The Origins Of Our Species Might Need A Rethink
On the outskirts of Beijing, a small limestone mountain named Dragon Bone Hill rises above the surrounding sprawl.
Along the northern side, a path leads up to some fenced-off caves that draw 150,000 visitors each year, from schoolchildren to grey-haired pensioners.
It was here, in 1929, that researchers discovered a nearly complete ancient skull that they determined was roughly half a million years old.
Dubbed Peking Man, it was among the earliest human remains ever uncovered, and it helped to convince many researchers that humanity first evolved in Asia.
Since then, the central importance of Peking Man has faded. Although modern dating methods put the fossil even earlier at up to 780,000 years old the specimen has been eclipsed by discoveries in Africa that have yielded much older remains of ancient human relatives.
Such finds have cemented Africa’s status as the cradle of humanity the place from which modern humans and their predecessors spread around the globe and relegated Asia to a kind of evolutionary cul-de-sac.
But the tale of Peking Man has haunted generations of Chinese researchers, who have struggled to understand its relationship to modern humans.
“It’s a story without an ending,” says Wu Xinzhi, a palaeontologist at the Chinese Academy of Sciences’ Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing.
They wonder whether the descendants of Peking Man and fellow members of the species Homo erectus died out or evolved into a more modern species, and whether they contributed to the gene pool of China today.
Keen to get to the bottom of its people’s ancestry, China has in the past decade stepped up its efforts to uncover evidence of early humans across the country.
It is reanalysing old fossil finds and pouring tens of millions of dollars a year into excavations. And the government is setting up a US$1.1-million laboratory at the IVPP to extract and sequence ancient DNA.
In its typical form, the story of Homo sapiens starts in Africa. The exact details vary from one telling to another, but the key characters and events generally remain the same. And the title is always ‘Out of Africa’.
In this standard view of human evolution, H. erectus first evolved there more than 2 million years ago.
Then, some time before 600,000 years ago, it gave rise to a new species: Homo heidelbergensis, the oldest remains of which have been found in Ethiopia.
About 400,000 years ago, some members of H. heidelbergensis left Africa and split into two branches: one ventured into the Middle East and Europe, where it evolved into Neanderthals; the other went east, where members became Denisovans a group first discovered in Siberia in 2010.
The remaining population of H. heidelbergensis in Africa eventually evolved into our own species, H. sapiens, about 200,000 years ago.
Then these early humans expanded their range to Eurasia 60,000 years ago, where they replaced local hominins with a minuscule amount of interbreeding.
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