BIO 200 Lecture Notes - Lecture 22: Archosaur, Bipedalism, Passerine
20 Nov 2018
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Outline: jaw muscles anchored to openings in skull bone behind eye: muscle connect to bone= strong, synapsids: 1 hole behind eye socket [some extinct reptiles] Therapsids: evolved from early synapsids and led to mammals: diapsids: 2 holes behind eye socket [all surviving reptile incl birds & Archosaurs: mono; 1st able to walk on 2 legs (bipedal); rows of bony plates on backs (modern crocs) Dino improved on archosaur design: legs point directly down under body (fast & agile) Lizards & snakes aka squamates:limbless, some venomous. Turtles & tortoises: no teeth, hard shells (vertebrae fused to top) Turtle= aquatic; many still lay eggs on land. Crocodilians: large predators; primarily aquatic and ambush hunt. Eyes on top of heads to see and breathe underwater. Parental care: both m&d protect; babies travel inside parent"s mouth. Evolved from archosaurs: therapodsevolved feathers: was bipedal, pelvis pointing backwards [all good traits for. Keel= firm anchor for flight muscles to pull against.
