BIO SCI 94 Lecture Notes - Lecture 6: Sympatric Speciation, Phylogenetic Tree

• School: UC-Irvine
• Department: Biological Sciences
• Course: BIO SCI 94
• Professor: Robin Bush

Document Summary

Clicker question: two closely related species of toads live in large, clearly separated geographic areas of. A third species similar to them lives in the narrow zone between. This third species is probably an example of ___. Presence of the ancestral species in the intermediate zone would probably have prevented speciation from occurring: because of gene flow. Node: point within the tree where a branch splits into two or more branches. Outgroup: taxon that diverged prior to the taxa that are the focus of the study. Root: the most ancestral branch in the tree. Polytomy: node that depicts an ancestral branch dividing into three or more descendant branches, indicates insufficient data were available to resolve which taxa are more closely related. Assumes that the most likely explanation or pattern is the one that implies the least amount of change. Clicker question: consider the phylogenetic tree based on the dna sequence of species a e below.