View allAll Photos Tagged ectoderm
Essas cores são fantásticas!!
Iratauá-grande - Gymnomystax mexicanus
Oriole Blackbird
Mario Martins, obrigada pela identificação!!
"A melanina é um pigmento produzido pela pele. Sua função na coloração da plumagem das aves é fundamental: sem ela o azul e o verde não existiriam e o pavão seria todo branco.
Os pigmentos são substâncias coloridas, de origem mineral ou orgânica, que dão origem à maior parte das cores do nosso meio. Nos seres vivos, alguns pigmentos dotados de propriedades particulares, são indispensáveis à vida. É o caso - nos vegetais - da clorofila. Nos animais, a hemoglobina, que dá ao sangue a sua cor vermelha, assegurando o transporte de gás (oxigênio) saído da respiração.
A melanina, que deve seu nome à sua cor negra, não é assim tão indispensável, mas a sua abundância na natureza e as suas propriedades fazem com que ela desempenhe uma função não menos importante. As aves são, com os insetos, os seres vivos que fazem o mais belo uso dela, uma vez que eles devem o essencial ao seu adorno.
Os melanócitos estão situados na derme, sob a camada geradora da pele. A pena é produzida por um folículo que corresponde a uma elevação da ectoderme. Os melanócitos migram então para o folículo e vão colonizar a futura pena. Esses passam por sua base, se bem que sua extremidade se forma em primeiro lugar.
Finos prolongamentos permitem aos melanócitos injetarem, com precisão, a melanina na pena. Disso resultam desenhos muito precisos (finas estrias, pontuações etc.).
A melanina é, antes de tudo, um pigmento. E a cor de um pigmento depende das radiações que ele reenvia: é amarelo se reenvia amarelo, marrom se reenvia marrom, branco se ele reenvia igualmente todas as radiações, e negro se não reenvia nenhuma. Neste último caso, toda a luz recebida é absorvida.
Por ser uma proteína, contribui assim para tornar as penas mais robustas. Dessa forma é que o eixo de muitas penas, principalmente as de vôo (asas e cauda), é inteiramente impregnado de melanina marrom ou, mais comumente, de melanina negra.
As cores das plumagens têm para as aves uma grande importância; elas são a carteira de identidade da ave e têm uma função numa linhagem, principalmente no período de reprodução. O aparecimento de uma plumagem nupcial, os cortejos que acompanham a formação do casal, são igualmente indícios da importância da cor da plumagem nas aves e com ela, a importância da melanina."
(Atualidades Ornitológicas - Revista SOBC 2002)
The Sunburst/Starburst Anemone aggressively defends its territory from other anemones which are genetically dissimilar. When it encounters a different genetic colony, the anemones extend specialized tentacles (called acrorhagi). The white tips of acrorhagi have a concentration of stinging cells (nematocytes) and are used solely to deter other colonies from encroaching on their space. The nematocysts sting the ectoderm of the invader, causing tissue necrosis and forcing the competitor to move away.
X-Files
Description: The subject portrayed is a female. At first, I believed this was gonna be easy to identify, as are most Argiope spiders. At first glance, I was sure it was not an Argiope argentata, and a quick Google search gave no clues as to the identity. I started to believe it was gonna be difficult to identify this one. I came across Argiope trifasciata. It looked different, but a few individuals (probably young) looked practically identical to mine and were identified as Argiope trifasciata. See the links below. Both are identified as trifasciata and look different, so it's either a wrong ID or they vary a lot. The second link shows an individual close to identical to mine.
www.naturalista.mx/observations/1891397
www.naturalista.mx/observations/1907112
In Brazil, we have Argiope argentata, Argiope legionis, Argiope savignyi and Argiope trifasciata, so it is one of those. It's not the argentata or savignyi. So it's either a trifasciata in an early development stage or a legionis. It looks really close to trifasciata, but there are zero pictures of Argiope legionis in the Internet, so I can't be sure about this ID. Here is a link to the study of Argiope legionis:
www.scielo.br/pdf/zool/v26n2/a17v26n2.pdf
Due to this uncertainty, I'll leave the post as Argiope sp..
Their web are characteristic, with X patterns or zig-zag patterns, which are called "stabilimenta". These patterns exist to ensnare possible prey and, possibly, to prevent the destruction of the web by larger creatures. The males are much, much smaller than the females. The male will spin a web around the female when the mating time comes. The egg sac, which contains somewhere around 400 to 1400 eggs, is then laid on the web by the female, The eggs are sometimes parasitized. Argiope are large spiders and can bite, but bites from these creatures are really, really rare, and even then, the venom is harmless to humans and animals, and can be compared to a bee sting. They belong in the order Araneae, suborder Opisthothelae, infraorder Araneomorphae, superfamily Araneoidea, family Araneidae and subfamily Argiopinae.
The body is covered by an exoskeleton, or cuticle. Some regions of the cuticle are hardened, or sclerotized, whereas others are soft and flexible but, in general, the exoskeleton tends to be softer than that of most insects and crustaceans.
The body is composed of two tagmata; the anterior cephalothorax, or prosoma, and the posterior abdomen, or opisthosoma. The two are connected by a narrow waist, or pedicel. The bulbous ovoid abdomen is much larger than the cephalothorax. The cephalothorax consists of the fused head and thorax of the proarachnid ancestors. It is flattened dorsally and covered by a broad, flat, sclerotized, exoskeletal plate known as the carapace. A pair of oblique cephalic grooves on the carapace marks the line of fusion of the ancestral head and thorax. The head is anterior to the cephalic grooves and the thorax posterior to them. The carapace is covered by a pelt of fine setae visible only with magnification.
The anterior end of the cephalothorax bears four pairs of large eyes, some of which are elevated on small tubercles. Each possesses a single large, transparent lens bulging above the carapace surface. The anterior median eyes, or main eyes, are homologous to simple ocelli of other arthropods. They are anteriormost and face forward. The remaining three pairs are secondary eyes derived from compound eyes of chelicerate ancestors and include, from anterior to posterior, the anterior lateral eyes, posterior lateral eyes, and posterior median eyes. The eyes point in different directions and are simple, rather than compound.
The chelicerae are the first appendages of the cephalothorax and are composed of two articles. The proximal article is the large basal piece attached to the anterior end of the cephalothorax under the edge of the carapace. It contains powerful muscles and a duct from a poison gland in the cephalothorax.
The second, or distal, article of the chelicera is a slender, sharp, hollow fang at whose tip the poison duct opens. The second cephalothoracic appendages are the pedipalps. These long, slender, leglike appendages are composed of six articles. The enlarged proximal article, or coxa, attaches to the ventral side of the anterior thorax immediately posterior to the fangs. The median process of the coxa is a setose plate known as the pedipalpal endite, or gnathobase, that masticates food and mixes it with digestive enzymes. Distally the pedipalps are sensory whereas proximally they are used to manipulate food. Those of males are modified to transfer sperm to the female. The remaining cephalothoracic appendages are four pairs of similar walking legs. Each is composed of a linear series of seven articles named, in order from proximal to distal: coxa, trochanter, femur, patella, tibia, metatarsus, and tarsus. The distal tip of each tarsus bears tiny claws.
The legs have abundant setae, most or all of which are sensory receptors, chiefly mechanoreceptors sensitive to vibrations, touch, and air movements. Slit sense organs sensitive to strain in the cuticle are present at various places on the body, especially on the legs. Trichobothria, which are special, long, slender setae, are sensitive to very weak air movements. Chemoreceptors are present on the tarsi, especially those of the first legs.
Most of the ventral surface of the cephalothorax is protected by a large, heavily sclerotized sternum formed by the fusion of four embryonic sternites. Anterior to the sternum is a small triangular labium which extends anteriorly between the bases of the pedipalpal coxae. The labium is movable along its articulation with the sternum. It is the sternite of the pedipalpal segment.
The chelicerae, pedipalpal coxae, and labium surrounding the mouth enclose the preoral cavity that precedes the mouth. Within the preoral cavity is a prominent conical labrum located on the midline. Pushing the chelicerae and pedipalpal coxae aside reveals the labrum. The mouth is a triangular opening on the posterior surface of the labrum and is covered and closed by the labium. It can be seen by moving the labium posteriorly on its hinge. The heavy fringes of setae on the pedipalpal coxae and labium filter the slurry resulting from external predigestion before it enters the mouth. Large particles are excluded and only liquid and very small particles enter the mouth.
The pharynx is a long, narrow, almost vertical tube extending dorsally from the mouth. The pharynx dilator muscle extends from the pharynx to the midline of the carapace. Contractions of this muscle dilate the pharynx and draw liquid food in through the mouth from the preoral cavity.
A slender esophagus extends posteriorly from the dorsal end of the pharynx. In about the middle of the cephalothorax it widens to form the stomach. The pharynx, esophagus, and stomach are all part of the foregut and as such are derived from ectoderm and lined with exoskeleton.
The stomach dilator muscle extends from the dorsal wall of the stomach to the midline of the carapace. Its action is similar to that of the pharynx dilator. Together the stomach and pharynx suck food into the gut.
A narrow intestine, or midgut, exits the posterior end of the stomach and passes through the pedicel to the abdomen. The midgut is endodermal and has no cuticular lining. A one-way valve prevents the reverse flow of food out of the midgut when the stomach dilates.
Tubular anterior digestive ceca arise from each side of the anterior end of the intestine in the cephalothorax. These twisting, cylindrical glands ramify through the interior of the cephalothorax but lie out of the plane of section and may be difficult to discern.
In the abdomen the intestine passes dorsal to the ovary to reach the anus at the posterior end. The large, conspicuous cloacal chamber (or stercoral pocket) opens into the posterior end of the midgut. The gut posterior to the cloacal chamber is the hindgut, or rectum. The hindgut is ectodermal, like the foregut, and lined with cuticle. Posterior digestive ceca open from the midgut and fill much of the space in the abdomen. Most of the posterior digestive cecum is dorsal to the ovary.
The large nerve ring is the easily recognized white mass in the center of the cephalothorax. It consists of a brain, or supraesophageal ganglion, lying on the dorsal surface of the posterior esophagus and a much larger subesophageal ganglion ventral to the esophagus. The two are connected by paired circumesophageal connectives.
The segmental ganglia, which in primitive arthropods are arranged along a ventral nerve cord, in spiders have moved anteriorly and are concentrated in the subesophageal ganglion as part of the nerve ring. There is no nerve cord and the many peripheral nerves arise from the nerve ring to serve the body. The optic nerve to the eyes enters the brain anteriorly and a large abdominal nerve exits the posterior end of the subesophageal ganglion and runs along the ventral edge of the intestine, through the pedicel, to the abdomen.
