1) I'm not seeing any discussion of group survival. At an individual level, a lot of human behavior can look counterproductive, but makes sense at the group sense. If a genetic line evolves to support other members of the same (or similar) line, then that line as a whole has a better chance of lasting.

2) If anyone's interested in longer discussions of these (and they are interesting):

- _The_Red_Queen_ (why we sleep around) http://www.amazon.com/Red-Queen-Evolution-Human-Nature/dp/00...

- _The_Dark_Side_Of_Man_ (why we rape, kill) http://www.amazon.com/Dark-Side-Man-Michael-Ghiglieri/dp/073...

Note that the 2nd tries to make political/policy conclusions which IMHO don't hold up. However, the scientific work in the text is pretty enjoyable.