Shh! - a quiet admission

Vernon Jenkins (
Mon, 15 Mar 1999 22:02:02 +0000

To the Forum:

I came across this interesting article in yesterday's 'Telegraph':


EVOLUTION experts are quietly admitting that one of their most
cherished examples of Darwin's theory, the rise and fall of the peppered
moth, is based on a series of scientific blunders.

Experiments using the moth in the Fifties and long believed to prove the
truth of natural selection are now thought to be worthless, having been
designed to come up with the "right" answer. Scientists now admit that
they do not know the real explanation for the fate of Biston betularia,
whose story is recounted in almost every textbook on evolution.

According to the standard account, only one version of Biston existed
before the mid-19th century: a white variety, peppered with black spots.
During the Industrial Revolution its numbers plummeted because it became
easy prey for birds as it rested on the pollution-blackened trunks of
trees. In its place a mutant, pitch-black form of the peppered moth
began to thrive, as it could rest on tree trunks without fear of being
eaten. Precisely as predicted by Darwin's theory of natural selection,
this "fitter" mutant moth rapidly outnumbered the white version,
reaching 100 per cent levels in some industrial areas.

During the Fifties, however, naturalists discovered a resurgence of
the white variety, prompting the belief that Darwin had struck again
through the Clean Air Acts, which had led to the return of unpolluted
trees. These allowed the white moths to regain their Darwinian
ascendancy, while the numbers of the now all-too-visible black variety

This neat example of Darwinian evolution in action has been thought to
be supported by solid evidence in the form of experiments begun in the
Fifties by the late Oxford University scientist Bernard Kettlewell. But
now evolution experts are pointing to blunders in Kettlewell's research
that undermine the theory about the rise and fall of Biston.

Scientists are beginning to concede that the white variety flourished
again well before the return of pollution-free trees, while the black
type continued to thrive in areas unaffected by industry. Experiments
have also shown that neither moth chooses resting places best suited to
its camouflage. Most damning of all, despite 40 years of effort,
scientists have seen only two moths resting on tree trunks - the key
element of the standard story and Kettlewell's experiments.

According to Michael Majerus, a Cambridge University expert on the moth,
Dr Kettlewell tried to confirm the standard story simply by pinning dead
moths on to parts of the trees where they could be seen easily by birds.
Dr Majerus said: "He stuck them on low branches because he wanted to sit
in his hide and watch them being eaten. They actually seem to rest in
the shadows under branches, which makes even the black ones difficult to
spot by birds."

Scientists are now beginning to doubt even the basic presumption that
birds were responsible for the changing fortunes of the different types
of Biston.

According to Prof Jerry Coyne, an expert on evolution at the University
of Chicago, when Dr Kettlewell could not get the moths he needed
naturally, he bred them in his laboratory.

Prof Coyne said: "That could affect their vigour, so the level of bird
predation he saw was just due to the fact that his moths were raised in
the lab. In one case, Kettlewell actually used to warm them up on the
bonnet of his car."

Prof Coyne insisted, however, that the moths are almost certainly an
example of natural selection: "I'm certainly not saying Darwin is wrong.
The real cause is probably connected with pollution - but beyond that I
wouldn't want to go." He said, however, that Dr Kettlewell's
widely-quoted experiments are essentially useless. "There is a lot of
wishful thinking and design flaws in them, and they wouldn't get
published today."

Some fear that the new theories will be seized on by creationists to
fuel "sensationalist" claims questioning all evidence for Darwin.
Richard Dawkins, the professor of the public understanding of science at
Oxford University and author of The Selfish Gene, said: "The details of
any experiments done 40 years ago are bound to be vulnerable to detailed
criticism. But, in any case, nothing momentous hangs on these

Robert Matthews, Science Correspondent

Of course, Richard Dawkins and others will be well aware that the
peppered moth has for many years been trumpeted as a living example of
evolution in action(even of 'macro-evolution', in some quarters!), and
that this delusion will have influenced many hundreds of thousands of
impressionable minds. They may even find satisfaction in the fact that
the lie will, undoubtedly, affect many more, for as the commentator (an
evolutionist) points out, "...(the story of) Biston
recounted in almost every textbook on evolution." And, I might add,
every encyclopedia carrying a section on 'Evolution'.

It is therefore clear that, as with the 'Piltdown hoax' and the
forgeries of Ernst Haeckel, it will take many years before this
disgraceful example of evolutionist subterfuge can be flushed out of our
educational systems. Yet, as Dawkins observes, "...nothing momentous
hangs on these experiments."


Vernon Jenkins
[Musician, Mining Engineer, and Senior Lecturer in Maths and Computing,
the Polytechnic of Wales (now the University of Glamorgan), 1954-87]