Perry:
My recent reading list has included the following:
Can We Be Good Without God? by Robert Buckman, MD
The God Delusion by Richard Dawkins
Both authors address your questions, Buckman from the point of view of a social humanist, and Dawkins from the point of view of a scientist who believes in the process of natural selection.
A lot of people who are "believers" have some gross misunderstandings of evolution and natural selection. For example, Dawkins explains that natural selection does not occur by "random chance", as many creationists/believers would think it does. Both authors discuss how religion may have developed and how morality may have developed in the human species.
You can probably find both books available at your local public library. You'll find some enlightening answers about atheism and evolution if you take the opportunity to read them.
Now to answer your question:
Is Atheism/Evolutionism Dangerous?
I personally think it all depends on the individual. You can have good atheists and bad. You can have good religious people and bad religious people. Believing in God doesn't necessarily stop people from murdering others, or being abusive to women and children and animals. For the religious person, all they have to do is "repent" before their death and God will forgive them.
Atheism and/or humanism requires a great deal of self-awareness, being in touch with one's own values and ethics, and personal accountability for one's own actions. For example, I no longer abide by the JW euphemism to "wait on Jehovah" when I want to change something in my life. I take responsibility for figuring out what exactly needs to change, what steps are required to achieve that change, and putting the plan in action to effect the change that I want. I know that I cannot fall back on the "just following orders" excuse if I treat someone else poorly, or if I do something that goes against my own principles - I will have to live with the understanding that I caused harm to someone else, and that I don't get a do-over.