Farewell to Species - eclectic classification

[Pierre Deleporte]

Comment to Ken Kinman and Don Colless (texts below)

Don Colless suggests to provide cladograms with non-strictly phylogenetic
classifications containing names for paraphyletic groups.
The Kinman System does just that, simply the phylogeny is not given under
the form of a graph, but by a system of codes, and warnings are introduced
to label paraphyletic groups. You can change the codes (or the graphs)
without changing the names.

The lasting debate concerns the meaning (information content) of names used
in classifications. Names cannot by themselves give at the same time a
complete phylogenetic AND gradistic information (i.e. apomorphy-based AND
plesiomorphy-based groups).

As far as I understand them, the solutions proposed by Colless and Kinman
consist in providing TWO linked classificatory systems.
Perhaps for reasons of preserving some stability of the terminology, in
both cases the suggestion is to keep names for paraphyletic groups, and
provide graphs of codes for the phylogeny. But under the same logic, the
reverse could be suggested: use names for monophyletic groups, and give
codes (or other, clearly differenciated names, e.g. the vernacular
"reptiles") for grades.

Contra Colless, I think that the UTILITY of a classification is an
important issue, as well as the communicability of its information content.
Hence the need for logical coherence of a classificatory system.
Both Kinman and Colless turn the difficulty by providing in fact two
systems, one for the phylogeny, another for grades, and they give the
correspondence between the two systems (codes for the names, or graphs for
the names).

Pierre Deleporte


>Date:         Mon, 1 Feb 0100 16:46:33 +1100
>Sender: Taxacom Discussion List <TAXACOM at USOBI.ORG>
>From: Don Colless <donc at SPIDER.ENTO.CSIRO.AU>
>Subject:      Farewell to species (but not yet!)
>The only thing that's "broke" in 
>the Linnean system - and that might need "fixing" - is that a
>classification MAY not be 100% isomorphic with a cladogram; and
>therefore (horror of horrors) might lead to misleading inferences
>in, say, biogeography. But if the cladogram is available,the
>biogeographer can use THAT more easily than any classification.
>And the rest of us wouldn't be plagued with problems of UTILITY
>of a classification.
>


>Date:         Mon, 31 Jan 2000 21:12:53 PST
>Reply-To: Ken Kinman <kinman at HOTMAIL.COM>
>Sender: Taxacom Discussion List <TAXACOM at USOBI.ORG>
>From: Ken Kinman <kinman at HOTMAIL.COM>
>Subject:      Re: Farewell to Species
>
>>Hugh wrote:
>>My conclusion is that (traditional) nomenclature and
>>phylogenetic systematics are two different things, each with its own
>>purpose, and almost by definition not compatible. If they were to be made
>>such, useful properties of at least one of the systems would be lost.
>>******************************************************
>     It is precisely the above, almost universal, continuing
>"misconception" that I am trying to correct.  The Kinman System: Toward A
>Stable Cladisto-Eclectic Classification of Organisms (Kinman, 1994) combines
>both: (1) the greater predictive ability of cladistic systems; and (2) the
>practicality, relative stability, and anagenetic (evolutionary-distance)
>information of traditional eclectic systems of classification.
>      Therefore David Hull (1979:437) no longer needs to bemoan that "no
>methods have been set out thus far which permit the inclusion of both sorts
>of information [genealogy and divergence] in a single classification in such
>a way that both are retrievable."  Such methods have been proposed, if
>people would just take notice.
>





Pierre Deleporte
CNRS UMR 6552 - Station Biologique de Paimpont
F-35380 Paimpont   FRANCE
Téléphone : 02 99 61 81 66
Télécopie : 02 99 61 81 88