[Taxacom] panbiogeography critique

John Grehan jgrehan at sciencebuff.org
Sun Jun 28 10:18:24 CDT 2009

> bounces at mailman.nhm.ku.edu] On Behalf Of mivie at montana.edu
> Clearly should have stayed out of this discussion, it is not going to
> change anything by getting into  it, but sometimes I go over the edge.
> Spending your life in a wheelchair can make you grumpy, I am finding.
> a few corrections:

No worries. Anyone who participates on this list is probably "over the

> > Michael feels
> > that panbiogeography is ridiculous and teaches his students this,
> Again, not what I said. 

The quote is " I and many others still ridicule panbiogeography at every
opportunity -- I did it this morning with some students."

So I think Heads can be forgiven to interpreting "I did it this morning
with some students" to mean "that panbiogeography is ridiculous and
teaches his this". 

I do ridicule it, but mostly because of the
> bizarre practitioners, and never in an actual teaching environment.  

But see above.

In what way are the practioners "bizarre"?

It is
> hard to actually talk about Croizat's books with a straight face (have
> actually tried to read them?).  

Yes I have read them. Also read plenty of 'standard' books that are
sometimes no better or worse.

In the conversation I cited, I was having
> a discussion with grad students and am guilty as admitted of ridicule,
> not as stated above.

Clarification understood, but the inference was reasonable I think.

> Mainstream religion believes in talking snakes, but that does not make
> good science.

But in science publishers such as OUP seem to be pretty conservative and
citing other fields may not be germane. If the nature of the publisher
has no bearing on being mainstream, then the opinions by critics of the
method don't really add to much either. They are just opinions that may
or may not be correct. But some comments below.

Cracraft's "oversimplistic interpretation" claim my or may not be
correct. But if "oversimplistic" interpretations result in successful
geological predictions then so what?

> "Most applications of the panbiogeography
> method tend towards the narrative rather than the analytical"

This could be said of all dispersalist accounts (the analysis being the
phylogeny, the narrative being the dispersalist claims). This claim
about panbiogeography ignores the fact that the panbiogeographic method
is analytical.

> "...they strongly advocate using biogeographic distributions
> as evidence of phylogenetic relationships, but their examples have
> preconceived notions of relationships built into them."

Who knows what this might mean. The fact is that the use of
biogeographic relationships has generated phylogenetic predictions that
have been later corroborated through biological analysis.

> "The authors are strong supporters of the importance of systematics,
> but they are short on specific analytical procedures of how
biogeography might be used to infer relationships."

Hard to figure that one out.

> Serious problems inherent in the Panbiogeography method, which have
> documented in the literature ad nauseum.

No they have not. Just theoretical objections to a method that works.
That's the bottom line - the method does work. No one has demonstrated
that the standard tracks and nodes do not exist, that there are no ocean
basin correlations of global patterns of distribution, that there are no
centers of basal evolution, that there are no correlations between
distribution and tectonics, that Croizat was wrong about the tectonics
of the Galapagos or the Americas. One can theoretically debate any
method theoretically, but the bottom line is the result (in my opinion).

John Grehan

More information about the Taxacom mailing list