From: "John Latter" <jorolat@...>
> "Segmentation and Vertebrate Origins" - very interesting stuff
> Cliff and
> from a number of perspectives!
> I've only read as far as the end of The Appendicular Skeleton so
> far - I
> wanted to read it all to gain an overview before making any
> comments...

It's all about one simple thing: simple multiplication of bodies
to form
trains of identical organisms living as one; and a subsequent slow
process
of loss and distortion within those trains. This gross morphology
theory is
an extrapolation from morphological data. If it's true it will
mutually
support theories about other aspects of organisms.

>...the evolution of snakes is a 'sideways step' in a similar
>manner to
> that of flatfish.

I have snakes evolving much earlier than presently thought, maybe
even in the Cambrian. This ancestor might have limbs (losing limbs
is
easy) but most importantly it would have a long axial skeleton, so
that snakes can evolve without the addition of new axial segments.
Snake can escape the mud which mires and entombs both fishes and
tetrapods, so I have no problem postulating unknown very early
snakes. An arboreal habitat is another point against
fossilization.

> from the
> perspective of an internal evolutionary mechanism, the
> cytochrome c info
> found in Dayhoff's Atlas of Protein Structure and Function is
> particularly relevant. Another way of putting it, is that snakes
> may be
> 'an exception that proves the rule' and consequently do not
> /initially/
> have to be 'accounted for' to any great degree.

I suspect that this info fits with a variety of theories. For me
the
internal constraint on the evolution of gross morphology is simply
that
skeletal evolution doesn't create new parts or segments; it can
only
modify a complex primitive structure through loss and distortion.
The formation of this progenitor was a one-time pre-Cambrian
event.

> On a more immediate and practical level I would like to put your
> site on
> my "Reciprocal Links" and "Evolinks" pages. It doesn't matter
> (from my
> point of view) that you haven't got a links page - if you want
> me to go
> ahead just send a couple of lines describing your site and I'll
> add it
> as soon as I can.

Thanks, any link is appreciated. I'll have to think about the
ring,
because I plan to do something different to promote the article.

Thanks for reading the thing.

Cliff