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For years, archaeologist Huw Groucutt and his team had driven one particular stretch of desert on their way to dig sites in Saudi Arabia. As they drove they caught glimpses of what looked like bones, emerging from the slowly eroding sand. Finally, in 2014, the team decided to explore the array of bones at Al Wusta. Within two years, amidst more than 800 fossilized animal bones and nearly 400 stone artifacts, they discovered something remarkable: the middle digit of a finger bone, from what appeared to be a modern human.
Anatomically modern, that is. The fossilized finger dated to at least 85,000 years ago.
[...] The discovery is “a dream come true, because it supports arguments that our teams have been making for more than 10 years,” said archaeologist Michael Petraglia, another co-author of the study, in a press conference. “This find together with other finds in the last few years suggests that modern humans, Homo sapiens, are moving out of Africa multiple times during many windows of opportunity in the last 100,000 years or so.”
The question of how humans left Africa has been debated ever since it became widely accepted that Homo sapiens did indeed evolve from ancestral species in Africa, rather than Asia. (That latter hypothesis was proposed by scientists like Ernst Haeckel, and preferred by many anthropologists until as recently as 60 years ago; some modern researchers still argue for multiple evolutionary jumping off points, based on fossil finds in China). In the past decade, some geneticists have argued for a single dispersal event from Africa around 60,000 years ago, based on the decreasing genetic diversity in populations that are farther from Africa.
But others believe that the order of events was a bit more complicated.
“Our previous work found that multiple dispersals, with the first one being older than the 50,000 to 70,000 [years-ago] migration, are most compatible with the pattern of both cranial and genetic variation observed among people today,” said Katerina Harvati, director of paleoanthropology at the University of Tubingen, Germany, by email.
Harvati, who wasn’t involved in the research, said she would be cautious in definitively assigning the finger fossil a Homo sapiens identity due to the fact that its shape overlaps with other hominin species. But the fossil does fit the larger pattern of discoveries made in the region. Skulls belonging to Homo sapiens found in Qafzeh and Skhul in Israel have been dated back to 100,000 years and 120,000 years respectively, and the discovery of a human jawbone from Misliya Cave was dated to around 177,000 years earlier in 2018.
All of these fossils suggest humans left Africa much earlier than 60,000 years ago. But the new finger bone suggests some populations continued moving, beyond the Levant and into the Arabian Peninsula.
[...] The finger gestures to another question as well: What happened to the population that made it all the way to Arabia? Were they forced to move forward, or retreat when the environment became inhospitable once more within centuries after they arrived?
(Score: 3, Informative) by HiThere on Wednesday April 11 2018, @05:59PM (4 children)
There are multiple strands of evidence leading to the "out of Africa again and again" interpretation, and a few that lead to a "out of Africa and back again and again" interpretation.
This is a very interesting fossil, but to me it doesn't seem all that paradigm breaking.
You need to remember that when a theory is first proposed it is proposed in the simplest form that fits all the data available at that time. As more data accumulate, the theory needs to be rendered more complex to account for it. But there's nothing really surprising in the idea that groups of people migrated back and forth over the centuries, there just originally wasn't any need to assume that, so they picked the simpler form of the theory that didn't assume complications like that.
Last time I checked (in a popular source) there were about 8 major flows of population back and forth indicated by genetic analysis. Many of them were, admittedly, a bit uncertain. This is partially because genetic data doesn't preserve well outside living animals.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 0) by Anonymous Coward on Wednesday April 11 2018, @06:41PM (3 children)
Properly, it isn't called a theory at that point.
It's called a hypothesis.
We need to see|use that word more often.
...and there are many MANY things that never rise beyond the level of hypothesis and make it to "theory".
Theory is actually the highest level[1] that an idea can achieve in science.
It means that a notion has stood up to lots of examination and nobody has been able to shoot holes in it.
[1] There used to be a thing called a law where a notion was described by an equation.
I don't think any new thing has been called a law in quite some time.
-- OriginalOwner_ [soylentnews.org]
(Score: 2) by Reziac on Thursday April 12 2018, @06:09AM (1 child)
How do I mod this " +1 Pedantic " ??
And there is no Alkibiades to come back and save us from ourselves.
(Score: 0) by Anonymous Coward on Thursday April 12 2018, @09:56PM
That's OK. It's the thought that counts. 8-)
-- OriginalOwner_ [soylentnews.org]
(Score: 2) by HiThere on Friday April 13 2018, @04:40PM
Not really. They predicted a action and looked for evidence. They found it. and it was supportive of the theory.
The problem is, there were other, less likely, ways the evidence they found could also have occurred. But they did find the genetic evidence, so I think it counts as a theory. In fact, they found evidence weakly indicating that population flows had gone back and forth more often than they had expected. So though the evidence was, indeed, inconclusive it did substantiate an even stronger version of their hypothesis than they had expected. I think, then, that it counts as a theory, albeit one that needs more substantiating evidence. The finger bone counts as additional substantiating evidence, but it doesn't show which way the group of from which it was extracted was headed.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.