BIOLOGY 1M03 Lecture Notes - Lecture 11: Synapomorphy, Marsupial, Convergent Evolution
31 Jan 2017
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Researchers analyze characteristics of species (genetic, morphological, behavioural, etc) to infer phylogenetic relationships among species. There are four general strategies for using data to estimate trees: 1. Going to focus on the phonetic and cladistics approaches in this class. Based on computing a statistic that summarizes the overall similarity among taxa. A computer program compares the statistics for different populations and builds a tree that clusters the most similar populations together. Distance matrix: higher the #, the lower the sequence: what you end up with: differences between taxa with large differences correspond to large distances on the tree and vise versa. Attempts to minimize the number of changes on a tree that are need to explain the observed data. Data consider trait evolution on many phylogenies select the phylogeny with the least number of changes. An assumption that the most likely explanation is the simplest pattern. Focuses on synapomorphies, which are shared derived characters.
