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From www.discovery.org/csc:
The Strength of Natural Selection in the Wild
All Those Darwinian Doubts
Wichita Eagle
March 9, 2005
NOTE: The article below is the full version by Dr. Berlinski. The Wichita
Eagle opted to shorten the piece to only 400 words.
The defense of Darwin’s theory of evolution has now fallen into the hands of
biologists who believe in suppressing criticism when possible and ignoring it
when not. It is not a strategy calculated in induce confidence in the scientific
method. A paper published recently in the Proceedings of the Biological Society
of Washington concluded that the events taking place during the Cambrian era
could best be understood in terms of an intelligent design – hardly a position
unknown in the history of western science. The paper was, of course,
peer-reviewed by three prominent evolutionary biologists. Wise men attend to the
publication of every one of the Proceeding’s papers, but in the case of Steven
Meyer’s "The origin of biological information and the higher taxonomic
categories," the Board of Editors was at once given to understand that they had
done a bad thing. Their indecent capitulation followed at once.
Publication of the paper, they confessed, was a mistake. It would never happen
again. It had barely happened at all. And peer review?
The hell with it.
“If scientists do not oppose antievolutionism,” Eugenie Scott, the Executive
Director of the National Center for Science Education, remarked, “it will reach
more people with the mistaken idea that evolution is scientifically weak.”
Scott’s understanding of ‘opposition’ had nothing to do with reasoned
discussion. It had nothing to do with reason at all. Discussing the issue was
out of the question. Her advice to her colleagues was considerably more to the
point: "Avoid debates."
Everyone else had better shut up.
In this country, at least, no one is ever going to shut up, the more so since
the case against Darwin’s theory retains an almost lunatic vitality.
Look – The suggestion that Darwin’s theory of evolution is like theories in the
serious sciences – quantum electrodynamics, say – is grotesque. Quantum
electrodynamics is accurate to thirteen unyielding decimal places. Darwin’s
theory makes no tight quantitative predictions at all.
Look – Field studies attempting to measure natural selection inevitably report
weak to non-existent selection effects.
Look – Darwin’s theory is open at one end since there are no plausible account
for the origins of life.
Look – The astonishing and irreducible complexity of various cellular structures
has not yet successfully been described, let alone explained.
Look – A great many species enter the fossil record trailing no obvious
ancestors and depart for Valhalla leaving no obvious descendents.
Look – Where attempts to replicate Darwinian evolution on the computer have been
successful, they have not used classical Darwinian principles, and where they
have used such principles, they have not been successful.
Look – Tens of thousands of fruit flies have come and gone in laboratory
experiments, and every last one of them has remained a fruit fly to the end, all
efforts to see the miracle of speciation unavailing.
Look – The remarkable similarity in the genome of a great many organisms
suggests that there is at bottom only one living system; but how then to account
for the astonishing differences between human beings and their near relatives –
differences that remain obvious to anyone who has visited a zoo?
But look again – If the differences between organisms are scientifically more
interesting than their genomic similarities, of what use is Darwin’s theory
since it’s otherwise mysterious operations take place by genetic variations?
These are hardly trivial questions. Each suggests a dozen others. These are
hardly circumstances that do much to support the view that there are “no valid
criticisms of Darwin’s theory,” as so many recent editorials have suggested.
Serious biologists quite understand all this. They rather regard Darwin’s theory
as an elderly uncle invited to a family dinner. The old boy has no hair, he has
no teeth, he is hard of hearing, and he often drools. Addressing even senior
members at table as Sonny, he is inordinately eager to tell the same story over
and over again.
But he’s family. What can you do?
The Strength of Natural Selection in the Wild
Discovery Institute
April 25, 2005
Like Hell itself, Darwin’s theory of
evolution is often said to be protected by walls that are at least seven miles
thick, in that it is not only true, but unassailable. It is a considerable
irony, therefore, that some of the most cogent criticisms of Darwin’s theory are
the result of work undertaken by very orthodox members of the biological
establishment itself. Such criticisms are inevitably designated as calls for
further research. They are, nonetheless, what they are.
A recent study by J.G. Kingsolver et al (hereinafter Kingsolver) entitled ‘The
Strength of Phenotypic Selection in Natural Populations, published in
the March 2001 issue of The American Naturalist, is an interesting
example. It is field studies of natural selection that is at issue in this
study. Such studies are addressed to living species under natural conditions,
and it comes as something of a surprise to learn that despite very long-standing
claims by evolutionary biologists to have established the robust viability of
natural selection as a biological force, the overwhelming number of such studies
have been conducted only in the past fifteen years.
Kingsolver’s study is second-order in nature: It analyses and discusses sixty
three field studies dealing with sixty two species that have been reported in
the literature since the publication of J.A. Endler’s well-known monograph,
Natural Selection in the Wild, published in 1986.
The statistical methods by which Kingsolver proceeded are simple to the point of
triteness. One the one hand, there are a series of quantitative biological
traits, chiefly morphological in nature; and on the other hand, certain
quantitative measure of fitness. Beak length in finches is a typical
morphological trait, and survival, mating success or fecundity typical measure
of fitness. Using the methodology first introduced by R. Lande and S. J. Arnold
in their 1983 study, ‘The Measurement of selection on correlated
characteristics,’ published in Evolution, 37, Kingsolver proposed to define
selection in terms of the slope of the regression between a quantitative trait
of interest and specific measures of fitness. This provides an estimate of the
strength of selection.
Natural selection disappears as a biological force and reappears as a
statistical artifact. The change is not trivial. It is one thing to say that
nothing in biology makes sense except in the light of evolution; it is quite
another thing to say that nothing in biology makes sense except in the light of
various regression correlations between quantitative characteristics. It hardly
appears obvious that if natural selection is simply a matter of correlations
established between quantitative traits, that Darwin’s theory has any content
beyond the phenomenological, and in the most obvious sense, is no theory at all.
Be that as it may, the real burden of Kingsolver’s study lies in the
quantitative conclusions it reaches. Two correlations are at issue. The first is
linear, and corresponds to what in population genetics is called directional
selection; and the second quadratic, and corresponds either to stabilizing or
disruptive selection. These are the cornerstones of the modern hill and valley
model of much of mathematical population genetics. Kingsolver reported a median
absolute value of 0.16 for linear selection, and a median absolute value of 0.10
for quadratic selection. Thus an increase of one standard deviation in, say,
beak finch length, could be expected to change fitness by only 16 percent in the
case of linear selection, and 10 percent in the case of quadratic selection.
These figures are commonly understood to represent a very weak correlation. Thus
if a change in the length of a beak’s finch by one standard deviation explains
16 percent of the change in the population’s fitness, 84 percent of the change
is not explained by selection at all.
These results, although at odds with those reported by Endler, are not in
themselves astounding. It is when sample sizes pass beyond samples of 1000 that
results become far more difficult to accommodate, for under these circumstances,
Kingsolver reported, both linear and quadratic selection were virtually
non-existent.
The significance of these results is, of course, not entirely clear. Kingsolver
goes no further than observing that “important issues about selection remain
unresolved.” Considering the fundamental role of both linear and quadratic
selection in population genetics and in popular accounts of Darwin’s theory, one
of those “unresolved” issues may well be whether natural selection exists to any
appreciable extent, and if it does, whether it plays any real role in biological
change altogether.
These considerations may assume some importance when it comes to assessing the
widely repeated claim that Darwin’s theory is as well-established as physical
theories such as general relativity or quantum mechanics