Subsequent research has cast a great deal of doubt on this entire scenario. It turns out that Peppered Moths don't normally rest on tree trunks but in the crown of the trees, that researchers (including Kettlewell) released moths by day (even though they are a nocturnal species), that many (not including Kettlewell) in fact pinned dead moths to trunks rather than use live ones in their capture-recapture experiments. In addition, neither the distribution of the various color morphs nor that of the lichens fit the patterns predicted by pollution rates, either during the industrialization or following emission controls (when white moths made a comeback in some regions). The problems unearthed have been so serious that what had been called "Darwin's missing evidence" has been deemed invalid even by evolutionary scientists. (For a summary of these problems, the reader is referred to chapter 7 of Jonathan Wells' Icons of Evolution.) Nonetheless, since evidence for the evolutionary paradigm is so scant, this invalidated tale is still a prominent feature in most modern textbooks (with no mention of its problems).
But again, suppose we ignore (for the sake of argument) the fact that subsequent research has shown that the Kettlewell scenario does not provide the evidence for which Darwinists hope. Let us be generous and grant that perhaps further research will discover a mechanism (consistent with natural selection) that explains the change in Peppered Moths. Then, as evidence for macroevolution, we have the same problem here as we had with the green toothpicks. We have--at the end of the experiment--merely a different frequency of the same phenotypes already present at the beginning. Phillip Johnson has stated the problem well (in Darwin on Trial)...
Why do other people, including experts whose intelligence and intellectual integrity I respect, think that evidence of local population fluctuations confirms the hypothesis that natural selection has the capacity to work engineering marvels, to construct wonders like the eye and the wing? Everyone who studies evolution knows that Kettlewell’s peppered moth experiment is the classic demonstration of the power of natural selection, and that Darwinists had to wait almost a century to see even this modest confirmation of their central doctrine. Everyone who studies the experiment knows that it has nothing to do with the origin of any species, or even any variety, because dark and white moths were present throughout the experiment. Only the ratios of one variety to the other changed. How could intelligent people have been so gullible as to imagine that the Kettlewell experiment in any way supported the ambitious claims of Darwinism?At least two pitfalls (obstacles to objective truth) can be seen in the Peppered Moth story. First, moth researchers used invalid methods and jumped to wrong conclusions primarily because of an inordinant desire to provide evidence for a popular--but evidentially-impoverished--theory. Second, had their conclusions not been spurious, these same researchers (and their popularizers, including textbook editors still today) have been guilty of failing to see the scalar limitations of their results. Evidence of natural selection working at the level of a species quite simply is irrelevant as evidence for macroevolution.
As a scientist, I only hope that the Peppered Moth may serve as a reminder to avoid these pitfalls long after it has been finally discarded as a significant piece of evidence for Darwinian evolution.