The heart is a large curved tube in the anterior dorsal region of the abdomen. Anteriorly it narrows to form the anterior aorta passing through the pedicel to the cephalothorax. Posteriorly it becomes the posterior aorta opening into the posterior abdomen. Its walls bear ostia and it is supported by alary ligaments. An aorta extends from the heart in the abdomen to supply the hemocel with blood.
The chief excretory organs are a pair of very long, narrow Malpighian tubules in the abdomen. They open into the cloaca and are midgut (endodermal) derivatives.
The ovary is a long white organ in the middle of the abdomen. Its walls bear distinctive vertical folds and eggs are clearly visible within it. It connects with the female gonopore at the base of the epigynum via an oviduct.
A wide variety of different kinds of silk glands can be seen ventral to the ovary. Each connects to spigots on the spinnerets via ducts. Silk glands are not muscular and is pulled, or drawn, out of the spigots as the abdomen is moved away from an attachment point. Silk is composed of the protein fibroin and is comparable to nylon in strength. It is liquid when extruded but solidifies when placed under tension by the “drawing out” process. An orb weaver, such as Argiope, has many different kinds of silk, each secreted by a different kind of gland. Six types of silk glands are known in spiders.
Other sources: lanwebs.lander.edu/faculty/rsfox/invertebrates/argiope.html
en.wikipedia.org/wiki/Argiope_(spider)
Text revision: Marina de Azevedo Guerra (www.facebook.com/marina.guerragymnopaedist)
Feeding type: Predator.
PROJECT NOAH (Português): www.projectnoah.org/spottings/515498806
YOUR BABY IS DUE Aug 28:
You are currently 4 WEEKS PREGNANT
Estimated Date of Conception: Dec 05, 1988
(4 weeks 3 days or 1 months)
This is based on the cycle length provided, not an average cycle length of 28 days, however it is still an estimate.
PROGRESS: You are 12% of the way through your pregnancy.
12% Weekly Development WEEK 1 & 2
Weeks 1 & 2 of your pregnancy is Nov 22, 1988 - Dec 05, 1988
Baby Conceived: It's ovulation time. If sperm and egg meet, you're on your way to pregnancy.
WEEK 3: Week 3 of your pregnancy is Dec 06, 1988 - Dec 12, 1988
Implantation occurs: Your baby is a tiny ball of several hundred cells that are rapidly multiplying and burrowing into the lining of your uterus. The cells that become the placenta are producing hCG, the pregnancy hormone. It tells your ovaries to stop releasing eggs and keep producing progesterone. Once there's enough hCG in your urine, you'll get a positive pregnancy test result.
WEEK 4: Week 4 of your pregnancy is Dec 13, 1988 - Dec 19, 1988 - Positive Pregnancy Test: Your baby is an embryo made up of two layers, the hypoblast and the epiblast. The placenta is developing and preparing to provide nutrients and oxygen to your growing baby. The amniotic sac is developing and will surround and protect your baby while it continues to grow.
WEEK 5: Week 5 of your pregnancy is Dec 20, 1988 - Dec 26, 1988 - Your embryo is now made up of three layers, the ectoderm, the mesoderm and the endoderm which will later form all the organs and tissues. You might start to feel the first twinges of pregnancy such as tender breasts, frequent urination, or morning sickness.
WEEK 6: Week 6 of your pregnancy is Dec 27, 1988 - Jan 02, 1989
Heartbeat detectable by ultrasound. Your baby's heart is beating about 160 times a minute and the nose, mouth and ears are taking shape. Lungs and digestive system are forming organs.
WEEK 7: Week 7 of your pregnancy is Jan 03, 1989 - Jan 09, 1989 - Your baby is forming hands and feet. Key organs like the stomach, liver and esophagus are beginning to form. Your uterus has doubled in size. The umbilical cord is transferring blood and waste between baby and mother.
WEEK 8: Week 8 of your pregnancy is Jan 10, 1989 - Jan 16, 1989 - The respiratory system is forming now. Breathing tubes extend from the throat to the branches of the developing lungs.
WEEK 9: Week 9 of your pregnancy is Jan 17, 1989 - Jan 23, 1989 - Your baby is nearly an inch long now. If you watch closely, you may see your baby move if you have an ultrasound done
WEEK 10: Week 10 of your pregnancy is Jan 24, 1989 - Jan 30, 1989 - Your baby's organs are growing and beginning to mature. The baby's head comprises half the length of the body.
WEEK 11: Week 11 of your pregnancy is Jan 31, 1989 - Feb 06, 1989 - Fingers and toes have separated and the bones are beginning to harden. External genitalia has almost completely formed.
WEEK 12: Week 12 of your pregnancy is Feb 07, 1989 - Feb 13, 1989 - The kidneys can now secrete urine and the nervous system is maturing. You baby may be curling all 10 toes, practicing opening and closing fingers and sucking a thumb. And mom should have gained from 0,5 -3 kgs.
WEEK 13: Week 13 of your pregnancy is Feb 14, 1989 - Feb 20, 1989 - Miscarriage risk decreases. Your baby now has unique fingerprints and the kidney and urinary tract are completely functional, that means she's peeing. And if you are having a girl, her ovaries are already full of thousands of eggs.
WEEK 14: Week 14 of your pregnancy is Feb 21, 1989 - Feb 27, 1989 - Your baby's facial muscles are getting a workout as he squints, frowns, grimaces and practices his first smile for you.
WEEK 15: Week 15 of your pregnancy is Feb 28, 1989 - Mar 06, 1989 - Your baby is looking more like a baby with legs growing longer than the arms and all her limbs moving. The ears are properly positioned on the side of her head and the eyes are moving from the side of the head to the front of the face. At your doctor's visit, he should offer you a quad screening test to check for Down's syndrome or other chromosomal abnormalities.
WEEK 16: Week 16 of your pregnancy is Mar 07, 1989 - Mar 13, 1989 - Baby's heart is pumping about 25 quarts of blood each day. His eyes are working and moving side to side even though the eyelids are still sealed. Mom will have a "pregnancy glow" due to increased blood supply.
WEEK 17: Week 17 of your pregnancy is Mar 14, 1989 - Mar 20, 1989 - Baby's skeleton is changing from soft cartilage to bone and her heart is now regulated by her brain. She's practicing her sucking and swallowing skills in preparation for that first suckle at your breast or the bottle. Mom's breasts may have increased a full bra size.
WEEK 18: Week 18 of your pregnancy is Mar 21, 1989 - Mar 27, 1989 - Gender reveal time. If you're having a girl, her uterus and fallopian tubes are formed and in place. If you're having a boy, his genitals are noticable now but he may hide them during an ultrasound. Are you feeling kickes and punches? Baby's hearing is also developing, so you may want to start talking to your baby.
WEEK 19: Week 19 of your pregnancy is Mar 28, 1989 - Apr 03, 1989 - Baby's brain is designating specialized areas for his 5 senses - vision, hearing, taste, smell and touch. A waxy protective coating called the vernix caseosa is forming on his skin to prevent wrinkling.
WEEK 20: Week 20 of your pregnancy is Apr 04, 1989 - Apr 10, 1989 - Your baby weighs about 300 grams and is the size of a small banana. Her uterus is fully formed this week and she may have tiny primitive eggs in tiny ovaries now. His testicles are waiting for the scrotum to finish growing and will begin their descent soon. Mom can expect to gain about 1/2 lb per week for the rest of her pregnancy.
WEEK 21: Week 21 of your pregnancy is Apr 11, 1989 - Apr 17, 1989 - Feel all that moving and shaking going on! Baby's arms and legs are in proportion now and movements are much more coordinated. Bone marrow is now helping the liver and spleen produce blood cells. The intestines are starting to produce meconium, the thick tarry looking stool first seen in baby's diaper.
WEEK 22: Week 22 of your pregnancy is Apr 18, 1989 - Apr 24, 1989 - Senses are growing stronger. Now she can hear your heart beat, your breathing and digestion. Sense of sight is becoming more fine-tuned and he can preceive light and dark. Hormones are now developing which will the organs the commands they need to operate.
WEEK 23: Week 23 of your pregnancy is Apr 25, 1989 - May 01, 1989 - Premature baby may survive. Baby's organs and bones are visible through his skin, which has a red hue because of the developing veins and arteries beneath. He'll become less transparent as his fat deposits fill in. Baby is also developing surfactant which will help the lungs inflate if baby is born prematurely
WEEK 24: Week 24 of your pregnancy is May 02, 1989 - May 08, 1989 - Baby's face is almost fully formed complete with eyelashes, eyebrows and hair. Right now her hair is white because there's no pigment yet. Between now and 28 weeks, the doctor should send mom for a glucose screening test for gestational diabetes.
WEEK 25: Week 25 of your pregnancy is May 09, 1989 - May 15, 1989 - Baby is gaining more fat and looking more like a newborn. Hair color and texture is in place. His lungs are maturing and preparing for that first breath. You might feel the baby having hiccups.
WEEK 26: Week 26 of your pregnancy is May 16, 1989 - May 22, 1989 - Brain-wave activity is on high That means baby can hear noises and respond to them with an increase pulse rate or movement. Eyes are beginning to open but they don't have much pigmentation. That will develop over the next couple months and may even continue to change until she's about 6-months-old.
WEEK 27: Week 27 of your pregnancy is May 23, 1989 - May 29, 1989 - Start talking to your baby . Baby may recognize both your and your partner's voices. This is the time to read and even sing to your baby. She now has taste buds so when you eat spicy food, your baby will be able to taste the difference in the amniotic fluid. Her mealtime comes about two hours after yours. Feel some belly spasms? Those are likely hiccups from that spicy food. It doesn't bother the baby as much as you. Baby also has settled in to a regular sleep cycle, but it may be different from mom's.
WEEK 28: Week 28 of your pregnancy is May 30, 1989 - Jun 05, 1989 - During the third trimester the brain triples in weight adding billions of new nerve cells. Senses of hearing, smell and touch are developed and functional. Your baby is having different sleep cycles, including rapid eye movement. That means she's dreaming.
WEEK 29: Week 29 of your pregnancy is Jun 06, 1989 - Jun 12, 1989 - Baby can breathe. Baby's bones are soaking up lots of calcium as they harden so be sure to consume good sources of calcium. We recommend taking Nordic Naturals and Fairhaven Health supplements.
WEEK 30: Week 30 of your pregnancy is Jun 13, 1989 - Jun 19, 1989 - Baby's brain is taking on characteristic grooves and indentations to allow for an increased amount of brain tissue. Bone marrow has taken over the production of red blood cells. This means she'll be better able to thrive on her own when she's born Baby is now weighing about 1.36 kgs and is 28 centimetres.
