Ridley's evolution book and panbiogeography

[John Grehan]

A while back there was a posting which, if I recall correctly, referred to
Ridley's evolution
book in support for panbiogeography not being left out of evolutionary
theory - or words to
that effect more or less (sorry my memory is not sufficient to recall the
detail). Ridley's
chapter on biogeography indicates otherwise. The chapter is full or
orthodox traditional
dispersal vs vicariance biogeography. Panbiogeography merits but a passing
comment that
Croizat established the reality of correlated distributions without
indicating the nature of
this correlation, and the only citation Ridley can suggest for all of
panbiogeography is the
discredited Croizat et al (1974) paper which was mostly a presentation of
Nelson's
vicariance biogeography.

Ridley has also bought into the vicariance biogeography
propaganda that vicariance biogeography has added to Croizat's ideas - we now
knbow more about continental drift (actually I don't see this as being
generated from
vicariance biogeography, but rather geology), and the importance of using a
"realistic
phylogeny" (which was never denied in panbiogeography anyway). Since
panbiogeography and vicariance biogeography (or so-called cladistic
biogeography)
represent fundamentally different concepts of biogeographic homology, the
claim that the latter is a development of the former is false.

Looking through the chapter one finds only three distribution maps (certainly no
biogeographic maps). The rest is claodgrams. Ridley's book is a good
demonstration
of the traditional abhorence of evolutionary biology for geography. It is this
denial of geography as an evolutionary character (reflected in the
subservience of geography to biological characters in Ridely's book) that
exemplifies traditional evolutionary
theory, and the demarkation by which panbiogeography may be recognized as a
distinct research program in evolutionary biology.


John Grehan