genetic vs morphological trace of phylogeny

[John Grehan]

At 07:40 AM 4/13/2004 -0700, Curtis Clark wrote:
>At 05:14 2004-04-13, John Grehan wrote:
>>Perhaps cladistics is not cladistics any more.
>
>That seems a rather fundamentalist response. Who owns cladistics, anyway? I
>submit that it is owned by the people who do it.

Maybe. Some argue that terms such as 'cladistics' are just labels and they
only represent what people using the term take it to mean. Consequently, it
is possible for a label to encompass a view that contradicts the concepts
embodied by earlier users. Perhaps this is what is happening in cladistics,
although its not entirely that simple in that there are cladists who
disagree with Curtis about DNA data etc. Some have suggested to me that DNA
analysis is just phenetics dressed up in cladistic terminology and
algorithms. It's something I am interested to understand better than I do
now.  And then I recall years ago that some systematists were arguing that
there is really no difference between phenetics and cladistics anyway. So
perhaps I should label myself more with 'fossil' taxa such as Rosa (and
more so perhaps than Hennig) than what might pass for cladistics according
to the perspective of Curtis and others.

>>Perhaps. Then again not having 'understood' might be leveled as what is
>>simply a different point of view.
>
>I see your point, but I imagine that most of us on the list would not
>accept such an excuse from a student in one of our classes. "I have a
>different point of view about the energetics of the Calvin cycle
>reactions." I wouldn't preclude a different point of view, but I would be
>less inclined to accept it from someone who had no familiarity with enzyme
>kinetics.

Glad I was never one of your students!

>>I was once told that I could not criticize vicariance cladistics unless I
>>could do cladistic theory back to front (that ability being measured
>>according to the authority of said individual). Never mind that the
>>individual did not see the converse being necessary for panbiogeographic
>>theory
>
>I would hold you both to a standard only somewhat less strict than he/she
>suggested for you.

Your choice. It's just an authority argument.

>>You will have noticed that several list members have commented and
>>sometimes debated panbiogeography without necessarily having a full
>>familiarity with either terminology or methodology. This has not prevented
>>me from attempting explanatory responses,
>
>The explanatory responses that I and others have provided about cladistics
>seem to me to have had little effect in your case. It is hard to teach or
>learn when everything is cast as a "difference of opinion".

It seems that what you are saying is that you are right any 'explanation'
you provide is obviously explanatory and the failure on my part to adopt
your position is therefore my fault. In my responses on panbiogeography I
never had the expectation that critics may necessarily agree or change
their view. It's their choice and has no necessary relationship with their
level of understanding.

John Grehan



>--
>Curtis Clark                  http://www.csupomona.edu/~jcclark/
>Web Coordinator, Cal Poly Pomona                 +1 909 979 6371
>Professor, Biological Sciences                   +1 909 869 4062

Dr. John Grehan
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