Primate mammals than the same size has a longer childhood (from weaning to sexual maturity). These are usually playing in knowledge gained. Later brought to maturity with the same size primate mammal compared to a longer life. And the average female life expectancy is longer than males.

  

Primate food source is very extensive. Most primates eat fruits, in order to absorb the digestible carbohydrates and fats for energy. However, other primates also need food, such as leaves or insects, for amino acids, vitamins and minerals (trace elements).

  

Baboon is the only major herbivorous primates. Tarsiers are the most carnivorous primates - eats insects, reptiles, and other animals. {Advanced intelligent life in the current scientific findings in humans with only other similar microbes in extreme environments - Extreme Life may find other planets or large in the universe, however, similar primate mammals in the visible Earth, the moon. Jupiter, Mars may not have even within the scope of these and other higher organisms. even if there had probably already extinct. As for whether within a larger universe, of course, can not all negative, however, there is the possibility, but not too much. extremophiles or other extreme life have then the possibility of a slightly larger universe in the development of change, extreme extreme biological life will produce and perish. everything is developing and changing universe, astrophysics, particle, expressing various forms of expression of life forms also is full of development and change.}.

  

Cosmic history summary table:

  

Temperature (K) Energy (eV) time (s) during physical Times

1032102810-44 Planck era

1028102410-35 grand unified era

10-35, -33 soaring inflation stage process

101310910-6 hadron era

101110710-2 lepton era .

10,101,061 neutrino neutrino decoupling decoupling

5 × 109 5 × 105 5 electron annihilation of electron-positron pairs

1,091,053 points nucleosynthesis era of light nuclides generated

400 million years of the formation of the first stars, reionization

Galaxies, large scale structure formation

2.725 3 × 10-4 137 billion years Modern

.

A brief history of the Earth's geology: for reference only, can be found in the relevant research monograph, the World Encyclopedia, Encyclopedia Britannica, Encyclopedia Americana, Wikipedia, Wikipedia and other websites on behalf of strata, representatives of the International Geological years.

Archean (AR, Archean Eon): about 4.567 billion to 25 billion years ago

Eoarchean (Ar0, Eoarchean Era): about 4.567 billion to 36 billion years ago

Paleoarchean (Ar1, Paleoarchean Era): about 3.6 billion to 32 billion years ago

The Archean (Ar2, Mesoarchean Era): about 32 billion to 2.8 billion years ago

Neoarchean (Ar3, Neoarchean Era): about 28 billion to 2.5 billion years ago

Proterozoic (PT, Proterozoic Eon): about 25 billion to 543 million years ago

Paleoproterozoic (Pt1, Paleoproterozoic Era): about 2.5 billion to 18 billion years ago

Before Hutuo discipline: about 2.5 billion to 23 billion years ago

Hutuo Ji (Ht): about 23 billion to 1.8 billion years ago

Mesoproterozoic (Pt2, Mesoproterozoic Era): about 1.8 billion to 10 billion years ago

Great Wall century (Ch): about 1.8 billion to 14 billion years ago

Early Great Wall World (Ch1):

Late Great Wall World (Ch2):

Jixianian (Jx): about 1.4 billion to 10 billion years ago

Early Jixian World (Jx1):

Late Jixian World (Jx2):

Neoproterozoic (Pt3, Neoproterozoic Era): about 10 billion to 543 million years ago

Qingbaikou (Qb): from about 10 million to 800 million years ago / tonian (Tonian Period): about 10 billion to 850 million years ago

Early Qingbaikou World (Qb1):

Late Qingbaikou World (Qb2):

Nanhua (Nh): about 800 million to 6.8 billion years ago / Cryogenian (Cryogenian Period): about 850 million to 6.3 billion years ago

Early Nanhua World (Nh1):

Nanhua Night World (Nh2):

Sinian (Z): about 6.8 billion to 543 million years ago / Ediacaran [Ediacaran Period, also known as the Neoproterozoic record Ⅲ (Neoproterozoic)]: about 635 million ~ 542 million years ago

Early Sinian (Z1):

Late Sinian (Z2):

Phanerozoic (PH, Phanerozoic Eon): about 543 million years ago - the future

Paleozoic (Pz, Paleozoic Era): about 543 million to 2.5 billion years ago

Early Paleozoic: about 542 million ~ 416 million years ago

Cambrian (∈, Cambrian Period): about 543 million to 4.9 billion years ago

Early Cambrian

The Cambrian

Late Cambrian

Ordovician (O, Ordovician Period): about 4.9 billion to 438 million years ago (say about 488 300 000 - 443 700 000 years ago)

Early Ordovician (O1):

Middle Ordovician (O2):

Late Ordovician (O3):

Silurian (S, Silurian Period): about 438 million to 4.1 billion years ago

Early Silurian (S1):

Middle Silurian (S2):

Late Silurian (S3):

Top Silurian (S4):

Late Paleozoic: about 416 million ~ 251 million years ago

Devonian (D, Devonian Period): 4.1 billion to 354 million years ago

Early Devonian

Middle Devonian

Late Devonian

Carboniferous (C, Carboniferous Period): about 354 million to 2.95 million years ago

Early Carboniferous (C1):

Late Carboniferous (C2):

Permian (P, Permian Period): about 295 million to 2.5 billion years ago

Early Permian (P1):

Middle Permian (P2):

Late Permian (P3):

Mesozoic (Mz, Mesozoic Era): about 2.5 million to 65.95 million years ago

Triassic (T, Triassic Period): about 2.5 billion to 205 million years ago

Early Triassic (T1):

Middle Triassic (T2):

Late Triassic (T3): geochronology / stratigraphic division

Jurassic (J, Jurassic Period): about 205 million ~ 137 million years ago

Early Jurassic (J1):

Middle Jurassic (J2):

Late Jurassic (J3):

Cretaceous (K, Cretaceous Period): about 137 million years ago ~ 65,950,000

Early Cretaceous (K1):

Late Cretaceous (K2):

Cenozoic (Cz, Cenozoic Era): approximately 65.95 million years ago - the future

Paleogene (E, Paleogene Period): about 6,500 million to 23.3 million years ago

Paleocene (E1): approximately 65.95 million - 55.8 million years ago

Eocene (E2): about 55.8 million - 33.9 million years ago

Oligocene (E3): about 33.9 million - 23.3 million

Neogene (N, Neogene Period): about 23.3 million to 260 million years ago.

Miocene (N1): about 23.3 million to 530 million years ago

Pliocene (N2): about 530 million to 2.6 million years ago

Quaternary (Q): about 260 million years ago - the future

Pleistocene (Qp): about 2.6 million to 1.15 million years ago

Holocene (Qb): about 1.15 million years ago - 1808

Anthropocene (Anthropocene epoch): about 1808 - Future

  

In the study of evolutionary history or geological processes on Earth, and sometimes do not necessarily need to know the exact time of geological events, but only needs to know the order between them, the only method of determining the sequence of geological events called relative geological time

Geological age and is closely related to human evolution.

  

Geologic Time Scale: <> light-years, a great span .1 trillion trillion years in 1oo years equal to .1 trillion light years ----- hundred light years distance traveled. astronomical. Encyclopedia of network resources. Encyclopedia Britannica, Encyclopedia Americana, Encyclopedia of life, Wikipedia and other geological]. " .

Implicit Phanerozoic:

Archean (Ar): 45 million years ago, lasted for 2.1 billion years.

Proterozoic (Pt): 24 million years ago, lasted for 1.83 billion years.

Phanerozoic:

Paleozoic (Pz):

Cambrian (∈): 5.7 billion years ago, lasted for 70 trillion years.

Ordovician (O): 5 million years ago, lasted for 60 trillion years.

Silurian (S): 4.4 billion years ago, lasted for 40 trillion years.

Devonian (D): 4 billion years ago, lasted for 50 trillion years.

Carboniferous (C): 3.5 billion years ago, lasted for 65 trillion years.

Permian (P): 2.85 billion years ago, lasted for 55 trillion years.

Mesozoic (Mz):

Triassic (T): 2.3 billion years ago, lasted for 35 trillion years.

Jurassic (J): 1.95 billion years ago, lasted for 58 trillion years.

Cretaceous (K): 1.37 billion years ago, lasted for 70 trillion years.

Cenozoic (Kz):

Tertiary (R): 67 trillion years ago, lasted 64.5 trillion years.

Paleocene: 65 trillion years ago for 9 trillion years.

Eocene: 56 trillion years ago, for 21 trillion years.

Oligocene: 35 trillion years ago, for 12 trillion years.

Miocene: 23 trillion years ago, for 18 trillion years.

Pliocene: 5 trillion years ago, continued 3.4 trillion years.

Quaternary (Q): 2.5 trillion years ago for 2.5 trillion years.

Pleistocene: 1.6 trillion years ago, continued 1.59 trillion years.

Holocene: 10,000 years ago. All accounts, a variety of opinions, strengths reference reading is not conclusive.

  

Geological time scale (refer to reading)

Implicit Phanerozoic:

Ancient offerings: 4.5 billion (some say 4.6 billion) to 38 billion years ago, 700 million years duration.

Archean (Ar): 38 billion to 2.7 billion years ago for 11 million years.

Proterozoic (Pt):

Early: 2.7 billion to 18 billion years ago, 900 million years duration.

Interim:

Changcheng Period: 18 billion to 1.4 billion years ago, for 4 billion years.

Jixianian: 1.4 billion to 10 billion years ago, for 4 billion years.

Late:

Qingbaikou: 10 million to 800 million years ago, the last 2 million years.

Sinian (Z): 8 million to 570 million years ago, 230 million years duration.

Wende Generation: 610 million to 6 million years ago, for 1 million years.

Phanerozoic:

Paleozoic (Pz):

Early:

Cambrian (∈): 5.7 billion to 510 million years ago, for six million years. Anomalocaris.

Ordovician (O): 5.1 billion to 439 million years ago, continued 71 trillion years. Great Ordovician radiation (GOBE, occurred in Phanerozoic evolution of a major biological event). Orthoceras.

The first mass extinction: 438 million years ago

Silurian (S): 4.39 billion to 408 million years ago, continued 31 trillion years. Pterygotus.

Late:

Devonian (D): 4.08 million to 362.5 million years ago, continued 45.5 trillion years. Dunkleosteus.

The second mass extinction: 3.6 billion years ago

Carboniferous (C): 3.625 billion to 290 million years ago, continued 72.5 trillion years. Giant spiders.

Permian (P): 2.9 billion to 245 million years ago, for 45 trillion years. Dimetrodon.

The third mass extinction: 245 million years ago, the number of more than 70%, 97% of species. Trilobites extinct.

Mesozoic (Mz):

Triassic (T):

Early:

Yin Duan Order: 2.5 million to 245 million years ago, for 5 trillion years.

order: 2.45 billion to 242 million years ago, for 3 trillion years.

{{See [US] • James Preston with, geographical thought history,

[English] R.J. Johnston of geography and geographers}}

<>.

  

AD 2,050- year 2, 100-year {according to the development of modern science and technology, the modern world economy, politics, military, religion, culture, education, resources, environment, ecology, population and so many data, rely on electronic computing model, rough analysis of historical development trends in context, focusing on human society and the whole world history evolution and developments, events, etc., but also a variety of scientific and technological research Advances according to generally study the changes in the natural, historical process of the universe and significant nature, and the universe mutations, etc. the main macro situation, roughly evolution situation, not microscopic scene from the time data, the reference data are also large, and the rest can be used as supplementary information. Therefore, the time span is very inconsistent.}

[Humans into Mars and return safely to Earth. Moon base, Mars base began preliminary work.

  

Marine rapid technological breakthroughs, the development of the Polar breakthrough.

  

Slow growth in the world economy, changes in the world situation changes.

     

Human population growth, resources and environment has deteriorated.

  

Reform of the United Nations / United Nations Special Representative of the Army / Secretary-General of the United Nations / United Nations permanent and non-permanent / United Nations International Tribunal / United Nations presences

States intensified competition, war occasionally occur. Various conflict-prone world pattern of gradual change, the new industrial revolution, technological revolution gaining momentum.

  

AD 21oo - AD 22oo years

  

The new mode of production

Slow world economic growth, after the strong boost

Planet revolution, the development of increasingly powerful universe, moon base, Mars base gradually established.

  

Polar development, ocean development, utilization or modification desert, mountain use

  

Increasingly powerful technological development, extension of human life, to overcome incurable diseases

  

When the nuclear threat of nuclear terrorism is still enveloped the world in some areas and hot spots of conflict have occurred, the individual fighting frequently.

The industrial revolution, agricultural revolution substantial progress, national wrestling competition

  

Increasing integration of the world, the world changes ASDC preliminary molding

  

Resource crisis, population growth, conflicts, local wars and danger

  

Enhanced role of the UN and rights. Enlarge the role of regional organizations of the United Nations to further strengthen the role of

Major issues of peace and security, economic development and human rights.

  

AD 23oo - AD 25oo years

  

Accelerate the integration of all aspects of the world / world politics / world economy / World Military / World Religions / World Science and Technology / world culture. National competition and uneven development, different, may go hand in hand, it may lead, lead the world, can not be generalized.

  

New world, a new world order / US., Russia, India, Europe, Japan, Argentina and other developing countries, appearing in a multi-polar unipolar lead unipolar or multi-pole to keep in hand, like a track and field race , long-distance running, sprinting, sprint, as runner-up or tied, but eventually there will still be a leader in the leading pack, leading the world. this hegemony in the traditional sense is significantly different.

  

Revolution Universe

  

AD AD 2,500- 3,000 years {post-industrial era. Intelligent modern industry, modern agriculture, a big step forward.

  

The situation in the world tend to be stable, easing Human society initially entered the planet. Moon man, Mars and other interstellar humanity.

  

The new economic structure economy / Economy - wisdom, and increasing social economic productivity, production tools, mode of production, relations of production, production resources.

Increased competition in the world. There are occasional conflicts and war.

  

When changes occur naturally universe, the earth, the moon is obvious. Earth's natural disasters is more common.

  

Two pole exploitation.

  

Moon person / Mars / Earth

  

Year 3,000 AD 5,000 years {human society entered the era of artificial intelligence, alien immigrants transformation shape.

  

Mankind enters the moons of Jupiter and other planets. Human detectors flying the solar system.

  

5th, 2000 --- AD 8,000 years

  

Earth society will also be significant changes and transformation.

  

AD 8, 2000 - 12th, 2000 / symbol year from now 2, ooo years -1o, ooo years as a symbol of the Earth {the revolution, the revolutionary planet, the universe will completely change the world revolution}

  

Super wisdom of the ages, super intelligence community came into being.

AD 15, 000 - AD 20, 2000

Wisdom biological robots appear.

Universe and change the planet. Human activity detector probe into the Milky Way and other galaxies. Humanity into other celestial bodies.

Highly intelligent life is found, but a similar extreme microbes. Planet touch state social model.

  

[Change the planet, the solar system change. Planet Earth and human survival in severe challenges and risks intensify.

  

AD 30, 000 - AD 50, 000 years {.. Human beings live on Earth, the Moon and Mars and other celestial bodies, planets society is gradually forming} planet survival technology gradually develop and grow, including Earth, Moon, Mars and the solar system are all in change, the planet of the world. survival and development more difficult and dangerous.

Changes in the universe. Planets and social crisis facing the challenges of changing times Earth's humanity, the Earth revolution.

  

AD 100, 000 - AD ******* years / 1oo, ooo years as a sign of macroeconomic data are used to study them, which is more in line closer to the natural and human history of the real world and the evolution of evolution trajectory image jump. empt a conclusion, clearly contrary to the true face of historical development, misleading and distorted the history and natural history of the world history of the universe.

AD 15o, ooo years ---- 2oo, ooo years

  

AD 3oo, ooo years --1, ooo, ooo-year history {Annals, 1oo years as a major landmark in.

