[Taxacom] classifications (was: no subject)

[Gurcharan Singh-satyam]

I find it interesting that animated discussions  emerge in this group 
periodically. If we believe in incorporating phylogeny in classifications, 
try hard to find out group/s of organisms which share common ancestory, then 
why do we insist on allowing recognition of paraphyletic taxa?. Although it 
is often difficult to detect paraphyly, but once it is established, it is 
really satisfying. It was shocking disbelief for many when Bremer as back as 
1981 suggested dividing angiosperms into a number of monophyletic groups and 
not simply into dicots and monocots (as was done then). Many at that time 
did not really understand paraphyly. Contemporary taxonomists ignored it. It 
took us nearly two decades to accept the suugestion, and I hope now no 
angiosperm taxonomist regrets it.
    We are spending a lot of funds, resouces and utilizing man power to 
establish organisms which share common ancestory, but having done that, why 
do we want to keep one or more members out of the taxon. Is it not the 
injustice for the taxon which is left paraphyletic and the researcher?. Are 
we to unite or split the families (families in formal sense and taxonomic 
rank),  which need to be kept together?


Gurcharan Singh


----- Original Message ----- 
From: "Mario Blanco" <mblanco at flmnh.ufl.edu>
To: "TAXACOM" <taxacom at mailman.nhm.ku.edu>
Sent: Friday, April 03, 2009 4:40 AM
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.
>
> -Mario
>
>
> 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:
> Ken,
> 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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