BIO 200 Lecture Notes - Lecture 21: Necturus, Pulmonary Vein, Ichthyostega
20 Nov 2018
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Moving heavy bodies- tetrapod links aka terrestrial feet (found in lobe finned ancestor) Gills won"t function in air- better lungs. Larger muscles need more o2- better hearts + circ system. Eggs dry out- reliance on water for reprod. Amphibians: double life in both water and land. Ichthyostega= one of first amphib w strong big forelimbs; better smell/hearing than fish. Cutaneous resp: absorb o2 thru skin + release co2 to. Pulmonary veins: specialized to retain o2 to heart for. Partially divided hearts: system not closed so limits repumping (faster rate of moving oxy blood around than fish) supplement lungs full o2 flow (oxy + deoxy often mix in heart) Frogs/toads: amphib w/o tails; must live near h20 for reprod. & metamorphosis (lay eggs in water to hatch as tadpoles which evolve into adults) Salamanders: long bodies & tails; large size range; moist places but some fully aquatic(mud puppies); also lay eggs in water but no metamorphosis.
