Saturday, January 15, 2005

Icons of ID: (Peppered moth) Bruce Grant letter to Pratt Tribune

Another foremost expert on the pepper moth is Bruce Grant. In 2000, Bruce Grant wrote a letter to the Editor of the Pratt Tribune Archives

In a now classic paper called Fine Tuning the Peppered Moth Paradigm published in Evolution 53 (3), 1999, pp. 980-984, Bruce Grant concludes:

Industrial melanism in peppered moths remains one of the best documented and easiest to understand.

The following is the text of the letter to the editor

Charges of fraud misleading

Letter to the Editor Pratt Tribune, December 13, 2000

In recent weeks your newspaper has printed letters debating revisions in high school biology curricula. Some of the correspondents have leveled charges of fraud directed at evolutionists for attributing changes in the colors of peppered moths to natural selection. As I am one of the evolutionary biologists who study peppered moths, I feel obliged to comment. Charges of fraud cannot be left unchallenged.

Some background about peppered moths is necessary. The common form of this moth species is pale gray. About 150 years ago, a black specimen was discovered near an industrial city in England. Over the years, the black (melanic) form became ever more common as the pale form became rare. By 1900 the black form exceeded 90 percent in peppered moth populations throughout the industrialized regions of England. The phenomenon was dubbed industrial melanism.

Because people knew that birds eat insects, scientists as early as 1896 suspected that birds were eating the different color forms of peppered moths selectively based on their degree of conspicuousness in habitats variously blackened by industrial soot. Extensive experimental work supports this view, although questions remain. Other scientists proposed that moths responded to the presence of pollutants by developing darker body colors. We now know from genetic analysis that the colors of adult peppered moths are determined by genes; thus, the changes in the percentages of pale to black moths over generations reflect changes in the genetic makeup of moth populations.

As industrial practices have changed in many regions, we have observed black moths plummet from 90 percent to 10 percent in the just the past few decades. Once again, we have observed significant genetic changes occur in moth populations. Evolution is defined at the operational level as genetic change over time, so this is evolution. Of the several factors known to produce evolutionary change, only natural selection is consistent with the patterns of the changes we see occurring in moth populations. Evolution examined at this level is as well established as any fact in science.

We still have work to do. We do not all agree about the relative roles of contributing factors, such as the flow of genes between moth populations in different regions, the importance of lichens on trees, where on trees moths might hide from predators, how important is differential predation, and so on. As in any branch of science, participants endlessly debate interpretations. Such wrangling is the norm, and it stimulates additional research. That is how we make progress.

Our debates have never been secret. For recent overviews of the controversies, please see FINE TUNING THE PEPPERED MOTH PARADIGM or . Yet, unwarranted charges of fraud, fakery and cover-ups repeatedly appear in letters printed in newspapers. In your paper, Ms. Katrina Rider "asserts" the peppered moth story is a hoax. She conveys the impression that dead moths were glued to trees as part of a conspiracy of deception. She seems unaware that moths were glued to trees in an experiment to assess the effect of the density (numbers) of moths on the foraging practices of birds. Taken out of the context of the purpose of the experiment, the procedure does sound ludicrous.

But, should we blame Ms. Rider for her outrage upon learning that moths were glued to trees? No. Instead, I blame Dr. Jonathan Wells, who wrote the article she cites as her source of information. While he has done no work on industrial melanism, he has written opinion about the work. To one outside the field, he passes as a scholar, complete with Ph.D. Unfortunately, Dr. Wells is intellectually dishonest. When I first encountered his attempts at journalism, I thought he might be a woefully deficient scholar because his critiques about peppered moth research were full of errors, but soon it became clear that he was intentionally distorting the literature in my field. He lavishly dresses his essays in quotations from experts (including some from me) which are generally taken out of context, and he systematically omits relevant details to make our conclusions seem ill founded, flawed, or fraudulent. Why does he do this? Is his goal to correct science through constructive criticism, or does he a have a different agenda? He never mentions creationism in any form. To be sure, he sticks to the scientific literature, but he misrepresents it. Perhaps it might be kinder to suggest that Wells is simply incompetent, but I think his errors are by intelligent design.

Bruce Grant

Professor of Biology

College of William and Mary

Williamsburg, Virginia

Source:Icons of Evolution by Jonathan Wells CRITICAL REVIEWS, LETTERS, AND ESSAYS

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