AD 1,5oo, ooo years --- 2, ooo, ooo years

  

New geological new astronomical - chronological universe

........... ********** ********* ----- Other omitted from the year 2ooo years ---- 2 ooo, ooo years, the time span has been great, too great astronomical, so far after the fact without connection, the length of the history of the human history of the universe has enough new geological new astronomy - universe chronology, abbreviation:.. new geological new astronomical - chronological universe / NNACU.

<Mutation nature of the universe, the Earth and endanger other planets. Planets and other parts of the universe, explosion.

  

Part of human destruction or extinction, celestial hazards, biological extinction inevitable dangers and disasters threaten mankind.

  

Humans to survive and continue to continue to survive in the planet and the universe. Planet survival techniques developed.

  

<Universe changes and natural hazards, diverse, compared to a variety of disasters to human society hundreds of millions of times stronger human society can survive, whether planet or perish disintegration, explosion, collapse, these are extremely important problems. so, problem solution natural history of the universe changes, or mutations, this is the key. even if mankind enters Mars, the moon, is also facing these life and death problems. (1) Natural Yu Zhou whether the overall collapse and collapse? (2) whether humans have enough wisdom and ability to escape this unscathed (3) the destruction of the universe is inevitable or necessarily has its chance, including (4) remains the most critical are:?.? the destruction of the universe as a whole or partial destruction, what will matter Ukraine has evolved into what? everything is emptiness. If this theory was established, the inevitable demise of mankind and the universe. In other words, human history will end naturally, will declare the demise of the universe. Should the universe there is no overall destruction and collapse, human life or other life will there are likely to survive. this is the article with particular emphasis on the two major propositions. scientific research and scientific reasoning is sometimes very important, but in the end still needs a lot of verifiable data and the like.

  

A. nothingness.

  

B. heat death of the universe theory: Heat Death Theory and cosmic contraction theory is opposed to, in this case, gravity is not strong, you can not go beyond the expansion of the universe appears therefore exponential expansion, heat evenly distributed in the universe is cold, dark TLC, the final will be an all-star by one end perish.

  

C. Vacuum metastability event: Event metastable vacuum exists in the universe is a basic unstable state, the universe we live in a stable edge to swing. Some scientists say the reasoning, the next few billion years, the universe will be at the edge of subversion, then at some point the bubble universe.

     

D. On the death of a black hole in the universe most substances are surrounded by a black hole, the galaxy is concerned, it contains a variety of stars in its center there is a supermassive black hole. When the stars fall into the black hole or the galaxy "event boundary", they will be disintegrated, in a finite universe, black holes will eventually engulf most of the material, the final residue of a dark universe.

  

E. cosmic cycle: the traditional view that the universe is eternal existence, in the big bang singularity theory of the universe starting model, the universe is cyclical, it will be permanently sustained expansion and contraction.

  

F. cosmic contraction theory: The most prominent theory of how the universe is the Big Bang theory of the beginning, at first only singularities all substances present in the form, which is an infinitely dense point, for some reason after the explosion, it is difficult to outward confidence speed expansion, culminating in today's universe. On the large contraction and the big bang theory contrary, gravity will eventually slow the universe's expansion, stagnation and contraction.

 

"Kepler's third law: T2 / R3 = K (= 4π2 / GM) {R: radius of the orbit, T: cycle, K: constant (nothing to do with the planet's mass, depending on the quality of the central object)}

The law of gravity: F = Gm1m2 / r2 (G = 6.67 × 10-11N • m2 / kg2, directions on their connection)

Gravity and gravitational acceleration celestial bodies: GMm / R2 = mg; g = GM / R2 {R: celestial body radius (m), M: celestial body mass (kg)}

4. satellites orbiting velocity, angular velocity, period: V = (GM / r) 1/2; ω = (GM / r3) 1/2; 1/2 {M T = 2π (r3 / GM): the central body mass }. "

1. Dark energy is too large, too little dark matter, cosmic expansion rate is too large, continue to accelerate the expansion and eventually unlimited expansion.

2 dark energy and gravity of various substances in the universe was flat, the universe will continue to slow down the expansion, the expansion rate will be closer to zero, but can never reach zero.

3 less dark energy, gravity dominates the expansion of the universe will continue to slow down, then stop the expansion, contraction steering, all matter in the universe ultimately shrink back into a point, and start all over.

   

In the first model (ie, closed universe), the expansion of the universe was sufficiently slowly that the gravitational difference between galaxies in the expansion slows down and eventually make it stop. Then start close to each galaxy, the universe began to shrink.

the first sort

  

In the second model (open space), the expansion of the universe was so fast that gravity make it slow although some never could make it stop. Nearby galaxies distance versus time. Distance to zero at the beginning of the last galaxies steady speed away from each other;

In the second type is always expanded model, additional space is curved, like a saddle. Therefore, in this case space is infinite.

  

Finally, there is a third class of solutions, expansion of the universe is just fast enough to avoid collapsing. Distance galaxies started from zero, always increases. However, although the speed of the galaxy apart will never become zero, this speed is getting slower.

In the third category Friedmann model just the critical rate of expansion, space is flat (it is unlimited).

  

Theoretical physicist noted, human or gradually decay into radiation, after its own collapse completely disappeared, or because the faster expansion of the universe to collapse.

According to Big Rip theory, dark energy will make the structure of the universe distorted, leading to the first galaxies tear, followed by a smaller black holes, planets and stars. Expansion of the universe is growing drag force, once it reaches more than galaxies gather

Another possible way to the end of the universe is called the "big contraction."

If the substance within the universe declining over time, there will be a large contraction, resulting gravitational forces become dominant. Gravitational contraction of the universe leads to the result that stars, galaxies and planets collide with each other, the universe collapse occurred. Theoretical physicist, said some areas within the universe has begun to collapse, the collapse of the universe will eventually devour its

According to Higgs theory, the phase change in ten billion of a second after the Big Bang occurred, resulting in changes in the structure of space-time.

Newtonian cosmology:

1 was observed at any point in the universe, the center of the universe were symmetrical

2 the same time measuring the universe points, density are equal

3 little universe in any other conduct particle measurements relations

About the structure of the universe are:

Gaitian said: day round as cover sheets, places such as chess game.

Ancient Greek and Roman doctrine of original universe

Water is the origin of the universe - Thales

The outermost layer of the universe is never extinguished Skyfire said - Pythagoras

Multilayer crystal ball says - Aristotle

Earth is the center - Ptolemy

Western medieval universe theory

After the Middle Ages, cosmology was included in the scholastic system, know the late Renaissance Copernicus based on astronomical observations long write "heavenly bodies" presented heliocentric. Bruno is further believed that the sun is not the center of the universe, the universe is infinite, there is no center.

  

The classic model of the universe

Newton's first classical mechanics and Euclidean geometry concepts to establish a system of absolute infinite universe.

Relativistic cosmological model

Einstein November 1915 published a general theory of relativity, space and time can not be pointed out substance alone, they established a limited boundless four-dimensional model of the universe.

Big Bang Theory Model

The expansion

20 years later, due to the cosmic microwave background radiation was confirmed, together with the further development of nuclear physics, the Big Bang model shine, to be recognized by the standard model of the universe.

String theory models of the universe

Gradually developed in the last century, superstring theory, at another point to establish a more esoteric string theory models of the universe, we proposed the concept model of the universe of 11 dimensions.

  

1, on a closed space model of the universe, we need to understand a closed space.

A closed space from any point of view, do not turn to it, all will return to the same place, the same as rotate about a point.

2, a closed space model of the universe

Closed space universe model rule is half closed space of all symmetric point directional movement at the same rate, the move does not coincide with any two points, and keep symmetry.

  

Now is the "big bang model of the universe" is called the standard model of the universe. In addition are non-standard cosmological model of the universe model.

Such as: steady state model of the universe, the universe cycle model, film universe, the mirror universe. . . and many more.

     

A theory, also known as the Big Bang cosmology. Compared with other models of the universe, it could indicate more observational facts. Its main point is that we think the universe had a period from hot to cold in the course of evolution.

Einstein field equations: R_uv-1/2 * R * g_uv = κ * T_uv

(Rμν- (1/2) gμνR = 8GπTμν / (c * c * c * c) -gμν)

Description: g_uv to metric, κ is a coefficient, can be slow to determine the Newtonian theory. "_" After the letter subscript "^" after the letter as superscript.

Meaning: matter energy space - momentum (T_uv) = distribution bends space (R_uv)

Form solution is: ds ^ 2 = Adt ^ 2 + Bdr ^ 2 + Cdθ ^ 2 + Ddφ ^ 2

Wherein A, B, C, D for the metric g_uv components.

Consider the energy - momentum tensor T_uv solution is more complex. The easiest is to make T_uv equal to 0,

2. The field equations contain the cosmological constant term:

R_uv-1/2 * R * g_uv + Λ * g_uv = κ * T_uv

Here Λ is the cosmological constant, which is the physical meaning of the universe vacuum field. Λ * g_uv the cosmological term.

If from

ds ^ 2 = Adt ^ 2 + Bdr ^ 2 + Cdθ ^ 2 + Ddφ ^ 2 [1]

Wherein A, B, C, D for the metric g_uv components.

Here ds is the expression of the degree of bending of space a short distance.

If understood in the physical sense, then, the universe items to the right-hand side, it is:

R_uv-1/2 * R * g_uv = κ * T_uv-Λ * g_uv

  

In 1929, American astronomer Hubble Hubble's law is proposed from the galaxy redshift galaxies and proportional,

In the expansion of the universe away from each other, he said.

State when the distribution of matter in the universe imbalance, the local structure of matter will continue to expand and contract changes, but the relative balance between the overall structure of the universe will not change.

In 1994, the Carnegie Institute of Friedman et al., With an estimated age of the universe when calculating the rate of expansion of the universe approach, the calculated values ​​obtained the age of 80 to 12 billion a year. However, according to the analysis of stellar spectra, the oldest stars in the universe age of 140 to 160 million years.

Wonderful spiral is the nature of the most common and most basic form of exercise substances. This spiral shape phenomenon for the understanding of the universe has an important role in enlightening, to a large spiral galaxy, small DNA molecules are produced in such a spiral line. Nature does not recognize straight form nature all the basic structure of matter are annular shape of the curve of movement. From atoms and molecules to planets, galaxies until galaxies, superclusters, without exception, no doubt, the vastness of the universe is a big whirlpool. Therefore, the establishment of a "spiral movement patterns of the universe model"

Origin of the universe

About whether the universe and how to initiate the debate throughout the history of the entire record. Basically there are two schools of thought. Many early traditions, as well as Judaism, Christianity and Islam that the universe is fairly recent creation of the past.

Two schools of thought believe that the universe is fundamentally unchanged over time. Because human life - the whole of recorded history is so short, the universe was never significantly changed during this period. In the framework of a stable and unchanging universe, and if it has existed forever or is limited in the long past birth problems.

Wormhole eruption, he said that: in a time and space to open the door of the origin of the universe we now live. In many parallel universe, there is a very ordinary parallel universe, in this universe, the largest mass of a black hole is constantly engulfed other celestial bodies in the universe, its quality is increasing, large enough to destroy all of its gravitational physical form when the energy released completely after the eruption stopped wormhole, time and space the door is closed. And emitted by high-energy particles, after a long evolution, the formation of the universe we are now living; the eruption of the wormhole into a parallel universe that previously an ordinary objects, which is why we can not find the center of the universe the reason.

  

According to the Big Bang theory, many scientists for decades has consistently supported our universe was born about 140 million years ago. Accordance with the interpretation of this theory, the universe formed in a very small volume and density of great explosive substances 140 million years ago, ejected material particles and energy, it is also since then began after the explosion had time and space mass and energy. Before the big bang happened, neither matter nor energy, of course, no life.

Solar System

The solar system is a system of celestial bodies bound by the gravitational force of the sun's composition, its maximum range can be extended to about 1 light-years away. The main members of the solar system are: solar (star), the eight planets (including Earth), and countless asteroids, many satellite

  

Astronomers object by analyzing light atomic absorption or release of an object is measured or far away from close to the earth, the light in a unique color or frequency of occurrence. When the object away from the Earth, these frequencies will move on the red spectrum.

  

Standard Big Bang model shows that the universe erupted from a singularity of infinite density. But I do not know what triggered this outbreak.

Simultaneously.

For most cosmologists, the most reasonable explanation of consistency, in the universe shortly after, some unknown form of energy so that the young universe expanded more than the speed of light. In this model, the universe is a three-dimensional film

  

Chaos in the celestial explosion, the birth of the Universe, at a certain time or never newborn newborn state, between its internal explosive remnants of interaction, while forming planet has gradually formed galaxies, in which galaxies are in the formation process gradually formed a multi-N Milky Way, the galaxy in which there is a there is a solar system, the solar system has eight planets, one of which is the Earth we humans live now. Earth is not life long ago, when the Earth's relatively far from the sun, in the Ice Age. When getting closer as the planet from the sun, in the solar system most suitable for life in the initiation position, and constitute the material elements of the earth in line with the initiation of life, we received after joining from foreign matter in the universe, the earth began appeared in the primordial seas, pristine ocean began to Earth this hotbed after a long time gave birth to the primitive life, initially the growth of plants, plant evolution to a certain extent, there has been a simple primitive life, primitive life began the evolution of life, which including the gradual evolution of the formation of prehistoric humans. Prehistoric modern humans than many larger head, looks also differ a lot, IQ is not high, can only be regarded as an animal. At that time the Earth has a primitive atmosphere, creating a long evolution of the planet's largest living things -

  

<Summary of the above, the relevant causes of the Universe, the model - the structure, the initial state of the universe and the universe final outcome, so a variety of cosmological theories and hypotheses, research and forecasting all kinds, have their own achievements, strengths and weaknesses to the decision to choose, locate one, it is difficult. achievements Natural scientific exploration, research is needed to support a variety of research and theory theory, not in the case failed to confirm, then under the broken language, non-judgment, especially cosmology, astronomy and probing depth study would be distant and long process. various theories and doctrines must be analyzed and gain the most valuable scientific certainty. after all, is an advanced human wisdom of primates, in front of the great deep natural universe, it is still very small childish. even then successful scientific discovery, scientific theorem, it is not absolutely perfect, especially humans triumphantly landed on the moon, Mars, Jupiter, etc. after that, there will be more great brilliant discoveries and achievements on Earth - some of the human race on Earth Research will be rewritten or remodeling. this is the correct understanding of their humanity, understand nature, meeting new milestone in the universe. for example, gravity come from, why stars spiral spin structure, the particles are present when the universe was formed it, universe, whether single or multi-dimensional universe whether the same state, different state, the initial state of the God particle of how the state of the big Bang before the universe, the destruction of the universe is matter thoroughly mound did it, human life or other advanced life in the planet and viability of the universe, and so forth. The critical issue is not resolved, other theories and doctrines, it is difficult to justify. Even the greatest scientist is difficult to make their theories impeccable. The final outcome of the universe, or whether the continuation of the collapse, and whether humans can survive the extinction or destruction, the key point is that the universe is still two major problems: 1. The explosion destroyed the universe collapse disposable destruction or periodic repeat? 2. Distribution of the universe with the state, different state of the universe at the beginning and final states, as well as the planet and human synchronous, asynchronous. ? Whole or in part, the evolution of the evolution of this is the essence of the problem, this is the universe - life theory by far the most important issue. Maybe not solve the big problem, it is difficult to achieve a breakthrough progress. Hypothesis no matter how powerful is also inseparable from experimental simulation studies must, otherwise, it will become airborne hug Court. Natural Sciences stressed empirical observation observation verification testing, the loss of these fans will astray. Heliocentric - geocentric debate lasted for hundreds of years, the theory of evolution is carried out hundreds of years of debate, it is proof. Around at 10:00 on June 30th, 1860, the President of the Conference of the British Association for the Advancement of Science, please Wilberforce Bishop stage presentation. He said: "God and the Church is not against science, but can not tolerate blasphemy, insulting human pseudo-science, Mr. Darwin's theory of evolution is the pseudo-science, it is the lack of conclusive scientific proof powerful, entirely hypothetical style, not registered humble hypothesis to support the entire thesis, therefore, religious insight, and the scientific community will not support this absurd theory, "he stressed:." boundaries between human beings and things in the world is clear, a only radish efforts no matter how impossible the evolution of adult "suddenly, Huxley Wilberforce hand pointing to the audience and asks:"! here even Mr. Huxley says he is a descendant of apes, then I would like to ask this gentleman:? ape ancestors that one of your grandfather, your grandmother or that side of it, "Wilberforce rostrum in the midst of applause and laughter, and many people cheered his speech. Next, people set their sights Huxley, at this time, Huxley even smiling sitting next to the President of the Royal Society Brody said softly:. "God has handed him my hand."

