Evolution and humans: more findings in Asia (Evolution)

by David Turell @, Friday, November 09, 2018, 19:13 (10 days ago) @ dhw

Africa may be the origin but ancient homo forms are turning up in China, suggesting H. erectus was there very early:

https://kopitiambot.com/2018/07/12/asia-cradle-of-humankind-new-fossil-finds-are-rewrit...

"At the time, the Peking Man remains were the oldest known fossils belonging to human ancestors. Their discovery in the 1920s and 30s caused a sensation, triggering declarations that the cradle of humanity had been found.

"The last decade has seen the discovery of new Asian fossils, among others by Chinese palaeoanthropologists with a renewed interest in their heritage. As key moments in our past are rewritten, the spotlight is once more turning to the East.

The first Peking Man remains were found in 1923, nearly 50km outside Beijing. Alongside the broad-nosed individuals with thick brows were burned animal bones, suggesting an early human ancestor capable of controlling fire.

***

"At the time, the Peking Man remains were the oldest known fossils belonging to human ancestors. Their discovery in the 1920s and 30s caused a sensation, triggering declarations that the cradle of humanity had been found. But just a few decades later, all eyes had turned to Africa. A slew of discoveries there left little doubt that it was our true ancestral home. As far as human evolution was concerned, Asia was out of the picture.

"Not any more. The last decade has seen the discovery of new Asian fossils, among others by Chinese palaeoanthropologists with a renewed interest in their heritage. As key moments in our past are rewritten, the spotlight is once more turning to the East.

"The first Peking Man remains were found in 1923, nearly 50km outside Beijing. Alongside the broad-nosed individuals with thick brows were burned animal bones, suggesting an early human ancestor capable of controlling fire.

***

"Dali Man, a 260,000-year-old skull found 14 years earlier in the central province of Shaanxi, had a similar mix of features, typical of “transitional forms”, that cannot be ascribed to any well-defined species. Although the Yunxian and Dali Man fossils are particularly fine examples, many more have been found in east Asia.

"Then, in 2009, Chinese scientists announced the discovery of a 110,000-year-old jawbone in the southern province of Guangxi. Though relatively primitive, it displayed a prominent human-like chin. The team classified it as Homo sapiens, which would mean that our species was in Asia a good 50,000 years before we previously thought.

***

"The tide began to turn in 2015, when 47 teeth were found inside a cave in Daoxian, in Hunan province, also in southern China. Teeth are one of the best ways to distinguish between hominin species, and these were distinctly human – belonging to our own species – not to mention very old. According to Wu Liu at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing and his colleagues, they had been lying around for 80,000 to 120,000 years.

"For Wu, the mounting evidence could only mean one thing: “Early modern humans were in southern China at least 100,000 years ago.”

***

"There seems little doubt that our direct ancestors ventured east out of Africa far earlier than the standard narrative allows.

"This is a huge change to the standard view. But it does not explain those weird transitional fossils from China that display a mix of Homo erectus and Homo sapiens features. Being hundreds of thousands of years old, they predate even the earlier exodus out of Africa. The most radical suggestion is that they are evidence that Homo erectus evolved into Homo sapiens in east Asia.

"The idea that we evolved from a number of separate populations was once regarded as maverick, but has become more respectable.

***

"A more likely explanation for the transitional fossils is that Asia, like Africa, was once home to various human groups that exchanged genes. Along with Homo erectus, genetic studies have revealed a number of hominins whose identity is still a mystery. Later, there was the diminutive “hobbit”, Homo floresiensis, found on the Indonesian island of Flores from 100,000 years ago, preceded by an ancestral species going back 700,000 years.

***

"If these various species interbred, they should have left behind hybrids scattered across Asia. Indeed, the surprisingly rich variety among east Asian fossils suggests hybridisation was widespread, says María Martinón-Torres, director of the National Research Centre on Human Evolution, in Burgos, Spain.

"Martinón-Torres and her colleagues have also shown that hominins in Africa and Eurasia did evolve relatively independently for a long time. When they examined 5,000 fossil teeth spanning 2.5 million years, they found that each continent had its own distinct type of teeth – strong evidence that Eurasia was a centre of speciation in its own right.

***

"The truth is, the story of our evolution is still being rewritten and we cannot be sure how it will turn out. What is certain is that Asia can no longer be sidelined. It is possible that the species we evolved from made its own migration into Africa before giving rise to us. Our ancestors then left Africa at least 100,000 years ago and travelled the breadth of Eurasia for millennia."

Comment: Interesting


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