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+---Topic: Hooper's 'Of Moths and Men' and reviews thereof started by niiicholas
Posted by: niiicholas on Sep. 21 2002,13:26
This thread is for accumulating links on Judith Hooper's recent book Of Moths and Men.
We might as well start with the link to the book:
< Of Moths and Men at amazon.com >
Most reviews of the book are positive, but my is not. Mine, posted at amazon.com:
Hooper gets the science wrong, August 27, 2002
Reviewer: ntamzek (see more about me) from Santa Barbara, CA United States
The fundamental rule of science journalism should be "first, get the science right". Unfortunately, Hooper's book is marred by One Big Mistake: namely, Hooper misrepresents the state of the scientific question on Kettlewell's explanation for industrial melanism in the peppered moth, namely differential predation by birds against moth morphs more or less cryptic in polluted woodlands. Reading Hooper's book, one would think that this thesis, what I call the "Bird Predation Theory" (BPT), was on the rocks. But this just ain't so -- if we read peppered moth researcher Michael Majerus' (2002) book Moths, we find him writing on page 252,
[E]very scientist I know who has worked on melanism in the Peppered moth in the field still regards differential predation of the morphs in different habitats as of prime importance in the case. The critics of work on this case and those who cast doubt on its validity are, without exception, persons who have, as far as I know, never bred the moth and never conducted an experiment on it. In most cases they have probably never seen a live Peppered moth in the wild. Perhaps those who have the most intimate knowledge of this moth are the scientists who have bred it, watched it and studied it, in both the laboratory and the wild. These include, among others, the late Sir Cyril Clarke, Professors Paul Brakefield, Laurence Cook, Bruce Grant, K. Mikkola, Drs Rory Howlett, Carys Jones, David Lees, John Muggleton and myself. I believe that, without exception, it is our view that the case of melanism in the Peppered moth still stands as one of the best examples of evolution, by natural selection, in action.
Hooper, however, presents the peppered moth case as if it were falling apart, a story which of course the press reviews have uncritically repeated.
Hooper's hero in the book is the one critic of the bird predation thesis who is actually a moth expert, Ted Sargent, although even here Sargent is actually an expert on an entirely different family of moths (the Underwings, e.g. Catocala) and has done almost no work on peppered moths. Hooper, however, gives Sargent a huge platform and gives his numerous critics, and their published rebuttals to Sargent, very short shrift. Hooper portrays Sargent as a lone rebellious American taking on the dogmatic British establishment, but of course American peppered moth researcher Bruce Grant, who supports the BPT and has done numerous studies on peppered moths specifically, is not given the same chance to make his case.
As for Sargent's actual arguments against the bird predation thesis, both Bruce Grant and Laurence Cook wrote articles rebutting Sargent's critique, but Hooper gives Cook's article merely a brief brush-off in a paragraph, completely ignoring, for example, Cook's statistical analysis of all the previous peppered moth experiments, proving a correlation between moth fitness and morph frequency with a >99% confidence. This was a direct rebuttal to Sargent's most important argument, that the statistical support for the bird predation thesis was weak, but Hooper doesn't deal with it directly like she should if she is going to advocate an alternative view.
Hooper does come up with a few arguments that not even the creationists have proposed -- most importantly, that Kettlewell faked his results, or almost as bad, unconsciously mislead himself. This is despite the fact that the predation and mark-release-recapture experiments have been repeated by other researchers and have in the main confirmed his results (see the articles by Cook, Grant, and the books by Majerus 1998 and 2002 for detailed reviews). The most astounding passage in Of Moths and Men occurs when Hooper spends a paragraph "squinting" at the tables in Kettlewell's paper, and she notes that Kettlewell's moth recapture numbers increase suddenly on July 1, 1953. The implication is that Kettlewell fudged things somewhere.