Please Henslow announced Huxley took the floor, Huxley said slowly: "If I have to choose my ancestors in the following two: one side is the ape, one side is an influential figure, and this figure but confusion in serious scientific discussions in black and white, sensational, then I will not hesitate to do what I choose simian ancestors!. "revisit the issues, over a hundred years. modern science does not refute the theory of evolution came when criticism sound, visible, for scientific discovery and understanding of the theory has always been controversy throughout human society. for a modern human evolution, scientists made a number of new research and discovery, also made a number of evolutionary hypothesis, but I believe that the theory of evolution is essentially established , though not perfect, is basically in line with the facts, the author has worked on a lot of comparative animal anatomy animal study human anatomy, but also include genes, cells and other biological engineering research experiments, such as the theory of evolution is not established, where and how humans to? provability basis and where is it? intelligent design Tenable? creationism. extraterrestrial theory, scientists have turned into a religionist. "

.

Combining history, teams face reality, we should adhere to the facts speak for scientific spirit, both to rational thinking, but also scientific proof to verify the facts, the truth can only verify in practice and the fact that inside, and not the opposite. Natural History history of the universe yet thus, the history of development of human society, the human history of the world should be even more so. rooted and noted, with facts to prove the practice of human society. simple inference inference prediction is important, but more important still is the fact that more iron, iron the chain of evidence, iron

Scientific tests to verify data and so on. Only the latter have completely invincible overriding powerful destructive force.

For example, human studies of the moon, Mars, Jupiter, various inferences inference Hypothesis academic endless variety of research experiments, also a lot of simulation, although there are quite significant scientific value, but only humans can personally board the Mars moon of Jupiter's moons, after and use scientific and technological means to obtain direct and indirect information data, etc., in order to obtain real results. huge intelligent robot power, but not absolute, and replace all of humanity itself practice and research. Therefore, only humans entirely social practice, in order to create the history of mankind. Should AI and completely separate human beings, that means the total collapse or collapse of the biological human world. Without the human organism, even more full of intelligent robots on Mars, which human society this is pointless and world history is not a simple science ethics, people - serious ethical problem machine or the like, but very naive absurd another example, intelligent robot wars world chess master, and indeed the man-machine war, intelligent robots. indeed extraordinary, Supreme Cou, however, no human presence, the great intelligent robot naturally lost his powerful meaning.

  

Taking the theme of world history, of course, is the existence of human society is the basis and premise, mainly to discuss the life of the world, taking into account the natural history of the universe's history, the purpose is to combine the two study analysis, it is necessary to prioritize, we can not categorically separated , complement each other bears. Thus, the entire history of the more clear image clearer. Today, many scientists and the world that the future outcome of the universe and human destruction is difficult to avoid and escape. in fact, this need not panicky, first of all, these from the modern human society is still very far away so-called "doomsday" "global explosion", etc., is not groundless, alarmist, is not optimistic; however, as the book, at least in the tens of millions of years later according to new research possible Earth, moon, Mars, Venus, Mercury, Jupiter's age can still maintain tens of millions of years. momentary or short-term changes will not disappear, so that the survival of mankind can continue tens of hundreds of thousands in millions of years. after thousands of years millions of years, should the survival of mankind, the planet had evolved into people, the Galaxy, Pegasus people, the universe of people. unless the entire universe collapse once and for all destroyed, otherwise, the universe of human offspring entirely possible to continue to continue t

Scientists at NIH's National Eye Institute have developed a promising gene therapy strategy for a form of Leber congenital amaurosis (LCA), a rare disease that causes severe vision loss in childhood. The scientists tested their approach using lab-made retinal tissues built from patient cells, called retinal organoids, one of which is pictured here. ⠀

⠀

Read more: www.nih.gov/news-events/news-releases/researchers-use-pat...

 

Credit: Anand Swaroop, Ph.D., NEI/NIH

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Sheep (pl.: sheep) or domestic sheep (Ovis aries) are a domesticated, ruminant mammal typically kept as livestock. Although the term sheep can apply to other species in the genus Ovis, in everyday usage it almost always refers to domesticated sheep. Like all ruminants, sheep are members of the order Artiodactyla, the even-toed ungulates. Numbering a little over one billion, domestic sheep are also the most numerous species of sheep. An adult female is referred to as a ewe (/juː/ yoo), an intact male as a ram, occasionally a tup, a castrated male as a wether, and a young sheep as a lamb.

 

Sheep are most likely descended from the wild mouflon of Europe and Asia, with Iran being a geographic envelope of the domestication center. One of the earliest animals to be domesticated for agricultural purposes, sheep are raised for fleeces, meat (lamb, hogget or mutton) and milk. A sheep's wool is the most widely used animal fiber, and is usually harvested by shearing. In Commonwealth countries, ovine meat is called lamb when from younger animals and mutton when from older ones; in the United States, meat from both older and younger animals is usually called lamb. Sheep continue to be important for wool and meat today, and are also occasionally raised for pelts, as dairy animals, or as model organisms for science.

 

Sheep husbandry is practised throughout the majority of the inhabited world, and has been fundamental to many civilizations. In the modern era, Australia, New Zealand, the southern and central South American nations, and the British Isles are most closely associated with sheep production.

 

There is a large lexicon of unique terms for sheep husbandry which vary considerably by region and dialect. Use of the word sheep began in Middle English as a derivation of the Old English word scēap. A group of sheep is called a flock. Many other specific terms for the various life stages of sheep exist, generally related to lambing, shearing, and age.

 

Being a key animal in the history of farming, sheep have a deeply entrenched place in human culture, and are represented in much modern language and symbolism. As livestock, sheep are most often associated with pastoral, Arcadian imagery. Sheep figure in many mythologies—such as the Golden Fleece—and major religions, especially the Abrahamic traditions. In both ancient and modern religious ritual, sheep are used as sacrificial animals.

 

History

Main article: History of the domestic sheep

The exact line of descent from wild ancestors to domestic sheep is unclear. The most common hypothesis states that Ovis aries is descended from the Asiatic (O. gmelini) species of mouflon; the European mouflon (Ovis aries musimon) is a direct descendant of this population. Sheep were among the first animals to be domesticated by humankind (although the domestication of dogs probably took place 10 to 20 thousand years earlier); the domestication date is estimated to fall between 11,000 and 9000 B.C in Mesopotamia and possibly around 7000 BC in Mehrgarh in the Indus Valley. The rearing of sheep for secondary products, and the resulting breed development, began in either southwest Asia or western Europe. Initially, sheep were kept solely for meat, milk and skins. Archaeological evidence from statuary found at sites in Iran suggests that selection for woolly sheep may have begun around 6000 BC, and the earliest woven wool garments have been dated to two to three thousand years later.

 

Sheep husbandry spread quickly in Europe. Excavations show that in about 6000 BC, during the Neolithic period of prehistory, the Castelnovien people, living around Châteauneuf-les-Martigues near present-day Marseille in the south of France, were among the first in Europe to keep domestic sheep. Practically from its inception, ancient Greek civilization relied on sheep as primary livestock, and were even said to name individual animals. Ancient Romans kept sheep on a wide scale, and were an important agent in the spread of sheep raising. Pliny the Elder, in his Natural History (Naturalis Historia), speaks at length about sheep and wool. European colonists spread the practice to the New World from 1493 onwards.

 

Characteristics

Domestic sheep are relatively small ruminants, usually with a crimped hair called wool and often with horns forming a lateral spiral. They differ from their wild relatives and ancestors in several respects, having become uniquely neotenic as a result of selective breeding by humans. A few primitive breeds of sheep retain some of the characteristics of their wild cousins, such as short tails. Depending on breed, domestic sheep may have no horns at all (i.e. polled), or horns in both sexes, or in males only. Most horned breeds have a single pair, but a few breeds may have several.

 

Sheep in Turkmenistan

Another trait unique to domestic sheep as compared to wild ovines is their wide variation in color. Wild sheep are largely variations of brown hues, and variation within species is extremely limited. Colors of domestic sheep range from pure white to dark chocolate brown, and even spotted or piebald. Sheep keepers also sometimes artificially paint "smit marks" onto their sheep in any pattern or color for identification. Selection for easily dyeable white fleeces began early in sheep domestication, and as white wool is a dominant trait it spread quickly. However, colored sheep do appear in many modern breeds, and may even appear as a recessive trait in white flocks. While white wool is desirable for large commercial markets, there is a niche market for colored fleeces, mostly for handspinning. The nature of the fleece varies widely among the breeds, from dense and highly crimped, to long and hairlike. There is variation of wool type and quality even among members of the same flock, so wool classing is a step in the commercial processing of the fibre.

  

Suffolks are a medium wool, black-faced breed of meat sheep that make up 60% of the sheep population in the U.S.

Depending on breed, sheep show a range of heights and weights. Their rate of growth and mature weight is a heritable trait that is often selected for in breeding. Ewes typically weigh between 45 and 100 kilograms (100 and 220 lb), and rams between 45 and 160 kilograms (100 and 350 lb). When all deciduous teeth have erupted, the sheep has 20 teeth. Mature sheep have 32 teeth. As with other ruminants, the front teeth in the lower jaw bite against a hard, toothless pad in the upper jaw. These are used to pick off vegetation, then the rear teeth grind it before it is swallowed. There are eight lower front teeth in ruminants, but there is some disagreement as to whether these are eight incisors, or six incisors and two incisor-shaped canines. This means that the dental formula for sheep is either

0.0.3.3

4.0.3.3

or

0.0.3.3

3.1.3.3

There is a large diastema between the incisors and the molars.

 

In the first few years of life one can calculate the age of sheep from their front teeth, as a pair of milk teeth is replaced by larger adult teeth each year, the full set of eight adult front teeth being complete at about four years of age. The front teeth are then gradually lost as sheep age, making it harder for them to feed and hindering the health and productivity of the animal. For this reason, domestic sheep on normal pasture begin to slowly decline from four years on, and the life expectancy of a sheep is 10 to 12 years, though some sheep may live as long as 20 years.

 

Skull

Sheep have good hearing, and are sensitive to noise when being handled. Sheep have horizontal slit-shaped pupils, with excellent peripheral vision; with visual fields of about 270° to 320°, sheep can see behind themselves without turning their heads. Many breeds have only short hair on the face, and some have facial wool (if any) confined to the poll and or the area of the mandibular angle; the wide angles of peripheral vision apply to these breeds. A few breeds tend to have considerable wool on the face; for some individuals of these breeds, peripheral vision may be greatly reduced by "wool blindness", unless recently shorn about the face. Sheep have poor depth perception; shadows and dips in the ground may cause sheep to baulk. In general, sheep have a tendency to move out of the dark and into well-lit areas, and prefer to move uphill when disturbed. Sheep also have an excellent sense of smell, and, like all species of their genus, have scent glands just in front of the eyes, and interdigitally on the feet. The purpose of these glands is uncertain, but those on the face may be used in breeding behaviors. The foot glands might also be related to reproduction, but alternative functions, such as secretion of a waste product or a scent marker to help lost sheep find their flock, have also been proposed.

 

Comparison with goats

Sheep and goats are closely related: both are in the subfamily Caprinae. However, they are separate species, so hybrids rarely occur and are always infertile. A hybrid of a ewe and a buck (a male goat) is called a sheep-goat hybrid, known as geep. Visual differences between sheep and goats include the beard of goats and divided upper lip of sheep. Sheep tails also hang down, even when short or docked, while the short tails of goats are held upwards. Also, sheep breeds are often naturally polled (either in both sexes or just in the female), while naturally polled goats are rare (though many are polled artificially). Males of the two species differ in that buck goats acquire a unique and strong odor during the rut, whereas rams do not.

 

Breeds

The domestic sheep is a multi-purpose animal, and the more than 200 breeds now in existence were created to serve these diverse purposes. Some sources give a count of a thousand or more breeds, but these numbers cannot be verified, according to some sources. However, several hundred breeds of sheep have been identified by the Food and Agriculture Organization of the UN (FAO), with the estimated number varying somewhat from time to time: e.g. 863 breeds as of 1993, 1314 breeds as of 1995 and 1229 breeds as of 2006. (These numbers exclude extinct breeds, which are also tallied by the FAO.) For the purpose of such tallies, the FAO definition of a breed is "either a subspecific group of domestic livestock with definable and identifiable external characteristics that enable it to be separated by visual appraisal from other similarly defined groups within the same species or a group for which geographical and/or cultural separation from phenotypically similar groups has led to acceptance of its separate identity." Almost all sheep are classified as being best suited to furnishing a certain product: wool, meat, milk, hides, or a combination in a dual-purpose breed. Other features used when classifying sheep include face color (generally white or black), tail length, presence or lack of horns, and the topography for which the breed has been developed. This last point is especially stressed in the UK, where breeds are described as either upland (hill or mountain) or lowland breeds. A sheep may also be of a fat-tailed type, which is a dual-purpose sheep common in Africa and Asia with larger deposits of fat within and around its tail.

 

Breeds are often categorized by the type of their wool. Fine wool breeds are those that have wool of great crimp and density, which are preferred for textiles. Most of these were derived from Merino sheep, and the breed continues to dominate the world sheep industry. Downs breeds have wool between the extremes, and are typically fast-growing meat and ram breeds with dark faces. Some major medium wool breeds, such as the Corriedale, are dual-purpose crosses of long and fine-wooled breeds and were created for high-production commercial flocks. Long wool breeds are the largest of sheep, with long wool and a slow rate of growth. Long wool sheep are most valued for crossbreeding to improve the attributes of other sheep types. For example: the American Columbia breed was developed by crossing Lincoln rams (a long wool breed) with fine-wooled Rambouillet ewes.

 

Coarse or carpet wool sheep are those with a medium to long length wool of characteristic coarseness. Breeds traditionally used for carpet wool show great variability, but the chief requirement is a wool that will not break down under heavy use (as would that of the finer breeds). As the demand for carpet-quality wool declines, some breeders of this type of sheep are attempting to use a few of these traditional breeds for alternative purposes. Others have always been primarily meat-class sheep.

 

A minor class of sheep are the dairy breeds. Dual-purpose breeds that may primarily be meat or wool sheep are often used secondarily as milking animals, but there are a few breeds that are predominantly used for milking. These sheep produce a higher quantity of milk and have slightly longer lactation curves. In the quality of their milk, the fat and protein content percentages of dairy sheep vary from non-dairy breeds, but lactose content does not.

 

A last group of sheep breeds is that of fur or hair sheep, which do not grow wool at all. Hair sheep are similar to the early domesticated sheep kept before woolly breeds were developed, and are raised for meat and pelts. Some modern breeds of hair sheep, such as the Dorper, result from crosses between wool and hair breeds. For meat and hide producers, hair sheep are cheaper to keep, as they do not need shearing. Hair sheep are also more resistant to parasites and hot weather.

 

With the modern rise of corporate agribusiness and the decline of localized family farms, many breeds of sheep are in danger of extinction. The Rare Breeds Survival Trust of the UK lists 22 native breeds as having only 3,000 registered animals (each), and The Livestock Conservancy lists 14 as either "critical" or "threatened". Preferences for breeds with uniform characteristics and fast growth have pushed heritage (or heirloom) breeds to the margins of the sheep industry. Those that remain are maintained through the efforts of conservation organizations, breed registries, and individual farmers dedicated to their preservation.

