Re: Last Word (har har!) on Linnaean vs. Phylogenetic Taxonomy

[Mickey Rowe <rowe@psych.ucsb.edu>]

[ Held back by technical glitch; since I'm here... note that this is
  *not* the way to shut down a thread (see administrative tab at
  www.dinosaurmailinglist.org if you want to know the right way), but
  I pass it along anyways for the perspective.  -- MPR ]

------- Start of forwarded message -------
Date: Fri, 30 Aug 2002 01:08:51 +0100
From: Mike Taylor <mike@miketaylor.org.uk>
To: dinosaur@usc.edu
In-reply-to: <4E5F47F8-BB0E-11D6-97F6-003065F5E6B0@mac.com> (message from John
        Conway on Thu, 29 Aug 2002 15:15:17 +1000)
Subject: Last Word (har har!) on Linnaean vs. Phylogenetic Taxonomy

With the hopefully endearing naivety of the profoundly ignorant, I am
now going to attempt the evidently impossible task of putting this
list's seemingly endless Linnaean vs. Phylogenetic debate to bed.

Here's what I think is the key insight:

> Date: Thu, 29 Aug 2002 00:41:31 -0700 (PDT)
> From: "Jaime A. Headden" <qilongia@yahoo.com>
> 
> Let me describe a parable.
> 
> Built a latticework, and set it down. On the bottom of the lattice
> work, set a melon. Above it and in succession, you set smaller
> fruits and veggies until a pea is at the top. The latticework sits
> in a field and is perfectly sensible.  [...] This is the Linnaean
> system, perfect in it's construction, easily patterned because you
> can see it from horseback. Don't get off, you'll see the flaws. Like
> actual organizational problems. Fruits and veggies are
> ansiospermous, but they certainly are not grouped properly in a
> hodge-podge.

OK, here's the the problem, Jaime says that the fruit and veg is "not
grouped properly" because the specimens that are classified "close to
each other" are not closely related.  That's a completely legitimate
critique -- _provided_ that what you're looking for in your
classification is that it reflect evolution.  That's often the case,
but not always.  Perhaps you've classified the fruit & veg because you
want to find a suitable snack to put in your pocket for later: in that
case, a classification by size is perfectly sensible.  Or if you want
to choose a selection of snacks for colour-blind people to pick off a
sheet of green paper, then classifying by colour is sensible.

Less fancifully, while we believe that ducks are more closely related
to swans than they are to chickens, a classification reflecting that
evolutionary hypothesis is of no use to a poultry farmer, who quite
rationally classifies birds according to how they taste.  "Pachyderms"
are a polyphyletic group, but they are still a useful way for big-game
hunters to think.

So for all these reasons, I am uncomfortable about people dismissing
Linnaean classification as "outdated" or even "useless".  What they
really mean by "useless" is "it doesn't serve my particular purpose";
and what they mean by "outdated" is "there are other, newer methods
that better serve my particular purpose".  To denigrate Linnaean
classification as "mere stamp collecting" may be a legitimate analogy,
but stamp-collectors will object to the "mere" part!  There may be
many valid fields of endeavour in which Linnaean classification is
very useful.  Great.  Go for it.

HOWEVER.

The purpose of _this_ list is scientific discussion of long-dead
animals.  Those animals can only possibly be understood in the light
of their evolutionary history -- there is no alternative, since they
are not here today for us to study molecular biology, social behaviour
or any of the other aspect that might lead us to use a different
classification scheme.  It seems self-evident to me that when studying
evolutionary relationships, we need to use a classification scheme
that reflects those relationships.

I think it's not coincidental that in recent list history, our most
vocal Linnaeist has been Ken Kinman, whose primary interest is not in
long-dead dinosaurs but bacteria.  Seems to me that his big mistake
(apart from going on and on and on ... :-) was trying to take a
classification model that works well on extant bacteria and trying to
apply it to extinct vertebrates!  (I'd be interested to know as well
what Philidor's "home taxon" is -- I have a hunch it might not be
dinosaurs.)

So inasmuch as this list's main purpose seems to be discussing
evolutionary relationships and hypotheses concerning these
relationships, it should be no surprise that phylogenetic
classification and taxonomy are used nearly universally.  With this
discussion having gone on so long and so loud in different forms, I
would like to politely request the Linnaeists among us to graciously
accept that this is what works best for what this list does -- and to
feel free to use other classification schemes in other fields of
endeavour.

I also invite the list administrators, the next time this ubiquitous
topic comes up, to consider moving it across to the DML-killed-threads
list whose address escapes me for the moment, but which Mickey and
Mary will know.

...

Then, in peace at last, we can all get back to discussing who is going
to call their first-born son "Turok" :-)

Thanks for listening.

 _/|_    _______________________________________________________________
/o ) \/  Mike Taylor   <mike@miketaylor.org.uk>   www.miketaylor.org.uk
)_v__/\  "I have always prided myself on being in a field that has
         no practical application" -- Palaeontologist James Farlow.
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