EVOLUTIONARY TREE OF LIFE
This evolutionary tree encompasses all living species on Earth. The common ancestor (the base of the tree) gave rise to three great branches: bacteria, microbes known as archaea, and eukaryotes (a group of species that includes us). The lengths of the branches reflect how much the DNA of each lineage has diverged from their common ancestor. They demonstrate that most of life's genetic diversity turns out to be microbial; the entire animal kingdom (shown at the upper right) are just a few twigs at one end of the tree.
Ref: Diagram and Text taken from: Carl Zimmer. Evolution (William Heinemann, 2002), p. 102. and reflects current information about the divergence of DNA within the kingdoms of living organisms.