BIOL-3030 Lecture Notes - Lecture 11: Paleozoic, Supercontinent, New Idea
Document Summary
Forefin closer to tetrapod limb than a hindfin (mosaic evolution: early tetrapod. Functional challenges of land: a quick recap: air is less dense and less viscous than water. Suction won"t work for feeding on land. Gills won"t work without the support of water (breathing will work with lungs: lose electrical and lateral line-sensory systems, air temperatures are less stable in air than in water (thermoregulation, risk of drying out on land. No, because greenland used to be much closer to the equator when these animals were alive: had limbs, but . Gills (blood vessel grooves on arches; bones that support gills house blood vessels that carry blood) ** the first tetrapods were aquatic, so first tetrapod features were not necessarily for living on land. Early tetrapods and evolution of development: polydactyly in fossil taxa 5 digits not ancestral for tetrapods. Developmental truncation = mechanism for getting 5 digits. If development is shortened, last features don"t appear.