BIOLOGY 1M03 Study Guide - Final Guide: Phenetics, Synapomorphy, Genetic Distance
14 Jul 2018
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Chapter 27 phylogeny and the history of life. 27. 1 tools for studying history: phylogenetic trees. Estimating phylogenies: researchers analyze morphological or genetic characteristics to infer evolutionary relationships, closely related species should share many characteristics and distantly related should share fewer characteristics, there are 2 strategies to use to data to estimate trees, 1. Phenetic approach computes a statistic that summarizes the overall similarity among populations based on the data (ex. Genetic distance bw gene sequences of 2 populations by analyzing bases). A computer builds a tree clustering similar populations and puts divergent populations on distant branches: 2. Problems with the phenetic and cladistic approach: traits can be similar in 2 species not because those traits were present in a common ancestor but because similar traits evolved independently in 2 distantly related groups (this is called. Homoplasy: homoplasy occurs when traits are similar for reasons other than common ancestry, ex.
