“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 ago, is that this was an ice age on Earth.
Over Earth’s long history, there have been a number of times when ice and snow covered a large 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 and US scientists. It suggests Peking Man is probably our oldest cold weather human being, said Darryl Granger, an atmospheric scientist at Purdue University whose research appears in Thursday’s edition of the journal Nature.
The average yearly temperature at the time in that part of China was around the freezing 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 accidental or controlled.
Second, fur. There is no evidence that Peking Man used simple tools to make more form-fitting clothes, it’s more likely he wore animal fur.
Lastly, 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 as Peking Man did to fight the cold?
72. According to the new research, Peking Man actually dates back to _______.
A. around 500,000 years ago B. over 200,000 years
C. about 770,000 years ago D. about 2 million years ago
73. What is the most important standard for scientists to decide an ice age?
A. The weather conditions. B. The continuous existence of any large ice sheets.
C. The average yearly temperature D. The long period of snowfall
74. Which of the following is true of Peking Man?
A. He is the oldest human being B. He used fire to keep warm
C. He wore form-fitting clothes made from fur with simple tools.
D. He might have been shorter and wider than previously thought.
75. The following are all the possibilities EXCEPT _______ that the Peking Man survived the cold weather.
A. putting up tents to keep the cold out B. wearing animal fur
C. using fire in their cave D. developing gradually to handle the cold.
度的下列说法中,物理含义正确的是