Fig. 3

Signatures of punctuational and gradual evolution on phylogenetic trees. a A phylogenetic tree which shows the signature of gradual evolution. That is, the total amount of evolutionary change, as measured by the path lengths, is not related to the number of speciation events that have occurred (see Fig. 2 caption for definition of terms, see blue line and points in c). b A phylogenetic tree which shows the signature of punctuational evolution. Evolutionary change accumulates at speciation events. Path lengths correlate with number of nodes, see red line and points in c