This is indeed a fascinating topic. From my perspective as a biochemist, the DNA sequence of the organism IS the organism, so the DNA sequence perforce defines the species. Geography and morphology are just approximations of the species. I'm not sure how deeply this notion has permeated the rest of biology from the molecular biological side, but it is inevitably the direction things are going to go. Until DNA sequencing becomes routine (i.e., a block box) and really cheap, we are stuck with morphology and to a secondary extent, geography. Operationally, the weakness in the biological species concept is that we can rarely if ever actually define the "breeding population." It is not really definable (in terms of "do this then this and you define the breeding population" using any doable steps) so it is not really a scientific concept. Jim Shields At 08:39 PM 10/30/2012 -0700, Nhu wrote: >This is such a juicy subject that I have to join (just for a little). > >It's always good remember that no one knows what a species truly is. >Taxonomy and the latest and fanciest science could not yet tell us that >yet. However, taxonomy has been pretty good at *recognizing* species. What >we humans recognize as species does not make something a species, but it >has its practical purposes. >..... ************************************************* Jim Shields USDA Zone 5 P.O. Box 92 WWW: http://www.shieldsgardens.com/ Westfield, Indiana 46074, USA Lat. 40° 02.8' N, Long. 086° 06.6' W