ABSTRACT
The extreme malleability or plasticity of cells early in their development is mirrored to a certain, if lesser, degree in the psychological, behavioral, and neural functioning of the developing organism. The early developmental adaptability of organisms has significance for our understanding of evolution that is different from the “genes-fortraits” view that is a fundamental assumption of the populationgenetic underpinning of the modern synthesis (Chapters 10 and 11). It is the purpose of the present chapter to make a case for the extragenetic or, better, the supragenetic developmental basis of evolutionary change through the genesis of novel behavioral phenotypes. To make things as clear as possible, I will contrast this developmental approach to evolution with
the population-genetic model of the modern synthesis. I should say at the outset that the present theory can be integrated with the population-genetic model, with the exception of the radically different role ascribed to genes in the two viewpoints.
