Hi John
One of the best accounts of speciation that I have read recently is by:
Martin Collinson "Shifting sands" taxonomic changes in the world of field
ornithology"
British Birds 94: 2-27, January 2001.
Using simple language (that appeals to me) with some good diagrams, he
clearly sets
out the background to both BSC and PSC and shows how genetics can be very
helpful
but is not the complete answer.
It is well worth reading.
Peter
PS Laurie's contribution was unreadable on my system??
At 01:40 AM 12/07/2002 +0000, you wrote:
I think almost all birds regurgitate the indigestible parts of whatever
they have swallowed. I remember finding some tiny little pellets next to a
favourite Red-capped Robin perch.
On the subject of the Biological Species Concept, Mayr and Diamond's Birds
of Northern Melanesia is the latest formulation of this theory and goes
into great detail on all the ins and outs (Mayr was the principal author
of this theory, I believe). And yes the problem of two populations which
don't overlap (two allopatric populations) is the most serious difficulty
with the theory. How do you test whether they would breed together in the
wild if they met? (captive birds are often less choosy about breeding with
close relatives).
And does anybody know of a comprehensible definition of the PSC? We talk
loosely about the 'genetic distance' between populations, but how is this
defined?
John Leonard
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John Leonard (Dr)
http://users.bigpond.com/john.leonard
PO Box 243, Woden, ACT 2606, Australia
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