Majerus on peppered moths, Hooper, and antievolutionists
zosdad
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Copyright 2003 TSL Education Limited
The Times Higher Education Supplement
August 8, 2003
SECTION: OPINION; No.1601; Pg.14
LENGTH: 815 words
HEADLINE: A Wing And A Prayer
BYLINE: Michael Majerus
BODY:
Creationists should stick to discourse on religion and leave the peppered
moth to get on with evolution, says Michael Majerus
We biologists in Britain have long felt superior to some of our US
counterparts because we do not suffer from legislation forcing us to teach
creationist creeds in biology. However, our self-satisfaction has now been
exploded. As of last year, one local education authority mandated that
creationism be taught in British schools as an alternative to evolution to
explain the diversity of life. At the root of that decision was a moth.
The peppered moth is the most famous example of Darwinian evolution - the
survival of the fittest. It is normally white with a dusting of black
speckling. But in 1848, a black, or melanic, form was found in Manchester
and spread rapidly in industrial areas. By 1895, 98 per cent of Mancunian
moths were black. The following year, the great Victorian lepidopterist J.
W. Tutt theorised that birds found these black moths harder to spot than
pale ones on trees denuded of their lichens by sulphur dioxide and darkened
by soot. In unpolluted regions, the white form was still better camouflaged
and remained predominant. Bernard Kettlewell verified this with his famous
bird predation experiments in the 1950s.
For 40 years thereafter, the story of the melanic moth was the example par
excellence of Darwinian evolution in action. But over the past five years,
its reputation, and that of scientists who worked on it, has been unfairly
tarnished.
In 1998, Oxford University Press published my book Melanism: Evolution in
Action, which details the complex evolutionary ecology of industrial
melanism. Jerry Coyne reviewed the book in the journal Nature. His article
was in essence favourable. But Coyne's main message was that "for the time
being we must discard the peppered moth as a well-understood example of
natural selection in action". I did not recognise this as a review of my
book and I had certainly not made such a claim.
Coyne's review, and a follow-up article in The Sunday Telegraph became
grist for the creationists' mill. This culminated in last year's
publication of Judith Hooper's Of Moths and Men: Intrigue, Tragedy and the
Peppered Moth. This book purports to give the untold story of the humble
creature's rise to fame. But it does not.
What it gives is an ill-informed, quasi-scientific, subjective potted
history of the peppered moth story, undermined throughout by Hooper's
relentless, unfounded suspicion of fraud, aimed at Kettlewell and his
mentor, E. B. Ford.
The book contains many factual errors, and Hooper demonstrates that she
understands little of evolution, and even less about the moth that is her
subject. Yet she deems herself capable of providing a more cogent critical
assessment of the case than a cohort of evolutionary geneticists and
entomologists who have spent years researching the moth. Moreover, she
smears the reputations of two dead scientists who cannot defend themselves.
Anti-evolutionists now argue that if the peppered moth story is dead, then
Darwinism is too. Nonsense. Evolution is defined as the change in frequency
of inherited traits over time. The black peppered moth, which inherited its
colouring according to Mendel's laws of genetics, did increase in
frequency, and now, following anti-pollution law, is declining.
This is proof of evolution. Furthermore, the speed and direction of the
changes can be explained only by natural selection. Hence, proof of
Darwinian evolution.
The only question that remains is whether Tutt's bird predation hypothesis
is sound. All the experimental work to date suggests that it is.
Kettlewell's work, and eight other independent studies, all point to bird
predation as the main factor in the rise and fall of the black peppered moth.
I have studied peppered moths for 40 years, have found more in the wild
than any other person alive, and have read more than 200 scientific papers
on the case. My conclusion is simple - this is still a perfect illustration
of evolution by natural selection.
The earth faces huge problems of overpopulation, diminishing resources,
loss of habitats and species extinctions. More than ever before, biologists
with an understanding of the complexities of ecological systems are needed.
Darwinian evolution is fact and, as Theodius Dobzhansky famously said,
"nothing in biology makes sense except in the light of evolution".
