More on human-orangutan analysis

[Richard Jensen]

John Grehan wrote:

> My current understanding is that in morphology it is
> possible to evaluate each character individually for homology and a shared
> derived status (this is the a priori part).

Assumptions of homology are necessary as first principles for any taxonomic
analysis.  These may be revised after the analysis is completed.  However, status as
a shared, derived character (synapomorphy) can only be determined a posteriori; if
we knew, going in, what the shared, derived characters were, there would be no need
for the analysis!

Dick
--
Richard J. Jensen              | tel: 574-284-4674
Department of Biology      | fax: 574-284-4716
Saint Mary's College         | e-mail: rjensen at saintmarys.edu
Notre Dame, IN 46556    | http://www.saintmarys.edu/~rjensen