 

Diet

Sheep are herbivorous mammals. Most breeds prefer to graze on grass and other short roughage, avoiding the taller woody parts of plants that goats readily consume. Both sheep and goats use their lips and tongues to select parts of the plant that are easier to digest or higher in nutrition. Sheep, however, graze well in monoculture pastures where most goats fare poorly.

 

Ruminant system of a sheep

Like all ruminants, sheep have a complex digestive system composed of four chambers, allowing them to break down cellulose from stems, leaves, and seed hulls into simpler carbohydrates. When sheep graze, vegetation is chewed into a mass called a bolus, which is then passed into the rumen, via the reticulum. The rumen is a 19- to 38-liter (5 to 10 gallon) organ in which feed is fermented. The fermenting organisms include bacteria, fungi, and protozoa. (Other important rumen organisms include some archaea, which produce methane from carbon dioxide.) The bolus is periodically regurgitated back to the mouth as cud for additional chewing and salivation. After fermentation in the rumen, feed passes into the reticulum and the omasum; special feeds such as grains may bypass the rumen altogether. After the first three chambers, food moves into the abomasum for final digestion before processing by the intestines. The abomasum is the only one of the four chambers analogous to the human stomach, and is sometimes called the "true stomach".

 

Other than forage, the other staple feed for sheep is hay, often during the winter months. The ability to thrive solely on pasture (even without hay) varies with breed, but all sheep can survive on this diet. Also included in some sheep's diets are minerals, either in a trace mix or in licks. Feed provided to sheep must be specially formulated, as most cattle, poultry, pig, and even some goat feeds contain levels of copper that are lethal to sheep. The same danger applies to mineral supplements such as salt licks.

 

Grazing behavior

Sheep follow a diurnal pattern of activity, feeding from dawn to dusk, stopping sporadically to rest and chew their cud. Ideal pasture for sheep is not lawnlike grass, but an array of grasses, legumes and forbs. Types of land where sheep are raised vary widely, from pastures that are seeded and improved intentionally to rough, native lands. Common plants toxic to sheep are present in most of the world, and include (but are not limited to) cherry, some oaks and acorns, tomato, yew, rhubarb, potato, and rhododendron.

 

Effects on pasture

Sheep are largely grazing herbivores, unlike browsing animals such as goats and deer that prefer taller foliage. With a much narrower face, sheep crop plants very close to the ground and can overgraze a pasture much faster than cattle. For this reason, many shepherds use managed intensive rotational grazing, where a flock is rotated through multiple pastures, giving plants time to recover. Paradoxically, sheep can both cause and solve the spread of invasive plant species. By disturbing the natural state of pasture, sheep and other livestock can pave the way for invasive plants. However, sheep also prefer to eat invasives such as cheatgrass, leafy spurge, kudzu and spotted knapweed over native species such as sagebrush, making grazing sheep effective for conservation grazing. Research conducted in Imperial County, California compared lamb grazing with herbicides for weed control in seedling alfalfa fields. Three trials demonstrated that grazing lambs were just as effective as herbicides in controlling winter weeds. Entomologists also compared grazing lambs to insecticides for insect control in winter alfalfa. In this trial, lambs provided insect control as effectively as insecticides.

 

Behavior

Sheep are flock animals and strongly gregarious; much sheep behavior can be understood on the basis of these tendencies. The dominance hierarchy of sheep and their natural inclination to follow a leader to new pastures were the pivotal factors in sheep being one of the first domesticated livestock species. Furthermore, in contrast to the red deer and gazelle (two other ungulates of primary importance to meat production in prehistoric times), sheep do not defend territories although they do form home ranges. All sheep have a tendency to congregate close to other members of a flock, although this behavior varies with breed, and sheep can become stressed when separated from their flock members. During flocking, sheep have a strong tendency to follow, and a leader may simply be the first individual to move. Relationships in flocks tend to be closest among related sheep: in mixed-breed flocks, subgroups of the same breed tend to form, and a ewe and her direct descendants often move as a unit within large flocks. Sheep can become hefted to one particular local pasture (heft) so they do not roam freely in unfenced landscapes. Lambs learn the heft from ewes and if whole flocks are culled it must be retaught to the replacement animals.

 

Flock behaviour in sheep is generally only exhibited in groups of four or more sheep; fewer sheep may not react as expected when alone or with few other sheep. Being a prey species, the primary defense mechanism of sheep is to flee from danger when their flight zone is entered. Cornered sheep may charge and butt, or threaten by hoof stamping and adopting an aggressive posture. This is particularly true for ewes with newborn lambs.

 

In regions where sheep have no natural predators, none of the native breeds of sheep exhibit a strong flocking behavior.

 

Herding

Farmers exploit flocking behavior to keep sheep together on unfenced pastures such as hill farming, and to move them more easily. For this purpose shepherds may use herding dogs in this effort, with a highly bred herding ability. Sheep are food-oriented, and association of humans with regular feeding often results in sheep soliciting people for food. Those who are moving sheep may exploit this behavior by leading sheep with buckets of feed.

 

Dominance hierarchy

Sheep establish a dominance hierarchy through fighting, threats and competitiveness. Dominant animals are inclined to be more aggressive with other sheep, and usually feed first at troughs. Primarily among rams, horn size is a factor in the flock hierarchy. Rams with different size horns may be less inclined to fight to establish the dominance order, while rams with similarly sized horns are more so. Merinos have an almost linear hierarchy whereas there is a less rigid structure in Border Leicesters when a competitive feeding situation arises.

 

In sheep, position in a moving flock is highly correlated with social dominance, but there is no definitive study to show consistent voluntary leadership by an individual sheep.

 

Intelligence and learning ability

Sheep are frequently thought of as unintelligent animals. Their flocking behavior and quickness to flee and panic can make shepherding a difficult endeavor for the uninitiated. Despite these perceptions, a University of Illinois monograph on sheep reported their intelligence to be just below that of pigs and on par with that of cattle. Sheep can recognize individual human and ovine faces and remember them for years; they can remember 50 other different sheep faces for over two years; they can recognize and are attracted to individual sheep and humans by their faces, as they possess similar specialized neural systems in the temporal and frontal lobes of their brains to humans and have a greater involvement of the right brain hemisphere. In addition to long-term facial recognition of individuals, sheep can also differentiate emotional states through facial characteristics.[68][69] If worked with patiently, sheep may learn their names, and many sheep are trained to be led by halter for showing and other purposes. Sheep have also responded well to clicker training. Sheep have been used as pack animals; Tibetan nomads distribute baggage equally throughout a flock as it is herded between living sites.

 

It has been reported that some sheep have apparently shown problem-solving abilities; a flock in West Yorkshire, England allegedly found a way to get over cattle grids by rolling on their backs, although documentation of this has relied on anecdotal accounts.

 

Vocalisations

Sounds made by domestic sheep include bleats, grunts, rumbles and snorts. Bleating ("baaing") is used mostly for contact communication, especially between dam and lambs, but also at times between other flock members. The bleats of individual sheep are distinctive, enabling the ewe and her lambs to recognize each other's vocalizations. Vocal communication between lambs and their dam declines to a very low level within several weeks after parturition. A variety of bleats may be heard, depending on sheep age and circumstances. Apart from contact communication, bleating may signal distress, frustration or impatience; however, sheep are usually silent when in pain. Isolation commonly prompts bleating by sheep. Pregnant ewes may grunt when in labor. Rumbling sounds are made by the ram during courting; somewhat similar rumbling sounds may be made by the ewe, especially when with her neonate lambs. A snort (explosive exhalation through the nostrils) may signal aggression or a warning, and is often elicited from startled sheep.

 

Lamb

In sheep breeds lacking facial wool, the visual field is wide. In 10 sheep (Cambridge, Lleyn and Welsh Mountain breeds, which lack facial wool), the visual field ranged from 298° to 325°, averaging 313.1°, with binocular overlap ranging from 44.5° to 74°, averaging 61.7°. In some breeds, unshorn facial wool can limit the visual field; in some individuals, this may be enough to cause "wool blindness". In 60 Merinos, visual fields ranged from 219.1° to 303.0°, averaging 269.9°, and the binocular field ranged from 8.9° to 77.7°, averaging 47.5°; 36% of the measurements were limited by wool, although photographs of the experiments indicate that only limited facial wool regrowth had occurred since shearing. In addition to facial wool (in some breeds), visual field limitations can include ears and (in some breeds) horns, so the visual field can be extended by tilting the head. Sheep eyes exhibit very low hyperopia and little astigmatism. Such visual characteristics are likely to produce a well-focused retinal image of objects in both the middle and long distance. Because sheep eyes have no accommodation, one might expect the image of very near objects to be blurred, but a rather clear near image could be provided by the tapetum and large retinal image of the sheep's eye, and adequate close vision may occur at muzzle length. Good depth perception, inferred from the sheep's sure-footedness, was confirmed in "visual cliff" experiments; behavioral responses indicating depth perception are seen in lambs at one day old. Sheep are thought to have colour vision, and can distinguish between a variety of colours: black, red, brown, green, yellow and white. Sight is a vital part of sheep communication, and when grazing, they maintain visual contact with each other. Each sheep lifts its head upwards to check the position of other sheep in the flock. This constant monitoring is probably what keeps the sheep in a flock as they move along grazing. Sheep become stressed when isolated; this stress is reduced if they are provided with a mirror, indicating that the sight of other sheep reduces stress.

 

Taste is the most important sense in sheep, establishing forage preferences, with sweet and sour plants being preferred and bitter plants being more commonly rejected. Touch and sight are also important in relation to specific plant characteristics, such as succulence and growth form.

 

The ram uses his vomeronasal organ (sometimes called the Jacobson's organ) to sense the pheromones of ewes and detect when they are in estrus. The ewe uses her vomeronasal organ for early recognition of her neonate lamb.

 

Reproduction

Sheep follow a similar reproductive strategy to other herd animals. A group of ewes is generally mated by a single ram, who has either been chosen by a breeder or (in feral populations) has established dominance through physical contest with other rams. Most sheep are seasonal breeders, although some are able to breed year-round. Ewes generally reach sexual maturity at six to eight months old, and rams generally at four to six months. However, there are exceptions. For example, Finnsheep ewe lambs may reach puberty as early as 3 to 4 months, and Merino ewes sometimes reach puberty at 18 to 20 months. Ewes have estrus cycles about every 17 days, during which they emit a scent and indicate readiness through physical displays towards rams.

 

In feral sheep, rams may fight during the rut to determine which individuals may mate with ewes. Rams, especially unfamiliar ones, will also fight outside the breeding period to establish dominance; rams can kill one another if allowed to mix freely. During the rut, even usually friendly rams may become aggressive towards humans due to increases in their hormone levels.

 

After mating, sheep have a gestation period of about five months, and normal labor takes one to three hours. Although some breeds regularly throw larger litters of lambs, most produce single or twin lambs. During or soon after labor, ewes and lambs may be confined to small lambing jugs, small pens designed to aid both careful observation of ewes and to cement the bond between them and their lambs.

  

A lamb's first steps

Ovine obstetrics can be problematic. By selectively breeding ewes that produce multiple offspring with higher birth weights for generations, sheep producers have inadvertently caused some domestic sheep to have difficulty lambing; balancing ease of lambing with high productivity is one of the dilemmas of sheep breeding. In the case of any such problems, those present at lambing may assist the ewe by extracting or repositioning lambs. After the birth, ewes ideally break the amniotic sac (if it is not broken during labor), and begin licking clean the lamb. Most lambs will begin standing within an hour of birth. In normal situations, lambs nurse after standing, receiving vital colostrum milk. Lambs that either fail to nurse or are rejected by the ewe require help to survive, such as bottle-feeding or fostering by another ewe.

 

Most lambs begin life being born outdoors. After lambs are several weeks old, lamb marking (ear tagging, docking, mulesing, and castrating) is carried out. Vaccinations are usually carried out at this point as well. Ear tags with numbers are attached, or ear marks are applied, for ease of later identification of sheep. Docking and castration are commonly done after 24 hours (to avoid interference with maternal bonding and consumption of colostrum) and are often done not later than one week after birth, to minimize pain, stress, recovery time and complications. The first course of vaccinations (commonly anti-clostridial) is commonly given at an age of about 10 to 12 weeks; i.e. when the concentration of maternal antibodies passively acquired via colostrum is expected to have fallen low enough to permit development of active immunity. Ewes are often revaccinated annually about 3 weeks before lambing, to provide high antibody concentrations in colostrum during the first several hours after lambing. Ram lambs that will either be slaughtered or separated from ewes before sexual maturity are not usually castrated. Objections to all these procedures have been raised by animal rights groups, but farmers defend them by saying they save money, and inflict only temporary pain.

 

Homosexuality

Sheep are the only species of mammal except for humans which exhibits exclusive homosexual behavior. About 10% of rams refuse to mate with ewes but readily mate with other rams, and thirty percent of all rams demonstrate at least some homosexual behavior. Additionally, a small number of females that were accompanied by a male fetus in utero (i.e. as fraternal twins) are freemartins (female animals that are behaviorally masculine and lack functioning ovaries).

 

Health

Sheep may fall victim to poisons, infectious diseases, and physical injuries. As a prey species, a sheep's system is adapted to hide the obvious signs of illness, to prevent being targeted by predators. However, some signs of ill health are obvious, with sick sheep eating little, vocalizing excessively, and being generally listless. Throughout history, much of the money and labor of sheep husbandry has aimed to prevent sheep ailments. Historically, shepherds often created remedies by experimentation on the farm. In some developed countries, including the United States, sheep lack the economic importance for drug companies to perform expensive clinical trials required to approve more than a relatively limited number of drugs for ovine use. However, extra-label drug use in sheep production is permitted in many jurisdictions, subject to certain restrictions. In the US, for example, regulations governing extra-label drug use in animals are found in 21 CFR (Code of Federal Regulations) Part 530. In the 20th and 21st centuries, a minority of sheep owners have turned to alternative treatments such as homeopathy, herbalism and even traditional Chinese medicine to treat sheep veterinary problems. Despite some favorable anecdotal evidence, the effectiveness of alternative veterinary medicine has been met with skepticism in scientific journals. The need for traditional anti-parasite drugs and antibiotics is widespread, and is the main impediment to certified organic farming with sheep.

 

Many breeders take a variety of preventive measures to ward off problems. The first is to ensure all sheep are healthy when purchased. Many buyers avoid outlets known to be clearing houses for animals culled from healthy flocks as either sick or simply inferior. This can also mean maintaining a closed flock, and quarantining new sheep for a month. Two fundamental preventive programs are maintaining good nutrition and reducing stress in the sheep. Restraint, isolation, loud noises, novel situations, pain, heat, extreme cold, fatigue and other stressors can lead to secretion of cortisol, a stress hormone, in amounts that may indicate welfare problems. Excessive stress can compromise the immune system. "Shipping fever" (pneumonic mannheimiosis, formerly called pasteurellosis) is a disease of particular concern, that can occur as a result of stress, notably during transport and (or) handling. Pain, fear and several other stressors can cause secretion of epinephrine (adrenaline). Considerable epinephrine secretion in the final days before slaughter can adversely affect meat quality (by causing glycogenolysis, removing the substrate for normal post-slaughter acidification of meat) and result in meat becoming more susceptible to colonization by spoilage bacteria. Because of such issues, low-stress handling is essential in sheep management. Avoiding poisoning is also important; common poisons are pesticide sprays, inorganic fertilizer, motor oil, as well as radiator coolant containing ethylene glycol.

