And when you take a ruthless process, and mix it up with some extreme political and social ideology, what you get is the pseudo-scientific distortion of scientific evolution: social darwinism in its many forms, the most extreme version of which resulted in the infamous movement of eugenics, but don't blame the Nazis for this one. This idea came from the Brits, got instituted by the Americans, and only then did it make it back across the Atlantic to Germany.
Fortunately, as Andrew Marr explains in the second part of the fascinating documentary Darwin's Dangerous Idea, a better understanding of evolution, as well of ethical philosophy, is giving rise to a new, positive sense of eugenics, one in which individual choice and autonomy, without government imposition, is helping create a healthier and more prosperous world.
Wow... we've come full circle :)