Peking Man grows much older in new study.A group of Chinese fossils known collectively as Peking Man dates to at least 400,000 years ago, considerably earlier than previous estimates, according to preliminary analysis of sediment at the site where the finds first emerged in 1921. If the revised age holds up, it suggests that Homo erectus-the species to which Peking Man belongs-lived in East Asia before modern humans did. The former age estimate of 200,000 to 300,000 years for the fossils raised the possibility that H. erectus and an early form of H. sapiens existed simultaneously in that part of the world. Even given a markedly older Peking Man, however, current debates over the nature of human evolution appear unlikely to vanish. For instance, Ian Tattersall tat·ter·sall also Tat·ter·sall n. 1. A pattern of dark lines forming squares on a light background. 2. Cloth woven or printed with this pattern. adj. of the American Museum of Natural History American Museum of Natural History, incorporated in New York City in 1869 to promote the study of natural science and related subjects. Buildings on its present site were opened in 1877. in New York City New York City: see New York, city. New York City City (pop., 2000: 8,008,278), southeastern New York, at the mouth of the Hudson River. The largest city in the U.S. sees no reason at this point to revise his opinion that H. erectus evolved only in East Africa as a dead-end species and that separate Homo species in Africa eventually led to modern humans. Alternatively, H. erectus may have spread from Africa to Europe and Asia, giving rise to H. sapiens in perhaps one geographic region, argues G. Philip Rightmire of the State University of New York at Binghamton Binghamton University, State University of New York, or their officially adopted name, Binghamton University, is a coeducational public research university located in Vestal, New York. . Rightmire acknowledges that the new Peking Man date will probably get a warm greeting from scientists who contend that modern humans evolved separately in Africa and Asia. But, he adds, "we need to wait and see if the revised date for the Chinese specimens is determined to be acceptable." Richard Teh-Lung Ku, a geochronologist at the University of Southern California The U.S. News & World Report ranked USC 27th among all universities in the United States in its 2008 ranking of "America's Best Colleges", also designating it as one of the "most selective universities" for admitting 8,634 of the almost 34,000 who applied for freshman admission in Los Angeles, directed the new study. It is slated to appear in the August Acta Anthropologica Sinica, a scientific journal published in China. Ku devised a technique in which he uses a mass spectrometer to analyze limestone crystals extracted from soil in the Chinese deposits, located in the Zhoukoudian cave near Beijing. From measurements of small amounts of radioactive uranium and thorium thorium (thôr`ēəm) [from Thor], radioactive chemical element; symbol Th; at. no. 90; at. wt. 232.0381; m.p. about 1,750°C;; b.p. about 4,790°C;; sp. gr. 11.7 at 20°C;; valence +4. in the limestone, Ku then calculated the material's age. The crystals were located just above the region where excavators unearthed the Peking Man fossils and are unlikely to be contaminated because they are so small, Ku asserts. Until now, he states, the dating of Peking Man relied on less precise analyses of fossilized fos·sil·ize v. fos·sil·ized, fos·sil·iz·ing, fos·sil·iz·es v.tr. 1. To convert into a fossil. 2. To make outmoded or inflexible with time; antiquate. v.intr. bone. Investigators have found at least 40 H. erectus individuals at the cave, as well as stone tools and evidence of fire use. |
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