Phylogeny

Phylogeny is the evolutionary relationship among organisms. It is an important tool in classification because it looks beyond mere morphological similarity to consider how one group of organisms is related to other groups. Phylogenetic thinking helps biologists understand the course of evolution and also highlights similarities in the way different organisms carry out their metabolic functions. Woese's three-domain concept and Whittaker's five-kingdom system (covered later in this chapter) …