BIO 180 Lecture 15:02

modification of gill arches bars of cartilage

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Unformatted text preview: - Modification of gill arches (bars of cartilage; support gills). What Did It Do? enabled fish to bite! Allowed capture and processing of wide array of food. - Spectacular radiation of jawed fishes followed. Transitional fossils have been found that show the evolution of an early, but completely nonfunctional form of the jaw is NOT par of the evidence scientists have collected for the idea that the jaw evolved from gill arches. The Tetrapod Limb - First land vertebrates (amphibians) arose from group of bony fish with sturdy fins and lungs: “lobe-finned fishes” (Sarcopterygii). - Related to modern-day lungfish and coelocanths. * Fins (supported by bone) limbs - All tetrapod limbs are homologous. What Did It Do? Allowed efficient movement on land. - Basic limb evolved into diverse forms for running, swimming, digging, flying etc. Feathers and Flight - Flight evolved independently in 3 vertebrate lineages: pterosaurs, bats, and birds. - Birds evolved from lineage of feathered, bipedal dinosau...
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This note was uploaded on 02/24/2014 for the course BIOL 180 taught by Professor Freeman during the Winter '07 term at University of Washington.

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