EEB267H1 Lecture 10: The Sarcopterygii Move Onto Land: Lectures 10 and 11
29 May 2017
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Document Summary
Ray-finned fishes like sturgeon can come to the surface and gulp air to fill their gas bladder. There is an evolutionary trend for gas bladder to lose function in buoyancy and function only in respiration water comes in the anterior and out the posterior nostril. Through time, the posterior nostril moves in to the back of the mouth. Now you can inhale with the anterior nostrils and take air directly into the lungs able to breath with mouth closed. Eeb267 page 1 enlarged scapula, radius, ulna, 2 carpals, multi-jointed radials. The wrist bones took very long to develop, after the leg developed. Eeb267 page 2 good elbow, more flex in the wrist, robust pectoral fins true tetrapod dorsoventrally flattened head with dorsally located eyes like a crocodile. It can move its head a little from side-to-side. Eeb267 page 3 big wafty tail--still primarily a swimmer doesn"t have a complete set of tarsal bones.
