Who bears the burden of proof: the creator of a statement, or the one who negates?  No one bothers to ask what is true in the first place, but, in a world of inquisitors, who's responsibility is it to provide evidence?

I read today that anteaters can consume thousands of ants in a moment.  Have humans evolved to be a mutualistic species like the ants, where the survival of the species is more important than the survival of one?  Or are we really out to only propagate our own personal set of genes?  I am pretty sure that it isn't so important for me to reproduce, but I feel an ingrained drive to support the success of those around me.  Could be upbringing, though.  I'm not sure.