WEEK 31: Week 31 of your pregnancy is Jun 20, 1989 - Jun 26, 1989 - Baby's brain is developing faster than ever and he's processing information, tracking light and perceiving signals from all five sense. She's probably moving a lot, especially at night when you're trying to sleep. Take comfort that all this activity means your baby is healthy. Mom may start feeling some Braxton Hicks contractions.
WEEK 32: Week 32 of your pregnancy is Jun 27, 1989 - Jul 03, 1989 - Baby can focus on large objects not too far away; toenails and fingernails have grown in along with real hair. He's practicing swallowing, breathing, kicking and sucking. All key skills for thriving after birth.
WEEK 33: Week 33 of your pregnancy is Jul 04, 1989 - Jul 10, 1989 - Immune system is maturing. The bones in your baby's skull are still pliable which makes it easier for her to fit through the birth canal. Your uterine walls are becoming thinner allowing more light to penetrate your womb. That helps baby differentiate between night and day.
WEEK 34: Week 34 of your pregnancy is Jul 11, 1989 - Jul 17, 1989 - Baby's fat layers are filling her out and will help regulate body temperture when she's born. If your baby is a boy, the testicles are making their way down from the abdomen to the scrotum.
WEEK 35: Week 35 of your pregnancy is Jul 18, 1989 - Jul 24, 1989 - Kidneys are fully developed and her liver can process some waste products. Most of her physical development is complete. She'll spend the next few weeks gaining weight and adding baby fat. Baby is settling lower into the pelvis preparing for delivery and this is called "lightening".
WEEK 36: Week 36 of your pregnancy is Jul 25, 1989 - Jul 31, 1989 - Hopefully your baby is in a head-down position. If not, your practitioner may suggest an external cephalic version to manipulate your baby into a head down position. The vernix caseosa has now disappeared.
WEEK 37: Week 37 of your pregnancy is Aug 01, 1989 - Aug 07, 1989 - Baby is considered full term. Baby is taking up most of the room in your womb so he's only kicking and poking you, no more somersaults. Baby is sucking her thumb, blinking eyes and inhaling and exhaling amniotic fluid.
WEEK 38: Week 38 of your pregnancy is Aug 08, 1989 - Aug 14, 1989 - Baby's eyes right now are blue, gray or brown but once they're exposed to light they may change color or a shade. The lanugo, the fine downy hair that covered his body for warmth is falling off in preparation for delivery. Her lungs have strenthened and her vocal cords have developed. That means she's ready for her first cry.
WEEK 39: Week 39 of your pregnancy is Aug 15, 1989 - Aug 21, 1989 - Baby is ready to make his debut. He's adding more fat as his pinkish skin turns white or white-grayish. He won't have his final pigment until shortly after birth.
WEEK 40: Week 40 of your pregnancy is Aug 22, 1989 - Aug 28, 1989 - This is the official end of your pregnancy but because due dates are just a calculation he might be "late." No need to worry, your body knows the right time to go into labor, or your doctor may suggest you be induced. At birth your baby's eye sight is a little blurry since central vision is still developing. Just say hello and he'll recognize your voice.
During the Process of Fertilization, the sperm and the oocyte cease to exist as such, and a new human being is produced.
I believe this tentacle belongs to the hydra known as Hydra viridissima or the green Hydra. The green colour is from the green algae Chlorella which live symbiotically in the gastrodermis, or inner layer of cells.
The body of the hydra is topologically a hollow spheroid, i.e., it is like a glove blown up with air. The cells walls of the body and tentacles are really only 2 cells thick. The inner cells, i.e., the green ones here, make up the gastrodermis which is responsible for digestion. The ectodermis is the lighter colored structure on the outside. There is a structureless lamellar layer in-between. This layer is evident in this micrograph.
The ectoderm's is covered with the nematocysts which fire a tethered harpoon into the prey. Roughly at the center top and bottom of this micrograph are two nematocists and the associated cavity for the "harpoon". The spines on the tentacle are sensors which trigger the nematocists. In-between the namatocists are the epitheliomuscular cells which are responsible for the muscular action. Finally there are smaller interstitial cells which are a form of stem cell. The web page sites.google.com/site/drjerrodhunter/home/cnidarians/hydra provides a very nice description.
Specimen from a spring next to the dam on the Dowagiac River.
Phase contrast immage at 400X original magnification from a Nikon MS inverted microscope. Photographed with Sony NEX 5N using a Leica MIKAS 1/3X adapter.
Cette Cnidaire dispose de huit tentacules, dont les nématocystes urticants peuvent provoquer de vives douleurs en cas de contact avec la peau. Couverte de minuscules points rouges qui sont en fait des faisceaux de cellules urticantes, elle possède une coloration rougeâtre, allant de l'orange au violet en passant par le rose. Son ectoderme (chapeau) est transparent et urticant et laisse entrevoir sa mésoglée, son endoderme et ses gonades. Elle possède aussi, en bas de l'ombrelle, quatre lobes buccaux dentelés, de couleur rosâtre, urticants et couverts d'un mucus gluant, qui capturent et paralysent les proies (petits animaux faisant partie du zooplancton) qui seront amenés vers la bouche.
Sa reproduction diffère de la plupart des autres méduses, puisqu'elle répand des ovules et du sperme qui, après s'être fécondés, deviendront des petites larves qui passeront directement au stade de méduse pour devenir peu à peu des adultes. Elle brille grâce à un mucus sécrété par son ectoderme lorsque la méduse est perturbée ou heurtée par les vagues (cf. wikipédia).
Very lucky section through a perfectly preserved human embryo in an intact tubal pregnancy. This is by far the most primitive embryo I have ever seen.
I think this is at about the same developmental stage as the Hertig-Rock embryo of 1945, which has been variously estimated at 16.5 or 19 days postovulation (4 to 5 weeks by conventional obstetrical dating, counting from the first day of the last menstrual period).
Embryo is the size of a sesame seed and I am BLOATED. Embryo is made up of three layers — the ectoderm, the mesoderm, and the endoderm. Read more: www.babycenter.com/6_your-pregnancy-5-weeks_1094.bc
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No Usage Allowed in Any Form Without the Written Consent of Serena Livingston
Description: Jelly fish are ancient creatures. Fossils have been found in rocks that are 650 million years old. Today there are more than 2000 species. Jelly fish are 95% water, 3% protein, and 1% mineral. There are two stages: an adult free swimming medusa and a sessile polyp. There is no backbone, brain, or heart. Adults drift with the currents, but can swim horizontally by pulsations of the bell to keep close to the surface. A primitive nerve net controls muscle contractions as it swims. The adult form is a transparent bell shape that ranges between 5-40 cm wide. Underneath is a central mouth surrounded by four oral arms that carry the stinging tentacles. From above four crescent shaped gonads surround the mouth. On the rim of the bell are eight sets of eye spots sensitive to light and eight statocysts that help orient jelly fish when swimming. Jelly fish are primitive organisms with an outer layer (ectoderm) that covers the external surface and an inner layer (endoderm) that lines the gut. Between these is a jelly layer or mesoglea. The simple digestive cavity acts as a gullet, stomach, and intestine. There is one opening between the oral arms that acts as a mouth, anus, and entrance for sperm (in females).
Distribution: Atlantic, Pacific, and Indian oceans
Habitat: Shallow coastal waters as well as brackish waters with a salt content as low as 0.6%. Jelly fish can survive in water from -6C to 31C. The optimum temperature is 9C to 19C
Food: Jelly fish are carnivorous plankton. They feed on fish eggs and larval fish and other plankton such as mollusks, crustaceans, copepods, etc. Food collects on the mucus surface of the jelly fish. Flagellar action of the tentacles passes the food items to the margin of the bell and then up into the mouth and stomach.
Reproduction and Development: Jelly fish are either male or female. Sexual reproduction begins when a male medusa releases sperm through its mouth. The sperm swim into the mouth of a nearby female where fertilization occurs. Further development into free swimming planula occurs in brood pouches along the oral arms. The planula settle on the ocean floor and attach to the bottom forming the polyp. Polyps bud asexually to produce free swimming larvae known as ephyra which grow into the adult medusa.
Adaptations: The transparent body makes a jelly fish less visible to predators. Oral arms have tentacles that carry cnidaria (stinging cells) that stun prey or deter predators. About 70 species are harmful to humans. The medusa can shrink in size when food is scarce and grow when it is abundant. Radial symmetry permits finding food in any direction.
Threats to Survival: Predators include sea turtles, ocean sun fish, spade fish, tuna, swordfish, and other large fish. Humans, particularly in China and Japan, capture and eat dried non-venomous jelly fish.
Status: Common
Zoo Diet: Newly hatched brine shrimp
Courtesy of the Toronto Zoo
Los espermatozoides nadan alrededor de 10hrs. desde la vagina al utero, y del utero hasta las tompas de falopio...
El ganador tarda 20 minutos en poder entrar.
En la tercera semana, el embrión sigue multiplicandose incansablemente, el ectodermo,el endodermo y el mesodermo, han comenzado su labor..
El embrión tiene el tamaño de una pequeña semilla, mas o menos como la de la foto. Y se parece a un renacuajo.
El cerebro y la columna vertebral ya se notan, pero aun siguen creciendo.
En el segundo mes, la cabeza del embrión es la mitad de la longitud del cuerpo. Los brazos, ya tienen manos, dedos y pulgares. Al igual que sus piernas...
En el tercer mes, el sexo es facil de identificarlo. El feto es capaz de orinar.
En el cuarto mes, el movimiento es más común. El abdomen se desarrolla de manera considerable, y la cabeza tiene un aspecto menos desproporcionado en relación con el resto del cuerpo....
En el quinto mes, al feto le ha comenzado a crecer pelo fino en todo su cuerpo y pelo grueso en cejas y pestañas. El feto aproximadamente a hora mide 25cm.
En el sexto mes, la cara se afina, las cejas son visibles, el dibujo de la nariz es más neto, las orejas son más grandes y el cuello se destaca. El bebe ya duerme y se despierta.
Septimo mes, el feto llega a pesar 1,5kg. y su estatura llega a 37 cm. los huesos del feto se estan poniendo más duros.. El feto ya pesa 1.700g. y mide 40cm. Si naciera ahora, tendria grandes posibilidades de sobrevivir.
En el octavo mes, algunos organos ya funcionan normalmente en particular el estomago, el intestino, los riñones... Otros todavia no estan del todo preparados como los pulmones o el higado.
El noveno mes, el bebe aumenta unos 20 o 30 gramos cada dia, se mueve menos por la falta de espacío.