Hooper, and the anti-evolutionists who cite her, should stick to topics
they know something about. Their creationist faiths belong in religious
education classes, not biology lessons.
Michael Majerus is a reader in evolution at Cambridge University. He spoke
on the peppered moth controversy at the Royal Entomological Society's
international symposium on evolutionary entomology at Reading University
last week.
==============
zosdad
numbers of insects each night is an experimental no-no? Does he have
any idea how difficult it is to command exactly 20 moths to be born
each night?
But anyhow, a better press piece than most. If anyone gets wind of
the Majerus article when it comes out, please post the ref/link.
http://news.independent.co.uk/world/science_medical/story.jsp?story=440067
====================
Of moths and men
The changing colours of the peppered moth have long been held up as
the perfect example of evolution in action. But is the insect's iconic
status based on fraudulent research? Steve Connor reports on a raging
Darwinian controversy
04 September 2003
This is the story of the moth that turned black when Britain had its
Industrial Revolution. It is a story told in any school biology book
as the canonical example of evolution in action. The light and dark
varieties of this moth were key players on the Darwinian stage. That
was until someone decided that it was time to rewrite scientific
history and declare the story of the peppered moth a myth. A myth,
furthermore, based on fraudulent research.
Doubts about the veracity of the peppered moth story first surfaced
about five years ago. Leading evolutionists began publicly to question
the landmark experiments that were supposed to demonstrate how the
dark and light forms of the moth were each better camouflaged against
being eaten by birds. When unpolluted trees were covered in lichen -
which is very sensitive to pollution - it was the light or "peppered"
form of the moth that more easily escaped the notice of predatory
birds. When trees were covered in soot or devoid of lichen, the black
"melanic" form was better disguised.
Last year these niggling doubts about the details of the experimental
design mutated into a full-blown conspiracy. Judith Hooper, an
American science writer, questioned not just the methodology of the
experiments carried out 50 years ago but, more seriously, whether the
scientific data they produced were indeed genuine.
In her book, Of Moths and Men, Hooper suggests that the (now deceased)
scientist involved in these studies may have actually perpetrated an
outright fraud in order to "prove" that the rise of the melanic form
of the peppered moth in 19th-century industrial Britain was the result
of better camouflage against birds. If true, it would mean that every
schoolchild who has ever been taught the story of the peppered moth
has effectively been fed a lie.
Although Hooper insists she is not a creationist - she argues that to
be uncritical of science is to turn it into dogma - her arguments are
widely cited in creationist circles. Believers in the literal truth of
the Bible, or in evolution by "intelligent design", have been quick to
seize on the controversy, claiming that it fatally undermines an
important plank of Darwinist teaching. Schools in America have come
under pressure to drop the peppered moth from their science
curriculum, and creationists in Britain are exploiting the doubts to
justify their own aberrant position.
And so this unprepossessing little insect, which sleeps by day and
flits from tree to tree by night, has become the latest weapon in the
creationist war against Darwin. Now, with Hooper's book reaching the
best-seller list, the evolutionists have decided to fight back.
Accepting the limitations of the original experiments, they are still
adamant that the peppered moth remains a perfect example of evolution
by natural selection.
Ironically, the roots of the dispute can be traced to a man who
arguably knows more about the peppered moth than anyone. Michael
Majerus, reader in genetics at Cambridge University, has made
industrial melanism one of his specialisms and has spent hours poring
over scientific papers - and many more hours scrambling around trees
at all times of day and night, watching and wondering about Biston
betularia.
"For 45 years I have bred, collected, photographed and recorded moths,
butterflies and ladybirds in Britain," he says. "I have run one or
more moth traps almost nightly for 40 years. I bred my first broods of
the peppered moth in 1964. I found my first peppered moth at rest in
the wild in the same year. As far as I am aware, I have found more
peppered moths at rest in their natural resting position than any
other person alive. I admit to being, in part, a moth man."
Oxford University Press asked Majerus to write a book on industrial
melanism for publication in 1998 to mark the 25th anniversary of
another book, The Evolution of Melanism by Bernard Kettlewell. It was
Kettlewell who carried out the seminal experiments in the 1950s that
were supposed to have demonstrated the role of predatory birds and
pollution in the evolution of the two forms of peppered moth.
