So humans are qualitatively different from, say, birds that pass seeds through their guts? I doubt there's a scientific basis for such a distinction.
Jane Shevtsov At 09:35 AM 5/2/2006, [EMAIL PROTECTED] wrote: >Apparently I responded too quickly without choosing my words >carefully enough. I do believe that by saying that a species >evolves in response to the environmental factors within an >ecosystem, I allowed for migration of an ecosystem or parts of an >ecosystem in response to stresses such as global climate >change. Also by saying that species introduced by man cannot become >native I believe that I allowed for other types of migration. > >Bob Mowbray > >-------------- Original message from William Silvert ><[EMAIL PROTECTED]>: -------------- > > > > This seems to imply that a species is native only if it evolves in the > > location where it is found, and that any species which arrives by > migration > > or other form of transport is not native. This is a very Eulerian > approach. > > In particular, with global warming we can expect species to drift towards > > the poles, so even though the entire ecosystem drifts polewards, > can we say > > that the component species cease to be native? > > > > Bill Silvert > > Habitat Ecologist ================================================================================================== "If you try and take a cat apart to see how it works, the first thing you have on your hands is a non-working cat." --Douglas Adams Jane Shevtsov co-founder, <http://www.worldbeyondborders.org/>World Beyond Borders science journalist, <http://www.jyi.org/>Journal of Young Investigators "When Kansas and Colorado have a quarrel over the water in the Arkansas River they don't call out the National Guard in each state and go to war over it. They bring a suit in the Supreme Court of the United States and abide by the decision. There isn't any reason in the world why we cannot do that internationally." --Harry S Truman
