(February 26, 2014 at 4:27 am)jg2014 Wrote: It is not fallacy of the beard because the definition of species is qualitative and there are no extremities. The fallacy of the beard is that quantitative changes cannot result in changes in quality. So one starts with a clean shaven individual, no hairs therefore no beard. One adds a hair at a time and one can never find the point at which beards start. Species unlike a beard is defined qualitatively, either they can produce fertile offspring or not.
Except that is not right. There are species of birds (ll try and find out what they are) that can mate with another species from the same familia which exist geographically near them but not those from further away however those that they can mate with can mate with those further away.
Imagine species A-B-C-D-E-F which circle the globe A can mate with B and F produces infertile offspring with C and E and cannot produce any offspring with D. B can mate with A and C and produce infertile hybrids with D and F but cannot produce anything with an E and so on.
Some may call them junk, I call them treasures.
