Daily Archives: April 10, 2009

Modern Synthesis

In his recent paper, Darwinian evolution in the light of genomics (Nucleic Acids Research, 2009, 1–24), Eugene Koonin outlines the principal concepts of the Modern Synthesis.

1. Undirected, random variation is the main process that provides the material for evolution.

2. Evolution proceeds by fixation of the rare beneficial variations and elimination of deleterious variations: this is the process of natural selection that, along with random variation, is the principal driving force of evolution according to Darwin and the Modern Synthesis.

3. The beneficial changes that are fixed by natural selection are ‘infinitesimally’ small, so that evolution proceeds via the gradual accumulation of these tiny modifications.

4. An aspect of the classic evolutionary biology that is related but not identical to the principled gradualism is uniformitarianism (absorbed by Darwin from Lyell’s geology), that is, the belief that the evolutionary processes remained, essentially, the same throughout the history of life.

5. Evolution of life can be presented as a ‘great tree’, as epitomized by the single, famous illustration of the Origin.

6. A corollary of the single tree of life (TOL) concept that, however, deserves the status of a separate principle: all extant diversity of life forms evolved from a single common ancestor.

Koonin then reviews how well these concepts (predictions?) have held up in light of the massive new information from genomics. His summary is below the fold.

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