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第四十八篇 Researchers Discover Why Humans Began Walking Upright

Most of us walk and carry items in our hands every day. These are seemingly simple activities tllat the majority of us don't question. But an international team of researchers, including Dr. Richmond from GW's Columbian College of Arts and Sciences, have discovered that human walking upright, may have originated millions of years ago as art adaptation to carrying scarce, high-quality resources.The team of researchers from the U. S. , England, Japan and Portugal investigated the behavior of modem day chimpanzees as they competed for food resources, in an effort to understand what ecological settings would lead a large ape～one that resembles the 6 million-year old ancestor we shared in common with living chimpanzees-to walk on two legs.

"These chimpanzees provide a model of the ecological conditions under which our earliest ancestors might have begun walking on two legs, " said Dr. Richmond.

The research findings suggest that chimpanzees switch to moving on two limbs instead of four in situations where they need to monopolize a resource. Standing on two legs allows them to carry much more at one time because it flees up their hands.Over time, intense bursts of bipedal activity4 may have led to anatomical changes that in turn became the subject of natural selection where competition for food or other resources was strong.

Two studies were conducted by the team in Guinea.The first study was conducted by the team in Kyoto University’s "Outdoor laboratory" in a natural clearing in Bossouo Forest. Researchers allowed the wild chimpanzees access to different combinations of two different types of nut-the oil palm Nut , which is naturally widely available, and the coula nut, which is not, the chimpanzees' behavior was monitored in three situations: (a)when only oil palm nuts were available, (b)when a small number of coula nuts were available, and(c)when coula nuts were the majority available resource.

When the rare coula nuts were available only in small numbers. the chimpanzees transported more at one time. Similarly, when coula nuts were the majority resource, the chimpanzees ignored the oil palm nuts altogether. The chimpanzees regarded the coula nuts as a more highly-prized resource and competed for them more intensely.

In such high-competition settings, the frequency of cases in which the chimpanzees startedmoving on two legs increased by a factor of four. Not only was it obvious that bipedal movement allowed them to carry more of this precious resource, but also that they were actively trying to move as much as they could in one go by using everything available—even their mouths.

The second study, by Kimberley Hockings of Oxford Brookes University, was a l4-month study of Bossou chimpanzees crop-raiding, a situation in which they have to compete for rare and unpredictable resources. Here, 35 percent of the chimpanzees' activity involved some sort of bipedal movement, and once again, this behavior appeared to be linked to a clear attempt to carry as much as possible at one time.

詞匯：

scarce aaj. 缺乏的，不足的；稀有的

bipedal adj. 二足的

chimpanzee n. 黑猩猩

anatomical adj. 解剖的

ape n. 無尾猿；類人猿

coula nuts(coula也可寫作cola或kola)可樂果

注釋：

1. GW’S Columbian College of Arts and Sciences：喬治·華盛頓大學(xué)哥倫比亞藝術(shù)與科學(xué)學(xué)院。喬治·華盛頓大學(xué)(George Washington University)的英文簡稱為GW, 是美國頂尖的私立大學(xué)之一，于l821年建校，位于美國首都華盛頓。

2. ecological settings：生態(tài)環(huán)境

3. bipedal activity：雙足活動

4. anatomical change：解剖學(xué)上的變化

5. Kyoto University：京都大學(xué)，是繼東京大學(xué)之后成立的疆本第二所國立大學(xué)，于l897年建校。京都大學(xué)主要校區(qū)位于日本歷史名城京都市。

6. Bossou：博蘇，幾內(nèi)亞的一個地名。博蘇森林生活著黑猩猩群落。

7. oil palm nut：油棕櫚堅(jiān)果

8. increased by a factor of four：增加了四倍

9. in one go：一口氣

10. Oxford Brookes University：牛津布魯克斯大學(xué)，劊立于1865年，是英國最具特色的綜合性大學(xué)之一。牛津布魯克斯大學(xué)位于世界學(xué)術(shù)名城——牛津。這里學(xué)風(fēng)濃郁、精英薈萃，歷來為求學(xué)圣地。

練習(xí)：

1. Which of the following statements is NOT true according to the first two paragraphs?

A. Many people question{he simple human activities of walking and carrying items.

B. Chimpanzee’s behaviors may suggest why humans Walk on two legs.

C. Human walking upright is viewed as all adaptation to carrying precious resources.

D. Our ancestors’ecological conditions resembled those of modem—day chimpanzees'.

2. Dr.Richmond conducted the experiment with the purpose of finding

A. when humans began walking on two legs.

B. what made our ancestors walk upright.

C. what benefits walking upright brought to our ancestors.

D. how walking upright helped chimpanzees monopolize resources.

3. Kyoto University’s study discovered that chimpanzees

A. regarded both types of nut as priced resources.

B. preferred oil palm nuts to coula nuts.

C. liked coula nuts better than oil palm nuts.

D. ignored both types of nut altogether.

4. Why did the chimpanzees walk on two limbs during Kyoto University’s experiment?

A. Because they imitated the human way of walking just for fun.

B. Because they wanted to please the researchers to get more coula nuts from them.

C. Because they wanted to get to the nut-rich forest faster by walking that way.

D. Because they Wanted to carry more nut with two free limbs.

5. What call we infer from the reading passage ?

A. Chimpanzees are in the same process of evolution as our ancestors Were.

B. Chimpanzees are similar to humans in many behaviors.

C. Walking oil two limbs and walking on four limbs each have their advantages.

D. Human walking On two legs developed as a means of survival.

答案與題解：

1. A 第一段第一句和第二旬說明，大多數(shù)人對人類直立行走習(xí)以為常，并不質(zhì)疑這種習(xí)慣。而A的內(nèi)容正好與此相反，所以是答案。其他選項(xiàng)所述內(nèi)容均可從第一段和第二段推斷出來。

2. B 文章報道，科學(xué)家通過實(shí)驗(yàn)證實(shí)黑猩猩直立行走是為了解放前肢，讓前肢搬運(yùn)對其生命至關(guān)重要的資源，從而推斷出人類祖先也經(jīng)歷了從四足到二足的進(jìn)化過程�？茖W(xué)家想通過對黑猩猩的實(shí)驗(yàn)解釋人類直立行走的成因。所以B是答案，A、C、D選項(xiàng)不是科學(xué)家進(jìn)行研究的目的。

3. C 第五段明白無誤地描述了黑猩猩全然不顧油棕櫚堅(jiān)果(ignored the oil palm nuts altogether)，集中精力搶運(yùn)可樂果。所以C是答案， B、C、D的內(nèi)容不符合文章原意。

4. D黑猩猩用后胺直立行走，搬運(yùn)資源的效率提高了四倍。選項(xiàng)D符合原意，是答案。選項(xiàng)A、B、C的內(nèi)容文章中沒有提到，所以不是答案。

5. D了解了通篇文章的意思，就會選擇選項(xiàng)D。人類直立行走是受生態(tài)環(huán)境所迫，是人類生存的一種手段，直立行走是自然選擇的結(jié)果。選項(xiàng)A和C的內(nèi)容文章中沒有涉及。文章中有選項(xiàng)B的內(nèi)容，但它不是文章的主旨。