biogeographic maps

John Grehan jrg13 at PSU.EDU
Mon Sep 20 22:49:22 CDT 1999

In an earlier posting I referred to "biogeographic maps" and received
an inquiry about what I meant by this term. I was using biogeographic
map to refer to any map that contained explicit biogeographic information
concerning the homology or other spatial significance of the distribution.
Thus a distribution map contains nothing but the distribution itself.
Examples of biogeographic maps may include dispersal routes, tracks,
or cladograms (and here I am referring only to cladograms maped onto
maps!). Thus, biogeographic maps are like biological classifications, they
are summaries of knowledge about the pattern.

Having thought more about Ridley's book there is one map - that of
dispersal among the Hawaiian chain - that would qualify as a biogeographic
map. And of course, the map of Wallace's regions is a biogeographic map
as well (although Ridley decided not to let his readership know that there
exists a fundamentally different concept of biogeographic homology and
classification to that of Wallace).

The general reluctance, disinterest, or whatever that evolutionary biologists
have about geography (by that I mean geography as an informative character
and object of direct analysis) is, to me at least, one of the most intruiguing
aspects of modern evolutionary biology. I wonder if it is a matter of
training, or
genetics (does the nature of evolutionary biology select people who are
not spatially attuned?) or something else? Ironically at the ecological
interface (and even some genetic studies) there is a great deal of interest
in spatial structure (mapping, gap analysis etc.) but this does not seem to
translate when it comes to general evolutionary theory.

Well, I admit to generalization, so expect to get shot down on some points
(should anyone be bothered).

John Grehan

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