Paul Griffiths: University of Queensland Department of Philosophy

Many evolutionary processes have been described in which a trait that initially develops in the members of a population as a result of some interaction with the environment comes to develop without that interaction in their descendants. Waddington’s genetic assimilation is importantly different from the rest of this ‘Baldwiniana’ because his explanatory focus was not on the selection pressures at the point of transition, but on how developmental systems come to be structured in such a way that these evolutionary transitions are readily accessible to evolving lineages. Waddington’s approach also replaces the simple contrast between ‘acquired’ and ‘innate’ with a non-dichotomous model of developmental canalisation and phenotypic plasticity that is in line with recent work on the evolution of development. From a Waddingtonian perspective evolutionary transitions between ‘innate’ and ‘acquired’ are only to be expected because those categories have little meaning in terms of developmental genetics and in some cases the difference between the ‘innate’ and ‘acquired’ may require only a minimal change in developmental mechanisms. But to see this it is necessary to use a gene concept suitable for thinking about development, and not a gene concept designed for theoretical population genetics or for the prediction of phenotypic differences within populations.
http://www.bec.ucla.edu/papers/Griffiths_2.4.07.doc