 

Common forms of preventive medication for sheep are vaccinations and treatments for parasites. Both external and internal parasites are the most prevalent malady in sheep, and are either fatal, or reduce the productivity of flocks. Worms are the most common internal parasites. They are ingested during grazing, incubate within the sheep, and are expelled through the digestive system (beginning the cycle again). Oral anti-parasitic medicines, known as drenches, are given to a flock to treat worms, sometimes after worm eggs in the feces has been counted to assess infestation levels. Afterwards, sheep may be moved to a new pasture to avoid ingesting the same parasites. External sheep parasites include: lice (for different parts of the body), sheep keds, nose bots, sheep itch mites, and maggots. Keds are blood-sucking parasites that cause general malnutrition and decreased productivity, but are not fatal. Maggots are those of the bot fly and the blow-fly, commonly Lucilia sericata or its relative L. cuprina. Fly maggots cause the extremely destructive condition of flystrike. Flies lay their eggs in wounds or wet, manure-soiled wool; when the maggots hatch they burrow into a sheep's flesh, eventually causing death if untreated. In addition to other treatments, crutching (shearing wool from a sheep's rump) is a common preventive method. Some countries allow mulesing, a practice that involves stripping away the skin on the rump to prevent fly-strike, normally performed when the sheep is a lamb. Nose bots are fly larvae that inhabit a sheep's sinuses, causing breathing difficulties and discomfort. Common signs are a discharge from the nasal passage, sneezing, and frantic movement such as head shaking. External parasites may be controlled through the use of backliners, sprays or immersive sheep dips.

 

A wide array of bacterial and viral diseases affect sheep. Diseases of the hoof, such as foot rot and foot scald may occur, and are treated with footbaths and other remedies. Foot rot is present in over 97% of flocks in the UK. These painful conditions cause lameness and hinder feeding. Ovine Johne's disease is a wasting disease that affects young sheep. Bluetongue disease is an insect-borne illness causing fever and inflammation of the mucous membranes. Ovine rinderpest (or peste des petits ruminants) is a highly contagious and often fatal viral disease affecting sheep and goats. Sheep may also be affected by primary or secondary photosensitization. Tetanus can also afflict sheep through wounds from shearing, docking, castration, or vaccination. The organism also can be introduced into the reproductive tract by unsanitary humans who assist ewes during lambing.

 

A few sheep conditions are transmissible to humans. Orf (also known as scabby mouth, contagious ecthyma or soremouth) is a skin disease leaving lesions that is transmitted through skin-to-skin contact. Cutaneous anthrax is also called woolsorter's disease, as the spores can be transmitted in unwashed wool. More seriously, the organisms that can cause spontaneous enzootic abortion in sheep are easily transmitted to pregnant women. Also of concern are the prion disease scrapie and the virus that causes foot-and-mouth disease (FMD), as both can devastate flocks. The latter poses a slight risk to humans. During the 2001 FMD pandemic in the UK, hundreds of sheep were culled and some rare British breeds were at risk of extinction due to this.

 

Of the 600,300 sheep lost to the US economy in 2004, 37.3% were lost to predators, while 26.5% were lost to some form of disease. Poisoning accounted for 1.7% of non-productive deaths.

 

Predators

A lamb being attacked by coyotes with a bite to the throat

Other than parasites and disease, predation is a threat to sheep and the profitability of sheep raising. Sheep have little ability to defend themselves, compared with other species kept as livestock. Even if sheep survive an attack, they may die from their injuries or simply from panic. However, the impact of predation varies dramatically with region. In Africa, Australia, the Americas, and parts of Europe and Asia predators are a serious problem. In the United States, for instance, over one third of sheep deaths in 2004 were caused by predation. In contrast, other nations are virtually devoid of sheep predators, particularly islands known for extensive sheep husbandry. Worldwide, canids—including the domestic dog—are responsible for most sheep deaths. Other animals that occasionally prey on sheep include: felines, bears, birds of prey, ravens and feral hogs.

 

Sheep producers have used a wide variety of measures to combat predation. Pre-modern shepherds used their own presence, livestock guardian dogs, and protective structures such as barns and fencing. Fencing (both regular and electric), penning sheep at night and lambing indoors all continue to be widely used. More modern shepherds used guns, traps, and poisons to kill predators, causing significant decreases in predator populations. In the wake of the environmental and conservation movements, the use of these methods now usually falls under the purview of specially designated government agencies in most developed countries.

 

The 1970s saw a resurgence in the use of livestock guardian dogs and the development of new methods of predator control by sheep producers, many of them non-lethal. Donkeys and guard llamas have been used since the 1980s in sheep operations, using the same basic principle as livestock guardian dogs. Interspecific pasturing, usually with larger livestock such as cattle or horses, may help to deter predators, even if such species do not actively guard sheep. In addition to animal guardians, contemporary sheep operations may use non-lethal predator deterrents such as motion-activated lights and noisy alarms.

 

Economic importance

Main article: Agricultural economics

Global sheep stock

in 2019

Number in millions

1. China163.5 (13.19%)

2. India74.3 (5.99%)

3. Australia65.8 (5.31%)

4. Nigeria46.9 (3.78%)

5. Iran41.3 (3.33%)

6. Sudan40.9 (3.3%)

7. Chad35.9 (2.9%)

8. Turkey35.2 (2.84%)

9. United Kingdom33.6 (2.71%)

10. Mongolia32.3 (2.61%)

World total1,239.8

 

Source: UN Food and Agriculture Organization

Sheep are an important part of the global agricultural economy. However, their once vital status has been largely replaced by other livestock species, especially the pig, chicken, and cow. China, Australia, India, and Iran have the largest modern flocks, and serve both local and exportation needs for wool and mutton. Other countries such as New Zealand have smaller flocks but retain a large international economic impact due to their export of sheep products. Sheep also play a major role in many local economies, which may be niche markets focused on organic or sustainable agriculture and local food customers. Especially in developing countries, such flocks may be a part of subsistence agriculture rather than a system of trade. Sheep themselves may be a medium of trade in barter economies.

 

Domestic sheep provide a wide array of raw materials. Wool was one of the first textiles, although in the late 20th century wool prices began to fall dramatically as the result of the popularity and cheap prices for synthetic fabrics. For many sheep owners, the cost of shearing is greater than the possible profit from the fleece, making subsisting on wool production alone practically impossible without farm subsidies. Fleeces are used as material in making alternative products such as wool insulation. In the 21st century, the sale of meat is the most profitable enterprise in the sheep industry, even though far less sheep meat is consumed than chicken, pork or beef.

 

Sheepskin is likewise used for making clothes, footwear, rugs, and other products. Byproducts from the slaughter of sheep are also of value: sheep tallow can be used in candle and soap making, sheep bone and cartilage has been used to furnish carved items such as dice and buttons as well as rendered glue and gelatin. Sheep intestine can be formed into sausage casings, and lamb intestine has been formed into surgical sutures, as well as strings for musical instruments and tennis rackets. Sheep droppings, which are high in cellulose, have even been sterilized and mixed with traditional pulp materials to make paper. Of all sheep byproducts, perhaps the most valuable is lanolin: the waterproof, fatty substance found naturally in sheep's wool and used as a base for innumerable cosmetics and other products.

 

Some farmers who keep sheep also make a profit from live sheep. Providing lambs for youth programs such as 4-H and competition at agricultural shows is often a dependable avenue for the sale of sheep. Farmers may also choose to focus on a particular breed of sheep in order to sell registered purebred animals, as well as provide a ram rental service for breeding. A new option for deriving profit from live sheep is the rental of flocks for grazing; these "mowing services" are hired in order to keep unwanted vegetation down in public spaces and to lessen fire hazard.

 

Despite the falling demand and price for sheep products in many markets, sheep have distinct economic advantages when compared with other livestock. They do not require expensive housing, such as that used in the intensive farming of chickens or pigs. They are an efficient use of land; roughly six sheep can be kept on the amount that would suffice for a single cow or horse. Sheep can also consume plants, such as noxious weeds, that most other animals will not touch, and produce more young at a faster rate. Also, in contrast to most livestock species, the cost of raising sheep is not necessarily tied to the price of feed crops such as grain, soybeans and corn. Combined with the lower cost of quality sheep, all these factors combine to equal a lower overhead for sheep producers, thus entailing a higher profitability potential for the small farmer. Sheep are especially beneficial for independent producers, including family farms with limited resources, as the sheep industry is one of the few types of animal agriculture that has not been vertically integrated by agribusiness. However, small flocks, from 10 to 50 ewes, often are not profitable because they tend to be poorly managed. The primary reason is that mechanization is not feasible, so return per hour of labor is not maximized. Small farm flocks generally are used simply to control weeds on irrigation ditches or maintained as a hobby.

 

Shoulder of lamb

Sheep meat and milk were one of the earliest staple proteins consumed by human civilization after the transition from hunting and gathering to agriculture. Sheep meat prepared for food is known as either mutton or lamb, and approximately 540 million sheep are slaughtered each year for meat worldwide. "Mutton" is derived from the Old French moton, which was the word for sheep used by the Anglo-Norman rulers of much of the British Isles in the Middle Ages. This became the name for sheep meat in English, while the Old English word sceap was kept for the live animal. Throughout modern history, "mutton" has been limited to the meat of mature sheep usually at least two years of age; "lamb" is used for that of immature sheep less than a year.

 

In the 21st century, the nations with the highest consumption of sheep meat are the Arab states of the Persian Gulf, New Zealand, Australia, Greece, Uruguay, the United Kingdom and Ireland. These countries eat 14–40 lbs (3–18 kg) of sheep meat per capita, per annum. Sheep meat is also popular in France, Africa (especially the Arab world), the Caribbean, the rest of the Middle East, India, and parts of China. This often reflects a history of sheep production. In these countries in particular, dishes comprising alternative cuts and offal may be popular or traditional. Sheep testicles—called animelles or lamb fries—are considered a delicacy in many parts of the world. Perhaps the most unusual dish of sheep meat is the Scottish haggis, composed of various sheep innards cooked along with oatmeal and chopped onions inside its stomach. In comparison, countries such as the U.S. consume only a pound or less (under 0.5 kg), with Americans eating 50 pounds (22 kg) of pork and 65 pounds (29 kg) of beef. In addition, such countries rarely eat mutton, and may favor the more expensive cuts of lamb: mostly lamb chops and leg of lamb.

 

Though sheep's milk may be drunk rarely in fresh form, today it is used predominantly in cheese and yogurt making. Sheep have only two teats, and produce a far smaller volume of milk than cows. However, as sheep's milk contains far more fat, solids, and minerals than cow's milk, it is ideal for the cheese-making process. It also resists contamination during cooling better because of its much higher calcium content. Well-known cheeses made from sheep milk include the feta of Bulgaria and Greece, Roquefort of France, Manchego from Spain, the pecorino romano (the Italian word for "sheep" is pecore) and ricotta of Italy. Yogurts, especially some forms of strained yogurt, may also be made from sheep milk. Many of these products are now often made with cow's milk, especially when produced outside their country of origin. Sheep milk contains 4.8% lactose, which may affect those who are intolerant.

 

As with other domestic animals, the meat of uncastrated males is inferior in quality, especially as they grow. A "bucky" lamb is a lamb which was not castrated early enough, or which was castrated improperly (resulting in one testicle being retained). These lambs are worth less at market.

 

In science

Sheep are generally too large and reproduce too slowly to make ideal research subjects, and thus are not a common model organism. They have, however, played an influential role in some fields of science. In particular, the Roslin Institute of Edinburgh, Scotland used sheep for genetics research that produced groundbreaking results. In 1995, two ewes named Megan and Morag were the first mammals cloned from differentiated cells, also referred to as gynomerogony. A year later, a Finnish Dorset sheep named Dolly, dubbed "the world's most famous sheep" in Scientific American, was the first mammal to be cloned from an adult somatic cell. Following this, Polly and Molly were the first mammals to be simultaneously cloned and transgenic.

 

As of 2008, the sheep genome has not been fully sequenced, although a detailed genetic map has been published, and a draft version of the complete genome produced by assembling sheep DNA sequences using information given by the genomes of other mammals. In 2012, a transgenic sheep named "Peng Peng" was cloned by Chinese scientists, who spliced his genes with that of a roundworm (C. elegans) in order to increase production of fats healthier for human consumption.

 

In the study of natural selection, the population of Soay sheep that remain on the island of Hirta have been used to explore the relation of body size and coloration to reproductive success. Soay sheep come in several colors, and researchers investigated why the larger, darker sheep were in decline; this occurrence contradicted the rule of thumb that larger members of a population tend to be more successful reproductively. The feral Soays on Hirta are especially useful subjects because they are isolated.

 

Domestic sheep are sometimes used in medical research, particularly for researching cardiovascular physiology, in areas such as hypertension and heart failure. Pregnant sheep are also a useful model for human pregnancy, and have been used to investigate the effects on fetal development of malnutrition and hypoxia. In behavioral sciences, sheep have been used in isolated cases for the study of facial recognition, as their mental process of recognition is qualitatively similar to humans.

 

Cultural impact

Sheep have had a strong presence in many cultures, especially in areas where they form the most common type of livestock. In the English language, to call someone a sheep or ovine may allude that they are timid and easily led. In contradiction to this image, male sheep are often used as symbols of virility and power; the logos of the Los Angeles Rams football team and the Dodge Ram pickup truck allude to males of the bighorn sheep, Ovis canadensis.

 

Counting sheep is popularly said to be an aid to sleep, and some ancient systems of counting sheep persist today. Sheep also enter in colloquial sayings and idiom frequently with such phrases as "black sheep". To call an individual a black sheep implies that they are an odd or disreputable member of a group. This usage derives from the recessive trait that causes an occasional black lamb to be born into an entirely white flock. These black sheep were considered undesirable by shepherds, as black wool is not as commercially viable as white wool. Citizens who accept overbearing governments have been referred to by the Portmanteau neologism of sheeple. Somewhat differently, the adjective "sheepish" is also used to describe embarrassment.

 

In heraldry

In British heraldry, sheep appear in the form of rams, sheep proper and lambs. These are distinguished by the ram being depicted with horns and a tail, the sheep with neither and the lamb with its tail only. A further variant of the lamb, termed the Paschal lamb, is depicted as carrying a Christian cross and with a halo over its head. Rams' heads, portrayed without a neck and facing the viewer, are also found in British armories. The fleece, depicted as an entire sheepskin carried by a ring around its midsection, originally became known through its use in the arms of the Order of the Golden Fleece and was later adopted by towns and individuals with connections to the wool industry. A sheep on a blue field is depicted on the greater/royal arms of the king of Denmark to represent the Faroe Islands. In 2004 a modernized arms has been adopted by the Faroe Islands, which based on a 15th century coat of arms.

 

Religion and folklore

In antiquity, symbolism involving sheep cropped up in religions in the ancient Near East, the Mideast, and the Mediterranean area: Çatalhöyük, ancient Egyptian religion, the Cana'anite and Phoenician tradition, Judaism, Greek religion, and others. Religious symbolism and ritual involving sheep began with some of the first known faiths: Skulls of rams (along with bulls) occupied central placement in shrines at the Çatalhöyük settlement in 8,000 BCE. In Ancient Egyptian religion, the ram was the symbol of several gods: Khnum, Heryshaf and Amun (in his incarnation as a god of fertility). Other deities occasionally shown with ram features include the goddess Ishtar, the Phoenician god Baal-Hamon, and the Babylonian god Ea-Oannes. In Madagascar, sheep were not eaten as they were believed to be incarnations of the souls of ancestors.

 

There are many ancient Greek references to sheep: that of Chrysomallos, the golden-fleeced ram, continuing to be told through into the modern era. Astrologically, Aries, the ram, is the first sign of the classical Greek zodiac, and the sheep is the eighth of the twelve animals associated with the 12-year cycle of in the Chinese zodiac, related to the Chinese calendar. It is said in Chinese traditions that Hou ji sacrificed sheep. Mongolia, shagai are an ancient form of dice made from the cuboid bones of sheep that are often used for fortunetelling purposes.