Entre los huesos persisten espacios fibrosos que se denominan fontanelas, estas se cerraran despues del que el bebe nasca...
Scientific Name: Aurelia aurita
Description : Jellyfish are ancient creatures. Fossils have been found in rocks that are 650 million years old. Today there are more than 2000 species. Jellyfish are 95% water, 3% protein, and 1% mineral. There are four life stages from birth to adult. There is no backbone, brain, or heart. Adults drift with the currents, but can swim horizontally by pulsations of the bell to keep close to the surface. A primitive nerve net controls muscle contractions as it swims. The adult form is a transparent bell shape that ranges between 5 and 40 cm wide. Underneath is a central mouth surrounded by four oral arms that carry the stinging tentacles. From above, four crescent shaped gonads surround the mouth. On the rim of the bell are eight sets of eye spots sensitive to light and eight statocysts that help orient jellyfish when swimming. Jellyfish are primitive organisms with an outer layer (ectoderm) that covers the external surface and an inner layer (endoderm) that lines the gut. Between these is a jelly layer or mesoglea. The simple digestive cavity acts as a gullet, stomach, and intestine. There is one opening between the oral arms that acts as a mouth, anus, and entrance for sperm (in females).
Distribution : Atlantic, Pacific, and Indian oceans.
Habitat : Shallow coastal waters as well as brackish waters with a salt content as low as 0.6 %. Jellyfish can survive in water from 6 ˚C to 31 ˚C. The optimum temperature is 9 ˚C to 19 ˚C.
Food : Jellyfish are carnivorous plankton eaters. They feed on fish eggs and larval fish and other plankton, such as mollusks, crustaceans, and copepods etc. Food is collected on the mucus surface of the jellyfish and by the tentacles. Flagellar action of the tentacles passes the food items to the margin of the bell and then up into the mouth and stomach.
Reproduction and Development : Jellyfish are either male or female. Sexual reproduction begins when a male medusa releases sperm through its mouth. The sperm swim into the mouth of a nearby female where fertilization occurs. Further development into free swimming planula (larval stage) occurs in brood pouches along the oral arms. The planula settle on the ocean floor and attach to the bottom forming the polyp. Polyps bud asexually to produce free swimming larvae known as ephyra, which grow into the adult medusa.
Adaptations : The transparent body makes a jellyfish less visible to predators. Oral arms have tentacles that carry nematocysts (stinging cells) that stun prey or deter predators. About 70 species are harmful to humans. The medusa can shrink in size when food is scarce and grow when it is abundant. Radial symmetry permits finding food in any direction.
Threats to Survival : Predators include sea turtles, ocean sunfish, spade fish, tuna, swordfish, and other large fish. Humans, particularly in some Asian countries, capture and eat dried non-venomous jellyfish.
Status : IUCN: Not Evaluated; CITES: Not Listed.
Zoo Diet : Cyclopeeze, and live brine shrimp.
Toronto Zoo Website
© All Rights Reserved
No Usage Allowed in Any Form Without the Written Consent of Serena Livingston
Description: Jelly fish are ancient creatures. Fossils have been found in rocks that are 650 million years old. Today there are more than 2000 species. Jelly fish are 95% water, 3% protein, and 1% mineral. There are two stages: an adult free swimming medusa and a sessile polyp. There is no backbone, brain, or heart. Adults drift with the currents, but can swim horizontally by pulsations of the bell to keep close to the surface. A primitive nerve net controls muscle contractions as it swims. The adult form is a transparent bell shape that ranges between 5-40 cm wide. Underneath is a central mouth surrounded by four oral arms that carry the stinging tentacles. From above four crescent shaped gonads surround the mouth. On the rim of the bell are eight sets of eye spots sensitive to light and eight statocysts that help orient jelly fish when swimming. Jelly fish are primitive organisms with an outer layer (ectoderm) that covers the external surface and an inner layer (endoderm) that lines the gut. Between these is a jelly layer or mesoglea. The simple digestive cavity acts as a gullet, stomach, and intestine. There is one opening between the oral arms that acts as a mouth, anus, and entrance for sperm (in females).
Distribution: Atlantic, Pacific, and Indian oceans
Habitat: Shallow coastal waters as well as brackish waters with a salt content as low as 0.6%. Jelly fish can survive in water from -6C to 31C. The optimum temperature is 9C to 19C
Food: Jelly fish are carnivorous plankton. They feed on fish eggs and larval fish and other plankton such as mollusks, crustaceans, copepods, etc. Food collects on the mucus surface of the jelly fish. Flagellar action of the tentacles passes the food items to the margin of the bell and then up into the mouth and stomach.
Reproduction and Development: Jelly fish are either male or female. Sexual reproduction begins when a male medusa releases sperm through its mouth. The sperm swim into the mouth of a nearby female where fertilization occurs. Further development into free swimming planula occurs in brood pouches along the oral arms. The planula settle on the ocean floor and attach to the bottom forming the polyp. Polyps bud asexually to produce free swimming larvae known as ephyra which grow into the adult medusa.
Adaptations: The transparent body makes a jelly fish less visible to predators. Oral arms have tentacles that carry cnidaria (stinging cells) that stun prey or deter predators. About 70 species are harmful to humans. The medusa can shrink in size when food is scarce and grow when it is abundant. Radial symmetry permits finding food in any direction.
Threats to Survival: Predators include sea turtles, ocean sun fish, spade fish, tuna, swordfish, and other large fish. Humans, particularly in China and Japan, capture and eat dried non-venomous jelly fish.
Status: Common
Zoo Diet: Newly hatched brine shrimp
Courtesy of the Toronto Zoo
Excerpt from torontozoo.com:
Jellyfish are ancient creatures. Fossils have been found in rocks that are 650 million years old. Today there are more than 2000 species. Jellyfish are 95% water, 3% protein, and 1% mineral. There are four life stages from birth to adult. There is no backbone, brain, or heart. Adults drift with the currents, but can swim horizontally by pulsations of the bell to keep close to the surface. A primitive nerve net controls muscle contractions as it swims. The adult form is a transparent bell shape that ranges between 5 and 40 cm wide. Underneath is a central mouth surrounded by four oral arms that carry the stinging tentacles. From above, four crescent shaped gonads surround the mouth. On the rim of the bell are eight sets of eye spots sensitive to light and eight statocysts that help orient jellyfish when swimming. Jellyfish are primitive organisms with an outer layer (ectoderm) that covers the external surface and an inner layer (endoderm) that lines the gut. Between these is a jelly layer or mesoglea. The simple digestive cavity acts as a gullet, stomach, and intestine. There is one opening between the oral arms that acts as a mouth, anus, and entrance for sperm (in females).
Vertebrados
Evolução
Peixes (ostéictes e condrictes (e quimeras (com operculo)))-> anfíbios (anura/apoda/urodela) -> Repteis ( ofidios, escamados, quelonicos e crocodilianos) -> aves (ratita e voadoras)
-> mamíferos
Cordados
notocorda - bastonete maciço e flexivel situado na linha mediana dorsal do corpo
fendas faringianas (branquias) - surgem nas laterais da faringe durante o desenv. do embrião e podem permancer quando adultos
Sistema nervoso central - origem: invaginação do ectoderma. tubo nervoso oco na região dorsal
Protocordados (pro, vieram primeiro, não possuem nem crânio nem vertebras) - Urocordados
São exclusivamente marinhos, fixos, tunicados (tunica resistente), sem coluna vertebral e com notocorda na cauda da larva. Ex. Ascidias.
Cefalocordados
São os unicos em que a notocorda permanece até a fase adulta.
Ex Afioxos (rep sex dióica)
Craniados Aquaticos ( não são peixes)
Clicostomados
Possuem boca circular com dentículos e 6 tentáculos em volta, não possuem mandíbula. são chamados de gnatostomados ou Ágnatos (sem mand.) Ex. Lampréias.
Peixes
Amniotélicos (menos os cart) secretam amônia
Pecilotermicos
Fecundação externa (maioria)
Coração com 2 cavidades simples( só passa uma vez pelo coração) completa (nao mistura)
Anamniotas ( não possuem amnio)
Respiração branquial
Ovíparos ( ovo externo Jovem Alevino-larva), Ovovivíparos ( ovo desenvolvido externo) ou Vivíparos ( sem ovo, desenvolve internamente)
Osteíctes - osseo- boca anterior, operculo, escamas diferenciadas/individuais, nadadeira homocerca e bexiga natatória (equilibrio hidrostatico) Ex.: baiacu piranha carapeba e epscada
Condrictes - cartilaginoso- boca vetral, fendas branquiais, escamas placóides, nadadeira heterocerca Ex.: tubarão cação e raias. equi. hidrostatico feito atraves dos teores de oléo no figado.
Holocéfalos - Opérculo, não tem escamas, cauda longa e flexivel, olhos muito grandes Ex Quimeras
Linha lateral - captura as vibrações na agua
Opérculo - Protege as branquias
Anfíbios ( primeiros terrestres)
epiderme lisa e úmida rica em glandulas que secreta muco
pecilotermicos
anamniotas
respiraçao branquial na larva e pulmonar e cutanea na fase adulta.
coração com 3 cavidades dupla e incompleta
excreção: amniotélicos quando larva e ureotélicos quando adultos
fec. externa, ovíparos - desenvolvimento indireta, larva girino.
Apoda sem patas cabra cega
anura sem cauda sapo e rã
urodela com tudo que tem direito, salamandra.
Rep. sapos, abraço nupcial.
Femea coacha pra atrai o macho que a abraça estmulando-a a soltar os ovulos na agua. Por sua vez, os macho joga os espermatozoides e então ocorre a fec, externa
Necessitam de agua pra reproduçao.
