Saturday, September 24, 2011

Deep history - 40,000 years without change

John Hawks and Dienekes have excellent posts on research that emphasizes the churn and chaos of the melding of the sentient apes into one vast world crushing species. The churn and transformations across Europe surprise everyone.

Paleogenetics is awe inspiring.

Both reference one related story; a story not of transformation but of stasis. The sequencing of a 100 year old hair follicle (yes, science fiction lives) tells the long story of the first Australians (emphases mine) ...

Australian Aborigine Hair Tells a Story of Human Migration - Nicholas Wade - NYTimes.com

.... The Aboriginal genome bolsters earlier genetic evidence showing that once the Aborigines’ ancestors arrived in Australia, some 50,000 years ago, they somehow kept the whole continent to themselves without admitting any outsiders...

... Based on the rate of mutation in DNA, the geneticists estimate that the Aborigines split from the ancestors of all Eurasians some 70,000 years ago, and that the ancestors of Europeans and East Asians split from each other about 30,000 years ago....

... the split times calculated by the Danish team are compatible with the more reliable archaeological dates, which record the earliest known human presence in Australia at 44,000 years ago. The Aborigines’ ancestors could have arrived several thousand years before this date.

The Aborigine occupation of Australia presents a series of puzzles, starting with the nature of their stone tools. The early stone tools found in Australia are much simpler than the Upper Paleolithic tools that appear in Europe at the same era...

... the first inhabitants of Australia must have possessed advanced boat-building technology to cross from the nearest point in Asia to Sahul, the ancient continent that included Australia, New Guinea and Tasmania until the rise of sea level that occurred at the end of the last ice age, 10,000 years ago. But there is no archaeological evidence for boats, Dr. Klein said.

Despite the Aborigines’ genetic isolation, there is evidence of some profound cultural exchange that occurred around 6,000 years ago. The stone tools become more sophisticated, and the population increased. The Aborigines did not domesticate plants or animals, but a wild dog, the dingo, first appears in the archaeological record at this time...

... How the dingo arrived in Australia is an “enigma,” Dr. Savolainen writes, because none of the other elements of Polynesian culture are found there...

... Even stranger, dogs always travel with their masters, yet there is no sign yet of Polynesian genes in the Aborigine population.

“Something remarkable happened in Australia 6,000 to 4,000 years ago, and it involved much more than the dingo,” Dr. Klein said.

50,000 years is a long time to be separated for a rapidly evolving animal. In 2007 Hawks told us "We are more different genetically from people living 5,000 years ago than they were different from Neanderthals." The European invaders of Australia must have been very different from the Australian aboriginals of the 19th century; much more different than Neandertals and ancient Egyptians. We will come to understand how different as more data is published from this genome.

There are so many fascinating aspects to this story, but one number stands above all. For about 40,000 years humans lived in Australia, and, as best we can tell, they didn't change. They were much like the humans who lived in Georgian caves for 30,000 years, but they lived into the modern era.

Forty thousand years.

Ten years ago we didn't have iPhones. Within two hundred years we will likely create artificial minds. In the unlikely event that we have heirs in 42,000 ACE they will be completely alien.

Forty thousand years, as ice came and went and oceans rose and fell.

If all other humans had died out, how long would they have lasted there unchanging? With a population of about 500,000 hunter gatherers over a vast territory they would not fall to disease. They faced no real predator threats. They had adjusted to radical climate change. Eventually some mass extinction event, a meteor or supervolcano, would end them -- but perhaps not for hundreds of thousands of years ...

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