BILD 3 Study Guide - Midterm Guide: Cassava, Unikont, Nitrogen Fixation
20 Apr 2016
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Document Summary
Node branching point, represents common ancestor: polytomy unresolved node. Branching pattern topology, informative: branching lengths not always informative. Monophyletic common ancestor and all descendants. Outgroup comparisons distinguish between ancestral and derived character states. Outgroup taxa outside of the ingroup. Homoplasy character shared between 2 or more species that was not present in the common ancestor, ex. Wings of bats and birds: convergent evolution similar features between groups that evolved independently of each other. Homology similarity due to a common ancestor: synapomorphies homologous trait, shared derived trait between 2+ groups. Parsimony best tree = one w/ fewest character changes to explain data. Molecular clocks provide a way of estimating age of evolutionary change: assures genetic change happens at constant rate, mutational change neutral, calibrate dna change w/fossil record --- calculate rate of change and extrapolate. Fossil record provides direct evidence of evolution, but erosion and weathering prevent this.
