Phylogeny with blue tips, red nodes, and green branches. Text on the right reads from top to bottom, Tips, Nodes, Branches

Internal Nodes are the connection points on a phylogeny. They represent some common ancestor between two tips or two groups of tips. For example, on this example phylogeny for apes, we see that humans and chimpanzees are joined by the internal node highlighted in Red.

Phylogeny of mammals. Text from top to bottom reads: Rodents, Howler, Baboon, Gibbon, Orangutan, Gorilla, Humans, Chimapnzees, Bonobos. A red dot sites at the node between chimpanzees and bonobos

 

Thus, this internal node represents some common ancestor between chimpanzees and humans (as well as Bonobos!). Nodes provide the inherent structure of phylogenies and are critically important to understanding the relationships between taxa.

Last modified: Thursday, 27 November 2025, 5:39 AM