All Living Things

If you want to brush up on you phylogeny, check out this detailed and easily accessible tree of life, provided by Discover Life, an online encyclopedia of Earth’s organisms. This tree, like the rest of the site, seems very accessible and navigable for laymen, as this convenient introduction shows:

Phylogeny is the organizing principle of modern biological taxonomy. A guiding principle of modern phylogeny is monophyly. A monophyletic group is considered to be one that contains an ancestral lineage and all of its descendants. Any such group can be extracted from a phylogenetic tree with a single cut.

The tree shown here provides a guide to the relationships among the major groups of extant (living) organisms in the tree of life. The position of the branching “splits” indicates the relative branching order of the lineages of life, but the time scale is not meant to be uniform. In addition, the groups appearing at the branch tips do not necessarily carry equal phylogenetic “weight.” For example, the ginkgo is indeed at the apex of its lineage; this gymnosperm group consists of a single living species. In contrast, a phylogeny of the eudicots could continue on from this point to fill many more trees the size of this one.

The glossary entries that appear below the tree are informal descriptions of some major features of the organisms described. Each entry gives the group’s formal scientific name, followed by the common name of the group. Numbers in square brackets reference the location of the respective groups on the tree.

It’s great to see how every living thing that’s ever existed is interconnected in some way. To think that all the beauty and biodiversity we see around us represents only 1% of all life that has ever existed; that all of it began with a humble collection of protein constituting primitive, single-celled organisms. Nature, by its very existence, is a miracle.