“Man’s mind, once stretched by a new idea, never regains its original dimensions.”
― Oliver Wendell Holmes, Sr.
Humans are unique among life on this planet, and much remains a mystery as to how we evolved. What steps came first? Why did we evolve this way and not that direction? Why are we the only human species left? What other paths might we have gone down in our evolution? And what directions might we go from here?
Where do modern humans come from?
The most bitterly debated question in the discipline of human evolution is likely over where modern humans evolved. The out-of-Africa hypothesis maintains that modern humans evolved relatively recently in Africa and then spread around the world, replacing existing populations of archaic humans.
Why did modern humanity expand past Africa about 50,000 years ago?
Roughly 50,000 years ago, modern humans expanded out of Africa, spreading rapidly across most of the world’s lands to colonize all continents except Antarctica. A number of scientists conjecture this migration was linked with a mutation that transformed our brains, leading to our modern, complex use of language and enabling more sophisticated tools, art and societies.
Why did we grow large brains?
There is no question that our large brains have provided humans an extraordinary advantage in the world. So what kicked off the push for a larger brain? One possibility is that increased smarts helped our ancestors make better tools. Another is that larger brains helped us interact better with each other. Perhaps radical changes in the environment also demanded that our ancestors deal with a shifting world.
Is human evolution accelerating?
Recent evidence suggests that humanity is not only still evolving, but that human evolution is actually accelerating, speeding up to 100 times historical levels after agriculture spread.