>>11576802>>11576810okay, i'm gonna back you guys up for a sec.
I agree, with the guy who said: what does allopolyploidalism have to do with speciation?
and while subspecies not breeding due to geographic isolation is true, the greater truth is that geographic isolation is one way to cause further speciation. that is, exchanging genes is likely to minimize the rate of or prevent speciation altogether.
humans simply haven't been geographically isolated for long enough to have speciated, and the same goes for most dog breeds.
natural mechanism of geographical isolation often rely on geologic processes that take hundreds of millions of years, so a few thousand years of isolation is not likely to result in speciation.
remember, humans share genetic similarily to plants and animals ranging from greater than 0% all the way up to 98%, an absolute value to the percent of genetic similarity doesn't really help because it's hard to point to exactly where we should draw the demarcation line of speciation defined by some measurable genetic similarity.
i think the best model is:
if genes are exchanged within a population, then you can get away with calling members of that population a species. if genes stop being exchanged (naturally, this is caused by geographic isolation) then speciation is likely to result.
