From what I have seen in my brief time at these boards, most everyone accepts microevolution, but only some accept macroevolution.
Microevolution occurs when cells make errors while copying the chromosomes during meiosis. Cells in a stressed organism are more likely to make these errors, partially explaining why species under pressure of enviroment or extinction are more likely to evolve.
The current accepted form of Evolution is when, over thousands or millions of years, many occurences of microevolution, coupled with isolation and natural selection, a species or breed, which may be exclusive from the original breed or species, is formed.
My questions are, since microevolution does happen, where is the point where it no longer happens? Is there some biological censor that prevents microevolution from isolating an animal from it's ancestors?
If so, what is it, and how is it activated?
Why can microevolution not form new species?