Cladistism and "Eclectism"

Pierre Deleporte Pierre.Deleporte at UNIV-RENNES1.FR
Tue Feb 5 18:08:04 CST 2002

At 10:05 05/02/2002 -0600, Tom Wendt wrote: (below)

May I suggest that the first form of life to evolve is effectively a 
species for the ecologist, but we simply don't need systematics and naming 
conventions for taxa when dealing with any species considered in isolation?
On one isolated species we can perform autecological studies, certainly not 
meaningful systematics.
This is not IMO a question of being old- or new- fashioned, but of what 
systematics is all about.
Systematicians have their own definition(s!) of species. For instance 
species as "terminal" populations or groups of populations, homogeneous for 
as set of characters carried by representative specimens.

It seems that "relationships" should also be specified. Cladists often talk 
of "relationships between taxa" as their criterion. If think it's worth 
recalling that, in practice, this notion concerns what may be inferred 
through the analysis of shared character states (likely synapomorphies), 
under some rules for constituting and analysing the data matrix. Patterns 
of relationships are never observed directly. A nested patterns of 
synapomorphies is inferred for a set of specimens and used to class them. 
This has nothing to do anyway with "relationships" of individuals in 
population biology.


>Thomas Pape says:
>"As T.DiBenedetto already pointed out: "we demarcate groups (species)
>relative to other groups"."
>If I interpret that correctly--and Tom's postings seems to say this--then a
>species has no reality in and of itself, but only in relation to other
>species.  (This would mean, as an aside, the the first "life" to evolve
>could not be considered a species until "it" split into two species.)  I
>know I'm old-fashioned, but I look at species as something real--fuzzy and
>bizarre and complicates often, but real.  Someone will surely reply to
>that:  they ARE real in the sense that they are a series of RELATIONSHIPS
>between individuals, populations, etc.  That's fair enough, but then we
>need not demarcate them only relative to other species, as argued above.
>Tom Wendt

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

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