WILD 3580 1st Edition Lecture 21Outline of Last Lecture I. ReptilesII. Evolution of Reptiles III. ClassificationOutline of Current Lecture I. SkinII. Circulatory System III. Feeding and Digestion IV. Teeth Current LectureI. Skin - Usually covered by scales o Vary among groupso Depends on amount of keratin - Function1. Prevent water loss 2. Protection 3. Ornamentation - Structureo 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 skinThese 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.- 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 speciesII. Circulatory System - Turtles, Lizards, and Snakes: 3 chambered heart o Incomplete division of the ventricleso Cardiac shunts keeps blood separated to some degreeo Mixing of oxygenated and deoxygenated blood- Crocodilians: 4 chambered hearto Complete division between ventricleso 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 III. Feeding and Digestion- Snakes and Lizards- swallow food wholeo 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 IV. 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
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