Re: Peppered moths again

Kevin O'Brien (
Wed, 31 Mar 1999 17:44:05 -0700

>Jonathan's response:
>The issue here is not a matter of opinion -- whether Majerus's or mine --
>it's a matter of evidence.

Is he really that naive? Of course it's a matter of evidence, but he is
asking us to believe his assessment of the evidence -- his opinion really --
over that of Majerus's. As such, it all comes down to who is the expert.
Majerus is clearly the expert, whereas Wells is merely well-read. As such,
it is Majerus's assessment we should believe, at least until Wells can
demonstrate a greater level expertise, or demonstrate a fatal flaw in the
peppered moth scenario, something he has so far failed to do.

>ALL the evidence points to the fact that peppered moths do not rest on tree
>trunks in the wild. Majerus acknowledges this in his 1998 book. It
>doesn't take a rocket scientist to see that this simple fact seriously
>undermines the relevance of Kettlewell's observations. The scientific
>method would require, at the very least, that observations be repeated on
>moths resting in their natural habitat.

Ideally, yes, but Wells is no biologist and so doesn't understand that in
field experiments one has to set up the experiment as best as one can.
Wells is speaking as a laboratory researcher, who can rigorously control
most if not all the circumstances of his experiments; as such he is imposing
his own rigorous standards on a field that cannot accept them without
compromising its ability to get results. In the field there are many
uncontrollable factors, so you use the most expedient method you can to
minimize those factors. Since it would have been practically impossible for
Kettlewell to observe which moths were being taken from their natural
resting places, Kettlewell did the next best thing. As Majerus affirms, he
was not acting fraudulently but expediently. Even in molecular biology
there are times when one must sacrifice accuracy for expediency.

Here is what Majerus has to say on the subject, as described by Frack:
"Many of Kettlewell's experiments were done on the exposed trunk because it
was the only location that could be studied at a distance, without
disturbing potential predators. Majerus makes very clear that initial
opposition to Kettlewell's claims concerning bird predation relied on both
entomologists and ornithologists denying that birds prey on adult resting
moths. Kettlewell (with animal behaviorist Niko Tinbergen) filmed birds
preying selectively on the moths both in polluted and unpolluted areas.
This could only be done on exposed trunks, and the comparison still appears
valid to me [Frack] (and others). In his discussion of these experiments,
Majerus refers to the experiments as 'inspired' (p. 109) since Kettlewell
covered all foreseeable forms of criticism (but apparently not Coyne's). As
I noted above, Majerus makes clear that Kettlewell understood there were
limits to his approach."

Besides, Majerus reports that the kind of experiments Wells demands should
be done in fact have been done in later years. I quote from Frack's post:
"Experiments with moths attached to these locations [branch-related resting
sites] support the cryptic advantage of earlier studies from trunks." One
has to wonder why Wells either does not know this or chooses to ignore it.
In any event it doesn't take a rocket scientist to see that Wells is totally
turned around on this issue.

>And it doesn't even take a scientist to see that photographs of peppered
>moths manually positioned on tree trunks do not represent their natural
>condition. The continued use of these photographs by textbook-writers
>constitutes deliberate misrepresentation, i.e., fraud.

Again, to quote Majerus: "The photographs are not part of science, they are
educational aids to illustrate the diffence in crypsis of the forms on
different backgrounds." In other words, the photos were not meant to serve
as scientific evidence, but to illustrate to nonscientists the degree to
which the different color phases stand out in different backgrounds. The
effect would have been the same whether the moths were photographed on tree
trunks or branches. As such, the photos do represent natural conditions,
modified for expediency of photography.

Wells is simply being overly critical about a minor point. No fraud was
ever intended and Wells has not presented any evidence that it was; all he
has offered is suspicion and inuendo.

>This is not an issue of creationism vs evolutionism.

On the contrary, this is the only reason for making a mountain out of this
particular molehill.

>I do not claim that
>the peppered myth validates the former or invalidates the latter.

But he is claiming that the peppered moth scenario is a myth, thus implying
that evolution is based on bad (even fraudulent) science. That certainly
would tend to invalidate evolution while by implication validating
creationism as true science.

>If the
>classical story were true it would not threaten creationism anyway, since
>it only involves changes within a species.

Which is evolution by definition. If Wells does not even acknowledge this,
how can we trust that anything he says about the peppered moth is truely

>What the peppered myth DOES do, in my opinion, is to demonstrate how a
>commitment to Darwinism can seduce otherwise good scientists into ignoring
>or even misrepresenting the evidence.

It is Wells who appears to be ignoring or misrepresenting the evidence,
based on his ignorance of experiments that verified Kettlewell's results, as
well as his misrepresentation of both those results and Kettlewell's
experimental technique. Not to mention his self-appointment as a more
qualified expert than Majerus. And as with all creationists, he offers no
evidence to support his claims, just paranoid suspicions and inuendo.

Kevin L. O'Brien