The climate crisis may lead the human race to decrease in size, as mammals (哺乳动物) with smaller bodies appear better able to deal with rising global temperatures, a leading fossil expert said.
Prof Steve Brusatte, a palaeontologist (古生物学家) at the University of Edinburgh, suggested that the way in which other mammals have previously responded to periods of climate change could offer an insight into humans’ future.
He compared the potential situation of people as similar to that of early horses, which became smaller in body size as temperatures rose around 55m years ago, a period called the Paleocene Eocene Thermal Maximum.
Writing in The Rise and Reign of the Mammals, Brusatte notes that animals in warmer parts of the world today are often smaller than those in colder areas, an ecological principle known as Bergmann’s rule. “The reasons are not entirely understood, but it is probably, in part, because smaller animals have a higher surface area compared to their size than bigger animals and can thus better get rid of extra heat” he writes.
Brusatte said that becoming smaller was “a common way that mammals deal with climate change”. He added, “That’s not to say every species of mammal would get smaller, but it seems to be a common survival trick of mammals when temperatures spike pretty quickly, which does raise the question: if temperatures do spike really quickly, might humans dwarf, might humans get smaller? And I think that’s certainly convincing.”
In a recent study, researchers studying human remains over the past million years have also suggested that temperature is a major predictor of body size variation, while scientists studying red deer have said that warmer winters in northern Europe and Scandinavia may lead to the body size of these animals becoming smaller.
However, not all experts agree that rising temperature causes mammals to decease. Prof Adrian Lister, of the Natural History Museum in London, said the relationship shown by the recent human remains study is weak, while the strong relationship between temperature and mammal body size may often result from the availability of food and resources.
Lister doubts whether humans will shrink as the climate heats. “We are not really controlled by natural selection,” he said. “If that was going to happen, you’d need to find large people dying before they could reproduce because of climate warming. That is not happening in today’s world. We wear clothes, we have got heating, we have got air conditioning if it is too hot.”
12. According to the passage, the early horses got smaller in body size
.
A.to keep cool | B.to save food |
C.to keep warm | D.to avoid being killed |
13. What does the underlined word “spike” in the 5th paragraph mean?
A.Rise | B.Drop | C.Balance | D.Change |
14. What is Brusatte most likely to agree with?
A.Every species of mammal would get smaller as the temperature goes up. |
B.Animals in warmer areas are definitely smaller than those in colder areas. |
C.Smaller animals have a higher surface area and so they can cool down quickly. |
D.The change of Mammals’ body size is closely related to their food and other resources. |
15. What’s the best title of the passage?
A.Climate Change Causes Natural Disasters. | B.Climate Change Leads to Heated Discussions. |
C.Climate Change Causes Changes in Body Size. | D.Climate Change Leads to Changed Lifestyle. |