Re: Limits of Kinds - now its crabs

Arthur V. Chadwick (
Mon, 17 Nov 1997 23:14:00 -0800

At 10:33 PM 11/17/97 -0600, Glenn wrote:
>I have a question then, how can a slow rate of change disprove evolution?
>Where is it written that evolution must proceed at 50 darwins per
>year/millennia/million year and if it drops below this rate, it is not
>evolution? I can't understand how a slow rate of change disproves evolution
>which is why these living fossils are advanced by creationists. It would
>be like saying that a slow moving creek disproves the theory that creeks
>flow to the sea. And I might add, that when I was a YEC I was under the
>impression that these living fossils were the same species. Maybe I was
>dumb, but I think most lay people think the same thing. Remember that I
>started out with a layman's knowledge of biology and geology and got my info
>from ICR.

I would ask how can the rates of amino acied change in proteins (or
ucleotide bases in DNA) be used as biological clocks? If these are
indications of the passage of time then stasis is an argument against time.

>But once again, there is considerable morphological change. Look at the
>difference in the position of the legs of Paleolimulus on page 563 compared
>to the legg orientation on p. 562. The legs stick out from something (I
>don't know the anatomical name) in Paleolimulus, that something is missing
>in Limulus and the legs point backwards. Limulus, the modern crab has six
>legs I count 5 on Paleolimulus (assuming the anterior thing is a leg it is
>unclear to me) Looking at the pictures one can easily see the differences
>between the Permian Paleolimulus,the Silurian Neolimulus, the pennsylvanian
>Euproops, and the devonian Koenigiella. When I think of things being similar
>I think of things that make me have to study them to differentiate them.
>Twins have a remarkable similarity; my brother and I were easily
>distinguishable from a glance
>Using what I can determine of your criteria of morphological change, one
>would have to remark that modern fish are remarkably unchanged from Devonian
>fish. Yet their isn't an ichthyologist who can't tell them apart
>instantly. The same must be said of trees which would have to be remarkably
>unchanged also.

These are still minor changes, possible controlled by change to a single
homeotic gene. They are equivalent to the differences among the 600 or so
species of Drosophila endemic to the Hawaiian Islands.