[Taxacom] Catalogue of Life (CoL) management classification draft document

Richard Zander Richard.Zander at mobot.org
Sat Jul 18 12:58:50 CDT 2009

Well, it's a little more complicated than that, Stephen. Read, for
example, Vern Grant's 2008 paper: Incongruence between cladistic and
taxonomic systems. Amer. J. Botany 90: 1263-1270. You may be able to get
it as a pdf (try Google scholar). 

Here are some mindbites:

There are two kind of monophyly, evolutionary and strict phylogenetic.
The former allows judgments of evolutionary process while the latter
emphasizes patterns.

Phylogenetics groups taxa by branching order as a series of sister
groups (following Hennig's Phylogenetic Method), while taxonomy groups
by both similarity and differences (following Darwin's Natural System).

Phylogenetic classification allows (ideally) no ancestor-descendant
relationships to be reflected in classification, while taxonomy allows
both ancestor-descendant and sister-group relationships (to the extent

Phylogenetics eliminates all traits that are not informative of
sister-group relationships, while taxonomy deals with all traits, even
unique traits informative only of macroevolution (ancestor-descendant
relationships involving evolutionary transitions between taxa).

Apparently dealing with ancestor-descendant relationships, that is,
speciation and generation of higher taxa, is (1) not possible with
sister-group analysis although inferences can be made, and (2) it is too
hard because it involves judgment. Phylogenetics is thus a crippled form
of taxonomy, focused on providing a quick fix and workaround for the
usual give and take of scientific thought. 

Creationism seeks to eliminate macroevolution from the classroom.
Phylogenetics tries to eliminate it from classification. The difference
in this respect between creationism and phylogenetics is that
creationism has failed.


-----Original Message-----
From: taxacom-bounces at mailman.nhm.ku.edu
[mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Stephen Thorpe
Sent: Saturday, July 18, 2009 1:16 AM
To: Tony.Rees at csiro.au
Cc: taxacom at mailman.nhm.ku.edu
Subject: Re: [Taxacom] Catalogue of Life (CoL) management classification
draft document

Dear Tony and other Taxacomers,

Biological classification is a mixture of scientific fact (i.e.,  
monophyly, or not) and subjective opinion (i.e., how big or small  
should a monophyletic group be without the need to split it). Both  
these factors taken together doesn't make life very easy, and it is  
all in perpetual flux, which also doesn't make it very easy. However,  
I don't think that the issue can be "managed" in quite the way that is  
envisaged by some. I have thought a great deal about this, for my  
Wikispecies work. My primary governing principle is that, subject to  
monophyly, classification is primarily a filing system to make  
information management easier. So, it doesn't really matter which  
classification is followed, PROVIDING that it is explicitly stated  
which one. The problem with adopting a particular classification for a  
large group (like the "Protista") is that advances in taxonomy happen  
on much smaller subgroups, so if you blindly follow one particular  
broad classification, then you cannot accommodate the advances very  
easily. Hence, I think you have to simply treat matters on a case by  
case basis, and just choose and specify a sensible classification for  
that particular case (and change it, if necessary, if something more  
convincing is published). To try to come up with a single "officially  
endorsed" classification would simply be to ignore the subjectivity  
and fallibility of taxonomy...

Stephen Thorpe
Honorary Research Associate
School of Biological Sciences
Tamaki Campus
University of Auckland
Private Bag 92019

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