But a modicum of investigation shreds Hooper's fraud hypothesis. What Hooper fails to look at seriously was that when Kettlewell released more moths, he recaptured more. Kettlewell started releasing far more moths on June 30th, and started catching far more moths on the morning of July 1st. In fact, when one does a linear regression, one discovers that "number of moths released" explains 80% of the variance in "number of moths recaptured". This is a nice strong linear relationship. Fraud is not a necessary explanation. Why didn't Hooper realize the obvious answer? Later in the book, Sargent keys off the same change in numbers, and he too mysteriously ignores the obvious explanation -- as in most of the book, Sargent's word is taken as gospel and is substituted for rigorous scientific evaluation.
In addition to the major issues discussed above, Hooper's book is peppered with small but disturbing mistakes of logic and science; there is a particularly nasty one about genetics that shows up Hooper's amateurishness (and frankly, that of her editors and glowing reviewers) rather blatantly. I will, however, leave these as exercises for future reviewers to acknowledge or not, so that readers of the reviews may distinguish the critical thinkers from the whatever-a-science-journalist-says-must-be-true types.
The peppered moth story is an awfully good story; but just as this doesn't make it true, it doesn't make it too good to be true either. Hooper's story, the story of a rebel (Sargent) overturning an oppressive orthodoxy is a "good story" also. As Hooper should know, the only way to tell if a "good story" is a true one is by a careful, balanced and weighted review of the evidence. The peppered moth researchers have and are doing this repeatedly, as every bit of new evidence comes in; this is their job as scientists; and their scientific conclusion is that Kettlewell's central finding, that bird predation is the agent of selection, remains firm. Hooper, however, chooses sensationalism, psychoanalysis, and a very selective review of authorities and evidence to reach her conclusion that the bird predation thesis is unsupported; this is the central flaw of her book.
(9 of 19 people found this review helpful!
Posted by: niiicholas on Sep. 22 2002,23:37
Here is the only review of Hooper that has come out thus far by a Real Live Peppered Moth Researcher: Bruce Grant. His take is notably different than the press commentary on Hooper.
< http://www.sciencemag.org/content/vol297/issue5583/#books >
Science 297, 940-941 (2002)
Sour Grapes of Wrath
A review by Bruce S. Grant
Of Moths and Men: Intrigue, Tragedy and the Peppered Moth
Fourth Estate, London, 2002. 397 pp. £15.99. ISBN 1-84115-392-3.
Of Moths and Men The Untold Story of Science and the Peppered Moth
Norton, New York, 2002. 397 pp. $26.95, C$38.99. ISBN 0-393-05121-8.
Mark Twain once quipped that reports of his death had been exaggerated. Recent reports exaggerate the death of industrial melanism as an exemplar of natural selection. The latest is Judith Hooper's Of Moths and Men, which promises "the untold story of science and the peppered moth." What it delivers is a quasi-scientific assessment of the evidence for natural selection in the peppered moth (Biston betularia), much of which is cast in doubt by the author's relentless suspicion of fraud. This is unfortunate. Hooper is a gifted writer. In places, her prose is quite enjoyable, even brilliant. But, sadly, the book is marred by numerous factual errors and by misrepresentations of concepts and controversies.
The fundamental problem is Hooper's failure to clearly distinguish the evidence for natural selection and the mechanism of selection. A dead body with a knife in its back is evidence that a murder has been committed. An inability to establish beyond reasonable doubt the guilt of the leading suspect does not mean that the murder did not occur.
Population geneticists define evolution as a change in allele (gene) frequency. Adult peppered moths come in a range of shades from mottled gray (pale) to jet black (melanic). We know from extensive genetic analysis that these phenotypes result from combinations of multiple alleles at a single locus. Changes in the percentages of the phenotypes in wild populations are well documented. The changes continue and are observable even now. The steady trajectory and speed of changes in allele frequencies indicate that this evolution results primarily from natural selection. J. B. S. Haldane's original calculation of a selection coefficient was estimated from the number of generations it took for the melanic phenotype to effectively replace the pale phenotype during the 19th century. More detailed records document recent changes. For example, near Liverpool, England, the melanic phenotype declined from 93 to 18% in 37 generations (one generation per year); this change is consistent with a 15% selective disadvantage to genotypes with the dominant (melanic) allele.
