Re: A tribute

[chris brochu <cbrochu@fmppr.fmnh.org>]

> - Oh, and another thing - how much of Greg and George's successful
>prediction was due to "cladistics in the current mode"?  Will any creditbe
>given to non-cladistics for a successful prediction?  I don't think
>so!Some applications of "Scientific principles" are more equal than
>others! 

I think a better way of phrasing it is this:  we operate by making
*phylogenetic* predictions.  The capacity to make predictions is one of the
hallmarks of science, and phylogenetics - regardless of the tree-building
method - makes them.  Cladistics is currently the most rigorous means
available for reconstructing the phylogeny of fossil vertebrates; we can
make phylogenetic predictions independent of the means used to derive the
phylogeny, but some phylogenies are more robust than others by virtue of
the methods and data sets applied to them.

I suspect what the original post might have been trying to say is that in
some cases, a cladistic analysis only serves to confirm what everyone
already knew.  Certainly, that is often the case - no one has suggested a
nonmonophyletic Vertebrata in recent years, for example.  But this is not
always the case.  A good example - cladistically, champsosaurs
(long-snouted things primarily from the Cretaceous and Tertiary of the
Northern Hemisphere) are very basal archosauromorphs.  Their lineage should
project into the Triassic, but when the tree saying this first came out,
the oldest champsosaurs were from the Cretaceous.  The tree predicted much
older champsosaurs, and lo and behold, we now have them in the Triassic.

Those predictions made by Greg Paul, John Ostrom, George Olshevsky, and
others that have become real were still made in a phylogenetic context,
whether or not that phylogenetic scheme was derived algorithmically or by
intuition. But did you notice that the predictions currently being
confirmed are those made both with and without cladistics, while those made
entirely without cladistics - e.g., BCF - have not yet found any
confirmatory evidence from new discoveries?  For example, BCF predicts the
future discovery of flying theropods that would fit cladistically toward
the base of Theropoda or Tetanurae.  So far, no such fossil has been found;
in fact, we keep finding more evidence that anything outside (Archaeopteryx
+ the living) didn't fly.

chris

-=--=--=--=--=--=--=--=--=--=
Christopher Brochu

Postdoctoral Research Scientist
Department of Geology
Field Museum of Natural History
Lake Shore Drive at Roosevelt Road
Chicago, IL  60605  USA

phone:  312-922-9410, ext. 469
fax:  312-922-9566

cbrochu@fmppr.fmnh.org