Phylogeny Friday is back, bitches! Katherine’s gotta add me to her list ASAP. In the glorious return of PhyFridays, I give you the root of the tree of life. In the upcoming editions we’ll zoom in on a few parts of the tree to illustrate the diversity of certain taxa of interest. It’ll be kind of like a reverse Ancestor’s Tale.
The image on your left shows the evolutionary relationships of the three domains of life: bacteria, archaea, and eukaryotes. Traditionally, the bacteria and archaea are known as prokaryotes, but prokaryotes are a paraphyletic taxon. Oh, how I hate paraphyletic taxa. This article argues that there is no benefit of using the term prokaryote, as it is a defined by what it is not (prokaryotes lack nuclei and organelles) and not by what it is.
This tree is the accepted paradigm of the evolution of life, so there ain’t much controversial here. It is important to recognize, however, that the majority of genetic diversity exists in what we consider “primative” single celled organisms. Next week, we’ll see how the majority of the “complex” critters (the eukaryotes) are poorly understood microscopic organisms.
Pace, NR. 2006. Time for a change. Nature 441: 289. doi: 10.1038/441289a