Répteis ( primeiros independentes de meio aq. pra reprodução. )
Pecilotérmicos
amniotas (com amnio)
pele seca e grossa
respiraçao pulmonar
coraçao com 3 cavidades, crocodilianos 4
ovíparos e alguns ovivíparos.
ofídios cobra
escamados lagartos
quelonios tartaruga e cagado - marinha possui respiração cloacal - cloaca faz tudo. rep, exc, filhotes e resp.
crocodiliano jacara e crocodilo
Aves (voadoras e ratitas)
corpo recoberto por penas, adaptação pra voo e proteção
glandula uropigiana, impermeabilizar as penas (agua nao fazer peso) e mante-las flexiveis
amniotos
homeotermicos (temperatura cte)
resp pulmonar
coraçao com 4 cavidades
arteria aorta voltada pra direita, diferente dos mamiferos
ovíparos (ext.)
reproduçao interna e rápida
ovos ricos em vitelo com casca, telolécito, heterolécito completo
pulmao com sacos aereos (corpo leve) reserva de oz, subida e descida, ausencia de bexiga e dentes.
ossos pneumáticos (ocos)
Quilha, osso externo, musculatura potente, equilibrio, ( aerodinamica)
papo controla a quantidade de comida e amolece o alimento antes da trituração na moela
no proventriculo ocorre a digestao quimica (banho) no intestino absorve nutrientes. Fezes sao eliminadas na cloaca
as aves engolem pedrinha que ajuda na tirturaçao dos alimentos no papo
Picture #28
Reino: Animalia
Filo: Arthropoda
Clase: Insecta
Orden: Coleoptera
Suborden: Polyphaga
Las luciérnagas o bichos de luz son una familia de coleópteros, caracterizados por la bioluminiscencia. Hay más de 2000 especies de la luciérnaga. Muchas especies se pueden encontrar en pantanos o en las áreas húmedas y boscosas, donde sus larvas tienen una fuente abundante del alimento.
En las noches cálidas, es posible ver a las luciérnagas hembras iluminarse para atraer a los machos que vuelan por encima. Si algo las molesta, apagan la luz de inmediato. Generan luz mediante un órgano especial que nace en la piel verdadera, bajo la quitina (ectodérmico), situado en la parte inferior del abdomen, en intervalos de 6 a 8 segundos. Esta luz se produce por un proceso de oxidación de la luciferina en presencia de la luciferasa, que ocurre muy rápidamente. Este proceso recibe el nombre de bioluminiscencia y emite una luz brillante con poca elevación de la temperatura. Algunas especies emiten la luz con esquemas definidos de variación en los intervalos y el número de destellos.
Algunos días después del acoplamiento, la hembra pone los huevos fertilizados, apenas debajo de la superficie de la tierra. Los huevos incuban durante 3 a 4 semanas y entonces salen de ellos las larvas, que tienen ojos simples. Algunas hacen madrigueras subterráneas, mientras que otras encuentran lugares en o debajo de la corteza de árboles.
Se caracterizan por poseer un par de antenas delgadas y articuladas, élitros y un prototorax modificado en forma tal que casi cubre la cabeza. En la amyoría de las especies es muy notorio el dimorfismo sexual: mientras los machos alcanzan un desarrollo completo similar al de otros coleópteros, las hembras conservan un aspecto larvario, con élitros reducidos a escamas y se parecen más a cochinillas que a escarabajos, con unas patas rechonchas y sin alas y a menudo solamente pueden ser distinguidas de las larvas porque tienen ojos compuestos.
Entry in category 4. Video loop; Copyright CC-BY-NC-ND: Yinan Wan
Video showing explant of frog (Xenopus) cells migrating onto each other. On the left are mesoderm cells and on the right ectoderm cells. Mesoderm cells became more and more motile over time and eventually crossed over to the right side. Movie taken by Zeiss Lattice light sheet microscopy. Xenopus explant has been an excellent system to study the mechanism of cell movement and embryonic development. Why did mesoderm cells become more motile? Why did cells send protrutions onto each other? The video showcases the power of this wonderful model organism to study basic questions in animal development.
Vocabulário:
- Filo: [Biologia] Série evolutiva de formas animais e vegetais.
- Annelida: Anelídeo (do latim annelus, pequeno anel + ida, sufixo plural).
- Peculiar: Particular, especial, próprio, privativo.
- Metameria: [Embriologia] Divisão primitiva da corda dorsal e dos tecidos vizinhos, em segmentos ou metâmeros.
- Anelídeos: Subdivisão ou classe de vermes.
- Simetria: Relação de tamanho ou de disposição que entre si devem ter as coisas ou as partes de um todo em relação a um ponto, eixo ou plano.
- Celomados: Cavidade geral (da maioria dos metazoários).
- Estruturados: Dotar com uma estrutura.
- Cilíndricos: Que tem forma de cilindro.
- Segmentados: Que está dividido em segmentos.
- Triblásticos: São animais que possuem três tipos de tecidos: ectoderme, Mesoderme e endoderme.
- Embrionários: Do embrião ou a ele relativo.
- Bilaterais: Que tem dois lados.
- Cavidade: Parte côncava de um corpo sólido.
- Dioicas: Àquela em que os sexos se encontram separados em indivíduos diferentes.
Anthopleura elegantissima, also known as the aggregating anemone or clonal anemone, is the most abundant species of sea anemone found on rocky, tide swept shores along the Pacific coast of North America. This cnidarian hosts endosymbiotic algae called zooxanthellae that contribute substantially to primary productivity in the intertidal zone. A. elegantissima has become a model organism for the study of temperate cnidarian-algal symbioses.
The polyps of Anthopleura elegantissima reach up to eight cm across the oral disk with approximately 100 tentacles in three or four rows around the margins of the oral disk. Most are olive to bright green (depending on the species of algal symbionts present) with tentacles tipped in pink. Individuals that live in microhabitats that are deficient in photosynthetically active radiation (PAR), such as under docks or in caves, lack symbionts and are pale yellow to white in color.
Pacific coast of North America from Alaska, United States to Baja California, Mexico.
This species of anemone is capable of reproducing both sexually and asexually. As adults, A. elegantissima release gametes into the water that join to form genetically unique individuals that settle on intertidal rock. This genetically distinct individual can then proliferate through binary fission. Some argue that this is not true reproduction but actually a form of growth. Fission is often prompted in the autumn by a decrease in the abundance of food and follows sexual spawning in summer. Over time, a single individual can generate a large colony of genetically identical polyps. Because of its ability to grow in this manner, the genetic entity of a colony is potentially immortal on an ecological time scale.
Anthopleura elegantissima is agonistic toward other individuals with different genetic disposition. When one colony of genetically identical polyps encounters a different genetic colony, the two will wage territorial battles. A. elegantissima has specialized tentacles called acrorhagi that are used solely to deter other colonies from encroaching on their space. When a polyp makes physical contact with a non-clonemate, it extends the acrorhagi to attack the competing anemone with stinging cells called nematocytes. Acrorhagi of the attacking anemone leave behind a 'peel' of the ectoderm and nematocysts that causes tissue necrosis in the receiving animal.
A study of two colonies on a boulder removed from the shore and brought into a laboratory revealed that hostilities between neighboring colonies follow the tides. As water rushed into the tank, warrior polyps inflated their acrorhagi, tripled their body length and began reaching into an empty swath of rock between the colonies. Occasionally, a polyp from one of the colonies would move into the spatial zone between the two colonies, acting as a scout, and would be attacked by the warrior polyps of the other clone. If the scout polyp received enough stings, it would be attacked by its clonemates upon return to its own colony. The return of an attacked scout to the clone with acrorhagial peel may serve to communicate the presence and identity of neighboring clones to the interior of the colony.
New York Aquarium Coney Island NY
Cette Cnidaire dispose de huit tentacules, dont les nématocystes urticants peuvent provoquer de vives douleurs en cas de contact avec la peau. Couverte de minuscules points rouges qui sont en fait des faisceaux de cellules urticantes, elle possède une coloration rougeâtre, allant de l'orange au violet en passant par le rose. Son ectoderme (chapeau) est transparent et urticant et laisse entrevoir sa mésoglée, son endoderme et ses gonades. Elle possède aussi, en bas de l'ombrelle, quatre lobes buccaux dentelés, de couleur rosâtre, urticants et couverts d'un mucus gluant, qui capturent et paralysent les proies (petits animaux faisant partie du zooplancton) qui seront amenés vers la bouche.
Sa reproduction diffère de la plupart des autres méduses, puisqu'elle répand des ovules et du sperme qui, après s'être fécondés, deviendront des petites larves qui passeront directement au stade de méduse pour devenir peu à peu des adultes. Elle brille grâce à un mucus sécrété par son ectoderme lorsque la méduse est perturbée ou heurtée par les vagues (cf. wikipédia).
TAXONOMY
Kingdom: Animalia
Phylum: Cnidaria
Class: Anthozoa
Subclass: Hexacorallia (includes stony corals, all sea anemones, tube anemones, and zoanthids)
Order: Actiniaria (sea anemones)
Family: Actiniidae (largest family of sea anemones)
Genus/species: Anthopleura elegantissima
GENERAL CHARACTERISTICS: Most are olive to bright green (depending on the species of algal symbionts present) with tentacles tipped in pink. The oral disk has approximately 100 tentacles in three or four rows around its margins. Those that are deficient in photosynthetically active radiation, such as under docks or in caves, lack symbionts and are pale yellow to white in color.
Disc 2-3 cm (0.78-1.2 in) across, under water.
DISTRIBUTION/HABITAT: Common in tide pools. The body of the anemone is firmly attached to rock substrate and detritus and sand adheres to the column almost covering them.
DIET IN THE WILD: Capture tiny crustaceans and other animals past their tentacles using their stinging nematocysts (also called cnidocytes) on the surface of their tentacles.
REPRODUCTION: To clone themselves, anemones split in half—literally tearing themselves apart (asexual reproduction). Aggregating anemones also reproduce sexually by broadcasting eggs and sperm.
PREDATORS: Their are few known predators but include the nudibranch Aeolidia papillosa, leather star Dermasterias imbricata and mosshead sculpin Clinocottus globiceps.
REMARKS: When one colony of genetically identical polyps encounters a different genetic colony, the two will wage territorial battles. A. elegantissima has specialized tentacles called acrorhagi to deter non identical colonies from encroaching on their space. It extends the acrorhagi to attack the competing anemone with nematocytes leaving behind a 'peel' of the ectoderm and nematocysts that causes tissue necrosis in the receiving animal.
Temperate Marine Sea Anemone (tidepool)
References
California Academy of Sciences Tidepool
Encyclopedia of Life eol.org/data_objects/27560182
Monterey Bay Aquarium
www.montereybayaquarium.org/animal-guide/invertebrates/ag...
Slatter Museum of the U. of Puget Sound www.pugetsound.edu/academics/academic-resources/slater-mu...
12-21-15, 1-14-16
I had to call the poison control center this morning to ask about a diaper rash cream he had on his face. A combination of ectoderm cream and canesten cream. He SAID he didn't eat any of it...but he's TWO. What can I believe?
This is a fairly extreme crop of the preceeding picture - as you can see, the 'black' part of the frogspawn is not spherical anymore.
Compared to last year's pictures, I estimate between the original "Day 2 and 3 stages", however those were indoors in the warm. These eggs are 6.5 days old, and at a temperature of 11 degreees C.
There is now a distinct change in the shape of the centre of the eggs - the cells are no longer visible, and they are no longer spheroidal.