 

Sheep play an important role in all the Abrahamic faiths; Abraham, Isaac, Jacob, Moses, and King David were all shepherds. According to the Biblical story of the Binding of Isaac, a ram is sacrificed as a substitute for Isaac after an angel stays Abraham's hand (in the Islamic tradition, Abraham was about to sacrifice Ishmael). Eid al-Adha is a major annual festival in Islam in which sheep (or other animals) are sacrificed in remembrance of this act. Sheep are occasionally sacrificed to commemorate important secular events in Islamic cultures. Greeks and Romans sacrificed sheep regularly in religious practice, and Judaism once sacrificed sheep as a Korban (sacrifice), such as the Passover lamb. Ovine symbols—such as the ceremonial blowing of a shofar—still find a presence in modern Judaic traditions.

 

Collectively, followers of Christianity are often referred to as a flock, with Christ as the Good Shepherd, and sheep are an element in the Christian iconography of the birth of Jesus. Some Christian saints are considered patrons of shepherds, and even of sheep themselves. Christ is also portrayed as the Sacrificial lamb of God (Agnus Dei) and Easter celebrations in Greece and Romania traditionally feature a meal of Paschal lamb. A church leader is often called the pastor, which is derived from the Latin word for shepherd. In many western Christian traditions bishops carry a staff, which also serves as a symbol of the episcopal office, known as a crosier, which is modeled on the shepherd's crook.

 

Sheep are key symbols in fables and nursery rhymes like The Wolf in Sheep's Clothing, Little Bo Peep, Baa, Baa, Black Sheep, and Mary Had a Little Lamb; novels such as George Orwell's Animal Farm and Haruki Murakami's A Wild Sheep Chase; songs such as Bach's Sheep may safely graze (Schafe können sicher weiden) and Pink Floyd's "Sheep", and poems like William Blake's "The Lamb".

I will probably not be able to get back on today to comment as I'm having a "Retinal scan" done later.

 

Home to England’s highest waterfall, descending a staggering 220 ft, Canonteign Falls is a breathtaking Devon attraction, and a wonderful day out for all the family.

Water rushing over Canonteign falls in Devon

 

Situated within Dartmoor National Park, in the heart of Devon’s Teign Valley, the waterfalls tumble down ancient rock formations to meet the tranquil lakes below, offering some of the most spectacular waterfall and woodland scenery in Devon.

 

The lakes and walks, now very well established, provide a combination of traditional English wetland vegetation along with selected exotic water plants.

 

A haven for wildlife, we are working together with the Devon Wildlife Trust to manage our lakes sustainably. Our Devon Wildlife Trust information boards examine the extraordinary dragonflies and damselflies that have made our lakes in Devon their natural habitat.

 

In the early 1990s the current Lord Exmouth constructed a further four lakes, and here, particularly in spring and early summer, carpets of yellow buttercups and orchids adorn the grassland. Taking the path alongside Lily lake leading to the wetlands and lower lakes, is one of the most fascinating nature walks in Devon, giving you the opportunity to spot kingfishers, bats, butterflies, wildfowl, dragonflies and otter; and the ancient wetland area close to the Elizabethan walled garden provides a habitat for swathes of yellow flag irises.

 

There are seven interconnecting lakes. The main Lily Lake has a central island with beautiful purple flowering rhododendrons in spring time and a provides safe cover for the many Mallard ducks and their ducklings in spring. Clearing of trees has been undertaken at the Falls end of the lake and the visitor can now enjoy a much enhanced view whilst walking around the Lake.

 

The six lower lakes are linked up with grassy walks and bridges. Planting combinations fo dogwood, acers, gunnera and pampas grass provide year round texture and colour.

 

www.canonteignfalls.co.uk/Facilities/the-lakes

A while ago we got in touch with Sr. X and asked if he'd be interested in doing a collaboration with us. We'd always liked his style and thought we may well be able to have some fun with a bit of street work. After knocking a few ideas round between us we settled on the idea of a stare off using the same image of a rather angry man as our starting point and seeing where we'd end up each doing it in our own style. So, with a somewhat unnatural day of sunshine promised for Sunday we packed up the id-iomobile and set off for the East End with hope in our hearts.

 

We'd had to guesstimate the size of the gates based on a photo but it turns out that we'd got the measurement just about spot on. So far, so good. Once we'd made the requisite amount of mess for his face it was just a matter or adding the stencil again and getting some shading in there. Meanwhile, Sr. X was adding his signature paint splashes that give a certain motion to the whole thing. At this point I remembered the LED's we'd brought along so it was decided to have some laser eyes that would hopefully give the whole piece a bit of a lift when darkness fell. I'm not entirely sure how long they last but I'm hoping maybe a week or so (if they haven't been stolen or removed by that time). I'm not sure who's going to win the stare off but all the loser has got to look forward to is some permanent retinal damage...

 

Cheers

 

id-iom

A study of the effects of high voltage and household cleaning products on instant pull apart color film.

 

Materials: Fujifilm FP100-45C Instant Color Film, various household cleaning products (bleach, vinegar, baking soda, hydrogen peroxide, salt, rubbing alcohol), 15,000 volt neon tube ballast.

 

Copyright Phillip Stearns

Every few minutes the past couple of days, someone was emphatically stating that you must NOT!!!!!! look at the sun directly during the eclipse, and they are right. Bad idea unless you are into serious irreversible retinal damage. Not this photographer. I recalled an eclipse when I was young and watching the dappled sun under our cherry tree showing the sun’s eclipse progress and being quite enthralled by it all. With that in mind, and while enjoying a cup of tea with our neighbours, we watched the openings in the maple tree adjacent to our deck act as multiple pinhole cameras showing large images of the sun as the moon passed its face. Here we see as good as it got here in Grimsby, Ontario at peak. Simple, and safe. Oh, and we did watch the live NASA coverage as well, so no, not quite up to NASA’s standards but simple, safe and effective. Now for 2024’s total eclipse in this area. - JW (BTW – the newspaper was put there to show the date and also to show how large the images were.)

 

Date Taken: 2017-08-21 Time: 14:32:29 – peak eclipse time in Grimsby, Ontario

 

Tech Details:

 

Taken using a hand-held Nikon D7100 fitted with a Nikkor 12-24mm lense set to 15mm, ISO400 (Auto ISO), Aperture priority mode, f/4.5, 1/50 sec. PP in free Open Source GIMP: Kept it really simply, just tweaked the highlights slightly on the SOOC jpeg and then did the usual stuff.

Jellyfish, also known sea jellies, are the medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria.

 

Jellyfish are mainly free-swimming marine animals with umbrella-shaped bells and trailing tentacles, although a few are anchored to the seabed by stalks rather than being mobile. The bell can pulsate to provide propulsion for highly efficient locomotion. The tentacles are armed with stinging cells and may be used to capture prey and defend against predators. Jellyfish have a complex life cycle. The medusa is normally the sexual phase, which produces planula larvae; these then disperse widely and enter a sedentary polyp phase, before reaching sexual maturity.

 

Jellyfish are found all over the world, from surface waters to the deep sea. Scyphozoans (the "true jellyfish") are exclusively marine, but some hydrozoans with a similar appearance live in freshwater. Large, often colorful, jellyfish are common in coastal zones worldwide. The medusae of most species are fast-growing, and mature within a few months then die soon after breeding, but the polyp stage, attached to the seabed, may be much more long-lived. Jellyfish have been in existence for at least 500 million years, and possibly 700 million years or more, making them the oldest multi-organ animal group.

 

Jellyfish are eaten by humans in certain cultures. They are considered a delicacy in some Asian countries, where species in the Rhizostomeae order are pressed and salted to remove excess water. Australian researchers have described them as a "perfect food": sustainable and protein-rich but relatively low in food energy.

 

They are also used in research, where the green fluorescent protein used by some species to cause bioluminescence has been adapted as a fluorescent marker for genes inserted into other cells or organisms.

 

The stinging cells used by jellyfish to subdue their prey can injure humans. Thousands of swimmers worldwide are stung every year, with effects ranging from mild discomfort to serious injury or even death. When conditions are favourable, jellyfish can form vast swarms, which can be responsible for damage to fishing gear by filling fishing nets, and sometimes clog the cooling systems of power and desalination plants which draw their water from the sea.

  

Names

The name jellyfish, in use since 1796, has traditionally been applied to medusae and all similar animals including the comb jellies (ctenophores, another phylum). The term jellies or sea jellies is more recent, having been introduced by public aquaria in an effort to avoid use of the word "fish" with its modern connotation of an animal with a backbone, though shellfish, cuttlefish and starfish are not vertebrates either. In scientific literature, "jelly" and "jellyfish" have been used interchangeably. Many sources refer to only scyphozoans as "true jellyfish".

 

A group of jellyfish is called a "smack" or a "smuck".

 

Definition

The term jellyfish broadly corresponds to medusae, that is, a life-cycle stage in the Medusozoa. The American evolutionary biologist Paulyn Cartwright gives the following general definition:

 

Typically, medusozoan cnidarians have a pelagic, predatory jellyfish stage in their life cycle; staurozoans are the exceptions [as they are stalked].

 

The Merriam-Webster dictionary defines jellyfish as follows:

 

A free-swimming marine coelenterate that is the sexually reproducing form of a hydrozoan or scyphozoan and has a nearly transparent saucer-shaped body and extensible marginal tentacles studded with stinging cells.

 

Given that jellyfish is a common name, its mapping to biological groups is inexact. Some authorities have called the comb jellies and certain salps jellyfish, though other authorities state that neither of these are jellyfish, which they consider should be limited to certain groups within the medusozoa.

 

The non-medusozoan clades called jellyfish by some but not all authorities (both agreeing and disagreeing citations are given in each case) are indicated with on the following cladogram of the animal kingdom:

 

Jellyfish are not a clade, as they include most of the Medusozoa, barring some of the Hydrozoa. The medusozoan groups included by authorities are indicated on the following phylogenetic tree by the presence of citations. Names of included jellyfish, in English where possible, are shown in boldface; the presence of a named and cited example indicates that at least that species within its group has been called a jellyfish.

 

Taxonomy

The subphylum Medusozoa includes all cnidarians with a medusa stage in their life cycle. The basic cycle is egg, planula larva, polyp, medusa, with the medusa being the sexual stage. The polyp stage is sometimes secondarily lost. The subphylum include the major taxa, Scyphozoa (large jellyfish), Cubozoa (box jellyfish) and Hydrozoa (small jellyfish), and excludes Anthozoa (corals and sea anemones). This suggests that the medusa form evolved after the polyps. Medusozoans have tetramerous symmetry, with parts in fours or multiples of four.

 

The four major classes of medusozoan Cnidaria are:

Scyphozoa are sometimes called true jellyfish, though they are no more truly jellyfish than the others listed here. They have tetra-radial symmetry. Most have tentacles around the outer margin of the bowl-shaped bell, and long, oral arms around the mouth in the center of the subumbrella.

Cubozoa (box jellyfish) have a (rounded) box-shaped bell, and their velarium assists them to swim more quickly. Box jellyfish may be related more closely to scyphozoan jellyfish than either are to the Hydrozoa.

Hydrozoa medusae also have tetra-radial symmetry, nearly always have a velum (diaphragm used in swimming) attached just inside the bell margin, do not have oral arms, but a much smaller central stalk-like structure, the manubrium, with terminal mouth opening, and are distinguished by the absence of cells in the mesoglea. Hydrozoa show great diversity of lifestyle; some species maintain the polyp form for their entire life and do not form medusae at all (such as Hydra, which is hence not considered a jellyfish), and a few are entirely medusal and have no polyp form.

Staurozoa (stalked jellyfish) are characterized by a medusa form that is generally sessile, oriented upside down and with a stalk emerging from the apex of the "calyx" (bell), which attaches to the substrate. At least some Staurozoa also have a polyp form that alternates with the medusoid portion of the life cycle. Until recently, Staurozoa were classified within the Scyphozoa.

There are over 200 species of Scyphozoa, about 50 species of Staurozoa, about 50 species of Cubozoa, and the Hydrozoa includes about 1000–1500 species that produce medusae, but many more species that do not.

 

Fossil history

Since jellyfish have no hard parts, fossils are rare. The oldest unambiguous fossil of a free-swimming medusa is Burgessomedusa from the mid Cambrian Burgess Shale of Canada, which is likely either a stem group of box jellyfish (Cubozoa) or Acraspeda (the clade including Staurozoa, Cubozoa, and Scyphozoa). Other claimed records from the Cambrian of China and Utah in the United States are uncertain, and possibly represent ctenophores instead.

 

Anatomy

The main feature of a true jellyfish is the umbrella-shaped bell. This is a hollow structure consisting of a mass of transparent jelly-like matter known as mesoglea, which forms the hydrostatic skeleton of the animal. 95% or more of the mesogloea consists of water, but it also contains collagen and other fibrous proteins, as well as wandering amoebocytes which can engulf debris and bacteria. The mesogloea is bordered by the epidermis on the outside and the gastrodermis on the inside. The edge of the bell is often divided into rounded lobes known as lappets, which allow the bell to flex. In the gaps or niches between the lappets are dangling rudimentary sense organs known as rhopalia, and the margin of the bell often bears tentacles.

  

Anatomy of a scyphozoan jellyfish

On the underside of the bell is the manubrium, a stalk-like structure hanging down from the centre, with the mouth, which also functions as the anus, at its tip. There are often four oral arms connected to the manubrium, streaming away into the water below. The mouth opens into the gastrovascular cavity, where digestion takes place and nutrients are absorbed. This is subdivided by four thick septa into a central stomach and four gastric pockets. The four pairs of gonads are attached to the septa, and close to them four septal funnels open to the exterior, perhaps supplying good oxygenation to the gonads. Near the free edges of the septa, gastric filaments extend into the gastric cavity; these are armed with nematocysts and enzyme-producing cells and play a role in subduing and digesting the prey. In some scyphozoans, the gastric cavity is joined to radial canals which branch extensively and may join a marginal ring canal. Cilia in these canals circulate the fluid in a regular direction.

  

Discharge mechanism of a nematocyst

The box jellyfish is largely similar in structure. It has a squarish, box-like bell. A short pedalium or stalk hangs from each of the four lower corners. One or more long, slender tentacles are attached to each pedalium. The rim of the bell is folded inwards to form a shelf known as a velarium which restricts the bell's aperture and creates a powerful jet when the bell pulsates, allowing box jellyfish to swim faster than true jellyfish. Hydrozoans are also similar, usually with just four tentacles at the edge of the bell, although many hydrozoans are colonial and may not have a free-living medusal stage. In some species, a non-detachable bud known as a gonophore is formed that contains a gonad but is missing many other medusal features such as tentacles and rhopalia. Stalked jellyfish are attached to a solid surface by a basal disk, and resemble a polyp, the oral end of which has partially developed into a medusa with tentacle-bearing lobes and a central manubrium with four-sided mouth.

 

Most jellyfish do not have specialized systems for osmoregulation, respiration and circulation, and do not have a central nervous system. Nematocysts, which deliver the sting, are located mostly on the tentacles; true jellyfish also have them around the mouth and stomach. Jellyfish do not need a respiratory system because sufficient oxygen diffuses through the epidermis. They have limited control over their movement, but can navigate with the pulsations of the bell-like body; some species are active swimmers most of the time, while others largely drift. The rhopalia contain rudimentary sense organs which are able to detect light, water-borne vibrations, odour and orientation. A loose network of nerves called a "nerve net" is located in the epidermis. Although traditionally thought not to have a central nervous system, nerve net concentration and ganglion-like structures could be considered to constitute one in most species. A jellyfish detects stimuli, and transmits impulses both throughout the nerve net and around a circular nerve ring, to other nerve cells. The rhopalial ganglia contain pacemaker neurones which control swimming rate and direction.

 

In many species of jellyfish, the rhopalia include ocelli, light-sensitive organs able to tell light from dark. These are generally pigment spot ocelli, which have some of their cells pigmented. The rhopalia are suspended on stalks with heavy crystals at one end, acting like gyroscopes to orient the eyes skyward. Certain jellyfish look upward at the mangrove canopy while making a daily migration from mangrove swamps into the open lagoon, where they feed, and back again.

