Peppered Moth Problems

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Bernard Kettlewell (1907-1979), of Oxford University, UK, introduced the Peppered Moth industrial melanism story as evidence for evolution by Natural Selection in 1955. Since then it has appeared in almost every biology text as evidence for evolution. The publication 'Melanism Evolution in Action', by Majerus, reviewed by Jerry Coyne in Nature vol. 396, p. 35, lists the following problems with Kettlewell's story:

1) The moths do not rest on tree trunks. Exactly two moths have been seen on tree trunks in more than 40 years. Kettlewell actually glued two dead moths on the tree trunk to take photographs.

2) Moths have no tendency to choose matching backgrounds.

3) Kettlewell's results have not been replicated in later studies.

4) The shift in moth population did occur but took place well before new lichens grew on polluted trees. A parallel shift in moth population occurred in U.S. industrial areas but there was no change in lichens.

(Ref. peppered moth, Natural Selection, Kettlewell)

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