Tree of life

According Charles Darwin's theory of evolution, the tree of life is a phylogenetic tree that links together all species.

Completeness
Only a small percentage of the nearly two million species recognized have been put into phylogenetic studies, so the tree of life is incomplete. It is currently unknown how many species there are, so the size of the complete tree of life is unknown.

Main patterns
The tree of life is divided into three "Domains"; Eukaryota, Archaea, and Eubacteria.