Species evolve to meet the environment. An intelligent species changes the environment to suit itself. As soon as a species becomes intelligent, it should stop evolving.
Larry NivenThe reader has certain rights. He bought your story. Think of this as an implicit contract. He's entitled to be entertained, instructed, amused; maybe all three. If he quits in the middle, or puts the book down feeling his time has been wasted, you're in violation.
Larry NivenAs for AIDS, it's a plague. We are human, we get plagues. They come along every so often, kill off two thirds of the population; in the next generation it's a quarter; after that it's a childhood disease.
Larry Niven