Does an atheist have to believe in evolution?

actually, one doesn't believe in evolution. Muck like no one believes in science. A more appropriate word would be "understands" or "accepts" (though not in the same sense as accepting Jesus as the savior or something like that).

actually, your moral feelings may be logical. Let's use Kant as an example. Ever hear of the categorical imperative? The logical basis for doing what is right, and if I understand Kant correctly, moral. Also, if you follow the golden rule, it too is on a logical basis. You treat others well so that they treat you nice. Treating them badly would be quite illogical, especially if they were a gang of murderers, for example.