[Taxacom] Usefulness vs. convenience

[Kenneth Kinman]

Hi Barry, 
       Thanks for agreeing that the difference is probably
marginal. And I completely agree that context is important. In your
pharmacologist example, it does seem marginally more efficient (or at
least convenient) to answer using one taxon instead of two. But in the
real world, the price (the negatives) to taxonomy of such marginal
efficiency is very high. [NOTE: In general, there is clearly too much
emphasis on convenience in our modern world, and we often pay for it
dearly down the line in many different ways].             
       I would rather endure the inconvenience of giving
(or receiving) an answer with two taxa if the two-word answer is precise
and unambiguous. But if someone's answer to a question is taxon
Dinosauria, does that mean the paraphyletic Dinosauria or the
holophyletic Dinosauria (which also includes birds). Even today, both
usages still occur, and the older literature almost exclusively uses the
paraphyletic meaning. Same for the answer "Pongidae"---are they talking
about the paraphyletic Pongidae (including chimps and gorillas), or the
just the orangutan lineage?   As you said, the end-user doesn't usually
have a classification at hand to clarify such ambiguities, but a
two-word answer (mother-group and exgroup) can be much less ambiguous
and only slightly less efficient or convenient.   
        Of course, we wouldn't have this particular
class of problem if strict cladists hadn't "appropriated" (that sounds
more polite than "hijacked") paraphyletic taxon names and converted them
into clades. And now there are proposals to restrict taxa like Amphibia
and Aves to crown groups only. A paraphyletic Amphibia is still very
useful, but some seem intent on continuing to muddy the taxonomic waters
even further. 
        And even when they just throw a paraphyletic
taxon on the trash heap (and thankfully don't radically change its
meaning), it can still have negative consequences. Kingdom Protista (as
part of the Five Kingdom classification) has long served as a convenient
paraphyletic group of all eukaryotes except Metazoa, Metaphyta, and
Fungi. Cavalier-Smith has done a fine job of gradually elucidating the
relationships within Kingdom Protista. Unfortunately, he also divided
this perfectly good taxon into separate Kingdoms that proved to be
either wrong or controversial (which has puzzled me since he does
recognize some paraphyletic taxa). Strict cladists reacted by chopping
protists into long lists of clades (often more like alphabetical laundry
lists than classifications).        
       Therefore, protist classifications are now a big fat mess (far
too many different ones, some worse than others). Kingdom Protista was
very useful, but they couldn't resist breaking it up into more Kingdoms.
And my views on Three Domains of life (vs. Five Kingdoms) are well
known.... In summary, the "authoritarians" who gave us the Five Kingdoms
of life understood how useful, stable, and convenient this
classification is. It was a mistake to try to "fix" something that
wasn't broken. Kingdom Protista was a very useful taxon (and still is
for those who continue to use it). 
           ---------Ken Kinman                  
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Barry wrote:   
With respect to your question, I would only say that many end-users of a
classification will not have the full classification on paper or screen
in front of them.  Imagine a pharmacologist asking a taxonomist what
group's taxa to search for species that produce a certain
phytochemical.  For the taxonomist to be able to recommend a
holophyletic taxon is at least marginally more efficient that having to
specify a paraphyletic taxon _plus_ its ex-group.   This may be
putting a pretty fine point on it, but "usefulness" depends partly on
context.