A great piece from Charles C. Mann from five years ago, where you can see the genesis of The Wizard And The Prophet.
For hundreds of thousands of years, our species had been restricted to East Africa (and, possibly, a similar area in the south). Now, abruptly, new-model Homo sapiens were racing across the continents like so many imported fire ants. The difference between humans and fire ants is that fire ants specialize in disturbed habitats. Humans, too, specialize in disturbed habitats—but we do the disturbing.