Biogeography and geological evidence etc.

P.Hovenkamp Hovenkamp at NHN.LEIDENUNIV.NL
Mon Feb 3 12:19:26 CST 2003


Dear all,

Time for my 2 cts worth:
Going through John Grehans posts, I come up with the following statements
(emphasis mine):

"
In the Galapagos paper I describe how Croizat predicted the tectonic
significance of the Galapagos from biogeographic patterns before the
tectonic structures of the seafloor was documented. It is this correlation
that may have more significance for understanding the origin of the
Galapagos biota than whether one believes in this or that geohistorical
theory for the area (and there are at least four major competing
geohistorical-tectonic theories for the region). The predicted correlation
actually <emphasis PH>allows the biogeographer the opportunity to suggest
which model or
models may be more representative of history than the other way around
</emphasis PH>.
"
next quote:
"
One might argue from a
stratigraphic point of view that Lord Howe Island is not old enough, or
been above water long enough. These are geological theories that may or may
not be true, and are contingent upon theories about the geological
formations of the immediate area. Thus one <emphasis PH>cannot presuppose
that these
theories are anything more than just that and the biogeographic picture
does not have to be made subordinate to those theories</emphasis PH>
"
Pondering these two quotations, it seems to me that Panbiogeography (if I
may take the utterances of John Grehan as statements of Panbiogeography) is
eager to have geology/tectonics informed by biogeography, but at the same
time prohibits biogeography to be informed by geology/tectonics. Now I can
understand the feelings that drive this position, but I can't see its
justification. If one allows the one to be informed by the other, one
assumes some sort of connection. Why then is it not allowed to use this
connection the other way?

Peter Hovenkamp




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