Not so long ago the human story of evolution seemed simple and linear like a straight line of progression. The old story postulated that as one ancient species of human ancestor began to die out it was replaced by a new and more evolved human species until finally came the dawning of Homo sapiens (modern humans). The story was simple and straight in its progression, its evolution.
Today, however, that simple story no longer holds true and instead of human evolution being a straight line of evolution it is, in fact, more akin to a twisted bush or braided stream. The simple story of our evolution went out the door as soon as we started to find different species of ancient human ancestors coexisting sometimes for long, long periods of time. And then the old simple story REALLY went out the door when we began to discover that various ancient human ancestors interbred with modern humans! That turned everything we thought we knew upside down and inside out!
Frankly, the old simple story was a very egotistical story geared towards praising ourselves as modern humans. But, the discovery of coexisting species and hybridisation suddenly threw what we thought we knew into chaos and we began to realize that ours is a much more complex story, indeed.
According to the Out of Africa Theory (OOA) about 2.8 million years ago our genus, Homo, evolved out of our more ape-like ancestor Australopithecus. This discover came in March of this year when we found a jaw and teeth in Afar, Ethiopia that appear to be the oldest human fossil remains ever found. These fossil remains most likely belonged to Homo habilis although they resemble features akin to Australopithecus. H. habilis was ape-like but it had a face that projected less than the Australopithecines.
The OOA theory holds that our ancestors began to migrate out of Africa and into Asia via the Levant during the time of Homo erectus. This species was most likely our direct ancient ancestor and was the first known species to come out of Africa in large numbers. These migrations began around 1.8 million years ago. H. erectus was the first hunter-gatherer and has been found in the Far East near Beijing the capital of China.
Time went on and our story became even more complex it seems. The Denisovans seemingly appeared out of nowhere and lived in vast spaces in Asia and they interbred with Neanderthals living there and possibly with H. sapiens. Denisovan DNA is found today in peoples from the Philippines to the Pacific Islands! This may have been around 50,000 years ago.
And those Neanderthals! We know today of at least two times when they overlapped with our own species complicating our evolutionary tree even more! They appeared in Europe about 250,000 years ago and spread across northern Asia and the Levant and they lived there until just 190,000 years ago. And we know that people outside of Africa have Neanderthal DNA which is proof positive that they interbred with H. sapiens. And that mating seems to have happened not once, not twice, but MANY times!
According to the OOA theory H. sapiens appeared in Africa around 200,000 years ago and when some of our species migrated out of Africa around 120,000 years ago or so our first stop was the Levant and Asia. Thus, we have tens of thousands of years to interact and interbreed with other species of ancient human ancestors!
Just when we thought we had it all figured out again along comes the Red Deer Cave People! In fact, it seems Asia was their home and they too interbred with modern humans, H. sapiens. Anyone getting the idea we like to interbreed? Evidence for this came from two caves in China, the Longlin Cave and the Moludong Cave. Bones found in the Maludong caves resemble the earliest species of the Homo genus BUT they only date to just 14,000 years ago! Bones found in the Longlin Cave date to only 10,500 years ago complicating our story even more!! And that’s not all because they look like the bones of a HYBRID of a modern human, H. sapiens, and some species much more archaic!! We aren’t sure which species these modern humans interbred with and we won’t know until we get more DNA evidence and the results may once again turn everything we THOUGHT we knew in this twisted evolutionary bush upside down!!
For millennia it now appears a variety of human species coexisted and interbred in Asia and elsewhere and today our once so simple straight line story is OBVIOUSLY NOT FACTUAL. Ours is a story full of mystery and interbreeding. Ours is a story twisted and even going forth and back again. A story of not only evolution but sometimes one of de-evolution!! Nothing is ever so simple in life and it now appears that has always been the case when it comes to the HUMAN STORY. And so, like a twisted bush or a braided stream we move on through time thinking we know our origins BUT as new evidence comes forth we may find once again that what we THOUGHT we knew was not and what we thought not …….. WAS.