notes for exam 2

notes for exam 2 - XI. Functional Design of skull A....

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XI. Functional Design of skull A. Modification of early dermatocranium 1. Early amphibians- derived from fish of the subclass Sarcopterygii, Superorder Osteolepiformes (lungfish- extant examples) a. First amphibians- Order Stegocephalia: heavily plated skull known as anapsid= no temporal openings (fenestra) which are seen in turtles. 1) Skull of later amniotes derived from anapsid condition b. Early amphibians- loss of bones of snout, freedom of back of skull from attachment to bones of pectoral girdle 1) Associated with transition to land-greater freedom of movement of forelimbs- necessary for terrestrial movement 2. Feeding in aquatic medium- suction-teleosts a. Water viscous, draws prey in b. Maxilla and premaxilla slide dorsally-mandible moves ventrally and forward c. Sides of “throat”- buccal cavity expands laterally (suction produced) 3. Feeding in air- jaw adductor muscle important: largely enclosed by bony dermatocranium a. Muscle contraction- shortens and thickens. Erosion of bone necessary to allow for
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This note was uploaded on 05/28/2011 for the course BIO 345 taught by Professor Dr.macessey during the Spring '10 term at N. Colorado.

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notes for exam 2 - XI. Functional Design of skull A....

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