Species as "Hypotheses"

Gurcharan Singh chani at SIFY.COM
Thu Jul 15 16:28:25 CDT 2004


On July 15, 2004 Guy redeuilh  wrote:
>Systematists has been using "taxon" for decades and when cladistics came to
the fore cladists followed this usage. The only >difference appears to be
that any cladistically acceptable taxon should be a clade.
>The draft-PhyloCode has no reason to use the word "taxon": the only taxon
>that can get a name under the PhyloCode is a clade (Art 1.1).

Guy Redeuill,  I understand has provided a appropriate assessment to
conclude discussion on the use of term "taxon" which has been used by
systematists for a very long time when refering to a group of organisms
(Taxonomic group), and  not wanting to talk about the rank (although we know
the rank from the name if used)  . The term "clade" is more appropriate in
phylogenetic discussion especially when monophyletic groups are recognized.
PhyloCode is still not sure about any rank above the species, and all such
groups are merely "clades", whereas the APG classification does recognize
species, genus, family and order , but not any formal higher ranks.
Introduction of term taxon in PhyloCode would be futile unless we are
satisfied  that ranks conforming to Linnaean hierarchy are essential for
meaningful usage of an appropriate classification, especially when we are
attempting to have a uniform Phylogenetic code for all living organisms.
Larger the database of organisms, more essential is the need for
hierarchical arrangement. Thorne (2003) has shown us the way in recognizing
monophyletic and fitting them in hierarchical arrangement. Assigning the
degree of confidence (A,B, C) to the group recognized can go a long way in
improving classification.

Gurcharan Singh

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Dr. Gurcharan Singh
Department of Botany                  Res. 932 Anand Kunj
S. G. T. B. Khalsa College                    Vikas Puri
University of Delhi                                 New Nelhi-110018
Delhi-110007, INDIA                            INDIA
Phone: 27666469                                Phone: 25531534,
9810359089
                       mail: singhg at satyam.net.in
                               chani at sify.com

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