What is the mechanism that prevents microevolution to become macroevolution?

I don't understand what kind of evidence could be presented to you that you wouldn't simply disagree with and consider it refuted.

We aren't divided into races and such. When you actually look at the physical traits that are viewed to constitute "race" in humans, there's no identifiable divisions. Rather, every one of those traits exists on a smooth continuum between individuals.Why do we have the makeups we have? Natural selection operating on random mutation. Future generations develop the same attributes as your ancestors because you inherit your genetics from your ancestors. There's no "modification" of DNA necessary, by climate or anything else, for that to happen. It's simple reproduction. Where else would you get attributes except from your ancestors? Who the hell knows? That's a word creationists made up to confuse the issue. Some scientists use it too, but it's never been clear what they mean by it, either.As far as I know, there's just "evolution." It's the model that explains why life on Earth is so diverse at present because of natural selection and random mutation. If you were both a creationist and an evolutionist, then you don't know what evolution is, or how it works. Or else you don't understand what is meant by "creationist", which is specifically someone who denies the accuracy of the scientific model of evolution.Evolution is an entirely accurate theory with amazing explanitory power. And it's more than sufficient to account for the diversity and history of life on Earth. There's far more than enough evidence to conclude that. To assert that evolution is "bollocks as a whole" is to be pretty ignorant of what evolution actually is.

What good points would those be? Well, again, parents don't have random offspring, they have offspring determined by whatever genetic payload they wind up passing on.We define "species", scientifically, as a reproductive community. Obviously, offspring and their parents must be part of the same reproductive community because there's gene flow between them (in one direction anyway.)Speciation - the creation of a new species from an old one - occurs when a portion of a population is split from the whole. Subject to different pressures and isolated, genetic differences accrue until genetic incompatibility is too great to allow interfertile hybridization. That's the gist of it, anyway. You've never had a tan? You don't think that the darkening of your skin in response to sunlight is just coincidence, do you?Ever have a sunburn, though? Pretty painful, right? If you were going to be out in the sun all day, having skin that was already tan would have been a considerable advantage, right? So is it really so surprising to find that the people who live in hot, sunny Africa have dark skin?Now, I'm not saying that the sun makes people black (although you may get a tan from the sun, it's not a tan you pass on to your children.) What I'm saying is that people who had been born with genetics that programmed them to produce a certain amount of melanin in advance would have had an advantage over those who didn't, or who had much less.I don't know. Doesn't seem that complicated to me, I guess. Maybe I don't understand what you're asking?

My apologies for being caucaso-normative. A rude oversight on my part. The time periods are confirmed by the convergence between geologic and genetic data. Maybe you could elucidate your concerns? If speciation is false then where do all the new species come from? On what? The fact that the conclusions of science are tenative and based on the best evidence we have at the time?I don't see that as a contentious point, or even a significant one. It's never been asserted that science always gets it right. Science is mostly right, and getting righter; things like creationism never change no matter what evidence is found and so are completely and eternally wrong. What? Elaborate, please. Speciation I explained. Common ancestry seems obvious. What's to explain?