[Taxacom] endless debate
mblanco at flmnh.ufl.edu
Sat Apr 4 01:58:08 CDT 2009
thanks for pointing out my error. Yes, I meant to say "splitting a
monophyletic taxon and leave one of them paraphyletic." And just in
case, I know you can also split a monophyletic taxon into two
monophyletic ones. That does not change my position. Whatever
classification system you consider best is ALWAYS going to be a matter
of opinion, because we all have different criteria to judge the
"evolutionary information" and usefulness of a classification.
Nomenclatural stability is much more straightforward to quantify, and I
think the instability from revised classifications, more than enforcing
strict monophyletic groups, is what upsets a lot of people. But is that
a valid reason to preserve the status quo of previous classifications? I
What you perceive as "progressively worse" I perceive as "progressively
better". Yet another example of how dependant on each one's viewpoint
this whole issue is. I might be younger than you, and not have produced
classifications from bacteria to mammals (I prefer to restrict myself to
the few groups I know best). But I've studied and discussed these issues
long enough to know that I am not going to change my position that
easily, especially when faced with arguments that invoke authority ("I
have more experience than you, therefore I must be right").
I know I am not going to convince you, and many others that think like
you; but I hope you realize that you are not going to convince us
either. It is a stalemate.
Just a reminder: classifications are tools to organize information. They
do not in themselves generate information about the organisms we study.
Use the classification that you consider best for your purposes, and let
others do the same.
-------- Original Message --------
From: kennethkinman at webtv.net (Kenneth Kinman)
Hi Mario and other taxacomers,
Maximizing evolutionary information is just one contentious
issue. Other issues are maximizing usefulness (balance, easier to use,
etc.) and minimizing instability. As one who has produced
classifications for about 35 years (for taxa from bacteria to mammals),
I've found that cladifications are more problematic on all three of
these issues. As a college student, I was extremely impressed when I
saw my first mammal cladification in the 1970's. I too initially
thought that this was the wave of the future. However, I realized after
a couple years that cladistics main value was as an analytical
methodology, but that second step cladistics (strict cladification) was
going to cause as many problems as it solved.
Decades later, it seems to be getting progressively worse.
Today, I think too many people don't really understand paraphyly fully.
That many students have been taught that it is as bad and unnatural as
polyphyly is particularly disturbing. That you said below that
splitting a monophyletic group creates "two paraphyletic ones" (which is
not true) indicates to me that perhaps you haven't really yet delved
into the subject sufficiently to render a "fully informed" judgment at
this time. Like I said, it took me a couple of years of studying many
different classifications to change my mind about "strict
cladifications". It is very easy to get caught up with all the good
that has come from cladistic analyses, and to overlook the drawbacks of
strict cladifications. This is especially true today, after decades of
paraphyletic taxa being demonized.
Mario Blanco wrote:
How to maximize evolutionary information is the contentious issue then.
In my opinion (and that of many others), it is achieved by recognizing
only monophyletic taxa. In your opinion (and that of many others, too),
it is achieved by a combination of phenetics, phylogenetic, and phyletic
information, in your own words. That will forever remain a matter of
opinion; there is nothing black and white about it, except in different
people's minds. And that is why I believe this discussion will never
end. The arguments will continue going back and forth, as they have been
for a long time!
And yes, when I talk about "separating groups that belong together", of
course I am talking about splitting a monophyletic taxon into two
paraphyletic ones. That was obvious from my point of view. Of course you
have different criteria for deciding what groups belong together (or
not), and you can be as assertive as I am when expressing your opinion.
I guess I should have added "according to my criteria" to that sentence.
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