[Taxacom] Propaganda (was: Molecules vs. Morphology)

[Kenneth Kinman]

Hi Stephen,
      I am quite aware of the Xenoturbella contamination problem.  It
clearly demonstrates that a sloppy extraction can lead to totally
inaccurate results (make sure you aren't extracting genetic material
from the stomach or intestines).
       However, this does not excuse using such sloppy science as an
argument against the kind of consistent molecular evidence that Grehan
continues to rail against.  That my acceptance  (among that of other
researchers) of molecular methods might be too UNCRITICAL is not a major
problem in my opinion, and rather it is Grehan's uncritical acceptance
of morphology alone that is leading him to problems.  As for
Scydmaenidae, I have no knowledge or specific interest in that
particular case, but its relevance is probably not as relevant as one
might think.  If the evidence there is equivocal, that is one thing, but
comparing it to the orangutan case is probably a stretch at best.
          ------------Ken Kinman
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Stephen Thorpe:
     I think there is something in what John says - specifically there
is  "propaganda" associated with molecular methods, but realistically it
is the UNCRITICAL acceptance of the molecular over morphological that
leads to problems. The Scydmaenidae example is relevant here. To argue
for "total evidence" sounds all well and 
good, but what if half of it  points one way, and half of it the other?
Sometimes it seems like  every new method gives a different result!
Another good example  involves the enigmatic Xenoturbella. Are people
familiar with the  story? An uncritical molecular analysis revealed that
it was a bivalve  mollusc without a shell! Then it was discovered: 
Bourlat, S.J.; Nielsen, C.; Lockyer, A.E.; Littlewood, D.T.J.;  Telford,
M.J. 2003: Xenoturbella is a deuterostome that eats molluscs.  Nature,
424: 925-928.