Our growth in knowledge and understanding of evolutionary relationships as a result of the growing evidence has allowed us to begin to assemble species and other taxa into graphic representations of relationship known as phylogenetic trees. This symbology reflects Darwin's original visualization of evolution as a many-branched tree, where the tip of each branch represents a separate species. Forks in the tree branches represented the divergence of two species. The closer a species is to a fork in the tree, the more closely it is related to the species from which it had diverged. The more distant a species is from the fork, the more distant the relationship.

Using evidence, such as that provided by comparative anatomy, developmental biology, and molecular biology, modern taxonomists are able to construct and test phylogenetic trees for species of interest to their studies.