Did your science textbook teach that peppered moths prove evolution?

Here’s a post by Jonathan Wells at Evolution News, which re-caps the history of the peppered moths experiment.

Excerpt: (links removed)

The peppered moth story is familiar — even overly familiar — to most readers of ENV, so I will summarize it only briefly here. Before the industrial revolution, most peppered moths in England were light-colored; but after tree trunks around cities were darkened by pollution, a dark-colored (“melanic”) variety became much more common (a phenomenon known as “industrial melanism”). In the 1950s, British physician Bernard Kettlewell performed some experiments that seemed to show that the proportion of melanic moths had increased because they were better camouflaged on darkened tree trunks and thus less likely to be eaten by predatory birds.

Kettlewell’s evidence soon became the classic textbook demonstration of natural selection in action — commonly illustrated with photos of peppered moths resting on light- and dark-colored tree trunks.

By the 1990s, however, biologists had discovered several discrepancies in the classic story– not the least of which was that peppered moths in the wild do not usually rest on tree trunks. Most of the textbook photos had been staged.

In the 2000s the story began disappearing from the textbooks. British biologist Michael Majerus then did some studies that he felt supported the camouflage-predation explanation. But before he died of cancer in 2009, he only managed to publish a report of his study in the Darwin lobby’s in-house magazine Evolution: Education and Outreach. Now four other British biologists have presented his results posthumously in the Royal Society’s peer-reviewed Biology Letters. In an accompanying supplement, the authors presented their version of what they call “the peppered moth debacle.” And a debacle it certainly is, but not in the way they think.

According to Charles Darwin, natural selection has been “the most important” factor in the descent with modification of all living things from one or a few common ancestors, yet he had no actual evidence for it. All he could offer in The Origin of Species were “one or two imaginary illustrations.” It wasn’t until almost a century later that Kettlewell seemed to provide “Darwin’s missing evidence” by marking and releasing light- and dark-colored moths in polluted and unpolluted woodlands and recovering some of them the next day. Consistent with the camouflage-predation explanation, the proportion of better-camouflaged moths increased between their release and recapture.

Throughout the 1970s and 1980s, however, researchers reported various problems with the camouflage-predation explanation, and in 1998 University of Massachusetts biologist Theodore Sargent and two colleagues published an article in volume 30 of Evolutionary Biology concluding “there is little persuasive evidence, in the form of rigorous and replicated observations and experiments, to support this explanation at the present time.” (p. 318)

The same year, Michael Majerus published a book in which he concluded that evidence gathered in the forty years since Kettlewell’s work showed that “the basic peppered moth story is wrong, inaccurate, or incomplete, with respect to most of the story’s component parts.” (p. 116) In a review of Majerus’s book published in Nature, University of Chicago evolutionary biologist Jerry Coyne wrote: “From time to time, evolutionists re-examine a classic experimental study and find, to their horror, that it is flawed or downright wrong.” According to Coyne, the fact that peppered moths in the wild rarely rest on tree trunks “alone invalidates Kettlewell’s release-and-recapture experiments, as moths were released by placing them directly onto tree trunks.”

In 1999, I published an article in The Scientist summarizing these and other criticisms of the peppered moth story, and in 2000 I included a chapter on peppered moths in my book Icons of Evolution. Then, in 2002, journalist Judith Hooper published a book about the controversy titled Of Moths and Men. Hooper accused Kettlewell of fraud, though I never did; my criticism was directed primarily at textbook writers who ignored problems with the story and continued to use staged photos even after they were known to misrepresent natural conditions.

Jonathan has actually written about a number of  misleading things that you may mind in Biology textbooks.

Here are the sections in his book “Icons of Evolution“:

  • The Miller-Urey Experiment
  • Darwin’s Tree of Life
  • Homology in Vertebrate Limbs
  • Haeckel’s Embroys
  • Archaeopteryx–The Missing Link
  • Peppered Moths
  • Darwin’s Finches
  • Four-Winged Fruit Flies
  • Fossil Horses and Directed Evolution
  • From Ape to Human: The Ultimate Icon

Dr. Wells holds a Ph.D in Molecular and Cell Biology from the University of California at Berkeley.

8 thoughts on “Did your science textbook teach that peppered moths prove evolution?”

  1. Yes, but the texts don’t present the Piltdown Man fraud any more. It only took 40 years to expose the naturalists’ fraud in that case – but plenty of time to brainwash a couple of more generations.

    I still hear some a-theists quote Miller-Urey. I always remind them that the Sagan books are outdated fairy tales, and should be disposed of, lest one’s brain rot.


    1. Oh my gosh, he believed in the oscillating model of the universe!!!!! It’s deader than the flat-Earth! But he believed it and taught it to all these school children just to get away from the Big Bang cosmology. He is not a great scientist, he is a jackass.


      1. Well, he IS a jackass – and a not-very-happy one at this moment in time. (Or out of it!)

        But, I heard that they opened the new Cosmos series with his infamous (and totally asinine) unsupported assertion that “The Cosmos is all that is or was or ever will be.” If true, another generation is being effectively brainwashed-by-say-so. (I didn’t watch it, because I value the tranquility of my gastrointestinal system too much.) Even the New A-theists, long on assertion and straw man attacks, and short on science and logic, do not quote such nonsense much anymore as “plausible evidence for a-theism.”

        Yes, oscillating and eternal universes have gone bye-bye, which closes off premise 2 of Kalam, forcing the a-theist to make quite “spectacular” claims regarding premise 1. I actually had an a-theist say to me “prove the physics of nothingness, prove the physics of nothingness!” as an (alleged) attack on premise 1. I told him that it just MIGHT be time to return to Planet Pelosi for his scheduled R&R. :-)


  2. Fyi the youtube link is dead.

    This fairy-tale is still being used in public school science textbooks today, along with Haekel’s fake embryos.

    I wouldn’t be surprised if the rest of the icons listed above are as well.


  3. Thinking back 20+ years to my high school biology class, I don’t remember reading anything about evolution in school EXCEPT that it was a theory, an unproven theory at that, and that was at a public high school.


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