The Genographic Project by the National Geographic Society is an effort to take a genetic approach to anthropology, which is essentially the study of the human story across cultures and throughout history. Recent findings from the project are startling food for thought.
Dr. Spencer Wells, an explorer-in-residence for the Society, says research suggests that the human race stood at the brink of extinction nearly seventy thousand years ago. Apparently, severe drought in Africa (which was the only continent inhabited by humans, at the time) had reduced populations to small isolated groups, threatened by the harsh climate. Estimates from another study at Stanford University suggest as few as two thousand individuals constituted the entire human race at this point. Population growth didn't occur again until the early Stone Age.
At least for me, the concept of human extinction poses several questions. The most basic of these, of course (at least for anyone with any sort of curiosity), is an exploration into the identity of the planet. What would Earth look like, had humanity died off? Moreover, what would have taken the place of humankind? Surely, this seems the stuff of science fiction (a la I am Legend), but the question still stands.
Perhaps the most crucial (and even pessimistic) conclusion that I can draw from this is that human life must fight against so many forces in order to survive that it's any wonder we've made it this far. So many things could go wrong - and so many things had to go right for us to be here - that the best we can do at this point is simply to stop wasting time.