Agreement Finally!!? (was Paraphyly)
tdib at OCEANCONSERVANCY.ORG
Thu Jan 17 16:42:40 CST 2002
From: Ken Kinman
The only thing that is separating us is a
trivial semantic thing which is easily corrected. Every time we recognize a
synapomorphy as being the origin of a clade, I would call that a "cut". But
hey, let's just call it a "boundary" so we can avoid the semantics.
Ken, Not only are you, as Curtis has pointed out, a treasure-trove of
information about the diversityof life, you also seem to be such a nice
person - I feel bad to be such an obstinate stickler. But no, our
differences are a lot more than semantics.
The only difference between us eclecticists and the you strict
cladists is that we also find it useful to regard that very same "boundary"
as the termination of a taxon (in this case Amphibia). Strict cladists want
all taxa to be "open-ended" (i.e., all boundaries are origins only), while
the rest of us want to regard some of those same boundaries as terminations
as well (for a variety of reasons).
I really don't understand your motivations Ken. We agree that a divergence
in the flow of descent, recognized by an apomorphy is the only appropriate
beginning point for a taxon. I dont't know why we agree on that - for my
part, I feel that way because that divergence is a natural event, directly
relevant to the evolution of life in all its diversity. As a scientist, I
want to describe and understand what really happens in the world. I suspect,
but don't know, that you agree - hence your distaste for polyphyletic
groups, no matter how useful anyone else might claim that one might be.
For the same reason, I will close off a taxon when the taxon disappears from
the real world. It is not that I "want" taxa to be open-ended - what I
"want" is to accurately describe what happens in the real world. You will
close off a taxon with extinction as well, I am sure, so we are still in
But then you come along and mess up this beautiful natural system of
classifying diversity with this insistence that some taxa, at your
discretion, will be artifically terminated at some point you deem important
(for a variety of reasons, you say). I cannot think of a single reason why
you or anyone else would want to do this. Not to a scientific
classification. You are violating the most basic principle of an empirical
science - to try to accurately describe what happens in the real world. Yes
the evolution of the amnion is significant - it marks a divergence in
descent at the origin of the lineage we call Amniota. But it did not
terminate anything in the real world. What you end up doing is offering us a
mapping of the categories in your mind, rather than the lineages that
actually evolved in the real world. I am not saying that this is something
totally uninteresting - but it is not a scientific classification, and it
should never be confused with one.
This is not just semantics.
The only question in my mind is which boundaries are the most
uncontroversial and useful as terminations of major "truncated clades"
Yeah, well of course. It would be and always was a question in everyones
mind who ever engaged in such a project. And of course everyone would have
their own personal set of answers. Why bother though??? Why not stick to the
scientific principles that got you this far? Forget about truncating clades
- we want amd need to know what the real ones are!!!
I realize that you are not closed to this understanding - hence your great
efforts to reconcile your classification with the real cladistic lineage
history. So here is a proposal for you - why not publish 2 volumes - one
being the "Kinman Summary of Our Contemporary Knowledge of the Real Lineages
of Life's History". This would be an enormously valuable contribution - I
would run out tomorrow and buy 10 copies - promise! Then in volume two you
could present "A Map of Ken Kinman's Mind: Categories of Life Forms". You
could reference this volume to the first with all sorts of clever markers so
that readers can relate these categories to real lineages while at the same
time having the benefit of your opinions as to what categories you think are
important. I admit I would probably not read this book, but other people
might. Serve your diverse audiences.
I would just suggest that you try to minimize confusion by not labelling the
categories in vol. 2 with scientific sounding names - maybe you could use
lower case for those.
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