The eggs have expanded and an ectoderm now covers the surface of the embryo.
When I was harvesting my ringless honey mushrooms, on one mushroom, a hammerhead worm that has a long, flattened body and a broad head: it is a planarian, a free-living flatworm of the phylum Platyhelminthes (from the Greek “platy” meaning flat, and “helminth” meaning worm)., among the simplest animals comprised of 3 germ layers (ectoderm, mesoderm, and endoderm), yet possessing a complex anatomy of organ systems with striking molecular and physiological conservation to mammalian tissues
__________________________________________
Hammerhead Flatworm – 2020SEP25 – Charlotte, NC
Going out for my annual ringless honey mushroom harvest (cf. my albums 2018AUG23 & 2018AUG22), I saw something else.
Something definitely toxic, terrestrial, and considered terrifying...
...A hammerhead flatworm native to tropical and subtropical regions but that has become invasive worldwide.
Picking the mushroom cap with the hammerhead worm, I went inside to get my cell phone camera, which I could hold using one hand to capture images, keeping an eye on the other hand with the wriggly worm slithering over the mushroom cap
...and then I learned this about it after I went and put it back!
Hope you enjoy the 34% of 49 captures I took this drizzly day!
Phylogenetic mapping of Hox expression. The neighbor-joining and Bayesian phylogenies (Figure 2 and S1) were pared to remove all bilaterian sequences. The strict consensus topology shown here depicts the relative relationships among Nematostella sequences. Each of the Nematostella Hox-related sequences is coded according to whether its expression is restricted along the primary (O/A) body axis or the secondary (directive) body axis (Y = yes; N = no). A yellow Y in the directive column signifies that the expression is bilateral (both sides of the directive axis), and a red Y indicates that the expression is unilateral. The character state found in the terminal taxon is indicated in the colored boxes. The internal nodes are shaded to indicate the character states found in hypothetical ancestors. For each gene, the spatial expression is depicted on a diagram of the juvenile polyp. In the case of Dlx, anthox6a and anthox1, the expression pattern that is depicted actually occurs earlier, in the larval stage, but it is represented on a diagram of the polyp to facilitate spatial comparisons with the other genes. The polyp is drawn in lateral view with the overlying ectoderm (dark gray) partially peeled away to reveal the underlying endoderm of the body column (light gray) and the lumen of the pharynx (white). The pharynx is drawn as though everted. Only one representative tentacle is shown. The mesoglea, a largely acellular layer of connective tissue that separates the endoderm from the ectoderm, is depicted as a thin black line. Gene expression is depicted as black shading in the endoderm or ectoderm. The major regions along the primary body axis are demarcated with dotted lines: Ph = pharynx; H = head; C = column; F = foot. Cross-sectional views through the body column (at the arrowheads) are shown for Gbx, anthox7, anthox8a, anthox8b, anthox6a, anthox1a, and NVHD065.
this animal was recently recontextualized for me in a very interesting way. C. pyrrhus are known to be very good substrate-matchers, and rattlesnake camouflage coloration is known to affect predation rates. the balance among possible mechanisms that achieve this at the meta-population, population, and individual levels is not explored; it could be behavioral, it could be evolutionary, (i think) likely it is a combination of those two. this individual was seen in an area where most animals are vibrantly yellow, and most animals that are not yellow are gray and tan, and this biphasic locality exists as a tiny unique pocket within a (much) larger, mostly-monophasic (the gray and tan phase) region, and this is at the western edge of the species's range (range edges are often where genetically-weird stuff happens, both because range edges tend to occur near to where tolerance limits occur, and because there's less convergent selection on subpopulations on edges relative to subpopulations that are receiving gene flow from all directions). this individual seems to me to be representative of the regional gray and tan phase, but in which something to do with the concentration of melanin in the ectoderm has been amplified, to cover the animal in black spots so dense that the animal looks black when received as a whole. this can probably happen by accident (it's not quite melanism or hypermelanism the way that that is usually expressed in snakes), and for a long time my interpretation was that it was just an accident... but last time i visited this site, i found out that less than 20 years ago, a very large area around the site had burned in a wildfire. burn scars still persist in the area; a visitor can see burn marks on old woody stems in the area, and ash stains on many rocks... 20 years later. 15 years ago? 10 years ago? maybe even 5 years ago? for a long time the dominant substrate color (i would guess soils and rock faces) was probably black. certainly this is not proof that the local subpopulation evolved or chose (or a combination of these) substrate matching to a black, wildfire-generated substrate, but the idea is thought provoking.
seen on Kumeyaay land.
Scientific Name: Aurelia aurita
Description : Jelly fish are ancient creatures. Fossils have been found in rocks that are 650 million years old. Today there are more than 2000 species. Jelly fish are 95% water, 3% protein, and 1% mineral. There are two stages: an adult free swimming medusa and a sessile polyp. There is no backbone, brain, or heart. Adults drift with the currents, but can swim horizontally by pulsations of the bell to keep close to the surface. A primitive nerve net controls muscle contractions as it swims. The adult form is a transparent bell shape that ranges between 5-40 cm wide. Underneath is a central mouth surrounded by four oral arms that carry the stinging tentacles. From above four crescent shaped gonads surround the mouth. On the rim of the bell are eight sets of eye spots sensitive to light and eight statocysts that help orient jelly fish when swimming. Jelly fish are primitive organisms with an outer layer (ectoderm) that covers the external surface and an inner layer (endoderm) that lines the gut. Between these is a jelly layer or mesoglea. The simple digestive cavity acts as a gullet, stomach, and intestine. There is one opening between the oral arms that acts as a mouth, anus, and entrance for sperm (in females).
Distribution : Atlantic, Pacific, and Indian oceans
Habitat : Shallow coastal waters as well as brackish waters with a salt content as low as 0.6%. Jelly fish can survive in water from -6C to 31C. The optimum temperature is 9C to 19C
Food : Jelly fish are carnivorous plankton. They feed on fish eggs and larval fish and other plankton such as mollusks, crustaceans, copepods, etc. Food collects on the mucus surface of the jelly fish. Flagellar action of the tentacles passes the food items to the margin of the bell and then up into the mouth and stomach.
TAXONOMY
Kingdom: Animalia
Phylum: Cnidaria
Class: Anthozoa
Subclass: Hexacorallia (includes stony corals, all sea anemones, tube anemones, and zoanthids)
Order: Actiniaria (sea anemones)
Family: Actiniidae (largest family of sea anemones)
Genus/species: Anthopleura elegantissima
GENERAL CHARACTERISTICS: Most are olive to bright green (depending on the species of algal symbionts present) with tentacles tipped in pink. The oral disk has approximately 100 tentacles in three or four rows around its margins. Those that are deficient in photosynthetically active radiation, such as under docks or in caves, lack symbionts and are pale yellow to white in color.
Disc 2-3 cm (0.78-1.2 in) across, under water.
DISTRIBUTION/HABITAT: Common in tide pools. The body of the anemone is firmly attached to rock substrate and detritus and sand adheres to the column almost covering them.
DIET IN THE WILD: Capture tiny crustaceans and other animals past their tentacles using their stinging nematocysts (also called cnidocytes) on the surface of their tentacles.
REPRODUCTION: To clone themselves, anemones split in half—literally tearing themselves apart (asexual reproduction). Aggregating anemones also reproduce sexually by broadcasting eggs and sperm.
PREDATORS: Their are few known predators but include the nudibranch Aeolidia papillosa, leather star Dermasterias imbricata and mosshead sculpin Clinocottus globiceps.
REMARKS: When one colony of genetically identical polyps encounters a different genetic colony, the two will wage territorial battles. A. elegantissima has specialized tentacles called acrorhagi to deter non identical colonies from encroaching on their space. It extends the acrorhagi to attack the competing anemone with nematocytes leaving behind a 'peel' of the ectoderm and nematocysts that causes tissue necrosis in the receiving animal.
Temperate Marine Sea Anemone (tidepool)
References
California Academy of Sciences Tidepool
Encyclopedia of Life eol.org/data_objects/27560182
Monterey Bay Aquarium
www.montereybayaquarium.org/animal-guide/invertebrates/ag...
Slatter Museum of the U. of Puget Sound www.pugetsound.edu/academics/academic-resources/slater-mu...
12-21-15
La Ciencia en la literatura: el CSIC, la cepa cancerígena MNA y Tiempo de silencio (1962), novela de impotencia y frustración.
Ponente: D. Nicolás Guerra Aguiar
"Detente. coge el receptor-emisor negro, ordena al Ministro del ramo, dile que la investigación, ¡oh Amador!, la investigación bien vale un ratón." (Pág. 8. Ed. duodécima. Barcelona. Seix-Barral, 1978)
"De ahí surgirá tal vez la nueva posibilidad de que el cáncer inguinal no sea inguinal, sino axilar. De que no de estirpe ectodérmica sino mesodérmica" (Pág. 25)
¿CÓMO ES LA TORTUGA MORA?
La Tortuga mora (Testudo graeca) es un quelonio que raramente llega a los 30 cm de longitud y que habita el Mediterráneo occidental: Noroeste de África, islas de Cerdeña, Sicilia y Malta, sur de la Península Italiana, y algunos enclaves, de España: Murcia y Almería, Doñana y una pequeña zona al suroeste de la Isla de Mallorca. Diversos investigadores consideran a esta población diferente a la que se encuentra en Grecia y otros países cercanos, que constituiría una especie diferente, basándose en características morfológicas, ecológicas y etnológicas (Highfleld, 1990).
La Tortuga mora, protagonista del Proyecto Testudo
La presencia de las tortugas moras en el sureste ibérico parece muy remota. Así al menos lo atestiguan los restos subfósiles encontrados en la zona, con una antigüedad comprendida entre los 35.000 y 150.000 años, que confirmarían el carácter autóctono de la especie en la zona, contrariamente a lo que ocurre en otros enclaves de nuestra geografía, como ocurre con Mallorca, y también con las islas próximas a Italia, donde parecen haber sido introducidas desde el norte de África.
Entre la zona noroeste de la provincia de Almería y el suroeste de la Región de Murcia, dominada por la escasez de precipitaciones en torno a los 200 mm anuales, donde predomina la vegetación estépica, de matorrales y arbustos de pequeño porte, vive la más importante población española de Tortuga mora. Se distribuye por un numeroso mosaico de poblaciones aisladas entre sí, como consecuencia de la fragmentación de su hábitat debido a la intensa roturación de tierras y a la construcción de infraestructuras.
Las tortugas prefieren las zonas de escasa pendiente y vegetación de pequeño porte, y seleccionan en estos lugares las umbrías. Aunque en algunas zonas llegan a encontrarse densidades que superan las 10 tortugas por hectárea, la media no supera los 5 ejemplares, y en muchos lugares apenas se encuentra un solo ejemplar por hectárea.
