Subspecies

[Michael Gochfeld]

My understanding of subspecies is like Chris': designation of geographic 
variation with an implication of the potential for interbreeding and 
interfertility (and no negative selection against hybrids) where the two 
subspecies (often called races) come in contact. 

But again, that concept which is largely ornithological, may not fit for 
other groups of organisms with very different biology (in fact it 
probably doesn't fit all that well for many birds, where new information 
suggests that formerly designated subspecies are now full "biological" 
species.  And to top that off, more and more molecular folks are calling 
into question whether the biological species is more than a human 
artifact. 

Mike Gochfeld