Eugenics

[cliffy1]

would the Earth thrive or would mankind die off?

Earth would thrive if mankind died off. If smart people are not reproducing much but not so intelligent people are, the human race would just dumb down until they were too stupid to survive. We are already up to our necks in garbage. If the human race were to get any dumber, we would all perish in our own effluent. After a few hundred years, the rest of life that survived would thrive. See The World Without Us: http://www.worldwithoutus.com/index2.html