Dressed in khaki shorts and fortified with a supply of gin and cigars,
Kettlewell would camp out for weeks doing what he enjoyed most -
studying moths and butterflies. Although he carried out the earliest
and most important field experiments on the peppered moth, and was
widely viewed as a brilliant naturalist, this former medical doctor
with a lacklustre degree in zoology was not considered a particularly
good scientist.
"Bernard Kettlewell was a highly gifted amateur lepidopterist," says
Professor Bryan Clarke, a geneticist at the University of Nottingham
who knew him personally. "He was not a trained scientist. He never got
to understand the refinements of theory, as can be seen in his book,
which is embarrassingly bad. None the less, he had an extraordinary
capacity for organising and executing studies in the field. More or
less single-handedly, he accomplished what was then the largest and
most demanding set of experiments ever carried out under natural
conditions."
Kettlewell conducted his fieldwork under the auspices of a towering
intellectual figure within Oxford University's zoology department in
the 1950s. EB Ford, known as Henry to his colleagues, was the father
of ecological genetics, a new discipline in the 1920s and 1930s that
attempted to place Darwinism on a more solid footing. For all his
brilliance, Ford was an eccentric, a misogynist who refused to give
lectures to female students, a social snob and a gentleman scientist
who would probably have been happier living in Victorian England.
According to Judith Hooper, Ford was also a megalomaniac intent on
getting the results he wanted from Kettlewell's experiments. She
insinuates that Ford pressured Kettlewell into producing the data that
would fit the accepted but still unproven theory of how the melanic
form of the peppered moth rose to prominence during the Industrial
Revolution. (It rose from virtually zero to 100 per cent frequency in
the most polluted parts of Britain prior to the Clean Air Act of
1956.)
In perhaps his most famous field experiment, Kettlewell released large
numbers of light and dark peppered moths - marked with dots of paint -
into two woods, a polluted one with no lichens near Birmingham, and a
lichen-festooned wood in Dorset. After recapturing the marked moths
using a light trap, Kettlewell found that the dark melanics had
survived better in the Birmingham wood and the light form had survived
better in Dorset. When he released moths on to the trunks of polluted
and unpolluted trees, he witnessed how easy it was for birds to eat
the melanics against the lichen-covered bark, and the light form
against the sooty, lichenless bark. His colleague Niko Tinbergen even
managed to record the predation on 16mm film.
"It was the reciprocal nature of the results from the two woods,
together with the visual record on film, that had such an impact on
the scientific community and finally convinced the sceptics," Majerus
says. There was no doubt that the two forms were better suited to the
different environments, with the melanics having a greater chance of
survival in a polluted environment. Furthermore, Majerus says: "The
mechanism of selection - differential bird predation - had been
identified and demonstrated."
For Kettlewell and Ford, the experiments were a triumph. They showed
that the rise of the black moth since the 19th century was due to the
spread of environmental pollutants, which had progressively blackened
British trees, so giving the melanic moth a cryptic advantage over its
light cousin, which was mostly confined to unpolluted woodland in the
West Country until its recent re-emergence after the Clean Air Act. It
became the standard story of evolution by natural selection,
illustrated with photographs of the two moths on the trunks of
polluted and unpolluted trees.
But nearly 50 years later, Majerus began to spot flaws in the design
of Kettlewell's experiments and the way they had been simplified for
schools. Peppered moths do not usually rest during the day on the
trunks of trees - where Kettlewell released them in the bird predation
experiment - preferring higher branches tucked out of sight. Photos in
schoolbooks showing peppered moths resting on tree trunks are staged,
sometimes using dead moths. They bear little resemblance to what
occurs in nature.
Then there was the problem of how Kettlewell did his experiment. He
released far too many moths in a small area for natural population
densities to be represented, making any feeding trial highly
unnatural. The moths were also a mixture of laboratory-bred and
wild-caught individuals, which he failed to distinguish: an important
omission, as each might behave differently. He released his moths in
daylight rather than during the night, when moths are normally active.
