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Thursday, November 27, 2008

The IDiot Version of Reality

It is absolutely safe to say that if you meet somebody who claims not to believe in evolution, that person is ignorant, stupid or insane (or wicked, but I’d rather not consider that).

Richard Dawkins
Check out this posting by Barry Arrington on Uncommon Descent [Peppered Moth Idolatry].
The venerable peppered moth (Biston betularia) has popped up a couple of times in recent posts. It seems that some of our Darwinian commenters (see, e.g., qwerty017 in comment [2] here) have not gotten the memo – the peppered moth myth has been completely exploded. Don’t take our word for it. Uber-Darwinist Jerry Coyne says in the November 1998 edition of Nature: “For the time being we must discard Biston as a well-understood example of natural selection in action.” Why else would the popular school text Biology pull its discussion of Biston as an example of “evolution in action”?
Here are some examples of scientists who have not heard message from the IDiot's.

Douglas Futuyma in his textbook Evolution published in 2005 (p. 293).
Until the 1930s, most evolutionary biologists followed Darwin in assuming that the intensity of natural selection is usually very slight. By the 1930s, however, examples of very strong selection came to light. One of the first examples was INDUSTRIAL MELANISM in the peppered moth (Biston betularia). ...
There are many scientific papers on the "myth" as well. Here's the abstract from Saccheri et al. (2008).
Historical datasets documenting changes to gene frequency clines are extremely rare but provide a powerful means of assessing the strength and relative roles of natural selection and gene flow. In 19th century Britain, blackening of the environment by the coal-fired manufacturing industry gave rise to a steep cline in the frequency of the black (carbonaria) morph of the peppered moth (Biston betularia) across northwest England and north Wales. The carbonaria morph has declined across the region following 1960s legislation to improve air quality, but the cline had not been comprehensively described since the early 1970s. We have quantified changes to the cline as of 2002, equivalent to an interval of 30 generations, and find that a cline still exists but that it is much shallower and shifted eastward. Joint estimation of the dominant fitness cost of carbonaria and dispersal parameters consistent with the observed cline change indicate that selection against carbonaria is very strong across the landscape (s approximately 0.2), and that dispersal is much greater than previously assumed. The high dispersal estimate is further supported by the weak pattern of genetic isolation by distance at microsatellite loci, and it implies that in addition to adult dispersal, wind-dispersed first instar larvae also contribute to lifetime dispersal. The historical perspective afforded by this study of cline reversal provides new insight into the factors contributing to gene frequency change in this species, and it serves to illustrate that, even under conditions of high dispersal and strong reverse selection acting against it, complete erosion of an established cline requires many generations.
Wow, this is a tough call. Who are you going to believe, evolutionary biologists like Futuyma and Sacheri et al., or an IDiot like Barry Arrington?

There's no rush. Take a microsecond or two to make up your mind.

See Revenge of the Peppered Moth. Ohmygod! These photographs are faked!, and Peppered Moths and the Confused IDiots for some insight into why one textbook got cold feet in 2000.

Saccheri, I.J., Rousset, F., Watts, P.C., Brakefield, P.M. and Cook, L.M. (2008) Selection and gene flow on a diminishing cline of melanic peppered moths. Proc. Natl. Acad. Sci. USA 105:16212-16217. [doi:10.1073/pnas.0803785105]


  1. Since the latest work by Majerus, hasn't Jerry Coyne changed his mind on the peppered moth front? I'm pretty sure I read that somewhere.

  2. That last question is simply confusing the issue and giving the ignorant a get-out opportunity. ;-)

  3. I thought they didn't have a problem with 'microevolution' anyway?