The peppered moth does not demonstrate evolution because no speciation occurs, or because the original experiments were fraudulent.
I. Evolution not equivalent to speciation
Industrial melanism in the peppered moth was never intended as an example of speciation in the first place, but rather as an example of microevolution through natural selection. If the standard account of the peppered moth is correct, then industrial melanism does in fact constitute an example of evolution; one must simply be clear about exactly what is being claimed.
II. False allegations of fraud
I should comment briefly on a flap that arose at the turn of the millennium regarding the original peppered moth experiments. A few respectable scientists argued that the original peppered moth experiments were flawed. In typical fashion, a number of disreputable creationists seized upon those arguments and blew them all out of proportion, claiming that the experiments had been hoaxes or that they did not demonstrate natural selection at all. One should read this letter by Bruce Grant, one of the reputable scientists in question, who rebuts the charge that fraud was involved in the peppered moth experiment, and affirms that the original experiment does indeed demonstrate natural selection quite clearly. Kenneth R. Miller also provides a very readable presentation of the whole matter. Finally, the conclusions of the original experiments were confirmed by new observations made by Michael Majerus (Cook et al. 2012).
Cook LM, Grant BS, Saccheri IJ, and Mallet J. 2012. Selective bird predation on the peppered moth: the last experiment of Michael Majerus. Biology Letters 8:609-612. Electronic version: 10.1098/rsbl.2011.1136 (available online)
Last updated: 15 Nov 2014
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