Fig. 3

Interpretation of the age of groups based on branching pattern. In these two trees, all species evolved the same time. In tree (a) both the turtle and man obviously seem of the same age, as they share a root and simply diverge at one point. In tree (b) the sister group of humans has been expanded by the group of birds. A common misconception is to call human an older group or earlier branching group in tree b. Of course, this is not applicable, as the bird–turtle and human branches diverge at the same time, and the bird–turtle branch simply diverges at an additional time. In most cases, the interpretations of earlier branching are interpretations focused on the number of branching events in different lineages