Animales ectodermos, las tortugas disminuyen casi totalmente su actividad durante el periodo invernal, que solo interrumpen ocasionalmente los días de mejor tiempo. Abandonan este letargo a finales de Febrero o primero de Marzo, cuando la temperatura llega a unos 20ºC., su actividad aumenta progresivamente con la temperatura.
Por regla general cada hembra pone entre 3 y 7 huevos, con una media de 33,21 x 26,84 mm, la incubación se prolonga entre los meses de julio, agosto y septiembre. Las tortuguitas nacen y a finales de Agosto o a principios de Septiembre. Las cópulas se inician a finales de Marzo, pero la mayor actividad ocurre a mediados del mes de Abril para ir luego diminuyendo durante el mes de Mayo.
A finales de Mayo o primeros de Junio la hembra busca un lugar llano de tierra no muy blanda y abrigado de una planta, más o menos orientada hacia el este. De esta manera los huevos reciben el calor más suave de la mañana y a medio día recibe la sombra que, proporcionan las plantas que los protege. En verano la falta de alimento y el excesivo calor hacen que reduzcan notablemente su actividad a las primeras horas del día y últimas de la tarde, permaneciendo a veces durante muchos días casi completamente inmóviles, cobijadas bajo rocas, arbustos o agujeros abandonados de animales. El cambio de temperatura y las primeras lluvias otoñales devolverá a la actividad a las tortugas.
via
Using tattooing to introduce biology, the concept borrows on tattoo arts’ mainstream recognition to entice students. In short, an embedding of scientific knowledge within an immediately relevant topic. Despite comparatively technical terminology the article details considerations that should ideally be further understood by artists and clients alike. The latest entry in the academic discussions sections, large expansions are planned for the guide over the coming months
| ‘Because tattoos are applied to the skin, the process turns skin anatomy into a teaching moment. Two mutually dependent layers make up the skin: the epidermis and the dermis. There are four anatomical layers (called strata) of epidermis on the human body; they are derived from the ectoderm. From the most superficial to the deepest, those layers are called the stratum corneum (20-30 cell layers thick), stratum granulosum (3-5 cell layers thick), stratum spinosum (5-10 cell layers thick), and stratum basale (1 cell layer thick). Cells at the surface are dead, whereas the deeper layers closer to the dermis are living cells. At areas of high friction (feet and palms of the hands), an extra layer called the stratum lucidum is between the stratum granulosum and the stratum spinosum. Dermis rests on the subcutaneous fatty layer called the panniculus adiposus. The area that adheres the epidermis to the dermis is referred to as the dermoepidermal junction and has two layers; the lamina lucida connects to the epidermis, and the lamina densa connects to the dermis. Dermis is derived from the mesoderm, and its main function is to sustain and support the epidermis
To apply a tattoo, the artist pulls the skin tight and adjusts the rate at which the needle delivers ink to ensure that a sufficient force is supplied to the needle, which is a function of the client’s body fat ratio and the chosen area for the tattoo application (professional tatto artist Michael Adkins, pers. comm.). A solid needle injects ink pigments as a suspension into the skin dermis approximately 1-4 mm deep. The process destroys the four layers of epidermis, the layer between the epidermis and dermis, and the first layer of dermis as the needle penetrates the skin to deliver the ink. Skin can vary, depending on its anatomic location and the sex and age of the individual. Skin thickness depends on dermal, not epidermal, thickness. Because epidermis does not contain blood vessels, bleeding occurs only when the artist has punctured down into the dermal region (at least) with the needle
After ink delivery, granulation tissue forms, trapping the dye in fibroblasts in the superficial dermis. The ability to properly apply a tattoo is related to the experience of the artist. If the ink is not applied to the correct skin layer, the body will shed the tattoo as the epidermis is naturally shed. The initial vibrancy of a tattoo fades quickly because only a portion of the ink stays in the dermis; an unknown fraction of pigment is moved by the lymphatic system. When tattoos are applied to hands and feet, color or vibrancy fades faster because the tattoo is applied below one more skin layer. Because tattooing involves both the homogenization of the epidermal surface and the implantation of foreign ink in the dermal layer, cellular death occurs and results in a scabbing process… | full article
Tattoo Concierge | The Artists’ Choice
Drawing On Popular Culture appeared first on Tattoo Concierge
Source: www.TattooConcierge.com/drawing-popular-culture/
tattooconcierge.wordpress.com/2017/06/16/drawing-on-popul...
Le cellule si dispongono in modo tale da circondare una cavità interna, ripiena di liquido, (trofoblasto) e un ammasso cellulare interno (embrioblasto).
L’embrione è libero di fluttuare nell’utero per circa 48 ore prima dell’impianto, che avviene allo stadio di blastocisti.
L’impianto nell’endometrio del corpo dell’utero avviene per l’azione delle cellule trofoblastiche, in grado di produrre enzimi proteolitici che consentono l’erosione epiteliale della mucosa uterina e il contatto con il connettivo sottostante.
Inizia la crescita e la differenziazione cellulare: dall’embrioblasto si forma l’ectoderma e l’endoderma; le cellule della parte caudale dell’ectoderma si differenziano, proliferano e si insinuano verso l’interno, tra i due foglietti germinativi, a formare il mesoderma. L’ectoderma, formerà le parti più esterne come la pelle, i peli, i capelli, le unghie, ma anche il sistema nervoso e gli organi di senso. Il secondo strato, il mesoderma fornirà l’impalcatura di sostegno come le ossa e i muscoli, ma anche il sangue e l’apparato urogenitale. Il terzo strato, l’endoderma,produrrà gli organi interni per l’alimentazione e la respirazione (stomaco, fegato, polmoni).
All'interno dell'utero si forma il sacchettino che ospiterà l'embrione (sacco gestazionale). Successivamente inizia a rendersi evidente l'embrione stesso che in questo periodo ha la forma di un corpicciolo cilindrico.
La parte esterna dell'embrione, a stretto contatto con le pareti uterine, viene raggiunta dal sangue materno (inizio della circolazione utero-placentare) che fornisce il nutrimento.
Gli ormoni prodotti dall’embrione bloccano il ciclo mestruale della madre.
La Ciencia en la literatura: el CSIC, la cepa cancerígena MNA y Tiempo de silencio (1962), novela de impotencia y frustración.
Ponente: D. Nicolás Guerra Aguiar
"Detente. coge el receptor-emisor negro, ordena al Ministro del ramo, dile que la investigación, ¡oh Amador!, la investigación bien vale un ratón." (Pág. 8. Ed. duodécima. Barcelona. Seix-Barral, 1978)
"De ahí surgirá tal vez la nueva posibilidad de que el cáncer inguinal no sea inguinal, sino axilar. De que no de estirpe ectodérmica sino mesodérmica" (Pág. 25)
La Ciencia en la literatura: el CSIC, la cepa cancerígena MNA y Tiempo de silencio (1962), novela de impotencia y frustración.
Ponente: D. Nicolás Guerra Aguiar
"Detente. coge el receptor-emisor negro, ordena al Ministro del ramo, dile que la investigación, ¡oh Amador!, la investigación bien vale un ratón." (Pág. 8. Ed. duodécima. Barcelona. Seix-Barral, 1978)
"De ahí surgirá tal vez la nueva posibilidad de que el cáncer inguinal no sea inguinal, sino axilar. De que no de estirpe ectodérmica sino mesodérmica" (Pág. 25)
La Ciencia en la literatura: el CSIC, la cepa cancerígena MNA y Tiempo de silencio (1962), novela de impotencia y frustración.
Ponente: D. Nicolás Guerra Aguiar
"Detente. coge el receptor-emisor negro, ordena al Ministro del ramo, dile que la investigación, ¡oh Amador!, la investigación bien vale un ratón." (Pág. 8. Ed. duodécima. Barcelona. Seix-Barral, 1978)
"De ahí surgirá tal vez la nueva posibilidad de que el cáncer inguinal no sea inguinal, sino axilar. De que no de estirpe ectodérmica sino mesodérmica" (Pág. 25)
La Ciencia en la literatura: el CSIC, la cepa cancerígena MNA y Tiempo de silencio (1962), novela de impotencia y frustración.
Ponente: D. Nicolás Guerra Aguiar
"Detente. coge el receptor-emisor negro, ordena al Ministro del ramo, dile que la investigación, ¡oh Amador!, la investigación bien vale un ratón." (Pág. 8. Ed. duodécima. Barcelona. Seix-Barral, 1978)
"De ahí surgirá tal vez la nueva posibilidad de que el cáncer inguinal no sea inguinal, sino axilar. De que no de estirpe ectodérmica sino mesodérmica" (Pág. 25)
La Ciencia en la literatura: el CSIC, la cepa cancerígena MNA y Tiempo de silencio (1962), novela de impotencia y frustración.
Ponente: D. Nicolás Guerra Aguiar
"Detente. coge el receptor-emisor negro, ordena al Ministro del ramo, dile que la investigación, ¡oh Amador!, la investigación bien vale un ratón." (Pág. 8. Ed. duodécima. Barcelona. Seix-Barral, 1978)
"De ahí surgirá tal vez la nueva posibilidad de que el cáncer inguinal no sea inguinal, sino axilar. De que no de estirpe ectodérmica sino mesodérmica" (Pág. 25)
La Ciencia en la literatura: el CSIC, la cepa cancerígena MNA y Tiempo de silencio (1962), novela de impotencia y frustración.
Ponente: D. Nicolás Guerra Aguiar
"Detente. coge el receptor-emisor negro, ordena al Ministro del ramo, dile que la investigación, ¡oh Amador!, la investigación bien vale un ratón." (Pág. 8. Ed. duodécima. Barcelona. Seix-Barral, 1978)
"De ahí surgirá tal vez la nueva posibilidad de que el cáncer inguinal no sea inguinal, sino axilar. De que no de estirpe ectodérmica sino mesodérmica" (Pág. 25)
Hay Foliculos Pilosos
Tambien se le llama quiste dermoide invade las 3 caps ectodermo, mesodermo, endodermo.
pueden encontrar tejidos de todo tipo.
TAXONOMY
Kingdom: Animalia
Phylum: Cnidaria
Class: Anthozoa
Subclass: Hexacorallia (includes stony corals, all sea anemones, tube anemones, and zoanthids)
Order: Actiniaria (sea anemones)
Family: Actiniidae (largest family of sea anemones)
Genus/species: Anthopleura elegantissima
GENERAL CHARACTERISTICS: Most are olive to bright green (depending on the species of algal symbionts present) with tentacles tipped in pink. The oral disk has approximately 100 tentacles in three or four rows around its margins. Those that are deficient in photosynthetically active radiation, such as under docks or in caves, lack symbionts and are pale yellow to white in color.
