BSsqans-lect25 mamm

BSsqans-lect25 mamm - BIS 1B (Winter 2008) Study question...

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BIS 1B (Winter 2008) Study question answers: Mammals Lecture 25 1. Four characteristics that mammals share in common with birds include: There are many and they include endothermy, the 3 basic embryonic membranes that characterize the amniotes, extensive parental care and internal fertilization. 2. Two characteristics that distinguish mammals from all other vertebrates include: Mammals have mammary glands that secrete milk, and have a particular form of body covering called hair rather than reptilian scales or feathers. 3. Mammals derive from a lineage of reptiles with a peculiar pelvic bone structure. What is this characteristic structure and how does it differ from that of extant reptiles and from birds? Mammals derive from a lineage that included the therapsid reptiles, which in turn derive from a much older group, the synapsids, characterized by a skull with a single pair of temporal openings. The pelvic bonds do not distinguish this group as they do in the Saurschian Ornithischian dinosaurs. Birds have essentially the same pelvic structure as do the Ornithischians with a characteristic rod shaped bone that extends both anteriorly and posteriorly. 4. Trace the chain of major events from fertilization of the mammalian (human) egg through birth. Following fertilization, the egg moves down the fallopian tube and implants into the uterine wall. There the placental connection develops through which the female assists the developing embryo in various metabolic functions including excretion, respiration and feeding. 5.
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BSsqans-lect25 mamm - BIS 1B (Winter 2008) Study question...

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