I just can't believe how many such comments I'm seeing here. Where are the nerds?!
Selective breeding is based on positive feedback, where a human being selects the specimens with a desired trait and breeds them to get more of the same trait in the next generation. That's how you get house pets that do not stand a chance of survival in the wild.
What happened with the cockroaches is the same process conducted by mother nature; only the surviving ones can breed.
Now, here's the kicker for all of you high school dropouts. Both cases are essentially evolution according to the definition in wikipedia.