Monday, March 16, 2009

PEKING MAN LIVED 200,000 YEARS EARLIER THAN PREVIOUS ESTIMATES

Because I go into classrooms teaching "Prehistoric Peoples" this news is exciting for me and my volunteer teachers.

Peking man, the group of early humans whose fossils were discovered in the 1920s, lived hundreds of thousands of years earlier than previously believed, a new study says. Obtained by measuring the decay of isotopes in buried quartz grains, the data suggests Peking man lived at Zhoukoudian about 750,000 years ago, 200,000 years earlier than prior estimates, according to the study, led by Guanjun Shen of China's Nanjing Normal University.

Some researchers believe the discovery hints at two separate migrations of Homo erectus (of which Peking man is a subspecies) out of Africa: one into northeastern China and another into Southeast Asia.(Remember "Java Man" discovered in the late 19th century) The new dates would also place Peking man in a more hospitable, cooler time period in China's Zhoukoudian region, which today is the world's foremost source of Homo erectus fossils.

The findings could redraw the map of Homo erectus' journey out of Africa, suggests anthropologist Russell Ciochon, of the University of Iowa, who published an accompanying analysis of the study (both papers appear in March 15 2009 issue of the journal Nature).

Ciochon hypothesizes that a prolonged mass migration of Homo erectus from Africa, which began about two million years ago, eventually came to something like a fork in the road. Reaching southern China, the early humans would have come upon a subtropical forest, which would have proved uninviting to Homo erectus, who were accustomed to savanna and open woodlands, Ciochon suggests.

One group probably turned southeast and settled in Southeast Asia, he said. A second group likely turned northeast and moved into what is now China. Part of the group settled the Zhoukoudian region and eventually evolved into the Peking man subspecies, Homo erectus pekinensis.

The Peking man subspecies is believed to have walked fully upright, used sophisticated stone tools, and sported a brain three-fourths the size of a modern human's.

In northeastern China during the newly suggested time period, Homo erectus
would have likely found a food-rich region similar to the landscapes the
species had been accustomed to. Before Homo erectus' arrival in the Zhoukoudian region, "we think the climate got cooler and drier and maybe moved more toward grasslands, which would attract more game and, in turn, human hunters," Ciochon said.

However, New York University paleoanthropologist Susan Antón said she doesn't believe the new data provide evidence for two migrations into Asia. "It's certainly possible that there were two migrations-or six or nine," said Antón, who was not involved in the new study. "But in order to talk about that, you would really need to have some
evidence along the routes of those pathways and also some sort of anchor point in Africa" that ties both migrations to a single origination region, she said.

http://news.nationalgeographic.com/news/2009/03/090312-peking-man.html

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