[Taxacom] (endless subject)

Frederick W Schueler bckcdb at istar.ca
Fri Apr 3 11:29:20 CDT 2009

Alexander.Schmidt-Lebuhn at biologie.uni-goettingen.de wrote:

> Similarity lies in the eye of the beholder. 

* well, maybe that's the root of this unending thread, as I commented 
(below) at an earlier stage. If "overall phenotypic similarity" could be 
recognized as a stand-in for "ecological similarity," and could be 
measured on this basis, then there'd be some way of meaningfully 
measuring and discussing the phenomena that are now obliquely discussed 
under the heading of paraphyly.

Linnean ranks could serve to express the chronological age of 
holophyletic groups or to express "degree of difference," but if there's 
no metric for measuring "difference" there's no way to discuss it.

Forty years ago it would have been considered hopeless to express the 
phyletic connection between, say, an Elephant and a Bacterium, but we 
can do that now, so we've got a grip on the "vertical" time dimension of 
biotic diversity. What's needed as the next step in understanding is to 
come to grips with the conceptually more complex "horizontal," or 
ecological dimension(s).


             Bishops Mills Natural History Centre
           Frederick W. Schueler & Aleta Karstad
        RR#2 Bishops Mills, Ontario, Canada K0G 1T0
     on the Smiths Falls Limestone Plain 44* 52'N 75* 42'W
       (613)258-3107 <bckcdb at istar.ca> http://pinicola.ca
Frederick W Schueler wrote:
 >  I think the problem is, to cast it in Hegelian terms,
 > that when the thesis of cladistics was struggling
 > with the antithesis of phenetics in the 1960s and 1970s, there wasn't
 > ever a synthesis that incorporated phenetics' "overall similarity" into
 > new systematic procedures. "Holophyly" was such an engaging idea, and
 > "overall similarity" was so complex, and so dependent on the character
 > set analysed, and then so mixed up between phenotypic and genetic data
 > sets, that "overall phenotypic similarity" wasn't widely recognized as
 > a stand-in for "ecological similarity" in the same way that 
 > was recognized as a stand-in for "propinquity of descent." Just saying
 > "evolutionary systematics" & continuing in the old New Synthesis ways
 > didn't count as a new synthesis.
 > I'm not sure what such a synthesis would look like, & maybe old-
 > fashioned phenetics requires too much caliper work to be attractive,
 > but I think that ecological similarity would be somehow incorporated in
 > a systematics that reflected our best understanding of organisms. --
 > fred
 > ========================================================

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