Figure 1: Multiple evolutionary processes on a phylogenetic tree.

The hypothetical tree is painted with a collection of four processes (black, gold, blue and red), each of which reflects a distinct set of macroevolutionary (speciation, extinction, and trait evolution) parameters. Black represents the process Φ_R associated with the root node; all descendant lineages inherit Φ_R until reaching a tip or until Φ_R is terminated by a ‘downstream’ event. Events can occur at any position along a branch, and a single branch can thus be subdivided into sections belonging to different events. In addition, subtrees defined by events can be rendered paraphyletic by the occurrence of new events on sublineages. In this example, this occurs for both the root process (rendered paraphyletic by the occurrence of blue, red and gold processes), as well as the blue process (rendered paraphyletic by the gold process).