 

Box jellyfish have more advanced vision than the other groups. Each individual has 24 eyes, two of which are capable of seeing colour, and four parallel information processing areas that act in competition, supposedly making them one of the few kinds of animal to have a 360-degree view of its environment.

 

Box jellyfish eye

The study of jellyfish eye evolution is an intermediary to a better understanding of how visual systems evolved on Earth. Jellyfish exhibit immense variation in visual systems ranging from photoreceptive cell patches seen in simple photoreceptive systems to more derived complex eyes seen in box jellyfish. Major topics of jellyfish visual system research (with an emphasis on box jellyfish) include: the evolution of jellyfish vision from simple to complex visual systems), the eye morphology and molecular structures of box jellyfish (including comparisons to vertebrate eyes), and various uses of vision including task-guided behaviors and niche specialization.

 

Evolution

Experimental evidence for photosensitivity and photoreception in cnidarians antecedes the mid 1900s, and a rich body of research has since covered evolution of visual systems in jellyfish. Jellyfish visual systems range from simple photoreceptive cells to complex image-forming eyes. More ancestral visual systems incorporate extraocular vision (vision without eyes) that encompass numerous receptors dedicated to single-function behaviors. More derived visual systems comprise perception that is capable of multiple task-guided behaviors.

 

Although they lack a true brain, cnidarian jellyfish have a "ring" nervous system that plays a significant role in motor and sensory activity. This net of nerves is responsible for muscle contraction and movement and culminates the emergence of photosensitive structures. Across Cnidaria, there is large variation in the systems that underlie photosensitivity. Photosensitive structures range from non-specialized groups of cells, to more "conventional" eyes similar to those of vertebrates. The general evolutionary steps to develop complex vision include (from more ancestral to more derived states): non-directional photoreception, directional photoreception, low-resolution vision, and high-resolution vision. Increased habitat and task complexity has favored the high-resolution visual systems common in derived cnidarians such as box jellyfish.

 

Basal visual systems observed in various cnidarians exhibit photosensitivity representative of a single task or behavior. Extraocular photoreception (a form of non-directional photoreception), is the most basic form of light sensitivity and guides a variety of behaviors among cnidarians. It can function to regulate circadian rhythm (as seen in eyeless hydrozoans) and other light-guided behaviors responsive to the intensity and spectrum of light. Extraocular photoreception can function additionally in positive phototaxis (in planula larvae of hydrozoans), as well as in avoiding harmful amounts of UV radiation via negative phototaxis. Directional photoreception (the ability to perceive direction of incoming light) allows for more complex phototactic responses to light, and likely evolved by means of membrane stacking. The resulting behavioral responses can range from guided spawning events timed by moonlight to shadow responses for potential predator avoidance. Light-guided behaviors are observed in numerous scyphozoans including the common moon jelly, Aurelia aurita, which migrates in response to changes in ambient light and solar position even though they lack proper eyes.

 

The low-resolution visual system of box jellyfish is more derived than directional photoreception, and thus box jellyfish vision represents the most basic form of true vision in which multiple directional photoreceptors combine to create the first imaging and spatial resolution. This is different from the high-resolution vision that is observed in camera or compound eyes of vertebrates and cephalopods that rely on focusing optics. Critically, the visual systems of box jellyfish are responsible for guiding multiple tasks or behaviors in contrast to less derived visual systems in other jellyfish that guide single behavioral functions. These behaviors include phototaxis based on sunlight (positive) or shadows (negative), obstacle avoidance, and control of swim-pulse rate.

 

Box jellyfish possess "proper eyes" (similar to vertebrates) that allow them to inhabit environments that lesser derived medusae cannot. In fact, they are considered the only class in the clade Medusozoa that have behaviors necessitating spatial resolution and genuine vision. However, the lens in their eyes are more functionally similar to cup-eyes exhibited in low-resolution organisms, and have very little to no focusing capability. The lack of the ability to focus is due to the focal length exceeding the distance to the retina, thus generating unfocused images and limiting spatial resolution. The visual system is still sufficient for box jellyfish to produce an image to help with tasks such as object avoidance.

 

Utility as a model organism

Box jellyfish eyes are a visual system that is sophisticated in numerous ways. These intricacies include the considerable variation within the morphology of box jellyfishes' eyes (including their task/behavior specification), and the molecular makeup of their eyes including: photoreceptors, opsins, lenses, and synapses. The comparison of these attributes to more derived visual systems can allow for a further understanding of how the evolution of more derived visual systems may have occurred, and puts into perspective how box jellyfish can play the role as an evolutionary/developmental model for all visual systems.

 

Characteristics

Box jellyfish visual systems are both diverse and complex, comprising multiple photosystems. There is likely considerable variation in visual properties between species of box jellyfish given the significant inter-species morphological and physiological variation. Eyes tend to differ in size and shape, along with number of receptors (including opsins), and physiology across species of box jellyfish.

 

Box jellyfish have a series of intricate lensed eyes that are similar to those of more derived multicellular organisms such as vertebrates. Their 24 eyes fit into four different morphological categories. These categories consist of two large, morphologically different medial eyes (a lower and upper lensed eye) containing spherical lenses, a lateral pair of pigment slit eyes, and a lateral pair of pigment pit eyes. The eyes are situated on rhopalia (small sensory structures) which serve sensory functions of the box jellyfish and arise from the cavities of the exumbrella (the surface of the body) on the side of the bells of the jellyfish. The two large eyes are located on the mid-line of the club and are considered complex because they contain lenses. The four remaining eyes lie laterally on either side of each rhopalia and are considered simple. The simple eyes are observed as small invaginated cups of epithelium that have developed pigmentation. The larger of the complex eyes contains a cellular cornea created by a mono ciliated epithelium, cellular lens, homogenous capsule to the lens, vitreous body with prismatic elements, and a retina of pigmented cells. The smaller of the complex eyes is said to be slightly less complex given that it lacks a capsule but otherwise contains the same structure as the larger eye.

 

Box jellyfish have multiple photosystems that comprise different sets of eyes. Evidence includes immunocytochemical and molecular data that show photopigment differences among the different morphological eye types, and physiological experiments done on box jellyfish to suggest behavioral differences among photosystems. Each individual eye type constitutes photosystems that work collectively to control visually guided behaviors.

 

Box jellyfish eyes primarily use c-PRCs (ciliary photoreceptor cells) similar to that of vertebrate eyes. These cells undergo phototransduction cascades (process of light absorption by photoreceptors) that are triggered by c-opsins. Available opsin sequences suggest that there are two types of opsins possessed by all cnidarians including an ancient phylogenetic opsin, and a sister ciliary opsin to the c-opsins group. Box jellyfish could have both ciliary and cnidops (cnidarian opsins), which is something not previously believed to appear in the same retina. Nevertheless, it is not entirely evident whether cnidarians possess multiple opsins that are capable of having distinctive spectral sensitivities.

 

Comparison with other organisms

Comparative research on genetic and molecular makeup of box jellyfishes' eyes versus more derived eyes seen in vertebrates and cephalopods focuses on: lenses and crystallin composition, synapses, and Pax genes and their implied evidence for shared primordial (ancestral) genes in eye evolution.

 

Box jellyfish eyes are said to be an evolutionary/developmental model of all eyes based on their evolutionary recruitment of crystallins and Pax genes. Research done on box jellyfish including Tripedalia cystophora has suggested that they possess a single Pax gene, PaxB. PaxB functions by binding to crystallin promoters and activating them. PaxB in situ hybridization resulted in PaxB expression in the lens, retina, and statocysts. These results and the rejection of the prior hypothesis that Pax6 was an ancestral Pax gene in eyes has led to the conclusion that PaxB was a primordial gene in eye evolution, and that the eyes of all organisms likely share a common ancestor.

 

The lens structure of box jellyfish appears very similar to those of other organisms, but the crystallins are distinct in both function and appearance. Weak reactions were seen within the sera and there were very weak sequence similarities within the crystallins among vertebrate and invertebrate lenses. This is likely due to differences in lower molecular weight proteins and the subsequent lack of immunological reactions with antisera that other organisms' lenses exhibit.

 

All four of the visual systems of box jellyfish species investigated with detail (Carybdea marsupialis, Chiropsalmus quadrumanus, Tamoya haplonema and Tripedalia cystophora) have invaginated synapses, but only in the upper and lower lensed eyes. Different densities were found between the upper and lower lenses, and between species. Four types of chemical synapses have been discovered within the rhopalia which could help in understanding neural organization including: clear unidirectional, dense-core unidirectional, clear bidirectional, and clear and dense-core bidirectional. The synapses of the lensed eyes could be useful as markers to learn more about the neural circuit in box jellyfish retinal areas.

 

Evolution as a response to natural stimuli

The primary adaptive responses to environmental variation observed in box jellyfish eyes include pupillary constriction speeds in response to light environments, as well as photoreceptor tuning and lens adaptations to better respond to shifts between light environments and darkness. Interestingly, some box jellyfish species' eyes appear to have evolved more focused vision in response to their habitat.

 

Pupillary contraction appears to have evolved in response to variation in the light environment across ecological niches across three species of box jellyfish (Chironex fleckeri, Chiropsella bronzie, and Carukia barnesi). Behavioral studies suggest that faster pupil contraction rates allow for greater object avoidance, and in fact, species with more complex habitats exhibit faster rates. Ch. bronzie inhabit shallow beach fronts that have low visibility and very few obstacles, thus, faster pupil contraction in response to objects in their environment is not important. Ca. barnesi and Ch. fleckeri are found in more three-dimensionally complex environments like mangroves with an abundance of natural obstacles, where faster pupil contraction is more adaptive. Behavioral studies support the idea that faster pupillary contraction rates assist with obstacle avoidance as well as depth adjustments in response to differing light intensities.

 

Light/dark adaptation via pupillary light reflexes is an additional form of an evolutionary response to the light environment. This relates to the pupil's response to shifts between light intensity (generally from sunlight to darkness). In the process of light/dark adaptation, the upper and lower lens eyes of different box jellyfish species vary in specific function. The lower lens-eyes contain pigmented photoreceptors and long pigment cells with dark pigments that migrate on light/dark adaptation, while the upper-lens eyes play a concentrated role in light direction and phototaxis given that they face upward towards the water surface (towards the sun or moon). The upper lens of Ch. bronzie does not exhibit any considerable optical power while Tr. cystophora (a box jellyfish species that tends to live in mangroves) does. The ability to use light to visually guide behavior is not of as much importance to Ch. bronzie as it is to species in more obstacle-filled environments. Differences in visually guided behavior serve as evidence that species that share the same number and structure of eyes can exhibit differences in how they control behavior.

 

Largest and smallest

Jellyfish range from about one millimeter in bell height and diameter, to nearly 2 metres (6+1⁄2 ft) in bell height and diameter; the tentacles and mouth parts usually extend beyond this bell dimension.

 

The smallest jellyfish are the peculiar creeping jellyfish in the genera Staurocladia and Eleutheria, which have bell disks from 0.5 millimetres (1⁄32 in) to a few millimeters in diameter, with short tentacles that extend out beyond this, which these jellyfish use to move across the surface of seaweed or the bottoms of rocky pools; many of these tiny creeping jellyfish cannot be seen in the field without a hand lens or microscope. They can reproduce asexually by fission (splitting in half). Other very small jellyfish, which have bells about one millimeter, are the hydromedusae of many species that have just been released from their parent polyps; some of these live only a few minutes before shedding their gametes in the plankton and then dying, while others will grow in the plankton for weeks or months. The hydromedusae Cladonema radiatum and Cladonema californicum are also very small, living for months, yet never growing beyond a few mm in bell height and diameter.

 

The lion's mane jellyfish, Cyanea capillata, was long-cited as the largest jellyfish, and arguably the longest animal in the world, with fine, thread-like tentacles that may extend up to 36.5 m (119 ft 9 in) long (though most are nowhere near that large). They have a moderately painful, but rarely fatal, sting. The increasingly common giant Nomura's jellyfish, Nemopilema nomurai, found in some, but not all years in the waters of Japan, Korea and China in summer and autumn is another candidate for "largest jellyfish", in terms of diameter and weight, since the largest Nomura's jellyfish in late autumn can reach 2 m (6 ft 7 in) in bell (body) diameter and about 200 kg (440 lb) in weight, with average specimens frequently reaching 0.9 m (2 ft 11 in) in bell diameter and about 150 kg (330 lb) in weight. The large bell mass of the giant Nomura's jellyfish can dwarf a diver and is nearly always much greater than the Lion's Mane, whose bell diameter can reach 1 m (3 ft 3 in).

 

The rarely encountered deep-sea jellyfish Stygiomedusa gigantea is another candidate for "largest jellyfish", with its thick, massive bell up to 100 cm (3 ft 3 in) wide, and four thick, "strap-like" oral arms extending up to 6 m (19+1⁄2 ft) in length, very different from the typical fine, threadlike tentacles that rim the umbrella of more-typical-looking jellyfish, including the Lion's Mane.

 

Desmonema glaciale, which lives in the Antarctic region, can reach a very large size (several meters). Purple-striped jelly (Chrysaora colorata) can also be extremely long (up to 15 feet).

 

Life history and behavior

Life cycle

Jellyfish have a complex life cycle which includes both sexual and asexual phases, with the medusa being the sexual stage in most instances. Sperm fertilize eggs, which develop into larval planulae, become polyps, bud into ephyrae and then transform into adult medusae. In some species certain stages may be skipped.

 

Upon reaching adult size, jellyfish spawn regularly if there is a sufficient supply of food. In most species, spawning is controlled by light, with all individuals spawning at about the same time of day; in many instances this is at dawn or dusk. Jellyfish are usually either male or female (with occasional hermaphrodites). In most cases, adults release sperm and eggs into the surrounding water, where the unprotected eggs are fertilized and develop into larvae. In a few species, the sperm swim into the female's mouth, fertilizing the eggs within her body, where they remain during early development stages. In moon jellies, the eggs lodge in pits on the oral arms, which form a temporary brood chamber for the developing planula larvae.

 

The planula is a small larva covered with cilia. When sufficiently developed, it settles onto a firm surface and develops into a polyp. The polyp generally consists of a small stalk topped by a mouth that is ringed by upward-facing tentacles. The polyps resemble those of closely related anthozoans, such as sea anemones and corals. The jellyfish polyp may be sessile, living on the bottom, boat hulls or other substrates, or it may be free-floating or attached to tiny bits of free-living plankton or rarely, fish or other invertebrates. Polyps may be solitary or colonial. Most polyps are only millimetres in diameter and feed continuously. The polyp stage may last for years.

 

After an interval and stimulated by seasonal or hormonal changes, the polyp may begin reproducing asexually by budding and, in the Scyphozoa, is called a segmenting polyp, or a scyphistoma. Budding produces more scyphistomae and also ephyrae. Budding sites vary by species; from the tentacle bulbs, the manubrium (above the mouth), or the gonads of hydromedusae. In a process known as strobilation, the polyp's tentacles are reabsorbed and the body starts to narrow, forming transverse constrictions, in several places near the upper extremity of the polyp. These deepen as the constriction sites migrate down the body, and separate segments known as ephyra detach. These are free-swimming precursors of the adult medusa stage, which is the life stage that is typically identified as a jellyfish. The ephyrae, usually only a millimeter or two across initially, swim away from the polyp and grow. Limnomedusae polyps can asexually produce a creeping frustule larval form, which crawls away before developing into another polyp. A few species can produce new medusae by budding directly from the medusan stage. Some hydromedusae reproduce by fission.

 

Lifespan

Little is known of the life histories of many jellyfish as the places on the seabed where the benthic forms of those species live have not been found. However, an asexually reproducing strobila form can sometimes live for several years, producing new medusae (ephyra larvae) each year.

 

An unusual species, Turritopsis dohrnii, formerly classified as Turritopsis nutricula, might be effectively immortal because of its ability under certain circumstances to transform from medusa back to the polyp stage, thereby escaping the death that typically awaits medusae post-reproduction if they have not otherwise been eaten by some other organism. So far this reversal has been observed only in the laboratory.

