Figure 2

Figure 2 — An example of an evolutionary tree, or cladogram, comprising five species. Points at which splits occur are called nodes; nodes are linked to each other, or the species themselves (terminals), by branches. Coloured in green are two groups that form clades — they share a common ancestor at the node marked with a red dot. On the right are two groups that don’t form a clade — they share a common ancestor, but don’t comprise all descendants of that ancestor.