PCB-4674 Lecture Notes - Lecture 3: Archaea, The Nice
Document Summary
The nice thing about a hierarchical classification is that you can represent the relationships in a diagram called a tree. Tip: taxon, some group of organisms, it is some group being generalized about. It is the point where an ancestral taxon split into two or more descendent taxa. Root: base of the tree, and represents the oldest common ancestor of all the taxa in the tree. Clade: any node and all of its descendents. Closest relatives are those that are the most recent nodes whose names are next to each other at the top of the tree. Taxa listed next to eachother are not necessarily the most closely related, but the branches are the most closely related. Homologies clearly define the natural classification which gives us evidence of evolution. When two taxa share one homology, then tend to share several. The evolutionary explanation is that species are descended from common ancestors, through some process of evolution.
