Biology 1001A Chapter Notes - Chapter 20: Mosaic Evolution, Phylogenetics, Paraphyly
25 May 2016
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Document Summary
Phylogenies show the evolutionary history of a group of organisms. Phylogenetic trees are formal hypothesis identifying relationships among groups of organisms. Analysis of phylogenetic trees allow us to determine what traits came from a common ancestor and which ones evolved over time. Systematicists seek characteristics that are independent markers of underlying genetic similarity and differentiation. Often they have to rely on phenotype to determine these since fossil records are not always complete. Systematic characters are found in an organisms genome and not formed by the environment. Homologouss characters these reflect underlying genetic similarities and can indicate common ancestry. Analogous characters in different animals but serve the same function. Ancestral and derived characters mosaic evolution refers to the reality that in all evolutionary lineages some characters evolve slowly while others evolve quickly. Every species displays ancestral characters (old traits) and derived characters (new traits).
