BIO 200 Lecture Notes - Lecture 22: Squamata, Velociraptor, Pelycosaur
27 Jun 2015
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Reptile traits: reptiles are amniotes, amniotic eggs, eggs contain food source (yolk, airtight membrane (shell, external gestation: laying eggs, dry skin. Improved kidneys: excrete concentrated urine, water retention, reptiles are ectotherms, body temperature changes with environment, can maintain body temperature by moving in and out of the sun or heat source, strong jaws, muscles are anchored in temporal openings. Therapsids (early mammals: can bite much harder, diapsids: all extant reptiles, birds, and extinct dinosaurs, four extant groups of reptiles: tuataras, squamates, turtles/tortoises, and crocodilians. We inherited this trait: related to modern birds and crocodiles. Lepidosaurs (scaled reptiles: very rare today, widespread during mesozoic era. Turtles and tortoises: sharp beaks (lost true teeth, hard shell fused to body, turtles are terrestrial, tortoises are aquatic. Hooks and barbs create a continuous surface. Tail feathers are long, strong, and stabilizing. Body feathers are downy, weak, and warm. Used for warmth, mating, and flight: flight skeletons.
