I want to argue that the sudden appearance of species in the fossil record and our failure to note subsequent evolutionary change within them is the proper prediction of evolutionary theory as we understand it. […] Evolutionary sequences are not rungs on a ladder, but our retrospective reconstruction of a circuitous path running like a labyrinth, branch to branch, from the base of the bush to a lineage now surviving at its top.

"Bushes and Ladders in Human Evolution", p. 61 - Ever Since Darwin (1977)