Figure 1

Schematic depiction of dynamics in diversifying (A) and static (B) populations. In each panel, the initial distribution of a defining trait is shown with a dotted line. The population transitions to subsequent distributions are indicated with dashed and then solid lines. In A, further dynamics lead to a complete separation of the newly forming populations. In B, trait homogeneity may increase further. In either diversification or stasis, suppression of certain forms occurs: the intermediate forms in A and the diversifying forms in B become suppressed and may ultimately be excluded at trait values indicated with arrows.