About world-wide human population… 70,000 BC — Just a few thousand surviving humans The human species, Homo Sapiens, has existed for about 300,000 years. About 70,000 years ago there was a catastrophic eruption of the Toba super volcano. This cataclysm reduced the world-wide human population to only a few thousand. Many other species were also drastically reduced. 2,500 BC — 20 million humans Around 2500…