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Structure Data conference at the Mission Bay Conference Center in San Francisco on Wednesday & Thursday, March 9-10, 2016
An odd structure near the back of Natureland Park. Couldn't quite figure ou t what it was really for, but someone obviously wanted to construct it.
An unknown tank like structure originally buried beneath the ground, back from the cliff edge but due extensive Coastal Erosion, hundreds of feet of the cliff face has disappeared leaving structures like this exposed. Since this structure became exposed it has been unable to support its own weight breaking in half and leaving one half on the beach along with some large lumps of debris. My guess is the structure was possibly part of a sewage system, there is 'clinker' strewn around, used for filtering, possibly part of the early 1940's Coastal Artillery Battery and associated buildings were builtin this area, it was possibly connected, but later decommmissioned in favour of the new Battery at Easton Woods.
Structure Data conference at the Mission Bay Conference Center in San Francisco on Wednesday & Thursday, March 9-10, 2016
ANATOMY
Reptiles, the group that gave rise through evolution to birds and mammals, have the same basic body structure as those higher vertebrates. Yet just as birds and mammals changed from their reptilian ancestors, reptiles themselves underwent great changes over their millions of years of existence. This exhibit shows some anatomical features of the reptilian body and shows how structures differ among major groups of reptiles.
RETICULATED PYTHON (Python reticulatus)
Typically, snakes have a greatly elongated body and lack limbs. Some snakes such as this python (see partial skeleton) retain vestiges of the hind limbs, however. This skeleton is 7 meters (23 feet) long. Its 321 vertebrae in the body and 91 in the tail number close to the maximum known in snakes; individuals of some species may have fewer than 130 vertebrae. (Human beings have only 24.) A snake does not add vertebrae and ribs as it grows, but has its full amount before it is born or hatched.
KOMODO DRAGON LIZARD (Varanus komodoensis)
AMERICAN ALLIGATOR (Alligator mississippiensis)
These basically similar skeletons differ in many details evident only on close examination. As an aquatic animal, the alligator has a somewhat high, flattened tail for swimming and relatively small legs and feet. The land-dwelling Dragon has a more rounded tail and larger, more powerful legs. The large, heavy skull of the alligator would be a burden on land but is supported by the water. Another difference in these skeletons is the presence of abdominal ribs (gastralia) in the Alligator.
SKIN
Skin, the outermost covering, protects the body from micro-organisms, poisons and physical damage, retains fluids and minerals, and provides structural support. Its sensory receptors receive stimuli (eg, touch, temperature) from the environment, and it maintains the colors and some structural modifications of the species.
Reptile skin typically consists of rows of raised, hardened scales usually connected by soft, flexible tissue. The outermost layer (epidermis) of the skin forms the hard (keratinized) part of the scales. Such scales differ from fish scales, which form in a different part (dermis) of the skin. Amphibians, unlike reptiles, lack epidermal scales and usually maintain a moist skin that may function in respiration. Reptile skin lacks the feathers and hair that characterize birds and mammals, respectively.
Extensive use of reptile skins for purses, shoes and other leather products has led to massive slaughter, especially of crocodilians. Consequently, the survival of many species is endangered.
SKIN STRUCTURE
This cross-section of lizard skin shows two overlapping scales (350X). Important features are:
EPIDERMIS: Outermost skin layer. Its germinative cells produce daughter cells that move outward and transform into the hard, protective outer scale surface through the process of keratinization. Keratin is a strong protein in epidermal derivatives such as claws, fingernails and beaks. Periodically, the keratinized layer is shed and replaced (Growth and Longevity exhibit, Case 2).
DERMIS: Deeper, thicker skin layer, composed chiefly of fibrous connective tissue. Most pigment cells lie within the dermis. Most blood vessels (not shown) are in both the dermis and epidermis.
HINGE REGION: This area with loose folds allows distension of the skin between the keratinized scales.
