"Evening Standard", 15 April 2002
Peppered moths and a pinch of salt
Of Moths And Men: Intrigue, Tragedy and the Peppered Moth
Judith Hooper (Fourth Estate, £15.99)
Reviewed by Marek Kohn
As every schoolchild knows, given a passing acquaintance with the
inside of the biology lab, peppered moths are nature's way of telling us
Darwin was right. Originally, these insects were all pale, but then, as the
Victorian era began, black specimens began to appear. By the end of the
19th century, they had replaced the pale forms in the smoke-blackened
industrial regions of England; while the pale kind held on in the
countryside. In the 1950s, the Oxford researcher Bernard Kettlewell
showed that birds picked out the dark ones on tree trunks in unpolluted
areas, but ate more of the pale kind in urban areas where trunks were bare
of lichen.
With the aid of the Clean Air Acts and the decline of heavy industry,
nature then completed the story. Pollution decreased, and so did the
black moths. The textbooks celebrated this example of "evolution in
action".
Evolutionists had a trophy case-study that they could brandish at
creationists, and at other scientists who considered them inferior
because they could only interpret things that had already happened. For
once in nature, the story was simple and the case was closed.
As with human celebrities, though, the moths look chequered in
hindsight. Revisionists have pointed out anomalies in the evidence, such
as the prevalence of black moths in unpolluted East Anglia. They have
scrutinised the design of Kettlewell's experiments and found them sadly
wanting - not least because the moths don't actually sit on tree trunks
during daytime. They have failed to reproduce his neat results, and some
believe that these were too neat: sloppy procedure may have allowed
unconscious bias to massage the figures. Some scientists now feel that
the peppered moth should be suspended from the textbooks. For
creationists, as Judith Hooper observes in this absorbing account, it is
like capturing the enemy flag.
It is certainly a posthumous humiliation for Kettlewell, who in life never
quite managed to attain the standards Oxford demanded - one day he
found his nameplate annotated "He's not really a doctor", meaning that
he had a medical degree rather than a scientific doctorate. Hooper
depicts him as a gifted amateur naturalist who made a poor scientist;
outwardly a bluff cove, inwardly a tormented soul who paced his camp at
night like an office-bound executive, trying to douse his anxieties with
gin and cigars.
She suggests that he was the cat's-paw of the geneticist EB "Henry"
Ford, an arrogant and egregious figure who makes a natural villain for her
tale. But she tells her story with sensitivity and grace, and Ford
insidiously turns himself into a sympathetic character. He was a virtuoso
of high-table high camp, and therefore fluent in irony. The inveterate
namedropper acknowledged his peccadillo by referring to "my friend the
Pope"; the notorious detester of "female women" would raise his bowler
to the Kettlewells' nanny and inquire "How is your pussy?" Perhaps this
kind of thing plays better in the land of Kenneth Williams than in the
States, from whose perspective this skilful synthesis of scientific and
human detail is written. The moth story certainly did.
Britain has sustained a can-do attitude among evolutionists: many of
them have been singularly ready to believe that natural selection can and
does do everything interesting in nature. Much of the cold water poured
over peppered moths, and other putative examples of selection, has come
from the US. American moths take the contrarian stance too, dark
varieties commonly populating unpolluted regions.
Somewhat to Hooper's surprise, though, the scientific consensus holds.
"All of us in the peppered moth debate agree that the moth story is a
sound example of evolution produced by natural selection," affirms Jerry
Coyne, one of the evolutionists co-opted against their will by
creationists. It's just that, as Coyne puts it, we have seen the footprint of
natural selection, but we may not yet have seen the foot.
The peppered moth is no longer a neat textbook illustration, dark moth
and pale side by side, but normal science, phlegmatically reviewing its
shortcomings and striving to untangle nature. And, with the appearance
of a creationist specimen in the north of England, it bears an urgent load
on its wings. Of Moths and Men merits far more attention than its title
suggests.
Oryginal:
http://www.thisislondon.co.uk/dynamic/lifestyle/books/top_review.html?in_review_id=553181&in_review_text_id=519847
POWRÓT