Humans -homo sapiens - haven't changed genetically all that much in 50,000 years, but we have been busy.
Professor Murray Cox of Massey University's School of Fundamental Sciences joined Afternoons to discuss our early beginnings and what other species of hominins we mingled with.
Cox says all early humans, including Neanderthals, had their start in Africa and the first known human artwork, found in South Africa, is around 90,000 years old. The artwork was a series of crossed lines resembling a hashtag.
A museum display of a Neanderthal tribe. Photo: 123rf.com
“Of course, we’ve evolved a lot since then.”
While human-type species have been around 500,000 years, what we define as human – artworks, complex cultures and so on – are relatively recent.
“There’s no sort of line in the sand, but changes over time.”
He says if we went back 90,000 years to meet our ancestors, we would have some things in common.
“They would be eating food, much like us. Not microwaving it, of course, but cooking it on the campfire. They would have been talking, communicating and hunting – all sorts of things we kind of do today.”
Humans left Africa around 50,000 years ago and began knocking into all sorts of different groups of human-like species.
“We encountered all of these groups as we trotted out of Africa to our respective places around the world.”
There’s been a long standing theory that, as we left Africa, we began to wipe out other human-like groups like Neanderthals. But Cox says another possibility is that we simply mixed with them.
“We know Neanderthal and Denisovan populations were very small. Conversely, modern human populations when we started moving out of Africa grew really fast. We probably just interbred with them.”
The supporting evidence is that we all have Denisovan and Neanderthal DNA within us at moderately high frequencies.
“There’s a question, did we wipe them out, or did we become them in some sense.”
Skin colour differences between humans have been a driving force of many atrocities throughout history but Cox says pigmentation differences are relatively recent.
“If you go back and look at the first Europeans, they were dark-skinned and, in fact, the light skin colour we now associate with modern Europeans came in really recently. It only started changing around 5000-10,000 years ago.”
As for why it changed, there are a couple theories.
“The first idea is that it’s somehow to do with climate. In order to survive, we need vitamin D and we get that by processing sunlight on the skin. If you have very dark skin and you live at high latitudes in northern Europe, then it’s very hard to get vitamin D, so there might have been selection for lighter skin colours.
“The other idea is that it has nothing to do with that but is in fact sexual selection. People just liked people who had light skin and blue eyes and preferentially married them and then their children carried on these characteristics. We don’t really know, but those are the two main ideas.”
Cox says the health of early humans was relatively good and it wasn’t until we began to settle into villages and started farming that we started to get diseases and illness.
“During the early farming revolution you’d probably be lucky to live to 30 or 40. Of course, we have many more advances now so we live much longer. It was pretty rough 10,000 years ago.”
