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成才之路・英语人教版・选修8（通用本）路漫漫其修远兮吾将上下而求索L Units ---------------------- Meeting your ancestors■“Around 500,000 years ago, at the Peking Man Site at Zhoukoudian in Beijing's suburban Fangshan district, which is about 50 km from the city of Beijing, there lived early human beings, ” says a China history textbook.■The textbook now has to be revised. New dating techniques suggest the remains of Peking Man-found in the 1920s-are over 200,000 years older than previously thought. What's important about that date, about 770,000 years ago, is that this was■Over Earth's long history, there have been a number of times when ice and snow covered alarge part of its surface. Such periods are known as ice ages.■Earth is in an ice age now. It started about 2 million years ago. Despite the many warm periods since then, scientists regard the whole time as one ice age because of the continuous existence of at least one large ice sheet-the one over Antarctica.■ The new discovery was made by Chinese andUS scientists. It suggests Peking Man isprobably our oldest cold weather humanbeing, said Darryl Granger, an atmosphericscientist at Purdue University whoseresearch appe< the journal Nat ■The averagesday f s edition of yearlytemperature atthe time in thatpart of Chinawas around thefreezing mark,but it was too dry for an ice sheet, Granger said.■This raises a question. How did Peking Man survive the cold weather?■Rick Potts, a Smithsonian Institution human origins expert who wasn't involved in the research, raised three possibilities:■First, fire. Early findings showed signs of a fire in Peking Man's cave. But there has been debate about whether the fire was■Second, fur. There is no evidence that Peking Man used simple tools to make moreformfitting clothes. It's more likely he wore animal fur.■Last, he may have developed gradually to handle the cold. Peking Man may have experienced physiological changes that allowed more blood to flow to his hands and legs, Potts said. “People in general who live in colder climates tend to be shorter and wider, ” he explained.■ Unlike the times of Peking Man, today the global temperature is rising due to the greenhouse effect. In the future, could humans develop to handle the warmth just asPeking Man did to fight the cold?■最新研究发现北京人的年代应该是处于冰河世纪,比我们原先的估计早二十多万年。
