Both fossil evidence and DNA analysis using molecular clocks (estimates on historical mutation rates) agree that Homo sapiens is 150,000-200,000 years old. It is only in the past 50,000-60,000 years, however, that it has really taken off. Some ascribe the late take-off to chance. Others think the human mind crossed a threshold at that time, and the flourishing of humanity is the consequence.
The Economist, 1o de Novembro de 2012