Phylogenetic Trees

Evolutionary relationships, or phylogeny, involves studying evolutionary paths or lineages of organisms and is often represented by a phylogenetic tree .

A phylogenetic tree shows the points at which lineages have diverged and how new species have evolved from a common ancestor.

Phylogenetic trees can be determined according to the data derived from a number of sources, such as body structures, behavioural observations and biochemical data.

The more recent the branching point (i.e. the shorter the branch) on the tree is, the more closely related the species are.

Note

Phylogenetic trees can be drawn in different formats. The three trees below have identical relationships among species A, B, C, D, and E. These trees are just oriented differently.

Three variations on phylogenetic trees. For each, from the root, E on a basal branch, with the other branch to ABCD, from here further branches to A&B and C&D. They are slightly different - the first is vertically aligned with root at the bottom and leaves at the top, the second is horizontally aligned with root to the left and leaves on the right, and the third is vertically aligned but with angled rather than square branches. However, they all represent the same relationship.