F ile this under the heading: "Where life imitates open mic night at the comedy club."
A policeman is walking down the street when he happens on a man crawling around in the gutter under a corner streetlight. The policeman asks the rather obvious question, "Sir. What are you doing there in the gutter?" The man replies, "I've dropped my lucky silver dollar and I'm trying to find it." The policeman, always the helpful sort, bent over to help in the search. After about five minutes, the policeman asks, "Exactly where were you standing when you dropped your coin? Maybe we can guess where it rolled." The man replies, "Oh, I was standing about 100 yards up the street there when I dropped it." Stunned, the policeman asked, "Well, why on Earth are you searching for it way down here?" "Isn't it obvious?", replies the man. "The light is much better here."
OK, it's an old joke, but what does it have to do with Peppered Moths?
Before I answer that, let me tell you the story of Henry Bernard David Kettlewell, a man who, among other things obviously had too many names. Kettlewell, while a research fellow at Oxford under the tutelage of E.B Ford, undertook a research project investigating the phenomenon of the change in coloration of a local species of moth. The moth was formally known as Biston Betularia, but was better known as the Peppered Moth because of it's speckled coloring. This species had long been known to have two "varieties", one was light the other dark. The interesting thing was that before the 1800's many of the trees in the area had light colored trunks, either from light colored bark or from lichens (a fungus that grew on the sides of trees). During this same time, the larger population of Peppered Moths were light. There were dark moths in the population, but they were a distinct minority. By the mid 1800's, the industrial revolution was starting to impact the environment and pollution had caused a darkening of the tree trunks. It was noted that the population of dark versus light moths had reversed; now dark moths were the dominant color.
Kettlewell set out to explain this phenomenon of "industrial melanism". The working theory was that dark moths had a better survival rate because of their "camouflage" that made them blend in with the dark tree trunks, whereas light moths would be eaten by birds. For this experiment, Kettlewell started with a large number of moths and counted the light and dark moths. These moths were marked with a small amount of paint and released in the Birmingham woods. After a few days, light traps were used to recapture the moths. This population of moths included both marked (laboratory) moths and unmarked (wild) moths from the area. It was assumed that losses due to migration (moths that left the area) would be proportional for light and dark moths, so that the differences in the recapture population would be due to bird predation. As expected, the number of dark moths was significantly larger than the number of light moths. The experiment was repeated in Dorset where pollution had not affected the tree coloring and in this case, the expected results of higher numbers of light moths survived.
For years this example has been held up by Darwin supporters as the proof of the pudding for the theory of Evolution by Natural Selection. Bear in mind, that the claim was that this was an example of micro-evolution, not macro-evolution. In other words, it represented a change in the frequency of certain genes in the population of Peppered Moths, NOT speciation.
But is it really evolution that we witnessed? Alas, something was rotten in Britain. In fact, there were many rotten things...
Since I opened with the old joke about searching where the light was better, let's start with this point. Kettlewell was not an Entomologist. Therefore, it is not surprising that he ignored some critical facts about the Peppered Moths. First and foremost, he ignored the fact that the Peppered Moths are nocturnal creatures. To quote Edgar Winter, "They only come out at night" and return to their hiding places during the day. In his experiments, Kettlewell released his moths during the day. He did this so that he would be able to observe the moth behavior... In other words, the light was better. While this may seem like a minor issue, in fact, when released during the daylight, the Peppered Moths become disoriented and exhibit uncharacteristic behavior. They do things that they don't normally do, for instance (perhaps) landing on tree trunks where they might be targets for daytime predators. The fact of this disorientation has been demonstrated in many experiments since Kettlewell's.
The next flaw in the experiment was that Kettlewell (and others) assumed that the Peppered Moths had a tendency to land on tree trunks. However, this turns out not to be the case. The natural resting place for the Peppered Moths is still not completely understood, however it is clear that tree trunks are rarely the case. Too rare to implicate the trunk/moth coloration connection as a significant factor in natural selection. Actually, the uncertainty may be worse than this. Since the time of Kettlewell's experiment, a few things have been learned about birds. For instance, bird vision includes the ability to see into the UV spectrum, which means that mere coloration may not have rendered the few moths that do land on tree trunks invisible to the predators, independent of their coloration. Since we cannot ask the birds, we cannot determine if their assessment of effective moth camouflage agrees with human assessments or not, but it does call into question the basic assumption of cryptic coloration. This is not to say that natural selection due to predation or even due specifically to coloration was not a factor, only that the evidence to support it has not been demonstrated in this case. What we do know is that, since the moths tend to fly at night, their main predators are bats, not birds.
It probably goes without saying... but I'll say it anyway. Bats capture their prey in-flight (not resting on tree trunks or any other resting sites) and they use sound waves to locate their prey, not sight (so coloration is not a factor).
There were other irregularities in the experiments as well, the use of light traps to recapture moths (which may have increased the rate of predation in the proximity of the traps), the practice of gluing moths to trees (which incidentally accounted for the only observed incidents of bird predation on tree trunks), the observation of bird predation in lighted aviaries, and more. Not surprising is that the Kettlewell experiments were repeated all over the globe. What is surprising, at least to the scientists that promoted the Peppered Moth phenomenon as an example of natural selection, is that the results were not consistently repeatable. In other words, sometimes dark moths populated environments with light colored tree trunks and in other cases light moths populated environments with dark tree trunks.
I could extend this essay even deeper and show more flaws in this experiment, but my intent is not to lambaste Kettlewell for his poor scientific method. My real problem is that the Peppered Moth story is still used to demonstrate "evolution in action" in many scientific texts. Evolutionists will defend this example tooth and nail until faced with overwhelming evidence, then shift gears to proclaim that it is still a good "demonstration" of how evolution could work.
Case in point. Since moths don't typically land on tree trunks, Kettlewell used glue to attach dead, dark moths to dark tree trunks and dead, light moths to light tree trunks. He then photographed these moths to demonstrate the camouflage effect. The following comes from the National Center for Science Education (referring to and trying to justify these photographs):
"These pictures are illustrations used to demonstrate a point - the advantage of protective coloration to reduce the danger of predation. The pictures are not the scientific evidence used to prove the point in the first place. Compare this illustration to the well-known re-enactments of the Battle of Gettysburg. Does the fact that these re-enactments are staged prove that the battle never happened? The peppered moth photos are the same sort of illustration, not scientific evidence for natural selection."
I guess I can see their point. By the same scientific standards we should proclaim that cold fusion, demonstrated by Stanley Pons and Martin Fleischmann, of the University of Utah in 1989... (the results of which have never been repeated...) is an example of good science. After all, it served to "illustrate" how great it would be to discover a source of unlimited free energy!
What scientific good comes from promoting bad science? Scientist that still hold this up as an important example of Natural Selection in action are really trying to sell an idea. They believe the idea is right, therefore it is apparently justifiable to use bogus data to support that idea. It's not the first time bad science has been used to sell this idea... Nebraska Man, Piltdown Man, Java Man, Peking Man, Haeckel's Embryos, and more.
It's learning about this kind of science that makes me question everything. That, in itself is a good thing, but what about the budding young scientists that simply trust the accepted scientific views based on the accepted scientific evidence? When the real truth diverges from the perceived truth, how long does it take us to get to the real truth if it is unacceptable to explore the real gaps in scientific knowledge?