SCALE TYPES
Reptile scales vary in size, shape and number according to location on the body. For example, in most snakes the scales on the belly (ventral scutes) are enlarged transversely and are important in locomotion. These differ distinctly from the scales on the back.
Reptiles inherit their basic scale pattern, though temperature during embryonic development may influence scale size and number. Comparison of distantly related species reveals a wide variety of scale types. This diversity probably reflects adaptations for various functions, such as body water balance and reception of solar radiation. The lizards here illustrate various reptile scales.
OSTEODERMS
The deep layer of the skin (dermis) in many kinds of lizards, all crocodilians and on the legs and tails of some turtles contains discs or nodules of protective bone. Often these exist in rows corresponding to those of the outer epidermal scales. Nearly all surfaces of the South American Caiman, Caiman crocodilus, whose skin is shown here, are protected by osteoderms, which appear as numerous light patches on the x-ray photograph (claws and bones of the skull are light also).
COLOR CHANGE
In some lizards, particularly True Chameleons of the Old World and Anoles (American Chameleons) of the New World, individuals can change color completely and rapidly. Color change is stimulated by various factors, including excitement, temperature, lighting, and shade of the background behind the animal.
The Green Anole, Anolis carolinensis, shown here can change from brown to brilliant green, or vice versa, in a matter of minutes. Cross-sections (1,000X) show how color change is caused by movement of pigment within melanophores (brown pigment cells).
TEETH
Reptiles of different species may vary greatly in the food they eat, and this shows in their teeth. Seen here are the lower jaws of several reptiles, together with the enlarged drawings of the teeth. Teeth may differ in size and shape from one part of a jaw to another, serving different functions (piercing and holding, cutting, chewing), or may all be much the same. Unlike most mammals, which produce only two sets of teeth in a lifetime, most reptiles are continuously replacing teeth. A lizard may produce hundreds of new teeth in a year. In addition to teeth in the usual places on the jaws, snakes and some lizards also have teeth on bones on the roof of the mouth.
SKULLS
Evolutionary change may involve loss of parts (for example, limbs of snakes), multiplication of parts (vertebrae of snakes) or modification of shape and size of parts. These skulls exemplify such differences among certain bones in four major groups of reptiles.
TURTLE SHELLS
The shell, which may include up to 30 percent of a turtle's weight, is mostly bone, overlaid by skin. The large, hard plates conspicuous on most turtle shells are keratinized epidermal scales (scutes). The shell's bone forms by fusion of ossified structures in the deep skin (dermis) with vertebrae, ribs, and pectoral and pelvic girdles.
The epidermal scales of the upper shell (carapace) of this Snapping Turtle, Chelydra serpentina, are removed from the left side to reveal the bones beneath. Sutures between scales and those between underlying bones are not directly aligned, a feature which may result in greater strength.
LOGGERHEAD TURTLE, Caretta caretta
The turtle's skeleton is ingenious architecturally and peculiar biologically. The ribs, expanded and joined, form the main part of the upper shell (carapace), and the body vertebrae are immovably fused as part of the shell. Most unusual is the position of the dorsal bones of the shoulder girdle; these lie beneath the ribs rather than atop them, as in other vertebrates. The derivation of the bones of the lower shell (plastron) is unclear; they may incorporate ventral elements of the shoulder girdle and abdominal ribs.
Bony shell elements are somewhat reduced in these sea turtles. A typical land or fresh-water turtle would have a relatively larger, solid plastron firmly joined at the sides to the carapace.
Between those two metal boxes with the yellow stripes, there was a bus structure, you know, the little hut you can hide under when it's raining and you're waiting for the bus. Then the Pittsburgh Steelers won the Super Bowl and the hooligans decided it could not stand.
I lomo-tized this shot because frankly, it was boring without it.
The structure of this leaf cluster struck me so much that I couldn't bear to start my car (it was on the hood). Something about the way the leaves are growing off the thin branch is fascinating, and almost creepy, to me.
Second fire of the day it was spotted by crews responding to another structure fire about a mile away