It seems to me that we find more humor in things that are odd rather then in horrible things like death.
I can see how having triggers that causes us to laugh and have dopamine rushes would help with survival by both connecting with us others and dealing with life, so from an evolutionary perspective i think you're on the right track, however why do we find certain things funny and certain things not funny?
from my understanding, what is considered funny is not completely similar cross-culturally, however there is steady base-line, and that is things considered abnormal to social norms.
so why is that which is abnormal considered funny and do you think that plays a part in why our speices has evolved a sense of humor?