WEST-EBERHARD, M.J.: Bateson’s Dangerous Idea: Development as a Factor in Evolution

Development has been marginalized in evolutionary biology, having been portrayed as contradictory to Darwinian theory because it (1) detracts from selection as the cause of evolution, (2) implies Lamarckian inheritance, and (3) confuses proximate and ultimate causation. These claims are untenable. I outline a view of adaptive evolution that includes environment-sensitive development and is completely consistent with the modern genetic theory of natural selection, showing how this view applies to the origin, spread, and maintenance of fixed, phenotypically plastic, and polymorphic traits within populations, whether the traits are morphological, molecular, physiological or behavioral. Development is not only compatible with Darwinian theory it is an essential component of explanations in terms of natural selection, for development is the source of the phenotypic variation upon which selection acts. Environmentally induced developmental variants are likely more important in evolution than are mutational novelties.