Hello Cliff,
I've read your web pages (fairly quickly). I found them well written, but I
didn't find your theory at all convincing.
The single biggest problem is that you describe evolution through merging of
organisms entirely at the level of the phenotype. But, at some point, the
structure of the composite organism must have have become encoded in the
genotype. Without some hypothesis for how this might have happened, there's
a gaping whole at the centre of your theory.
In the absence of such a hypothesis, why should I believe that this process
is any more plausible than the conventional view that additional segments
were created by mutations? You dismissed this view in the following terms:
"Those who strive to explain elaborative evolution sometimes claim that
number of segments in a train such as the vertebral column can be increased
simply by a mutation that inserts complete segments into the series. Richard
Dawkins suggests that such additions may be accomplished "easily", through
"a simple process of duplication" (Dawkins 1986). I argue that such a
mutation would be like parabiosis, but with the additional attached body
accidentally reduced to the form of one perfect segment and accidentally
positioned perfectly within a series of segments; this seems virtually
impossible."
You seem to be attacking a straw man here. Dawkins is not suggesting that
the DNA code for the whole body is duplicated and then reduced. He's
suggesting that the code for a single segment is duplicated. Indeed, even
this may not be necessary. It's probable (but I'm not sure) that the code is
not repeated for identical or near-identical segments, but that that such
segments are coded once, with some gene controlling the number of times that
the code is expressed. If that's the case, then only a mutation in the
control gene is required.
Such extension by duplication would have been all the easier in the simpler
organisms of the pre-Cambrian period, where you claim that all the new
skeletal segments evolved.
I must also say that I found your argument regarding the zebra's stripes
utterly unconvincing. Many different camouflage patterns can be found on
animals--stripes, spots and patches of many shapes and sizes. The fact that
a small number of animals have striped patterns bearing a crude (extremely
crude) resemblance to their skeletal structure strikes me as nothing more
than a coincidence.
I also notice you have a tendency to explain away any contrary evidence in
the fossil record by ad hoc propositions of unknown types of organism. For
example:
"I suggest that many-segmented ancestors of snakes did exist in the
Paleozoic Era but that we happen to lack fossil evidence of them, and that
the pattern of reduction in number of segments does generally hold in
vertebrate lineages after the formation of the protovertebrate. Snakes are
unlikely to be fossilized, as they are adapted to move in mud, which can
mire and entomb tetrapods or fishes."
I don't rule out parts of your theory as theoretical possibilities. But
given its highly speculative and vague nature, I see no reason to overthrow
the much more well-considered (and plausible IMO) conventional view. (And
that's before we even start on the evolution of organs, for which you don't
have even an outline of a scenario.)
Richard Wein (Tich)
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