Morphologic and molecular studies suggest that our closest living relative species is the chimpanzee, although some of the evidence is conflicting. We do know that analysis of protein structure in both chimps and humans shows that approximately 98 percent of our gene sequences are functionally identical, meaning that if the gene sequences differ it is not enough to radically change the proteins produced from them. It is also estimated that our last common ancestor with the chimp would have lived at least five million years ago.

Cladogenesis is the formation of a group of species that share a common ancestor. Clado-genesis can occur as a result of adaptive radiation, which is the divergence or splitting of one species into several. When a species gradually changes over time to the extent that it becomes a “new” species but does not give rise to additional species (no divergence), this is described as anagenesis.