Doctored Evolution Data: The Piltdown Peppered Moth

DOCTORED EVOLUTION DATA: THE PILTDOWN PEPPERED MOTH

Copyright 1999 by Emerson Thomas McMullen

The peppered moth, Biston betularia, has been highly touted as an example of gradualistic evolution for more than forty years. The story is that this moth changed from its light form to dark as pollution from the industrial revolution in England darkened tree trunks, by killing the light-colored lichen on them and covering them with soot. Supposedly, birds easily saw the lighter moths resting on the darker bark and ate them. The overall peppered moth population shifted to its dark form. Later pollution declined, the tree trunks became lighter, and the reverse occurred. Supposedly the birds now easily saw and ate the moth's dark form on the light tree trunks, and so the overall moth population shifted to the lighter color.

Actually, peppered moths do not rest on tree trunks during the day; they hide in the shadows under branches and where the branch joins the tree,⁽¹⁾ so the whole story is wrong. The birds do not see the moths on the tree trunks because the moths are not there. Every picture of these moths on the trees is misleading - they are dead moths glued onto the tree trunks. Even the scientist (H.B.D. Kettlewell) who first studied this nocturnal moth put them onto those parts of the trees during the day where the birds could easily see them.⁽²⁾ No subsequent scientist has been able to replicate Kettlewell's behavioral experiments, especially his claim "that a significantly large proportion of each form rested on the correct background."⁽³⁾ It now seems that the moths have no tendency to choose matching backgrounds.

Even though the peppered moth never changed into anything else, it became a cherished icon of Darwin's idea of the origin of species, and the story appeared in textbooks and venues popularizing science.⁽⁴⁾ In reality, the story demonstrates adaption in action, not evolution in action, and even then it is flawed. University of Massachusetts biologist Theodore Sargent helped a NOVA documentary on the subject by gluing dead moths on trees for the cameras. Commenting on the textbooks and films about the peppered moth, he said "There have been a lot of fraudulent photographs."⁽⁵⁾ Jerry Coyne of the Department of Ecology and Evolution at the University of Chicago, reports that in forty years of research, exactly two moths have been seen resting on tree trunks. He said his own reaction to these revelations "resembles the dismay attending my discovery, at the age of six, that it was my father and not Santa Claus who brought presents on Christmas Eve."⁽⁶⁾

In retrospect, there were warnings that the peppered moth was a poor example for evolution. As early as 1937, E.B. Ford postulated that other factors besides coloration that were more important for moths like Biston.⁽⁷⁾ There was an excellent 1974 study by Lees and Creed, with great pictures of both colors of moths on tree trunks,⁽⁸⁾ and later a report, "Exploding the Myth of the Melanic Moth," in the 1986-7 New Scientist.⁽⁹⁾ These warnings were not heeded and, as a result, many evolutionists and their popularizers have put themselves and gradualistic evolution out on a limb.

It may be that what caused the peppered moth to change color was its diet while in the larval stage - T.R. Sargent and his coworkers have found that this applies to a different nocturnal moth.⁽¹⁰⁾ Whatever caused the change, it was not according to the story that was told to the public for forty years. We have had philosophers of science propose that there exists in science theory-laden interpretation, observation, and recollection. Here is an example of theory-laden data doctoring. Consciously or unconsciously, researchers manipulated the data to fit the theory - but is there more to the story than just this?

In the late 1980's I was teaching a history of science class at a major university. I was explaining that Darwin had no real evidence for his idea⁽¹¹⁾ and that it had gone into an eclipse by the end of the nineteenth century.⁽¹²⁾ I offhandedly mentioned that even though it had been revived in the twentieth century, there still was hardly any evidence. Immediately a biology major raised her hand and countered that the peppered moth is proof of evolution. I had read "Exploding the myth of the melanic moth" in the 1986/7 issue of New Scientist and was not about to concede the point. She answered that "Anyway, that is what they say in Biology."

I made a copy of the New Scientist article and gave it to her. I suppose I could have sent one to the Biology Department, but would it have done any good? I remembered getting a memo from some of the biologists: They were forming "committees of correspondence" to defend evolution against the attacks of the creationists. They wanted others to join. They were not looking for new or better research - they were looking for advocates and supporters. Here is where we leave science and touch on the naturalistic world view underlying the idea of evolution.

