Hello,
"Selfishness" a requirement for the human race? I don't think so. Let me
get a little anecdotal here. There is an algae (forgotten the specific
name sorry) which to live happily needs to sit part way between the
surface of a pool of water and the bottom. If it sits too low it gets no
oxygen. To help it not sink it forms a colony, in the colony some of the
algae takes a strange form and sort of forms a spongy mass which helps
the entire colony float. If a particular algae expresses this then it
looses out on respiration and reproduction significantly but if not
enough express this then the hole lot sinks and dies. If too much does
then the colony sits to high and not enough reproduction occurs.
The same is true of humanity (in my opinion) we need some selfless
people and we need some selfish people. With too many of either things
go a bit pear shaped.
Cheers,
Nick