Worse, he began to release more moths halfway through his experiment
when he failed to recapture enough individuals to make his results
valid. It is a cardinal error in science to change an experiment's
design midway through.
When Majerus listed these deficiencies in his 1998 book, Melanism:
Evolution in Action, one reviewer for the journal Nature, Professor
Jerry Coyne, an evolutionist at Chicago University, concluded that for
the time being evolutionists must discard the peppered moth as a
well-understood example of natural selection. "My own reaction
resembles the dismay attending my discovery, at the age of six, that
it was my father and not Santa who brought the presents on Christmas
Eve," Coyne wrote.
With such damning words, Coyne had set in train a series of events
that would culminate in the great peppered moth revisionism. One
British Sunday newspaper put it like this: "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." As Coyne was to remark later on, he
had unwittingly provided grist for the creationist mill.
Jonathan Wells of the University of California at Berkeley, who
receives funds from the Discovery Institute in Seattle - which
promulgates creationism - cited Coyne in his critical onslaught. "The
classical story, elegant and appealing though it may be, should no
longer be presented as a textbook example of evolution in action. If
the purpose of science education is to teach students how to do good
science, then instead of retelling the classical story, textbooks
would do better to focus on how science revealed its flaws," Wells
wrote.
With sentiments such as these gaining wider currency in the United
States and in Britain, Majerus has decided that the time has come to
set the record straight. "Judith Hooper displays her ignorance on
virtually very page of her book," he says.
In a forthcoming scientific publication, Majerus intends to describe
in detail why, with all the inherent faults of the Kettlewell field
studies, the story of the peppered moth is still the quintessential
example of Darwinism in action. "It is irrefutable proof of biological
evolution through the process of natural selection. What there is no
'scientific' proof of is that predation by birds has caused it - but
there is a tremendous amount of circumstantial evidence to suggest
that it is the cause," he says. In other words, the definitive proof
that birds are responsible has yet to be gathered, although what
evidence there is would amount to guilt beyond reasonable doubt in any
court of law.
Majerus says that eight experiments have since been carried out to
emulate Kettlewell's field studies, and each has addressed one or more
of Kettlewell's shortcomings, apart from one - proof that birds in the
wild are responsible for driving the changes in frequency of the dark
and light moths that are allowed to land where they like on a tree
while it is still night.
This weakest link in the peppered moth experiments is now being tested
by Majerus in a five-year experiment he has begun in his own rambling
back garden. He hopes that within three years he will have enough data
to address the final obstacle in the argument over what precisely has
caused the rise and fall of the moth that turned black. If his hunch
is right, birds will be shown to be the force of natural selection.
But even with this final piece of evidence, will the
anti-evolutionists be convinced that the peppered moth remains a
perfect example of Darwinism in action? "Sadly," admits Majerus, "I
doubt it."
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Val and Bert Harrop
"zosdad" <niiic...@yahoo.com> wrote in message
news:74227462.03091...@posting.google.com...
> Still contains some innaccuracies -- who says that releasing different
> numbers of insects each night is an experimental no-no? Does he have
> any idea how difficult it is to command exactly 20 moths to be born
> each night?
This book is a quick read, and it was fairly bad. I mean it was
well written, but it contained far too many references to evolution
that use religious language, ("priesthoods of science",
"catechisms", etc.) She spends an inordinate amount of time and
focus on Kettlewell's and Ford's personal lives and reveals a great
deal of information that is highly personal and I think contains
characterizations mainly designed to provide a negative picture
of the people involved. She has made outright errors about Darwin
& TH Huxley I think (Huxley an athiest, Desmond portrays him
as highly antiathiest), Darwin's tension with Fitzroy due to Fitzroy's
religious proclivities, Darwin "embraced" "survival of the
"fittest (fairly sure it was reluctantly inserted and much
regretted), and also she says PE is saltationalism!
She appears to have found Sargent highly sympathetic and
hard done by. That is not really a reason to smear people
who are dead, but there you are.