Tibetans live at altitudes of 13,000 feet, breathing air that has 40 percent less oxygen than is available at sea level, yet suffer very little mountain sickness. The reason, according to a team of biologists in China, is human evolution, in what may be the most recent and fastest instance detected so far.
More here at the link.
Yes, evolution may only be a theory, but the evidence in favor of it is massive. And now, we can actually see evolution in action from recent human history. The only discrepancy here is the number of years that this particular natural selection event took place - Biologists maintain 3,000 years, while archeologist claim it happened in 7,200 years. Nevertheless, we have ironclad proof that this evolution among Tibetans did happen.
And here is the problem that I have with certain people in the "Creationist" camp. They ask for proof of evolution, and time and time again, evidence is provided. Yet, when you ask them for proof that God created humans, they reply "Prove that God didn't create humans", which is the kind of an answer that speaks for itself, and as we all know, not a reply that is based even remotely on logical debate. You don't debate by asking people to prove a negative, especially when the scientific method dictates that evidence through experimentation and observation provides evidence that the theory is correct.
Yes, evolution is still a theory. So is relativity, a theory that is used today to focus an electron microscope. So is the periodic table of the elements, without which chemists would still be in the dark ages. And creationism? Hogwash, obviously, since absolutely no evidence has been provided to date that supports it. Of course, if and when creationists come up with even an iota of hard evidence to support their claims, I am willing to listen. As of now, though, I am still waiting.