BIOL 1001 Lecture Notes - Lecture 1: Ashton Kutcher, Lactase Persistence, Hox Gene
22 Apr 2016
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Document Summary
Major lineages and naming are separated by novelties. Amniotic egg (shelled or womb) amniotes. The way we describe major lineages on earth now is by their novelties. Early fossils of species that were very reptile like (tails, jaws) had structures that looked like they had feathers. The feather has a calamus (the stem) and the vane (the body) Then there are other species that have simple feathers. There are different types of feather that have different functions eg for flight or for insulation (down feather) which is not for flight. Some fossils show these different types of feather. Over time (recent fossils) show dinosaurs with feathers. The fossil evidence shows that it had feathers. Accumulating fossil record of feathers not for flight but for insulation thermoregulation structure. Evidence shows that feathers are a modified version of reptilian scales that have thermo-insulation function exaptation (earlier structure that had a different functionality than what it is today)
