FW: Islands, Science and Creationism

Curtis Clark jcclark at CSUPOMONA.EDU
Mon Apr 15 19:08:19 CDT 2002


At 08:42 2002-04-15, Bill Shear wrote:
>Now I'm confused.  The present-day Galapagos cannot be demonstrated to have
>had any land connection with previous archipelagos, and always has been
>separated from the South American continent or any other land mass by water.
>What possible other means of dispersal than "overwater" could account for
>the terrestrial biota found there?

(I'm not defending panbiogeography here, as vicariance biogeography and in
fact any scientific biogeography should work the same...) Let's say that
there is solid biological evidence that certain members of an island biota
are unlikely to have dispersed there; that in fact they all show a similar
*pattern* of occurrence, independent of their common lack of vagility. But
geologists say that the islands were never connected to the mainland.

A subservient biogeography would discard the biological evidence. After
all, the geologists must know what they are doing. They certainly knew what
they were doing when they claimed that the continents were immovable, and
we built an entire biogeography around that, so why should we switch now?

But a biogeography that is a science in its own right will take the
evidence to its logical conclusion. So what if that contradicts geology?
One or the other is likely to be wrong, and we deal with that by *looking
for additional evidence*.

Just as organisms in their beings carry traces of their entire evolutionary
history, in their locations they carry traces of their entire geographic
history. And just as preconceptions of homology have led us astray, so can
preconceptions of geographic history give us the wrong answers.




--
Curtis Clark                  http://www.csupomona.edu/~jcclark/
Biological Sciences Department             Voice: (909) 869-4062
California State Polytechnic University      FAX: (909) 869-4078
Pomona CA 91768-4032  USA                  jcclark at csupomona.edu




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