>The issue is not whether the use of drawings, per se, or the simplification
>of them is legitimate. The issue is whether they are accurate. Wells shows
>by use of simplified drawings that Haeckel's simplified drawings are
>inaccurate, and that the biological community has known this for a long time
>and done nothing in concert to correct the situation. Wells goes further and
>claims that not only are the drawings inaccurate, but that they are
>deliberate misrepresentations of the facts.
The historical situation is much more complicated than this. Please read
the research article by Michael K. Richardson and others ("There is no
highly conserved embryonic stage in the vertebrates: Implications for
current theories of evolution and development" in Anatomy and Embryology
(1997), vol. 196, p.91-106). Wells' discussion is really just a review of
Richardson's work.
Haeckel's drawing have gbeen questioned almost from the beginning but no
definitive demonstration of fraud (at least widely known) was provided
until relatively recently. the reason is that comparative embryology fell
out of favor with the biological community and very little original work
had been done. This is particularly true of animal groups not commonly
used as laboratory subjects. Richardson, specifically focused on the
vertebrate groups that Haeckel used.
The theory of recapitulation which Haeckel proposed was rejected early on.
I was introduced to Haeckle in school only as an historical interest and to
point out that recapitulation had been rejected.
Furthermore, Richardson strongly rejects the way his work has been
represented by Wells. So anyone who wishes to argue this issue needs to
read Richardson's paper.
In a letter to the editor of the journal Science (1998, vol. 280,
p.983-985), Richardson and his coauthors write: "Our work has been used in
a nationally televised debate to attack evolutionary theory, and to suggest
that evolution cannot explain embryology. We strongly disagree with this
viewpoint. Data from embryology are fully consistent with Darwinian
evolution. ... It also fits with overwhelming recent evidence that
development in different animals is controlled by common genetic
mechanisms."
The letter concludes with: "Haeckel's inaccuracies damage his credibility,
but they do not invalidate the mass of published evidence for Darwinian
evolution. Ironically, had Haeckel drawn the embryos accurately, his first
two valid points in favor of evolution [increasing differences between
species as they develop, and strong similarities between early human
embryos and those of other eutherian mammals] would have been better
demonstrated."
>Moreover, he then goes on to present the best current thinking on the problem
>of similarity/dissimilarity of embryos by presenting the developmental
>hour-glass model. He wrote, "Vertebrate embryos start out looking very
>different, then superficially converge midway through development at the
>'pharyngula' or 'phylotypic' stage, before diverging into the adult form."
I find this staement incredible. Haeckel's diagrams have been used
recently for the very purpose of supporting the "hour-glass" model and the
phylotypic stage. Richardson's paper was written to falsify that model!
In other words the rejection of Haeckle's drawings is tied to the rejection
of the phylotypic stage. This is even in the title of Richardson's paper:
"There is no highly conserved embryonic stage in the vertebrates." That
conserved embryonic stage is the phylotypic stage!
>The case of the peppered moths is a similar one. To show them resting on the
>trunks of trees, as they are pictured, is to misrepresent the facts. It has
>been known since 1980 that peppered moths do not normally rest on tree
>trunks. No one really knows yet where the moths rest on trees. Moreover the
>cause of melanism is still in dispute.
Again, Wells' critique of the work on evolutionary change in the peppered
moth was not his own but substantially drawn from the work of Michael
Majerus (Melanism: Evolution in Action" by Michael E.N. Majerus: Oxford
University Press,1998). Please read this book!
Wells quotes the following sentence from Majerus' book: "The findings of
these scientists show that the precised description of the basic peppered
moth story is wrong, inaccurate, or incomplete, with respect to most of the
story's component parts."
However, the next sentence reads: "When details of the genetics, behaviour,
and ecology of this moth are taken into account, the resulting story is one
of greater complexity, and in many ways greater interest, than the simple
story that is usually related."
Furthermore, a couple sentences later Majerus states: "First, it is
important to emphasize that, in my view, the huge wealth of additional data
obtained since Kettlewell's initial predation papers (Kettlewell 1955a,
1956), does not undermine the basic qualitative deductions from that work.
Differential bird predation of the typica and carbonaria forms, in
habitats affected by industrial pollution to different degrees, is the
primary influence on the evolution of melanism in the peppered moth."
This issue of posed pictures is of no consequence. The pictures are
clearly posed. I recognized this as a high school student - How else could
you get a picture of two different morphs together on the same background?
The moths do indeed rest on tree trunks, just not commonly. They seem to
prefer the undersides of branches and the branch/trunk joints. However,
the total number of resting moths observed in non-experimental settings is
very small. Interestingly, observations of the growth of lichens show that
the undersides of branches and the branch/trunk joints are the favored
locations for initial lichen growth. This would reinforce the Kettlewell's
conclusion that the light morph gained additional criptic advantage against
a lichen covered background.
The book by Majerus covers all tyoes of melanism in a wide range of species
and demonstrates that is a widely occurring phenomona with several
different causes. Melanism, and the peppered moth case study in
particular, is an excellent subject for teaching both how natural selection
works and how science works. Wells does a great disservice by implying
otherwise.
Keith
Keith B. Miller
Department of Geology
Kansas State University
Manhattan, KS 66506
kbmill@ksu.edu
http://www-personal.ksu.edu/~kbmill/
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