FW: Islands, Science and Creationism

Richard Jensen rjensen at SAINTMARYS.EDU
Tue Apr 16 12:40:53 CDT 2002


Curtis Clark wrote:

> At 11:22 AM 4/16/2002, Richard Jensen wrote:
> >I agree with the first part of this statement, but can't buy in to the second
> >part (i.e.,
> >an organism's current location carries traces of its entire geographic
> >history).
> >Knowing that species X is endemic to cedar glades in middle Tennessee tells us
> >nothing about it geographic history.
>
> The fact that species X also has feature 3 tells us nothing about its
> evolutionary history. In both cases, we need context--comparison with the
> distribution of character states in other taxa, the distribution of taxa in
> other areas. And I would venture (though John might disagree) that neither
> phylogeny nor biogeography is satisfactory in the absence of the other. (As
> a phylogeneticist, I am persuaded that phylogeny is more important to
> biogeography that the reverse.)

I disagree.  Knowing that a plant has vascular tissue (feature 3 in the specimen I
am examining) provides evidence of relationship to other plants also having
vascular tissue - that's a trace of its evolutionary history.  However, knowing
that it occurs in central China says nothing about its biogeographic history; all
we know is that it occurs in central China and no explanation of how it got there
or where it came from, can be inferred from that fact.

Of course, in the broader sense, you are right: context is everything (but context
was not part of your earlier comment).

Dick

--
Richard J. Jensen              TEL: 219-284-4674
Department of Biology      FAX: 219-284-4716
Saint Mary's College         E-mail: rjensen at saintmarys.edu
Notre Dame, IN  46556     http://www.saintmarys.edu/~rjensen




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