Just like the title says: Strictly from a biological perspective, what is the functional expectation of a human being.
No religious or philosophy-based answers will be accepted, we are talking biology not religion or philosophy.
Answers involving excessive psychology will be frowned upon unless found to be exceedingly insightful. (The brain is a biological entity)
If you are considering claiming this to be too broad or unanswerable consider the hypothetical question "what are the functional expectations of human feet" which can be answered fairly easily by a child with no formal training in biology. In my actual question I simply ask about the feet and the other parts attached to them.
Edit: Originally this question was titled "Strictly from a biological perspective, what is the purpose of a human existence." To clarify the question i have changed it to "Strictly from a biological perspective, what is the functional expectation of a human being."
Despite the concerns raised with the use of the word "purpose" the question was serving its purpose with the answers I am seeing. I did have some reservations about the word "purpose" as well, but I thought I would try it and see what others thought.
So if a human stomach has the overall functional expectation of mechanically and chemically breaking down and digesting food, what would be the overall functional expectation of a human as a whole? I am looking for not so much of psychologically specific functional expectations and more of physical functional expectations.
For instance a house cat's functional expectations are generally considered to be sleeping, eating, reproducing, socializing, hunting, etc.