They should not be thought of as being related. Atheism is not a religion and evolution is not it's dogma.
Evolution is related to science and evidence. Often once people begin seeing things this way a biproduct of this is atheism or agnosticism.
They are separate things. Evolution does pose problems for creationists and Abrahamic religions that try to explain everything from the perspective of bronze age goat herders.
Evolution = there is evidence of evolution.
Atheism = there is no evidence of "god"
Not really the same thing.