BIOL 1108 Lecture Notes - Lecture 9: Paraphyly, Euglena, Red Algae
Document Summary
A phylogenetic tree is a reasoned hypothesis of the evolutionary relationships among organisms. A phylogenetic tree is built on the basis of shared derived characters. The fossil record provides direct evidence of evolutionary history. Phylogeny and fossils provide independent and corroborating evidence of evolution. Phylogenetic tree depicts the process of speciation: the point where a branch splits is called a node. It represents the common ancestor from which the descendent species diverged. Core concept 1: a phylogenetic tree is a reasoned hypothesis of the evolutionary relationships among organisms. Each taxonomic group depicted can be expanded into its own phylogeny. The lengths of the branches were depicted somewhat arbitrarily here but sometimes they do mean something. O(cid:272)(cid:272)asionally, we"ll en(cid:272)ounter a tree in whi(cid:272)h (cid:271)ran(cid:272)h lengths are drawn proportional to time. Three possible resolutions, no pair of taxa is depicted as a sister group to the third taxon. With more information one of the three possibilities may become better supported.
