ABSTRACT
The best evidence strongly supports that all life currently on earth is descended from a single common ancestor. Over a period of at least 3.8 billion years, that single original ancestor has split repeatedly into new and independent lineages (i.e., species), and, on occasion, some of these otherwise independent lineages have come back together to form yet other lineages or to exchange genetic information. The evolutionary relationships among these species is referred to as their “phylogeny”, and phylogenetic reconstruction is concerned with inferring the phylogeny of groups of organisms. The ultimate goal is to infer the phylogeny of all life on earth.
