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Mechanisms of Evolution

Beyond Darwin and Neo-Darwinism

Phyletic gradualism

As described by Eldredge and Gould, the essential features of phyletic gradualism are:
1. New species arise by the transformation of an ancestral population into its modified descendants.
2. The morphological transformation is even and slow.
3. The transformation involves large numbers of organisms, usually the entire ancestral population.
4. The transformation occurs over all or a large part of the ancestral species' geographic range.

The above points are sometimes mistakenly ascribed to Darwinian evolutionary theory. However, Darwin’s description of, “very slow, intermittent action of natural selection” [ Ch. 4 ] disagrees with point 2, and another passage in Darwin’s Origin of Species disagrees with points 3 and 4. (adapted from here)

Tables  Mechanisms of Biological Evolution :  Gene Regulation in E.coli :


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