BIOL-UA 12 Lecture Notes - Lecture 9: Paleozoic, Mesozoic, Swim Bladder
18 Mar 2016
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Document Summary
Transition to land began in the paleozoic era. Animals began to make an impact on land by 460 mya. Vertebrates made the transition to land around 360 mya. Continental drift = led to a diversification of mammals. Order = quaternary, neogene, paleogene, cretaceous, jurassic, triassic. Lobed-fins = pectoral and pelvic have rod-shaped bones surrounded by a thick layer of muscle. Living fossil" = distinguished by its pectoral and pelvic fin. Modified swim bladder (lung) = buoyancy absorbs o2 and removes waste - lives in stagnant ponds and swamps. No limbs or hands similar to snake but actually a fish. Pectoral and pelvic fins evolved into limbs and feet with digits. Bones of the pelvic girdle (hind legs) fused to the backbone. No gill slits, evolved into eats for defecting airborne sounds), glands and other structures. Neck and shoulders, to allow separate movement of the head. Tiktaalik; a fishapod" fish qualities tetrapod qualities.
