WILD 3580 1st Edition Lecture 21 Outline of Last Lecture I Reptiles II Evolution of Reptiles III Classification Outline of Current Lecture I Skin II Circulatory System III Feeding and Digestion IV Teeth Current Lecture I Skin Usually covered by scales o Vary among groups o Depends on amount of keratin Function 1 Prevent water loss 2 Protection 3 Ornamentation Structure o Epidermis o Dermis Osteoderms small slivers of bone In turtles crocodilians and some lizards o Glands lipid or wax based compounds Function waterproofing scent communication defense Ex Musk glands in turtles musk glands in snakes Femoral glands in lizards Ecdysis regular shedding of the skin These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute II III IV Most snakes shed all in one piece how often depends on how fast they re growing Lizards shed in large patches Crocodilians and non shell skin of turtles will continually lose small pieces of skin Turtle scutes may shed periodically or retain scutes by adding new ones underneath it depending on specific species Circulatory System Turtles Lizards and Snakes 3 chambered heart o Incomplete division of the ventricles o Cardiac shunts keeps blood separated to some degree o Mixing of oxygenated and deoxygenated blood Crocodilians 4 chambered heart o Complete division between ventricles o Separation from pulmonary and somatic loops o Foramen of Panizza a small opening that connects the left and right aorta allowing some mixing of blood Efficient when diving Feeding and Digestion Snakes and Lizards swallow food whole o Depended on chemical digestion o Projectile feeding long tongue ex Chameleon Turtles and crocodilians swallow pieces of food o Rotational feeding aka death roll o Muscular gizzard stomach to mechanically digest food Speed of digestion is related to temperature Teeth Turtles no teeth o Has a boney beak made up of keratin o Tomium cutting edges of the beak Other reptiles have well developed teeth o Homodont all teeth of the same size and shape and have the same function ex Crocodile o Heterodont specialized teeth that vary in size shape and function
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