Randomness of Evolution

Dean A. Ohlman, the president of the Christian Nature Federation (Letters, Oct. 11), perpetuates the single most common misconception regarding the randomness of evolutionary change in his assertion that "because the secular humanist presupposes that natural things can only have natural causes, he concludes that design in the universe must have come about by change."

Assuming that he is referring to "design" in the organic world, and ignoring alternative evolutionary forces (most notably genetic drift), Ohlman, like most creationists, misstates selection theory. For his edification, as well as the other 59% of adult Californians who reject the evidence of evolution because it conflicts with their world view, adaptive evolution is not a random process.

As any of my UCI students would gladly inform him, evolution by natural selection is a two-step process; the production of genetic variability by mutation, chromosomal recombination and meiotic crossing over is entirely random; it does not respond to need. However, once genetic variation exists in a population, its fate--at least at the hands of natural selection--is entirely non-random.

Whether it increases in frequency due to a beneficial effect or decreases due to a deleterious effect on net reproductive output depends solely on the specific environmental constraints impinging on the population.

What Charles Darwin and Alfred Wallace noted 131 years ago was that organisms have been shaped by countless millennia of tinkering by this simple yet profound process of differential reproduction. So you see, Mr. Ohlman, creationists and evolutionists don't really disagree on whether design demands a designer, we simply disagree on the designer.


Department of Anthropology

University of California, Irvine

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