Evolutionary theory is changing in response to two advances: (1) a reappreciation of the significance of the early appearance of most of the major functional designs of organisms (Bauplane) in the Late Precambrian and Early Palaeozoic, and (2) a new understanding of the way that genetic mechanisms, and indeed the genome itself, have changed during geological time. Neo‐Darwinism, the theory that has held sway as the theory of evolutionary mechanism since the early 1940s, is being seen as an explanation for only relatively small modifications of organisms, but not for the production of the major architectural plans. It has become apparent that a more general model of evolutionary mechanisms will have to be produced, and that data from the fossil record, and the interpretation of past environments, will be at a premium. The opportunity for geologists to contribute to the development of a new synthesis of evolutionary theory has never been greater.