[Taxacom] [Biogeography Portal] RE: Ratites and frogs of New Zealand

[Ken Kinman]

Hi Anindo,
     From Mauro's post, sounds like he would like to do more than just 
"lump" me (perhaps even punch me in the face?).  ;-)   But seriously, I do 
understand his frustration with molecular clocks, which often run at varying 
speeds and can sometimes lead to false conclusions if you assume they always 
run at a constant rate.

     Anyway, to answer your question---my eclectic approach to taxonomy 
maintains that strict cladism has gone TOO far in trying to eliminate ALL 
paraphyletic taxa from our classifications.  Especially at higher taxonomic 
levels, I see no good reason to eliminate paraphyletic taxa like Amphibia 
(paraphyletic with respect to Amniota), Prokaryota (paraphyletic with 
respect to Eukaryota), Protista (with respect to Metaphyta and Metazoa), 
Pinophyta (with respect to Magnoliophyta), and so on.  Strict cladism taken 
to the extreme can be very destabilizing over time (most notably the 
PhyloCode, which I now strongly oppose since the extremists have largely 
taken control of its development).  Polyphyly is indeed unnatural, but 
paraphyly is natural and can be extremely useful (even necessary) as long as 
it is used in moderation and done explicitly.

     My compromise solution is to recognize paraphyletic groups where 
stability and utility are best served.  However, I also require that 
place-markers within such paraphyletic taxa explicitly show the cladistic 
placement of the exgroups----for instance, {{Metazoa}} and {{Metaphyta}} 
markers with Kingdom Protista showing that Metazoa evolved from Phylum 
Choanozoa and that Metaphyta evolved from Phylum Chlorophyta.  No going back 
to those days of sloppy, inexplicit paraphyly.  Eclecticists have to meet 
the strict cladists (at least the more moderate ones) halfway to achieve a 
compromise that meets the needs of both sides.  The more extreme elements of 
cladism (apparently a majority of PhyloCodists) demonstrate no desire to 
compromise at all, so I've given up on them.

     Anyway, my {{exgroup markers}} solve one of the major problems strict 
cladists have with eclectic classification, namely the paraphyletic 
placement of two sister groups on different taxonomic levels (such as 
Kingdom Metaphyta being sister group to an Order of charophytes).  The 
{{markers}} allow the sister group information to be explicitly shown.  I am 
primarily concerned with classifications at these higher taxonomic levels, 
but even at species level such paraphyly can be useful when it is clear that 
a "mother" species is ancestral to an island "daughter" species through the 
founder effect.

     The archives of Taxacom contain numerous examples of classifications 
which I have posted over the past several years which demonstrate how to do 
this in practice (angiosperms, molluscs, Diptera, Reptilia, Aves, Primates, 
Protista, and a lot of others I don't recall offhand).  It certainly is 
preferable to going the PhyloCode route, abandoning Linnean categories, and 
destabilize all our classifications to the point that only the PhyloCode 
"lawyers" will be able to understand them.
    ----Hope this helps,
             Ken Kinman
*********************************
>From: ANINDO CHOUDHURY:
>
>"I think I'll stick to a modern form of Darwinism and a more eclectic 
>approach
>to both taxonomy and biogeography."
>
>Be careful Ken, or Mauro will soon lump you in with the "Latin American
>school" of biogeography.. ;-).
>
>On a more serious note, I share some of your sentiments about the polemics.
>But I do have a question. I think I know what you are getting at when you 
>talk
>about an eclectic approach to biogeography. I am unclear as to what you 
>mean
>by an eclectic approach to taxonomy. Could you clarify? I am asking because 
>I
>primarily occupy myself with questions of species diversity and speciation,
>and taxonomic practice has bearing upon the issue.
>
>Regards
>Anindo
>Division of Natural Sciences
>St. Norbert College
>Wisconsin
>

_________________________________________________________________
Your Hotmail address already works to sign into Windows Live Messenger! Get 
it now 
http://clk.atdmt.com/MSN/go/msnnkwme0020000001msn/direct/01/?href=http://get.live.com/messenger/overview