Disc 2-3 cm (0.78-1.2 in) across, under water.
DISTRIBUTION/HABITAT: Common in tide pools. The body of the anemone is firmly attached to rock substrate and detritus and sand adheres to the column almost covering them.
DIET IN THE WILD: Capture tiny crustaceans and other animals past their tentacles using their stinging nematocysts (also called cnidocytes) on the surface of their tentacles.
REPRODUCTION: To clone themselves, anemones split in half—literally tearing themselves apart (asexual reproduction). Aggregating anemones also reproduce sexually by broadcasting eggs and sperm.
PREDATORS: Their are few known predators but include the nudibranch Aeolidia papillosa, leather star Dermasterias imbricata and mosshead sculpin Clinocottus globiceps.
REMARKS: When one colony of genetically identical polyps encounters a different genetic colony, the two will wage territorial battles. A. elegantissima has specialized tentacles called acrorhagi to deter non identical colonies from encroaching on their space. It extends the acrorhagi to attack the competing anemone with nematocytes leaving behind a 'peel' of the ectoderm and nematocysts that causes tissue necrosis in the receiving animal.
Temperate Marine Sea Anemone (tidepool)
References
California Academy of Sciences Tidepool
Encyclopedia of Life eol.org/data_objects/27560182
Monterey Bay Aquarium
www.montereybayaquarium.org/animal-guide/invertebrates/ag...
Slatter Museum of the U. of Puget Sound www.pugetsound.edu/academics/academic-resources/slater-mu...
12-21-15, 1-14-16
La queratina és una proteïna amb estructura fibrosa, molt rica en sofre, que constitueix el component principal que formen les capes més externes de l'epidermis dels vertebrats i d'altres òrgans derivats del ectoderm, fàneres com els cabells, ungles, plomes, banyes, ranfotecas i peülles. Una de les biomolècules la duresa s'aproxima a la de la queratina és la quitina, amb la qual no cal confondre, en ser aquesta última un polisacàrid.(La queratina s'utilitza a mes en productes capilars)
Tubipora musica
Organ Pipe Coral
Anthozoa Alcyonaria
Skeleton of colony. The colony consists of a large number of calcareous tubes formed by agglutination of the red mesodermal spicules, and in the living state covered by ectoderm, so that it is really an internal structure. The tubes are connected by transverse platforms, which arise separately from near the apex of each tube, the platforms from adjacent tubes fusing later into a continuous layer. These platforms consist of ectoderm, mesogloea and endoderm and from them new polyps arise by budding. In this way the colony tends to resemble an inverted pyramid. The basal stolon is not shown.
Maladie de Recklinghausen ou neurofibromatose de type 1 (NF1), dysfonctionnement du tissu ectodermique embryonnaire qui formera la peau, le système nerveux et l'oeil. MIM (Mendelian Inheritance in Man) +162200.
Dr. Khayati talks about the formation of three germ layers in today's video. The three germ layers are the endoderm, the ectoderm, and the mesoderm. Cells in each germ layer differentiate into tissues and embryonic organs. To know more about these germ layers in a fun manner, watch the video till the end!
Call - 8837800191 or visit our Website - drkhayatisantram.com/
#threegermlayers #endoderm #ectoderm #mesoderm #embryonicorgans #anatomy #Hurry #JoinNow #OnlineClasses #Anatomytuition #Medical #Anatomyclasses #Physiology #Medicalstudent #Doctors #Biology #Study #FunAtomy
Age: 346-344Ma
Viséan
Middle Mississippian Epoch
Carboniferous Period - Giant arthropods and amphibians, early reptiles, most plants fern or lycophyte-like, known for tropical forests and seas
Paleozoic Era - pre-Dinosaurs
Location: Lancashire
Clitheroe
Salthill Quarry
Rock Type: Course grained and coursely crinoidal limestone, with lots of calcite from crinoid structure, park of a knoll-reef from the Clitheroe Limestone Formation.
Specimen:
A large crinoid column about 3.5cm in diameter, 4cm at its widest, with the clear pentastellate axial canal visible. This section is only about 1-1.5cm tall
Species:
Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.
The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.
The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.
Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.
Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.
Bystrowicrinus westheadi is a newly described species (2013) based on remarkably large crinoid column (stem) fragments from the Lower Carboniferous (Mississippian) deposits at Salthill Quarry, Clitheroe, Lancashire, UK. These columns, long known about but previously not officially described or named, are unusual for their incredibly large size and distinctive pentastellate axial canal. The species name honours Stanley Westhead (1910–1986), a noted collector of fossil crinoids from Clitheroe whose contributions to the understanding of local crinoid fauna are still recognised today.
The columns of Bystrowicrinus westheadi are particularly noteworthy for their diameter, often reaching 3–6+cm, making them among the largest crinoid stems ever recorded. Their gross morphology includes a waisted shape in some pluricolumnals, where there is a sudden increase in diameter distally. This is unlike the gradual tapering beneath the crown seen in other crinoid stems and suggests a unique mesistele-dististele transition in Bystrowicrinus westheadi (that is, the transition between the thicker lower stem around the ‘root’ attachments (dististele), and the more flexible and narrow middle part of the stem (mesistele). This abrupt expansion may have served a stabilising function for the crinoid, facilitating attachment to the substrate by allowing room for the growth of robust, unbranched radices (roots). While the dististele appears inflexible, the distal mesistele shows flexibility at symplectial articulations.
The pentastellate shape of the axial canal is another unusual feature, especially given the column’s large size relative to its relatively small lumen. This structure would have allowed for limited soft tissue presence in the axial canal, predominantly serving nervous functions similar to extant crinoids, with nutrient absorption occurring through the ectoderm rather than much nutrient transport through the internal canal. Comparisons to Silurian crinoids showing radiating intracolumnal canals for nutrient transport, highlight that Bystrowicrinus westheadi likely lacked such extensive internal networks. However, the pentastellate canal and its extensions across the articular facets suggest a functional analog for slow nutrient and gas transport, potentially facilitating root development by branching to near each radix attachment site where the radial canals would occur, providing nutrients to the many radix holdfasts.
Despite the incomplete nature of the fossils, the considerable size of these crinoid stems implies they played a role in both anchoring the organism with their weight, and perhaps offering some form of protection. The absence of significant zoobiont infestation, common in other specimens from this site, may indicate a more defensive or protective function for the large columns of Bystrowicrinus westheadi.
Stanley Westhead, after whom this species is named, was an amateur geologist and prolific fossil collector in the Clitheroe area. His collection, now housed in the Natural History Museum, London, contains many rare and important crinoid specimens. While Westhead published little himself, his expertise in the local fossil echinoderm fauna was well respected, with several species described from his collection. His contributions to the field, especially regarding the crinoids of the Clitheroe area, continue to influence paleontological research today.
Echinodermata is a phylum of marine invertebrates that includes well-known groups like starfish, sea urchins, brittle stars, sea cucumbers, and crinoids. Echinoderms are characterised by their radial symmetry, typically arranged in fives, and their unique water vascular system, which aids in locomotion and feeding. This phylum is exclusively marine, and its members are often found on the sea floor, from shallow waters to the deep ocean. Echinoderms exhibit pentameral symmetry as adults, though their larvae are bilaterally symmetrical, reflecting their evolutionary relationship with other deuterostomes, including chordates.
Within this phylum, Class Crinoidea includes marine animals commonly referred to as sea lilies and feather stars. Crinoids are distinguished by their cup-shaped body (the calyx), a set of radiating arms, and a long stalk (in some species) that anchors them to the seabed. The arms are typically branched and covered with feathery extensions that aid in filter feeding, capturing small particles from the water. Though modern crinoids tend to be less prominent in marine ecosystems, they were once much more abundant and diverse, particularly during the Palaeozoic era.
Crinoids first appeared in the Ordovician period, about 480 million years ago, and quickly diversified. They were especially abundant during the Palaeozoic, with their greatest diversity occurring during the Carboniferous period, when extensive shallow seas created ideal conditions for large crinoid populations. Fossil crinoids are especially common in limestone deposits from this time, with entire beds of rock often composed almost entirely of disarticulated crinoid fragments, particularly their stems. These fossils are widespread in regions like the UK, where crinoid-rich limestone formations are frequently found.
Crinoids come in two main forms: stalked crinoids, or sea lilies, which attach to the sea floor via a flexible stalk, and unstalked crinoids, or feather stars, which are mobile and can swim or crawl along the substrate using their arms. In the fossil record, stalked crinoids were much more abundant, with long, segmented stalks that could grow several meters in length. The stalks are composed of individual ossicles, small calcareous plates that are commonly found as fossils, especially in Carboniferous limestone beds. The most well-known fossil remains of crinoids are these stem ossicles, which are often referred to as "Indian beads" due to their cylindrical shape.
Crinoids reached their peak during the Palaeozoic, forming extensive colonies in shallow seas, often in association with coral reefs. Their filter-feeding mechanism allowed them to occupy a specialised ecological niche, and they played an important role in marine ecosystems as suspension feeders. However, crinoids were significantly affected by the Permian-Triassic mass extinction about 252 million years ago, which wiped out many marine species. Although crinoids survived this event, their diversity and abundance were greatly reduced.
In the Mesozoic era, crinoids experienced a resurgence, though not to the same levels of diversity as in the Palaeozoic. Feather stars (unstalked crinoids) became more prominent during the Jurassic and Cretaceous periods, adapting to more mobile lifestyles compared to their sessile ancestors. Today, feather stars are found in a variety of marine environments, from shallow reefs to deep-sea habitats, while stalked crinoids are largely restricted to deep water.
Crinoids are unique among echinoderms in that they are suspension feeders, using their feathery arms to catch plankton and other small particles from the water. Their arms are lined with cilia that move captured food towards their central mouth, which is located on the upper surface of the calyx. This feeding strategy differs from other echinoderms, such as sea urchins, which graze on algae, or starfish, which are typically predatory.
Despite their decline in modern oceans, crinoids remain important in the fossil record due to their abundant and well-preserved remains, particularly in Palaeozoic and Mesozoic sedimentary rocks. The characteristic segmented stalks and calyx plates of crinoids make them highly recognisable fossils, and they provide key insights into the structure and biodiversity of ancient marine ecosystems. In particular, Carboniferous limestone deposits, such as those found in the UK, are often rich in crinoid remains, offering palaeontologists a detailed record of these once-dominant marine invertebrates.