You're not thinking very hard. How long does it generally take to get a new breed of dog? How many generations of E. Coli will occur over 200 years? Assuming a human generation length of 25 years, why would there be no evolutionary change over 8 generations?

Selection for existing attributes is plausible on 200-yr timescale. Pro-adaptive mutation is not.

To within measurement error, all attributes are pre-existing attributes. It's called "natural variation" and is the universally-accepted explanation for why we have sexual reproduction instead of budding. Right now, some people are more radiation-resistant than others.