If we were dealing with pure science, the formulation and testing of ideas about nature, then biologists would be cautious about teaching their students that the peppered moth story is evolution in action. The crux of the story is that birds eat those moths that visually stand out as they rest on tree trunks. However, the fact is that the peppered moth prefers to rest high up in the tree canopy. This preference was known to Kettlewell at least by 1958.⁽¹³⁾ Mikkola wrote about the peppered moth's preference in separate articles in 1979⁽¹⁴⁾ and 1984⁽¹⁵⁾ Sir Cyril Clarke reported in 1985 that all he and his coworkers had found in twenty-five years of observations is where the peppered moths do not spend the day: on the tree trunks.⁽¹⁶⁾

Surely the biologists where I had been teaching stayed current and knew all of the above. Yet they continued to teach the peppered moth story to their students as an example of evolution in action. And, over a decade later, nothing seems to have changed. There has been a lot more research showing additional weaknesses in the original story. For example, it had been assumed that birds see like us, but they do not. They have an ultraviolet capability that we do not have, and they may see colors better too.⁽¹⁷⁾ Also, simplifying assumptions were made to make mathematical calculations easier, but it turns out these cannot be made for the peppered moth.⁽¹⁸⁾ Nevertheless, the peppered moth story as an example of uniformitarian evolution in action continues to be taught. For instance, it can be found in the 1991 edition of George Gaylord Simpson's classic textbook⁽¹⁹⁾ (I studied the first edition as an undergraduate and still own the book); or in Raven and Johnson's Biology, 4th ed. (1996). The initial "hyping" of the peppered moth story as an example of evolution in action, and not adaption in action, and the subsequent refusal to modify or drop it in the light of new data, fits the contention that uniformitarian evolution is not science, but a social construct, divorced from reality. So we are facing something that is more than just theory-ladeness, it is driven by a completely naturalistic worldveiw.

For all the publicity of the supposed evidence of evolution's mechanism, there still remains the bigger questions. Why did the moth not evolve into something else as its environment changed? Exactly how did it evolve into a moth into the first place? Where did the information come from to program the change from an egg to a caterpillar to a pupa to a moth?

References

1. Jeremy Cherfas, "Exploding the myth of the melanic moth," New Scientist 112: 25 (1986/7).

2. Michael Majerus, a Cambridge University expert on the moth, as quoted in Robert Matthew's "Scientists pick holes in Darwin moth theory," electronic Telegraph, Sunday, 14 March 1999.

3. H.B.D. Kettlewell, "Darwin's Missing Evidence," Scientific American 200:48-53 (1959) p. 52.

4. Kettlewell helped develop a short movie clip on the peppered moth story and a slide/audiotape set, "The Experimental Study of Evolution," with the alternate title, "Evolution by Observation and Experiment." It came complete with a teacher's guide. He wrote an article, "Darwin's Missing Evidence," for the March, 1959 issue of Scientific American, and several books on, or related to, the subject.

5. Larry Witham, "Darwinism Icons Disputed," The Washington Times, 17 January 1999, p. D8.

6. Jerry A. Coyne, "Not black and white," Nature 396:35-36 (1998) p. 35.

7. E.B. Ford, "Problems of heredity in the Lepidoptera," Biological Review 12:461-503 (1937).

8. D.R. Lees and E.R. Creed, "Industrial Melanism in Biston Betularia: The Role of Selective Predation," Journal of Animal Ecology 44:67-83 (1975). (The article was received in 1974.)

9. A recent book is Michael E.N. Majerus' Melanism: Evolution in Action (Oxford: Oxford University Press, 1998).

10. T.R. Sargent, et. al., in M.K. Hecht, et. al., Evolutionary Biology 30:299-322 (1998).

11. Barry G. Gale, Evolution Without Evidence: Charles Darwin and the Origin of Species (Albuquerque: University of New Mexico Press, 1982).

12. Peter J. Bowler, The Eclipse of Darwinism: Anti-Darwinian Evolution Theories in the Decades around 1900 (Baltimore: Johns Hopkins University Press, 1983).

13. H.B.D. Kettlewell, "The importance of the micro-environment to evolutionary trends in the Lepidoptera," Entomologist 91:214-224 (1958); and "Darwin's Missing Evidence," p. 49.

14. K. Mikkola, "Resting site selection of Oliga and Biston moths (Lepidoptera: Noctuidae and Geometridae)," Acta Entomologica Fennici 45:81-87 (1979).

15. K. Mikkola, "On the selective force acting in the industrial of Biston and Oliga moths 9Lepidoptera: Geometridae and Noctuidae)," Biological Journal of the Linnaean Society 21:409-421 (1984).

16. C.A. Clarke, et. al., "Evolution in reverse: clean air and the peppered moth," Ibid, 26:189-199 (1985).

17. Majerus, Melanism, p. 126.

18. Ibid, pp. 116-117.

19. W.S. Beck, K. F. Liem, and G.G. Simpson, Life: An Introduction to Biology, 3rd ed. (New York: Harper Collins, 1991).

Acknowledgements

The picture of the moths is from Creation ex nihlio Magazine, 21: 56, (1999).