Darwinism and the expansion of evolutionary theory.

The essence of Darwinism lies in the claim that natural selection is a creative force, and in the reductionist assertion that selection upon individual organisms is the locus of evolutionary change. Critiques of adaptationism and gradualism call into doubt the traditional consequences of the argument for creativity, while a concept of hierarchy, with selection acting upon such higher-level "individuals" as demes and species, challenges the reductionist claim. An expanded hierarchical theory would not be Darwinism, has strictly defined, but it would capture, in abstract form, the fundamental feature of Darwin's vision--direction of evolution by selection at each level.