 

Locomotion

Jellyfish locomotion is highly efficient. Muscles in the jellylike bell contract, setting up a start vortex and propelling the animal. When the contraction ends, the bell recoils elastically, creating a stop vortex with no extra energy input.

Using the moon jelly Aurelia aurita as an example, jellyfish have been shown to be the most energy-efficient swimmers of all animals. They move through the water by radially expanding and contracting their bell-shaped bodies to push water behind them. They pause between the contraction and expansion phases to create two vortex rings. Muscles are used for the contraction of the body, which creates the first vortex and pushes the animal forward, but the mesoglea is so elastic that the expansion is powered exclusively by relaxing the bell, which releases the energy stored from the contraction. Meanwhile, the second vortex ring starts to spin faster, sucking water into the bell and pushing against the centre of the body, giving a secondary and "free" boost forward. The mechanism, called passive energy recapture, only works in relatively small jellyfish moving at low speeds, allowing the animal to travel 30 percent farther on each swimming cycle. Jellyfish achieved a 48 percent lower cost of transport (food and oxygen intake versus energy spent in movement) than other animals in similar studies. One reason for this is that most of the gelatinous tissue of the bell is inactive, using no energy during swimming.

 

Ecology

Diet

Jellyfish are, like other cnidarians, generally carnivorous (or parasitic), feeding on planktonic organisms, crustaceans, small fish, fish eggs and larvae, and other jellyfish, ingesting food and voiding undigested waste through the mouth. They hunt passively using their tentacles as drift lines, or sink through the water with their tentacles spread widely; the tentacles, which contain nematocysts to stun or kill the prey, may then flex to help bring it to the mouth. Their swimming technique also helps them to capture prey; when their bell expands it sucks in water which brings more potential prey within reach of the tentacles.

 

A few species such as Aglaura hemistoma are omnivorous, feeding on microplankton which is a mixture of zooplankton and phytoplankton (microscopic plants) such as dinoflagellates. Others harbour mutualistic algae (Zooxanthellae) in their tissues; the spotted jellyfish (Mastigias papua) is typical of these, deriving part of its nutrition from the products of photosynthesis, and part from captured zooplankton. The upside-down jellyfish (Cassiopea andromeda) also has a symbiotic relationship with microalgae, but captures tiny animals to supplement their diet. This is done by releasing tiny balls of living cells composed of mesoglea. These use cilia to drive them through water and stinging cells which stun the prey. The blobs also seems to have digestive capabilities.

 

Predation

Other species of jellyfish are among the most common and important jellyfish predators. Sea anemones may eat jellyfish that drift into their range. Other predators include tunas, sharks, swordfish, sea turtles and penguins. Jellyfish washed up on the beach are consumed by foxes, other terrestrial mammals and birds. In general however, few animals prey on jellyfish; they can broadly be considered to be top predators in the food chain. Once jellyfish have become dominant in an ecosystem, for example through overfishing which removes predators of jellyfish larvae, there may be no obvious way for the previous balance to be restored: they eat fish eggs and juvenile fish, and compete with fish for food, preventing fish stocks from recovering.

 

Symbiosis

Some small fish are immune to the stings of the jellyfish and live among the tentacles, serving as bait in a fish trap; they are safe from potential predators and are able to share the fish caught by the jellyfish. The cannonball jellyfish has a symbiotic relationship with ten different species of fish, and with the longnose spider crab, which lives inside the bell, sharing the jellyfish's food and nibbling its tissues.

 

Main article: Jellyfish bloom

Jellyfish form large masses or blooms in certain environmental conditions of ocean currents, nutrients, sunshine, temperature, season, prey availability, reduced predation and oxygen concentration. Currents collect jellyfish together, especially in years with unusually high populations. Jellyfish can detect marine currents and swim against the current to congregate in blooms. Jellyfish are better able to survive in nutrient-rich, oxygen-poor water than competitors, and thus can feast on plankton without competition. Jellyfish may also benefit from saltier waters, as saltier waters contain more iodine, which is necessary for polyps to turn into jellyfish. Rising sea temperatures caused by climate change may also contribute to jellyfish blooms, because many species of jellyfish are able to survive in warmer waters. Increased nutrients from agricultural or urban runoff with nutrients including nitrogen and phosphorus compounds increase the growth of phytoplankton, causing eutrophication and algal blooms. When the phytoplankton die, they may create dead zones, so-called because they are hypoxic (low in oxygen). This in turn kills fish and other animals, but not jellyfish, allowing them to bloom. Jellyfish populations may be expanding globally as a result of land runoff and overfishing of their natural predators. Jellyfish are well placed to benefit from disturbance of marine ecosystems. They reproduce rapidly; they prey upon many species, while few species prey on them; and they feed via touch rather than visually, so they can feed effectively at night and in turbid waters. It may be difficult for fish stocks to re-establish themselves in marine ecosystems once they have become dominated by jellyfish, because jellyfish feed on plankton, which includes fish eggs and larvae.

 

As suspected at the turn of this century, jellyfish blooms are increasing in frequency. Between 2013 and 2020 the Mediterranean Science Commission monitored on a weekly basis the frequency of such outbreaks in coastal waters from Morocco to the Black Sea, revealing a relatively high frequency of these blooms nearly all year round, with peaks observed from March to July and often again in the autumn. The blooms are caused by different jellyfish species, depending on their localisation within the Basin: one observes a clear dominance of Pelagia noctiluca and Velella velella outbreaks in the western Mediterranean, of Rhizostoma pulmo and Rhopilema nomadica outbreaks in the eastern Mediterranean, and of Aurelia aurita and Mnemiopsis leidyi outbreaks in the Black Sea.

 

Some jellyfish populations that have shown clear increases in the past few decades are invasive species, newly arrived from other habitats: examples include the Black Sea, Caspian Sea, Baltic Sea, central and eastern Mediterranean, Hawaii, and tropical and subtropical parts of the West Atlantic (including the Caribbean, Gulf of Mexico and Brazil).

 

Jellyfish blooms can have significant impact on community structure. Some carnivorous jellyfish species prey on zooplankton while others graze on primary producers. Reductions in zooplankton and ichthyoplankton due to a jellyfish bloom can ripple through the trophic levels. High-density jellyfish populations can outcompete other predators and reduce fish recruitment. Increased grazing on primary producers by jellyfish can also interrupt energy transfer to higher trophic levels.

 

During blooms, jellyfish significantly alter the nutrient availability in their environment. Blooms require large amounts of available organic nutrients in the water column to grow, limiting availability for other organisms. Some jellyfish have a symbiotic relationship with single-celled dinoflagellates, allowing them to assimilate inorganic carbon, phosphorus, and nitrogen creating competition for phytoplankton. Their large biomass makes them an important source of dissolved and particulate organic matter for microbial communities through excretion, mucus production, and decomposition. The microbes break down the organic matter into inorganic ammonium and phosphate. However, the low carbon availability shifts the process from production to respiration creating low oxygen areas making the dissolved inorganic nitrogen and phosphorus largely unavailable for primary production.

 

These blooms have very real impacts on industries. Jellyfish can outcompete fish by utilizing open niches in over-fished fisheries. Catch of jellyfish can strain fishing gear and lead to expenses relating to damaged gear. Power plants have been shut down due to jellyfish blocking the flow of cooling water. Blooms have also been harmful for tourism, causing a rise in stings and sometimes the closure of beaches.

 

Jellyfish form a component of jelly-falls, events where gelatinous zooplankton fall to the seafloor, providing food for the benthic organisms there. In temperate and subpolar regions, jelly-falls usually follow immediately after a bloom.

 

Habitats

Most jellyfish are marine animals, although a few hydromedusae inhabit freshwater. The best known freshwater example is the cosmopolitan hydrozoan jellyfish, Craspedacusta sowerbii. It is less than an inch (2.5 cm) in diameter, colorless and does not sting. Some jellyfish populations have become restricted to coastal saltwater lakes, such as Jellyfish Lake in Palau. Jellyfish Lake is a marine lake where millions of golden jellyfish (Mastigias spp.) migrate horizontally across the lake daily.

 

Although most jellyfish live well off the ocean floor and form part of the plankton, a few species are closely associated with the bottom for much of their lives and can be considered benthic. The upside-down jellyfish in the genus Cassiopea typically lie on the bottom of shallow lagoons where they sometimes pulsate gently with their umbrella top facing down. Even some deep-sea species of hydromedusae and scyphomedusae are usually collected on or near the bottom. All of the stauromedusae are found attached to either seaweed or rocky or other firm material on the bottom.

 

Some species explicitly adapt to tidal flux. In Roscoe Bay, jellyfish ride the current at ebb tide until they hit a gravel bar, and then descend below the current. They remain in still waters until the tide rises, ascending and allowing it to sweep them back into the bay. They also actively avoid fresh water from mountain snowmelt, diving until they find enough salt.

  

Parasites

Jellyfish are hosts to a wide variety of parasitic organisms. They act as intermediate hosts of endoparasitic helminths, with the infection being transferred to the definitive host fish after predation. Some digenean trematodes, especially species in the family Lepocreadiidae, use jellyfish as their second intermediate hosts. Fish become infected by the trematodes when they feed on infected jellyfish.

 

Relation to humans

Jellyfish have long been eaten in some parts of the world. Fisheries have begun harvesting the American cannonball jellyfish, Stomolophus meleagris, along the southern Atlantic coast of the United States and in the Gulf of Mexico for export to Asia.

 

Jellyfish are also harvested for their collagen, which is being investigated for use in a variety of applications including the treatment of rheumatoid arthritis.

 

Aquaculture and fisheries of other species often suffer severe losses – and so losses of productivity – due to jellyfish.

 

Products

Main article: Jellyfish as food

In some countries, including China, Japan, and Korea, jellyfish are a delicacy. The jellyfish is dried to prevent spoiling. Only some 12 species of scyphozoan jellyfish belonging to the order Rhizostomeae are harvested for food, mostly in southeast Asia. Rhizostomes, especially Rhopilema esculentum in China (海蜇 hǎizhé, 'sea stingers') and Stomolophus meleagris (cannonball jellyfish) in the United States, are favored because of their larger and more rigid bodies and because their toxins are harmless to humans.

 

Traditional processing methods, carried out by a jellyfish master, involve a 20- to 40-day multi-phase procedure in which, after removing the gonads and mucous membranes, the umbrella and oral arms are treated with a mixture of table salt and alum, and compressed. Processing makes the jellyfish drier and more acidic, producing a crisp texture. Jellyfish prepared this way retain 7–10% of their original weight, and the processed product consists of approximately 94% water and 6% protein. Freshly processed jellyfish has a white, creamy color and turns yellow or brown during prolonged storage.

 

In China, processed jellyfish are desalted by soaking in water overnight and eaten cooked or raw. The dish is often served shredded with a dressing of oil, soy sauce, vinegar and sugar, or as a salad with vegetables. In Japan, cured jellyfish are rinsed, cut into strips and served with vinegar as an appetizer. Desalted, ready-to-eat products are also available.

 

Biotechnology

The hydromedusa Aequorea victoria was the source of green fluorescent protein, studied for its role in bioluminescence and later for use as a marker in genetic engineering.

Pliny the Elder reported in his Natural History that the slime of the jellyfish "Pulmo marinus" produced light when rubbed on a walking stick.

 

In 1961, Osamu Shimomura extracted green fluorescent protein (GFP) and another bioluminescent protein, called aequorin, from the large and abundant hydromedusa Aequorea victoria, while studying photoproteins that cause bioluminescence in this species. Three decades later, Douglas Prasher sequenced and cloned the gene for GFP. Martin Chalfie figured out how to use GFP as a fluorescent marker of genes inserted into other cells or organisms. Roger Tsien later chemically manipulated GFP to produce other fluorescent colors to use as markers. In 2008, Shimomura, Chalfie and Tsien won the Nobel Prize in Chemistry for their work with GFP. Man-made GFP became widely used as a fluorescent tag to show which cells or tissues express specific genes. The genetic engineering technique fuses the gene of interest to the GFP gene. The fused DNA is then put into a cell, to generate either a cell line or (via IVF techniques) an entire animal bearing the gene. In the cell or animal, the artificial gene turns on in the same tissues and the same time as the normal gene, making a fusion of the normal protein with GFP attached to the end, illuminating the animal or cell reveals what tissues express that protein—or at what stage of development. The fluorescence shows where the gene is expressed.

 

Aquarium display

Jellyfish are displayed in many public aquariums. Often the tank's background is blue and the animals are illuminated by side light, increasing the contrast between the animal and the background. In natural conditions, many jellies are so transparent that they are nearly invisible. Jellyfish are not adapted to closed spaces. They depend on currents to transport them from place to place. Professional exhibits as in the Monterey Bay Aquarium feature precise water flows, typically in circular tanks to avoid trapping specimens in corners. The outflow is spread out over a large surface area and the inflow enters as a sheet of water in front of the outflow, so the jellyfish do not get sucked into it. As of 2009, jellyfish were becoming popular in home aquariums, where they require similar equipment.

 

Stings

Jellyfish are armed with nematocysts, a type of specialized stinging cell. Contact with a jellyfish tentacle can trigger millions of nematocysts to pierce the skin and inject venom, but only some species' venom causes an adverse reaction in humans. In a study published in Communications Biology, researchers found a jellyfish species called Cassiopea xamachana which when triggered will release tiny balls of cells that swim around the jellyfish stinging everything in their path. Researchers described these as "self-propelling microscopic grenades" and named them cassiosomes.

 

The effects of stings range from mild discomfort to extreme pain and death. Most jellyfish stings are not deadly, but stings of some box jellyfish (Irukandji jellyfish), such as the sea wasp, can be deadly. Stings may cause anaphylaxis (a form of shock), which can be fatal. Jellyfish kill 20 to 40 people a year in the Philippines alone. In 2006 the Spanish Red Cross treated 19,000 stung swimmers along the Costa Brava.

 

Vinegar (3–10% aqueous acetic acid) may help with box jellyfish stings but not the stings of the Portuguese man o' war. Clearing the area of jelly and tentacles reduces nematocyst firing. Scraping the affected skin, such as with the edge of a credit card, may remove remaining nematocysts. Once the skin has been cleaned of nematocysts, hydrocortisone cream applied locally reduces pain and inflammation. Antihistamines may help to control itching. Immunobased antivenins are used for serious box jellyfish stings.

 

In Elba Island and Corsica dittrichia viscosa is now used by residents and tourists to heal stings from jellyfish, bees and wasps pressing fresh leaves on the skin with quick results.

 

Mechanical issues

Jellyfish in large quantities can fill and split fishing nets and crush captured fish. They can clog cooling equipment, having disabled power stations in several countries; jellyfish caused a cascading blackout in the Philippines in 1999, as well as damaging the Diablo Canyon Power Plant in California in 2008. They can also stop desalination plants and ships' engines.

Nikon D80, Nikon 600mm + 2.0 Teleconverter, ISO 200, F/8, and exposure 1/500.

Quebec City, October 2007. It is a very beautiful city.

Caution: Don't look at the viewfinder while using high-power telephoto lens facing the sun as sunlight can cause permanent retinal damage!!!

 

Here comes the sun (Beatles):

www.youtube.com/watch?v=U6tV11acSRk

By looking through a patient’s widened pupil during a dilated eye exam, eye care professionals can view the retina—the postage stamp-sized tissue lining the back of the inner eye—and look for irregularities that may signal the development of vision loss.

Thanks to research, retinal imaging just keeps getting better. The images above, which show the same cells viewed with two different microscopic techniques, provide good examples of how tweaking existing approaches can significantly improve our ability to visualize the retina’s two types of light-sensitive neurons: light-sensing, color-detecting cone cells (orange) and lowlight-sensing rod cells (blue). Image by Johnny Tam/National Eye Institute.

Read more on the NIH Director's blog: directorsblog.nih.gov/2021/05/13/finding-a-way-to-better-...

Credit: Johnny Tam, National Eye Institute, NIH