Biogeography and geological evidence etc.

john Grehan jgrehan at SCIENCEBUFF.ORG
Wed Feb 5 11:48:21 CST 2003

Fred wrote:

>* I wonder, without evaluating the merits of any particular approach or
>example, if one cause of misunderstanding between pan- and nonpan-
>biogeographers isn't what one might call the different levels off
>synthesis. Pans want to construct purely distributional scenerios, in
>order to to be able to say what's purely biogeographic, and test these
>for agreement with the rest of earth history at the level of
>agreement/disagreement between scenerios based on data from different
>fields, while nonpans don't care so much if their biogeographic
>scenerios contain non-distributional (e.g. geological) elements, and
>test these directly against individual 'facts' of various kinds.

I would agree that there are some differences in approach that are perhaps
less a matter of confusion as they are not acceptable to
non-panbiogeographers. I agree with the comment that Pans want to construct
purely distributional scenarios as that is what makes the method
independent as a source of biogeographic reconstruction. However, the
'testing' part is not so much with agreement/disagreement since
disagreement represents a research anomaly rather than an automatic
refutation of one or other model (biogeographic vs geologic). That is why
novel geological predictions become interesting in that theory may precede
empirical knowledge for another discipline.

When Croizat predicted the existence of a major tectonic feature at the
Galapagos this was not an empirical finding for geology at that time. The
fact that this prediction has since been corroborated is interesting (at
least I think so) in that the biogeographic model (of land connections
between the Galapagos and the Americas etc) may be unacceptable to
Darwinian biogeographers, yet the model worked in predicting future
geological findings.

>Individual temperment, as well as availablitiy of data, may infuence
>which approach is more productive in particular situations, and each has
>its particular perils (as in any formal vs eclectic choice of method),
>but maybe neither is necessarily more appropriate or 'scientific...'

In panbiogeography one may point to successfully corroborated geological
predictions as one way of measuring productivity. Some may find this
success a measure of the scientific quality of panbiogeography in a
positive context in contrast to competing research programs that failed to
make such predictions (e.g. Darwinian biogeography) while to others this
panbiogeographic success is simply not worth of attention.


John Grehan
Director of Science and Collections
Buffalo Museum of Science
1020 Humboldt Parkway
Buffalo, New York 14211-1293
Voice 716-896-5200 x372
Fax 716-897-6723
jgrehan at

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