Evolution

As I was reading an excerpt from Charles Darwin called On the Origin of Species, a particular line really struck out to me.  It reads, "... during a long-continued course of modification, the slight differences, characteristics of varieties of the same species, tend to be augmented into the greater differences characteristic of species of the same genus.  New and improved varieties will inevitably supplant and exterminate the older, less improved and intermediate varieties."  

I completely understand how this is true with animals and those that simply die from natural selection, but it really doesn't sit well with me when regarding the human race.  To an extend I believe this was true for the majority of the history of the world, but we seemed to reach a point where the "varieties" of people evolve for both the better and the worse.

Lets use an example and say that a city of dumb people get in a war amongst themselves, the strong ones first kill off the weak ones, then the strongest end up surviving, reproducing, and children with stronger genes than their peers end up creating the next generation.  Now lets take the strong legions of men and have them fight against a small nation that has a little wisdom (such as the Persians & the Greeks).  The group with the wisdom, although not all strong men, end up surviving.  Soon intellectuals begin to grow, guns are developed, and now any dumb man on the street can shoot an intellectual.  Does this make the dumb man/men a better, superior individual in thought and might than the one they just shot?  I think not.  In fact, I completely believe that if civilizations get bad enough, they can entirely wipe out the elite wise and good people of the world.