[Taxacom] Diagnosing species

[pierre deleporte]

I view Richard's statement below as a nice illustration, in terms of 
population biology, of the fact that phylogenetic / "strict cladistic" 
classification is all about time and speciation events, i.e. history, 
rather than character similarity properly
(more on this in different threads in the Taxacom archive: the "universally 
shared property" of any clade-as-a-class would be simply be the historical 
property of "exclusive common descent", rather than characters properly;
corrolary: historical classification is certainly pretty good for... 
historical investigations ;-)

  just stirring a little bit...

Pierre


>From: "Richard Pyle" <deepreef at bishopmuseum.org>
>To: <taxacom at mailman.nhm.ku.edu>
>Date: Tue, 26 Jun 2007 17:35:43 -1000
>Hmmm....not sure I understand your use of "younger" in this context.  If
>subpobulation "A" fractions off of major population "B", then they are
>equally removed from each other in terms of time.  The fractional population
>may be more apt to fix mutations due to lower genetic "inertia", but this
>isn't a function of "age" ("younger"); it's a function of population size.
>The genomes of the individual organisms in the fractioned population are
>exactly as old as the genomes in the original population -- and, indeed,
>exactly as old as essentially all life on Earth -- about 3-4 billion years,
>give or take.


Pierre Deleporte
CNRS UMR 6552 - Station Biologique de Paimpont
F-35380 Paimpont   FRANCE
Téléphone : 02 99 61 81 63
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