BIOL 2200 Chapter Notes - Chapter 34: Keratin, Archaeopteryx, Ectotherm
31 Mar 2017
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Origin of tetrapods: discovery of tiktaalik fossil in 2006. Unlike fishes, has ribs that would have supported its body and breathe air. Features such as wrist, ribs and neck suggest that these were ancestral to tetrapod lineage. Amphibians: most basal group of tetrapods, salamanders. Some live in water, some live on land. Terrestrial salamanders walk with a side to side bend of body. Many aquatic salamanders retain larval features even when sexually mature: frogs. Sticky glands secrete poison, camoflauge, and bright warning colors are all defense mechanisms against predators: caecilians. Occupy tropical, moist areas: lifestyle and ecology of amphibians. Many go through metamorphosis and lose/gain features. 34. 5 amniotes are tetrapods that have a terrestrially adapted egg. Derived characters of amniotes: amniotic egg with 4 membranes (amnion, chorion, yolk sac, and allantois) Amnion compartment of fluid that acts as shock absorber. The rest function in gas exchange, storage of waste and nutrients, and transfer of nutrients.