We have amassed enormous records of changes in allele frequency in peppered moth populations that cannot be explained in the absence of natural selection. But what is the mechanism of selection? Even the answer "we have no clue" would not invalidate the conclusion that selection has occurred. Fortunately, the circumstances have left clues.
Geographic and temporal variations in the incidence of melanism correlate with atmospheric levels of SO2 and suspended particles. (The correlations are not perfect; gene flow by migration spreads alleles, even into populations where they are deleterious.) Light reflectance from tree bark declines as suspended particles increase. Across a range of backgrounds, the pale and melanic phenotypes are differently conspicuous to the human eye. As early as 1896, J. W. Tutt suspected that birds were selectively eating conspicuous phenotypes in habitats variously modified by industrial fallout; H. B. D. Kettlewell first tested Tutt's idea in the 1950s.
It is on Kettlewell and his experiments that Hooper focuses her attention. In a biography more akin to character assassination than to objective disclosure, she portrays Kettlewell as an insecure misfit so driven to please his "boss," E. B. Ford, that he is suspected (by Hooper) of fudging his data. She bases her case on experimental design changes that Kettlewell himself described in his papers and on a sudden increase in the recapture rate of marked moths released in polluted woodlands. Several obvious things that Hooper left unexamined affect the size of moth catches, and her case is unconvincing. In addition, she presents it as if the very evidence for natural selection in peppered moths depends on the validity of Kettlewell's experiments. But even the evidence for bird predation does not depend on them.
Fortunately, science assesses the correctness of work by testing its repeatability. Kettlewell's conclusions have been considered in eight separate field studies, of various designs, performed between 1966 and 1987. Some of the design changes--such as reducing the density of moths, randomly
assigning moths to trees, altering locations on trees where moths were positioned, and positioning killed moths to control for differences in viability and dispersal--were made to correct deficiencies identified in his original experiments. L. M. Cook's regression analysis of fitness estimates from these experiments plotted against phenotype frequencies at their various locations shows the studies to be remarkably consistent (1).
Other mechanisms of selection have been proposed. An inherent physiological advantage of melanic over pale phenotypes is consistent with the rise and spread of melanism, but the widespread decline in melanism that followed the Clean Air Acts obviates that interpretation. Although the possibility remains that physiological differences might be facultative (changing with conditions), so far no experimental work supports this idea. To date, only selective predation by birds is backed by experiment.
Hooper's book turns bizarre when she showcases American biologist T. D. Sargent as a wounded iconoclast whose career was stultified because Kettlewell dismissed his work. She argues that Sargent is now under attack because he questions the "classical explanation" for industrial melanism. Hooper garbles the controversy regarding background selection by moths, and she entertains Sargent's protracted speculation about phenotypic induction. (He has offered no evidence that melanism is an induced character in adult peppered moths.) But most egregious is Sargent's assertion that studies in North America falsify the classical explanation. The history of melanism in American peppered moths--which are conspecific with Kettlewell's moths, not a separate species as Hooper indicates--closely parallels what has occurred in Britain, and melanism is correlated in like manner with levels of atmospheric pollution (2). The American studies corroborate rather than contradict the classical explanation.
The case for natural selection in the evolution of melanism in peppered moths is actually much stronger today than it was during Kettlewell's time. Textbook accounts should be expanded to reflect this newer information, and they should not cite Of Moths and Men as a credible resource.
1. L. M. Cook, Biol. J. Linn. Soc. 69, 431 (2000).
2. B. S. Grant, L. L. Wiseman, J. Hered. 93, 86 (2002).
The author is in the Department of Biology, College of William and Mary, Williamsburg, VA 23187-8795, USA. E-mail: Geometrid@aol.com
Posted by: niiicholas on Sep. 24 2002,03:36
Another review (or rebuttal of positive Hooper reviews, actually) on Intelligent Design Update yahoogroup:
< http://groups.yahoo.com/group/IntelligentDesignUpdate/message/112 >
...quite good IMO, several points that haven't been made by anyone else yet...
Posted by: niiicholas on Sep. 24 2002,03:44
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