[Taxacom] classifications (was: no subject)

John Grehan jgrehan at sciencebuff.org
Fri Apr 3 06:24:51 CDT 2009

Beyond the paraphyletic and monophyletic classification differences are
also the different classifications that arise from different analyses. I
recently drafted a review of primate taxonomy for an anthropology
encyclopedia where I emphasized the reality that there is no shortage of
different classification schemes at various taxonomic levels. 

Previous published overviews of primate taxonomy had all presented a
single classification scheme despite the fact that various nodes were
highly contentious. Examples were the monophyly of primates with respect
to fossil members, monophyly of the Madagascar lemurs (with 3-4
alternative family level classifications), the tarsiers sister-group
relationship, and of course the monophyletic relationships within the
large-bodied hominoids. 

It seems to be the reality is that various phylogenetic relationships
are always in a state of flux - and maybe some will always be. Years ago
I wondered if the more people who studied a particular phylogenetic
group the more it would be unresolved. This came about in responses to
various biogeographic reconstructions such as Fagaceae where some would
say that one could not be sure about the biogeography because the
phylogenetic relationships were unresolved. Then I would show another
example of the same kind of biogeography with another group that was not
controversial and everyone was happy - even though the lack of
controversy probably just reflected the fact that nobody, apart from
perhaps an individual specialist, was working on the group!

John Grehan

-----Original Message-----
From: taxacom-bounces at mailman.nhm.ku.edu
[mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Mario Blanco
Sent: Thursday, April 02, 2009 7:11 PM
Subject: Re: [Taxacom] classifications (was: no subject)

   Ken, as a "strict cladist", I do not like classifications that allow
paraphyletic groups. If I want to see "ancestor-descendant information" 
I can simply consult the latest phylogenetic hypotheses on the group of
interest, as some have repeatedly said.

   And, do you really think you can convince everyone (even most people)
to use a moderately paraphyletic classification like yours? There will
always be many people like me, who prefer a strictly cladistic
classification. And there will always be a lot of people that prefer
much more paraphyletic classifications (e.g., accepting Reptilia), just
because it is easier for them to remember. That is why you are wrong
when you say that the APG could "very, very easily make their
classification almost universally acceptable" by allowing some
paraphyletic families.

    I like a monophyletic Ericaceae as it is in the APG system. If you
want to use your paraphyletic classification, that's fine; I will keep
using the APG one. What is the problem with that? As long as we
explicitly indicate which system we use, we will always know what
organisms you are talking about, and we can concentrate on learning more
about their biology instead of wasting time on fighting for competing
mental constructs (classifications).

    By the way, this is to discuss "issue No. 2" in Richard's post,
which does a great job at distinguishing the three separate lines of
discussion in this thread. And I agree with your other two points.


From:     kennethkinman at webtv.net (Kenneth Kinman)

     Well, I believe that a totally phylogenetic classification that is
broken by a single paraphyletic break is still totally phylogenetic in
an informational sense.  Using my {{exgroup}} markers you can still hook
the two resulting cladograms into a single large cladogram.  The
phylogenetic information is still 100%, but you add in some
ancestor-descendant information as a bonus.  
      But just for the sake of argument, let's say some might consider
the paraphyletic break reducing it from 100% to 90% phylogenetic (in
some philosophical way).  If traditionalists start using these "90%"
phylogenetic classifications, then almost everyone will be using highly
phylogenetic classifications that are identical or with very minor
differences.  All those very unphylogenetic classifications will
disappear.  You don't even have to meet them half-way.  Virtually all
classifications would become 90-100% phylogenetic, would become more
stable and more useful, and the differences would be very minor.  We
would be working together rather than working at cross purposes.
     The APG (Angiosperm Phylogeny Group) could VERY, VERY easily make
their classifications almost universally acceptable by (1) partially
reversing a couple cases of their excessive lumping at ordinal level;
and (2) allow some paraphyletic families instead of stubbornly
insistently that they must all be holophyletic.  For example, a
paraphyletic Ericaceae is a very small price to pay, and an
{{Epacridaceae}} exgroup marker allows us to keep 100% of the
phylogenetic information anyway.
       --------Ken Kinman
Mario wrote:
if "strict cladists" agreed to "allow occasional paraphyletic breaks",
we would no longer be "strict cladists". And I am puzzled as to how you
can view non phylogenetic classifications as "more phylogenetic".
 From Kenneth Kinman:
  "But until strict cladists agree to allow occasional paraphyletic
breaks, the destabilization and arguments will continue. Why they
wouldn't want to do this really puzzles me, as it would make all
classifications more phylogenetic."


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