BIOLOGY 544 Study Guide - Midterm Guide: Flight Feather, Plumage, Ridge Lift
11 Mar 2015
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List and explain as many lines of evidence as you can think of. Similarities include: scales on birds" feet, amniotic eggs, multiple bones in the jaw (reptilian palate),a single stape (inner ear bone) and a single occipital condyle. Bats and birds are homologous in terms of their forearms. Evidence for theropod descent: there were small, agile, bipedal and possibly warm-blooded theropods. The fossil showed asymmetric feathers, flight feathers, and an increased brain size --- includes visual centers for sight. Meaning digit 2 is actually 1 , 3 is actually 4. This was discovered through the analysis of gene expression during the growth of a chicken embryo. The alternative hypothesis is that birds evolved from thecodonts, a line of reptiles. Longisquama (long scaled reptile) is considered a possible ancestor in this hypothesis. With respect to birds, what is the evolutionary significance of the discovery of the fossils sinosauropteryx, Sinosauropteryx had dino fuzz, suggesting the origin of feathers.
