[Taxacom] hominid evidence

[Dr. David Campbell]

On the specific example of human-ape comparisons, a significant 
difficulty is that humans are morphologically highly apomorphic.  Our 
body plans are significantly modified for upright bipedal locomotion, 
whereas the apes retain a primarily climbing and knuckle-walking 
build.  Some help for this issue comes from a study of fossil 
hominids.  Exactly what to do with highly apomorphic taxa is a more 
general problem in phylogenetics, both in terms of the cladistic 
aversion to autapomorphies in classification and in terms of how to 
deal with a shortage of synapomorphies.  

Conversely, having only a few characters also gives little resolution.  
In particular, parsimony produces soft polytomies when presented with 
either identical data or a set of similar taxa differing only 
autapomorphically.

-- 
Dr. David Campbell
425 Scientific Collections Building
Department of Biological Sciences
Biodiversity and Systematics
University of Alabama, Box 870345
Tuscaloosa AL 35487-0345  USA