Transcript Reptiles
Jessica Brown Miila Hall Cold-blooded Tetrapods, four appendages Considered as the first animals on land with the ability to live and multiply on land (amniotic egg) Amniotic egg- a shelled, water-like sac that enables reptiles to complete their life cycles on dry land. Dry skin with scales 3-chambered hearts No metamorphosis Binocular vision Well-developed brain and a central nervous system Strong skeletal system with a rib cage Originated around 320-310 million years ago During the Carboniferous period Were called reptile-like amphibians because they could survive efficiently on land Jacques Gauthier discovered a cladistic definition of the crown group known as turtles, lizards, and snakes and crocidiles share common ancestors. Approx. 300 species of turtles Bony shell, limbs internal to the ribs, and a keratinized beak. Keratin is a resistant protein found in epidermally derived structures of amniotes Dorsal side of the shell is the carapace, which forms the fusion of vertebrate, expanded ribs, and bones in the skin. Long life spans- 14 or more years Turtles vulnerable to extinction due to predation, hunting, and threatened at time of birth. Types of turtles- sea turtles, green sea turtles, freshwater turtles 21 species Openings in the skull, triangular eye orbits, laterally compressed teeth Snout is elongated to capture food by sweeping their head. A flap of tissue near the back of the tongue forms a watertight seal so it can breathe without inhaling water into the mouth. A secondary palate separates the nasal and mouth passageways. Tail used for swimming, defense, and attacking Oviparous and display parental care of hatchlings. Include- alligators, crocodiles, gavials, and caimans Tuataras Lizardlike reptiles from Mesozoic era Two rows of teeth on the upper jaw and a single row in the lower jaw that can decapitate a small bird. Only present in offshore islands Oviparous Feed on insects Divided into three suborders: Suborder Sauria- Lizards 4,500 species Two pairs of legs Upper and lower jaw Oviparous yet some are ovoviviparous or viviparous Geckos, iguanas, chameleons Geckos are nocturnal and have Clicking vocalizations Adhesive disks allow them to cling to trees and walls Iguania are robust with short necks and distinct heads Flying dragons Chameleons have the ability to change color in response to illumination, temperature, or their behavioral state 2,900 species Around 300 are venomous Elongate and lack limbs, joints that make snake flexible, two hundred vertebrate Skull adaptations that allow the snake to swallow large amounts of prey Oviparous Reduction or loss of left lung an displacement of gall bladder, the right kidney, and often, the gonads. Vipers, cobras, and boas Worm lizards 135 species Specialized burrowers Legless and skulls are wedge or shovel shaped Skin has ringlike folds called annuli and loosely attaches to body wall Feed on worms and small insects Oviparous Skin has no respiratory functions Periodically shed the outer, epidermal layers of the skin called ecdysis Movement of lymph between the inner and outer epidermal layers loosens the outer epidermis. Chromatophores are primarily dermal in origin and function like those of amphibians. Cyptic coloration, mimicry, and aposematic coloration occur. Have a cervical vertebrate Tail loss, or autotomy, is an adaptation that allows a lizard to escape from predators The lizard regenerates the lost portion of the tail Laterally move in a horizontal plane Bipedal, meaning to walk on hindlimbs Most are carnivorous, although turtles can be herbivores Some have sticky tongues to catch prey Tongue extension in chameleons Snakes have a loose jaw that spreads apart to ingest prey much larger than their normal head size. After prey is captured, alternately the jaw thrusts forward and retracts The glottis is far forward so the snake can breathe during swallowing Blood must travel under higher pressures to reach body parts. Two atria, turtles have a patch of cells that act as a pacemaker Ventral aorta divide during development and become three major arteries All reptiles breathe intermittently. Exchange respiratory gases across the surface to avoid losing large quantities of water Larynx is present; vocal cords are absent To warm itself, a lizard may stand at an angle to the suns rays or press itself to warm surfaces. To cool itself, seeks shade or burrows itself. Cerebral hemispheres are somewhat larger causing an improved sense of smell Eyes swivel independently with binocular vision Nictitating membrane and a blood sinus to protect and cleanse the eye Possess a median, or parietal, eye can differentiate light and dark periods for the sun Olfactory senses are better developed Jacobson’s organs are pouches that open through the secondary palate into the mouth cavity. Rattlesnakes and other vipers have pit organs that are used to detect objects with temperatures different from their surroundings. Require kidneys to process wastes and little water loss. Excrete uric acid The behaviors to regulate temperature also help conserve water Produce salt glands to rid the body of excess salt Blood-filtering units are called nephrons Internal fertilization and the amniotic egg Tract of female before protective egg membranes are laid down around an egg Male reptiles, except tuataras, possess an intromittent organ for introducing sperm into the female tract Parthenogenesis can be present in some types of lizards Courtship functions in sexual recognitions Head-bobbing in males and revealing brightly colored patches of skin on the throat Entwines his body around the female and runs his chin along the female After egg is laid it is usually abandoned Shell- sturdy and leathery for protection Albumen- the “white” of the egg, contains protein Chorion- outermost membrane surrounding the embryo of the reptile Allantois- fetal membrane formed as an outgrowth of the embryo’s gut Yolk Sac- membranous sac containing yolk attached to the embryo Yolk- rich in protein and fat and nourishes the developing embryo Amnion- the innermost membrane that encloses the embryo