[Taxacom] Cyanoprokaryota help

[Richard Zander]

My apologies, Dan, but my response was directed at your asseveration
that:

 

"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."

 

My remarks were directed at the phrase "general convention of naming
exclusively monophyletic entities." Since avoiding naming nodes is also
part of this convention, neither molecular or morphological
phylogenetics can determine monophyly. This is true for species
relationships or deep lineages. Instead one must infer process from
cladistic diagrams, not classification directly.

 

Richard

 

A correction: Confusius said: "Those who wield the Numchucks of Truth in
haste may hit themselves in the kidney." I really meant "ancestral to
TWO or more derived..." not "ancestral to one or more derived..."  

 

____________________________
Richard H. Zander
Missouri Botanical Garden, PO Box 299, St. Louis, MO 63166-0299 USA  
Web sites: http://www.mobot.org/plantscience/resbot/
<http://www.mobot.org/plantscience/resbot/>  and
http://www.mobot.org/plantscience/bfna/bfnamenu.htm
<http://www.mobot.org/plantscience/bfna/bfnamenu.htm> 
Modern Evolutionary Systematics Web site:
http://www.mobot.org/plantscience/resbot/21EvSy.htm
<http://www.mobot.org/plantscience/resbot/21EvSy.htm> 
UPS and FedExpr -  MBG, 4344 Shaw Blvd, St. Louis 63110 USA

________________________________

From: daniel.lahr at gmail.com [mailto:daniel.lahr at gmail.com] On Behalf Of
Dan Lahr
Sent: Wednesday, March 20, 2013 6:47 AM
To: Richard Zander
Cc: taxacom at mailman.nhm.ku.edu
Subject: Re: [Taxacom] Cyanoprokaryota help

 

My apologies Richard, but I do not see how your commentary relates to
this thread.  I mean this comment literally, as in, you will have to
explain it a bit further.

We never discussed molecular vs morphological, I do not understand how
that is relevant here. We are also not discussing species relationships,
but deep lineages.  Additionally, I do not see a connection between your
interpretations of ancestor-descendant relationship scenarios and
phylogenetic resolution. In my view, both cases you have pointed out
only indicate error in the initial naming, ie, if a genus nests within
another, this means renaming is necessary.  This does not indicate a
general flaw with the reconstruction method.

Dan

 

On Mon, Mar 18, 2013 at 7:39 PM, Richard Zander
<Richard.Zander at mobot.org> wrote:



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
http://www.mobot.org/plantscience/bfna/bfnamenu.htm
Modern Evolutionary Systematics Web site:
http://www.mobot.org/plantscience/resbot/21EvSy.htm
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.

Dan



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-- 
___________________
Daniel J. G. Lahr, PhD

Assist. Prof., Dept of Zoology, 

Univ. of Sao Paulo, Brazil

+ 55 (11) 3091 0948 <tel:%2B%2055%20%2811%29%203091%200948>