15.Camels are well known for their ability to survive the hot and dry conditions of the desert,but a study suggests they once grew well in colder climates.Scientists have found fossilized(化石) parts of a leg bone belonging to a giant camel that lived in the forests of Canada's High Arctic about 3.5million years ago.
The research is published in the journal Nature Communication.Dr.Mike Buckley,an author of the paper from the university of Manchester,said,"What's special about this story is that this is the northernmost evidence of camels."The area was warmer than today 3.5 million years ago,but the ancient giant camels would have had to face long and bitter winter,with temperatures below freezing.There would have been snowstorms and about six months of darkness.
While scientists have known for some time that camels existed in North America,with the earliest creatures dating to about 45 million years ago,they were astonished to find a species at such a latitude(緯度).
Over the course of three investigations,which began in 2006,researchers from the Canadian Museum of Nature collected 30 pieces of the leg bone from Ellesmere Island in Canada.
Their size suggested that the animal was about 30% larger than today's camels,measuring about 2.7m from foot to shoulder.Despite its size,the researchers believe it would have been similar in appearance,although it probably had a thicker coat to stay warm.
To investigate further,the team took the protein found in the bone from the fossils and modern animals.Dr.Buckley said,"The results tell us that it is a direct ancestor of modern camels."
He said the findings provided a new insight into the evolution of this animal."It suggests that many of the adaptations that we currently think of,in terms of camels being adapted to warm desert-like environments,could have actually originated through adaptation to quite the opposite cold,bitter environments.Camels'humps(峰)which store fat could help get through an Arctic six-month winter.Their large eyes would have helped them to see in the low light,and their wide,flat feet would have been just as useful for walking on snow as they are on sand,"he explained.
28.What surprised the scientists when they found the giant camel fossils?C
A.Their size.
B.Their shape.
C.Their location.
D.Their number.
29.According to the text,the ancient giant camelsB.
A.could date to about 45million years ago
B.struggled to survive in severe conditions
C.were the first ancestors of modern camels
D.lived in an environment without light
30.Compared with modern camels,the ancient giant camelsA.
A.were much taller
B.had more humps
C.were slightly stronger
D.had thinner coat
31.We can infer from what Dr.Buckley said thatA.
A.giant camels had special adaptations for polar life
B.cold environments prevented giant camels developing
C.the cause of the extinction of gian camels remains unknown
D.the hard climates forced giant camels to find warm environments.
分析 本文告訴我們駱駝以其在沙漠炎熱干燥的條件下生存的能力而聞名,最近一項研究表明它們在寒冷的氣候中曾經(jīng)生長得很好,這是因為科學(xué)家發(fā)現(xiàn)了一只生活在加拿大北極森林的巨型駱駝化石,這一言論發(fā)表在雜志上后,引發(fā)了很多科學(xué)家的不同觀點,他們進(jìn)一步研究發(fā)現(xiàn)生活在加拿大北極森林的巨型駱駝是現(xiàn)代駱駝的直系祖先.
解答 28.C;細(xì)節(jié)理解題.根據(jù)文中"Dr.Mike Buckley,an author of the paper from the university of Manchester,said,"What's special about this story is that this is the northernmost evidence of camels."(曼徹斯特大學(xué)的論文作者巴克利博士說:"這個故事的特別之處在于,這是最北部的駱駝證據(jù)),可知當(dāng)科學(xué)家們發(fā)現(xiàn)了巨大的駱駝化石時,這讓科學(xué)家們大吃一驚的是他們的位置,故選C.
29.B;細(xì)節(jié)理解題.根據(jù)文中"but the ancient giant camels would have had to face long and bitter winter,with temperatures below freezing.There would have been snowstorms and about six months of darkness."(但是,古代的巨型駱駝不得不面對漫長而又苦澀的冬天,溫度低于冰點.可能會有暴風(fēng)雪和大約六個月的黑暗),可知古代的巨型駱駝在惡劣的條件下掙扎求生.故選B.
30.A;細(xì)節(jié)理解題.根據(jù)文中"Their size suggested that the animal was about 30% larger than today's camels"(他們的尺寸表明,這只動物比今天的駱駝大30%),可知與現(xiàn)代駱駝相比,古老的巨型駱駝更高大.故選A.
31.A;推理判斷題.根據(jù)文中"in terms of camels being adapted to warm desert-like environments,could have actually originated through adaptation to quite the opposite cold"(在駱駝被適應(yīng)溫暖的沙漠的環(huán)境中,實際上可能是通過適應(yīng)相對于相反的寒冷而產(chǎn)生的),可以推斷出巨大的駱駝對極地生活有特殊的適應(yīng)能力.故選A.
點評 本文考察學(xué)生的細(xì)節(jié)理解和推斷能力以及細(xì)心程度,只要抓住文章的關(guān)鍵詞,采用尋讀的方法查找細(xì)節(jié),就能找到正確答案.