[Taxacom] Cyanoprokaryota help

Richard Zander Richard.Zander at mobot.org
Mon Mar 18 17:39:54 CDT 2013

Not objective? The fundamental phylogenetic presupposition that of any
three species two are more closely related fails totally in two cases:

1) paraphyly, including nesting of genera among species of other genera.

2) when any one generalist, wide-ranging extant species can be easily
hypothesized as ancestral to one or more derived, highly specialized,
and possibly evolutionarily dead-end descendant species.

Both cases are common. Ergo phylogenetic resolution of branch order is
commonly random in both morphological and molecular analyses. This is
not even subjective much less objective.

Richard H. Zander
Missouri Botanical Garden, PO Box 299, St. Louis, MO 63166-0299 USA  
Web sites: http://www.mobot.org/plantscience/resbot/ and
Modern Evolutionary Systematics Web site:
UPS and FedExpr -  MBG, 4344 Shaw Blvd, St. Louis 63110 USA

-----Original Message-----
From: taxacom-bounces at mailman.nhm.ku.edu
[mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Dan Lahr
Sent: Monday, March 18, 2013 4:22 PM
To: Ken Kinman
Cc: taxacom at mailman.nhm.ku.edu
Subject: Re: [Taxacom] Cyanoprokaryota help

Hi Ken,

I am familiar with your views on strictly monophyletic classifications.
I personally find the discussion constructive for science.  However, I
have not been convinced that allowing paraphyletic classifications is a
good solution, but this is not the place to go into the gritty details.
Therefore, I stick to the general convention of naming exclusively
monophyletic entities.

Dividing life into Prokaryota and Eukaryota is unsatisfactory, because
these are grades and do not lead to any objectivity, and do not reflect
things we know about the true nature of the critters.

There may surely be a possibility that the root of life is within
bacteria, which would make eukaryotes and archaea simply branches on the
bacterial tree.  If so, then a lot of bacterial groups would need to be
renamed, because our understanding of the true diversity will remain
restrictive and flawed if we do not change the names.

The system allows relabeling when relabeling is needed.  The Woesian
revolution has shown that relabeling was needed, and relabeling ensued.


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