Expecting someone to post a detailed explanation of all the science behind evolution in a forum comment is like asking me to teach you to play the piano in a forum comment.
It's easier to just point you to the appropriate places for you to learn about the subject.
If you are truly interested in learning what science has to say on the subject of evolution, might I suggest going to your local library and start with The Selfish Gene by Richard Dawkins.
It's an excellent book and goes into much detail about evolution on the genetic level.