Peppered moth (Biston betularia), "mascot" of evolutionary theory
What do Creationists* and Islamists** have in common besides a willful misunderstanding of the scientific method? They both think they've found a "gotcha" in the controversy over the peppered moth, emblem and textbook example of evolution in action. There are two main forms of the moth, one speckled and one black:
The dark form appeared in Victorian Manchester, described at the time as "the chimney of the world", and had almost taken over from the speckled by the century's end. An entomologist named J.W. Tutt suggested that the dark ones were better concealed from birds in industrial districts, where pollution had stripped the lichen from the trees and covered them in soot. Half a century later, experiments by Bernard Kettlewell, of Oxford University, supported Tutt's hypothesis and made the peppered moths famous as a demonstration of evolution at a pace humans could observe. Then the dark forms duly went into decline along with smokestack industries and coal fires, making the textbook story complete. Yet in the past few years, Creationists and other anti-evolutionists have taken up the peppered moth as a stick with which to beat Darwinians . . .
Some years ago, [Dr Michael Majerus, who leads the Evolutionary Genetics group at Cambridge University] published a book in which he reviewed the studies done on the peppered moths. There were some anomalies, such as the appearance of dark moths in unpolluted areas, and it remained infernally difficult to do experiments which did not distort the untidy reality of life in the wild. These difficulties did not, however, shake his confidence in the story that Tutt had started a century before . . .
An entirely predictable selective process then occurred, as Creationists seized upon these words, disregarding his comment that plenty of better examples remained available. For opponents of evolutionary theory, it was like capturing the other side's mascots. The moths had become celebrities, early stars of natural history films (and well adapted to black and white television screens). They were easily grasped and memorable. Two moths side by side were enough to make the point, and the industrial background gave the story human interest.
**Imaginary Mechanisms of Evolution
[via Milt's Blog]
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