[Taxacom] Defining polyphyly

[Stephen Thorpe]

>and its apophyletic (or autophyletic) evolutionary dongle

What is a dongle??
http://www.wisegeek.com/what-is-a-dongle.htm

Stephen :)



________________________________
From: Richard Zander <Richard.Zander at mobot.org>
To: Curtis Clark <lists at curtisclark.org>; taxacom at mailman.nhm.ku.edu
Sent: Thu, 16 December, 2010 7:47:02 AM
Subject: Re: [Taxacom] Defining polyphyly

At the risk of hammering away at this, a paraphyletic group and its apophyletic 
(or autophyletic) evolutionary dongle are specified by synapomorphies on a 
cladogram. Taxa, on the other hand, are specified by diagnoses or descriptions, 
where the autapomorphies are important in evolution. Phylogeneticists do 
"tree-thinking" which to them means sister-group thinking and evolution of 
traits.

Thus, phylogeneticists specify only similarities, but evolutionary systematists 
use both similarities and differences. Both sister-groups and 
ancestor-descendant relationships are important, but even more important is the 
fact that taxa are what evolve, not relationships in a pattern.

 
* * * * * * * * * * * * 
Richard H. Zander 
Missouri Botanical Garden, PO Box 299, St. Louis, MO 63166-0299 USA 
Web sites: http://www.mobot.org/plantscience/resbot/ and 
http://www.mobot.org/plantscience/bfna/bfnamenu.htm
Modern Evolutionary Systematics Web site: 
http://www.mobot.org/plantscience/resbot/21EvSy.htm



-----Original Message-----
From: taxacom-bounces at mailman.nhm.ku.edu 
[mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Curtis Clark
Sent: Wednesday, December 15, 2010 8:38 AM
To: taxacom at mailman.nhm.ku.edu
Subject: Re: [Taxacom] Defining polyphyly

On 12/15/2010 5:09 AM, John Grehan wrote:
> There's the hinge of it all - whether paraphyletic groups are any more 
>'natural' than those that are polyphyletic.
A paraphyletic group can be specified by synapomorphies (a set for the 
stem group and other sets for the exgroups), so it is as "natural" as a 
monophyletic group. The question is rather, is it useful. And that's 
where the disagreement seems to center.

-- 
Curtis Clark                  http://www.csupomona.edu/~jcclark/
Director, I&IT Web Development                  +1 909 979 6371
University Web Coordinator, Cal Poly Pomona


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