Paraphyly=mistakes? (There's the rub)

Richard Pyle deepreef at BISHOPMUSEUM.ORG
Sat Jan 12 10:50:11 CST 2002

> >I hardly regard it as "artificial" that birds have feathers, can
> fly, etc.,
> >etc.; whereas reptiles do not.
> What about those recently discovered dinosaurs with feathers and no wings?

What about them?  As I have tried to emphasize, we can acknowledge the
evolutionary histories, and still opt for alternative names that serve a
more useful function to legions of biologists who study living (extant)
things. My point is that the names serve a function in communication among
biologists more fundamentally than they serve a function in representing
evolutionary histories.  In the vast majority of cases, the two functions
are in harmony -- but in special circumstances (defined in an earlier post),
many feel that the needs of general communication supercede the need for
strict reflection of inferred evolutionary history.

> And what if morganucodonts were still around? Would we put them *in*
> Mammalia or take the monotremes out?

Well, if that were the case, then fundamental communication needs might be
different than what they happen to be today, and the language (nomenclature)
might correspondingly be written in a different way.

> It's strange how so many of our paraphyletic groups either reflect
> ignorance-because-of-extinction, or
ignorance-because-of-not-paying-attention. Willfully using ignorance as a
> separation criterion for taxa strikes me as somewhat unscientific.

It strikes me the same.  But you seem to be implying that the only reason
one would prefer to maintain the nomenclature of the monophyletic "Aves"
separate from the paraphyletic "Reptilia" (for example) boils down to
ignorance of evolutionary affinities, when of course the majority of
biologists who prefer to maintain that nomenclature do so with full
awareness and acceptance of the evolutionary relationships as we currently
understand them to be.


Before anyone misreads my own position on this, let me make it absolutely
unambiguous right here and now that I believe that the "ultimate"
nomenclature and classification system for critters, weeds, and microbes
SHOULD *strictly* reflect the evolutionary history (restricting "special
cases" to those involving hybrid origin).  That is by FAR the most logical
scheme for assigning a hierarchical system of scientific names for
systematic classification, in my opinion!

So why am I making such a big fuss?  Because I think the taxonomic community
made a subtle but crucial (and certainly understandable) error of judgment
in collectively assuming that the Linnaean system (which is the basis of the
historically documented body of knowledge that we have about the living
world, and which both thrives and depends on stability to foster clear
communication) should be adopted as this "ultimate" system to
nomenclaturally represent evolutionary affinities. The Linnaean system has
been WONDERFULLY successful over centuries in allowing communication among
biologists.  Coincidentally, it seems deceptively well-suited for mapping
evolutionary relationships. But for the majority of its life, it was *not*
used explicitly for that purpose.  To redefine it in this way now does a
disservice, in my opinion, both to the value of historical knowledge of
organisms, AS WELL as to current and future generations of biologists who
will have to live with the legacy that we provide for them.

I believe that we are approaching a "cusp" in the timeline of systematic
biology. Over the next decades, not only will the ratio of "described
species" to "undescribed species" likely transition from it's current value
of "much less than one", to a value "much greater than one" (assuming
various current initiatives gain momentum); but also our ability to
elucidate evolutionary relationships will likely advance to the point where
phylogenies will be virtually complete, persistently stable, and universally
accepted.  When that time comes, the biologists of the day will be grateful
that we provided them with a nomenclatural language designed specifically
with that end-game in mind (rather than language designed without awareness
of basic evolutionary concepts, and heavily weighed by excess baggage).
Meanwhile, while we work towards achieving that utopia of taxonomy (and
towards designing and adopting the perfect phylo-nomenclatural system),
let's allow the Linnaean nomenclatural system to live out the rest of its
life in peace, serving the function that it has fulfilled so successfully
for so long.


P.S. I composed a reply to Tom DiBenedetto's post on the related thread of:
"Re: It's about NAMES, not clades  (RE: Ashlock was treated badly)", but
alas, the Taxacom server rejected it as too long. Given that this current
iteration of this particular topic of discussion seems to be near its end,
I'll refrain from sending a shortened version of that message to this list
(uproar of cheers and applause....)

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