Species anatomically similar to humans evolved about 200-250,000 years ago. We know from fossil records that the earliest humans evolved in Africa. The early homo-Sapiens were hunter gatherers, or foragers. This lifestyle required a lot of movement in order to continuously find new food sources.
The eruption of Mount Toba, some 74,000 years ago created a bottleneck effect in the human population causing numbers to fall to just a few thousand. Over the next 60,000 years, the human population continued to forage and migrate around the Earth. This caused geographical barriers and allowed humans to evolve.
About 11,000 years ago, the human population had increased to between 6 and 8 million, which is more foragers than the earth could sustain. This meant the end of foraging and the beginning of agriculture, civilization and modernity.
From Crash Course: Biology on YouTube presented by Hank Green.