Les Jones

Science > Evolution is More Than Natural Selection

From the AP via SayUncle Brutal Hugger:

A medium sized species of Darwin’s finch has evolved a smaller beak to take advantage of different seeds just two decades after the arrival of a larger rival for its original food source.

Nifty, but it doesn't advance Darwinism. What you're seeing there is evidence of natural selection. The more evolved (pun intended!) creationists have already taken natural selection into account. Natural selection can be seen during the timespan of an individual in the form of antibiotic resistance in bacteria and (as artificial selection) in the breeding of domestic animals. Natural selection is simply undeniable to anyone with a brain.

As pointed out during my senior-level course on evolution, however, Darwin's Origin of Species does a wonderful job of advancing the notion of natural selection, without ever proving how it could create the new species suggested in its title. That came about later, in part due to the modern synthesis of Darwinian natural selection with Mendelian genetics. (Genetics were unknown to people of Darwin's era, but the discovery of the discrete inheritability of genetic characteristics enhances the predictive value of Darwin's theory.)

The modern theory of the mechanism of evolution differs from Darwinism in three important respects:

1. It recognizes several mechanisms of evolution in addition to natural selection. One of these, random genetic drift, may be as important as natural selection.
2. It recognizes that characteristics are inherited as discrete entities called genes. Variation within a population is due to the presence of multiple alleles of a gene.
3. It postulates that speciation is (usually) due to the gradual accumulation of small genetic changes. This is equivalent to saying that macroevolution is simply a lot of microevolution.

In other words, the Modern Synthesis is a theory about how evolution works at the level of genes, phenotypes, and populations whereas Darwinism was concerned mainly with organisms, speciation and individuals. This is a major paradigm shift and those who fail to appreciate it find themselves out of step with the thinking of evolutionary biologists. Many instances of such confusion can be seen here in the newsgroups, in the popular press, and in the writings of anti-evolutionists.