December 16, 2008

From Brett Hilyer:

Re: “Other half” of Darwin’s theory passes test (Oct. 13): your author included this line in the third paragraph: “In gen­er­al, ev­o­lu­tion­ary the­o­ry holds that spe­cies grad­u­ally change be­cause of cer­tain mu­ta­tions that spread through their po­p­u­la­tions. These mu­ta­tions spread if, and only if, they’re ben­e­fi­cial—so that in­di­vid­u­als pos­sess­ing them sur­vive long­er, re­pro­duce more or both.”

This last part of the statement is incorrect, and contrary to Darwinian evolution. Mutations may spread if, and only if, their effects are beneficial to the replication of those mutated genes. A gene that helps an individual survive longer may not spread, if it does not also increases that individual’s, or a relative’s ability to reproduce more. Reproduction is the currency of natural selection, and given a choice between surviving and reproducing, an organism will always choose the latter. A more correct phrasing would be: “These mutations spread if, and only if, they’re beneficial—so that individuals possess ing them survive longer in order to reproduce more.” The “both” is simply incorrect.

Secondarily, this statement contradicts the well-established theory of kin selection in evolutionary biology. A mutate allele might decrease an individual’s ability to reproduce, in favor of an altruistic behavior toward close kin. Well-documented examples of kin selection include social insect species, naked mole rats and any species with a high degree of parental investment or familial care.

I don’t mean to nitpick, but I don’t consider this a mere arcane technicality. I study the philosophy of evolutionary biology as an undergraduate at the University of Washington, and I believe there is general lack of understanding of Darwin’s theory by the lay-public; I am concerned that articles like this are a part of the problem. If you are a publication of scientific integrity, as your advertising motif suggests, I think it would be prudent to publish a retraction and restatement of the aforementioned paragraph, as a service to your readers.

When one considers frightening statistics such as that half of this nation believes in a literal creation of man thousands of years ago, or that three candidates for the GOP primary in 2008 do not accept a century and a half of biological science, the threat of mass ignorance is a severe one. Unfortunately, science reporting in this country is sloppy, sexed-up drivel, epitomized by a recent Yahoo News headline: “Studies show dogs have sense of fairness.” Please.

Stand above the rabble, and do the right thing.

(Editors’ note: Definitions of evolution vary slightly among textbooks, but almost always convey the same basic idea. Discover Biology, Third Ed., by Michael L. Cain et al. (W. W. Norton & Co., 2006) offers the following description: “Each new generation of a species has the potential to introduce change to certain characteristics possessed by members of the group. If such a change imparts a survival or reproductive advantage to individuals possessing the new characteristic, it can be called an adaptation. Evolution occurs when adaptations accumulate over time and change the characteristic(s) that define the species.”

We asked the scientists who authored this study to check the accuracy of our article, and they did not dispute the statements at issue.)


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