Ah Illumination... so that's where he pulls it from! Irony is that we now
have the evolutionary sequence of whales and it took only about 10-15
million years that Stanley calls "preposterous". I suspect that bats evolved
even quicker, along with pterosaurs - the other "eye-blink"
evolution-of-flight example. Of course all such "instantaneous" lineages
show evolution towards their modern forms and retention of ancient
characters in their oldest forms - the first bat is still mostly a primitive
insectivore.
On a side note bats do kind of recapitulate some of what their ancestors
faced - young bats fly with less than adult wing proportions and less than
adult ability. Many don't survive - often walking back to their roosts in
exhaustion and falling prey to predators. A strong selective pressure exists
even in modern bats.
There's a lot we don't know but no reason to think there isn't more to
know...
Adam
>From: "Arthur V. Chadwick" <chadwicka@swau.edu>
>To: asa@calvin.edu
>Subject: Re: re-whales from rodents
>Date: Mon, 23 Aug 1999 08:24:10 -0700
>
>Is Johnson a bad evolutionary biologist?
>
>Johnson says "Nobody is proposing that an ancestral rodent (or whatever)
>became a whale or a bat in a single episode of speciation...." Please.
>Johnson is a lawyer! Does he know the difference between a whale and a
>rodent? Do you really expect him to? I think the emphasis ought (and quite
>properly so) to be on the point he is attempting to make, and not on the
>specific details of the paleontology. Lets argue about the point he is
>making, and not about whether he did or did not grab the correct ancestor.
>That borders on ad hominem argumentation. Now if he were a vertebrate
>paleontologist, then we could (if we had the facts straight ourselves),
>take him to task if he had made a mistake.
>
>Where did Johnson get his impression? Perhaps from reading Steve Stanley:
>
>"Let us suppose that we wish, hypothetically, to form a bat or a whale...
>[by a]
> process of gradual transformation of established species. If an
>average
> chronospecies lasts nearly a million years, or even longer, and we
>have at
> our disposal only ten million years, then we have only ten or fifteen
> chronospecies to align, end to end, to form a continuous lineage
>connecting
> our primitive little mammal with a bat or a whale. This is clearly
> preposterous... A chain of ten or fifteen of these might move us from
>one
> small rodent like form to a slightly different one, perhaps
>representing a
> new genus, but not to a bat or a whale! "
>Art
>http://geology.swau.edu
>
>
______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com