Thanks for your considerate reply. It was exactly the kind of
response I was hoping for. My post was not intended to be an
endorsement of Wells but rather it was kind of a knee jerk
reaction against the approach to debate that seems to be favored
by some. Wells made some specific allegations that can be dealt
with specifically. Instead, some seem to want to take the track
that Wells has no right to raise these objections since his
robes are not long enough and his hood is of the wrong color.
This I find enormously irritating and contrary to the spirit of
science. This is not directed at you. Unfortunately, do to lack
of time (as opposed to lack of interest) I was only able to
skim your posts. Perhaps the points you make below were already
made previously, in which case I apologize.
At 02:25 AM 4/18/99 -0700, Don wrote:
[...]
>
>Brian,
>
>There seems to be some confusion here. Jonathan Wells was not describing
>illustrations in scientific works (as far as I remember), which is what you
>appear to mean by "experimentalists" describing the conditions of
>experiments. The illustrations at issue are in textbooks, presumably such as
>those used in high school biology classes. These illustrations are usually
>used simply to show cryptic coloration vs contrast against two types of
>backgrounds. The authors of the textbooks cannot be assumed to be experts on
>peppered moths.
>
This occurred to me some time after I made my response. I remember
some time ago when all this first came up being interested in
knowing what all the fuss was about. I only own one textbook in
evolutionary biology (Evolutionary Biology, by Douglas Futuyma).
Looking in this book I found that the peppered moth was hardly
even mentioned. Only one full (but relatively short) paragraph
and one transition sentence in the following paragraph. There
are no photographs and Kettlewell merits only half of a sentence:
"...Kettlewell (1955) has shown that the forms differ greatly
in susceptibility to predation by birds." --Futuyma
Futuyma goes on to say:
"The black form has not become fixed in most localities, however,
and it is clear that its frequency is affected by other factors
than predation alone; for example, viability differs among the
genotypes even in the absence of predation (Lees 1981)." --Futuyma
This seems to me a very poor endorsement for what Wells
referred to as the "peppered myth":
#"I have used the term "peppered myth" to refer to the textbook story that
#cryptic coloration and selective predation are known to be the causes of
#industrial melanism because birds eat peppered moths off tree trunks. In
#light of the evidence, the peppered myth and its staged photographs should
#be abandoned, because they misrepresent the truth." --Wells
So, if Futuyma doesn't endorse the "peppered myth", who does?
Also, if this is really a critical case to evolution in general
and Darwinism in particular, then why does it merit only about
one third of a page in a 600 page text book?
My suspicion is (unconfirmed) that someone thought this was a
great example for high school texts because the mechanism is
so easily understood. Most likely, as you say, "The authors of
the textbooks cannot be assumed to be experts on peppered moths"
and so perhaps some inaccuracies appeared due to authors attempts
to present a simple example which turns out perhaps not to
be so simple.
One thing I've tried to do in the past few years is to see if
some particular controversial event or practice in evolutionary
biology or teaching of same also occurs in other fields. This is
in an attempt to ward off suspicions that certain things happen in
evolutionary biology because of metaphysical prejudices etc.
This particular incident reminded me of something I read in
Richard Feynman's biography. It seems that he had volunteered to
review physics textbooks for local schools and immediately became
enormously frustrated by the task. For one thing, it appeared to
him that he was probably the only reviewer who actually read the
books :). More to the point, he found really significant and
fundamental mistakes in these books. I would be inclined to
think, then, that if such is possible in elementary physics,
surely biology would not be immune.
>1) Unless the background of some statistically more likely part of the tree
>on which the moths rest differs significantly from the trunk (which Wells
>never claimed), what is the point in all this? Comparison with the
>background is what is being illustrated.
>
>2) Entomologist friends of mine who I have asked all agreed that they have
>always assumed most of these photos were staged. The photos are for
>illustrative purposes, not as scientific records. They are frauds if it is
>claimed that the were taken naturally and weren't.
>
>2) Michael Majerus stated in his message to me that he tells his students
>that many photos are staged. Also, that those in his book are all natural.
>
>3) Another peppered moth specialist I corresponded with (he does not wish to
>be brought into this discussion at this time) wrote to me (and cited, with
>quotes) that all his papers since the late '80's, and books he has
>contributed photos for, stated that the moths were staged (actually, he said
>"posed") to demonstrate cryptic coloration.
>
>4) The famous photos from Kettlewell's 1956 paper, reproduced in some
>textbooks, are associated clearly in the original with text discussing the
>fact that the specimens were released onto trees for experimental purposes
>dealing with cryptic coloration. The issue of whether this was the
>statistically "normal" position (which came up in the 1980's) was already
>discussed in Kettlewell's 1955 paper, as I pointed out previously.
Thanks for the above. I really had no reason to doubt that the
scientists in question were good experimentalists. Due to the
difficulty of their subject matter I imagine that they are much
better experimentalists than I'll ever be :). Thus, I'm not
surprised at all really that these things were clearly pointed
out in their research papers. That it could be otherwise was
really unthinkable to me. What I wanted to see was a clear
presentation of these facts since that is the best answer to
Jonathan's "complaints". It occurred to me later that perhaps
you had already done this in previous posts that I may have
missed due to skimming. If so, I apologize for that.
Don:===
>How much
>of Kettlewell's description should carry over into school textbooks depends
>on just how confused you think students are going to get in understanding
>that light-colored moths are harder to see than black ones on a light
>background, and the reverse is true on dark-colored backgrounds.
>
What occurred to me originally was that a photograph of a moth
sitting on an exposed tree trunk will reinforce not only the
idea of increased visibility due to coloration but also increased
visibility due to being out in the open on an exposed tree trunk.
Perhaps I'm feeble minded, but being in an exposed position
seems to accentuate the importance of coloration and to accentuate
the hypothesis that such coloration affects bird predation. One gets
a ready minds eye picture of how easy it would be for a bird to
swoop in and nail that sitting duck :).
Don:==
>Both peppered moth specialists with whom I have corresponded have told me
>that Wells unjustified in his claims (actually, they were more explicit).
>That being the case, Wells claims of fraud, lying and scandal seem a trifle
>harsh. A more civilized approach would be to contact the American Biology
>Teachers Association, explain the situation, ask them to evaluate the
>problem with experts, and allow them to determine if future editions of
>textbooks need to change the illustrations captions or text to make the
>situation clear. I don't think any students are going to die in the mean
>time.
This is a great recommendation. If creationists want to follow
this up then I recommend deleting all rhetoric and insinuations
of fraud.
Brian Harper
Associate Professor
Applied Mechanics
The Ohio State University
"All kinds of private metaphysics and theology have
grown like weeds in the garden of thermodynamics"
-- E. H. Hiebert