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(纬度).
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 本文告诉我们骆驼以其在沙漠炎热干燥的条件下生存的能力而闻名,最近一项研究表明它们在寒冷的气候中曾经生长得很好,这是因为科学家发现了一只生活在加拿大北极森林的巨型骆驼化石,这一言论发表在杂志上后,引发了很多科学家的不同观点,他们进一步研究发现生活在加拿大北极森林的巨型骆驼是现代骆驼的直系祖先.
解答 28.C;细节理解题.根据文中"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."(曼彻斯特大学的论文作者巴克利博士说:"这个故事的特别之处在于,这是最北部的骆驼证据),可知当科学家们发现了巨大的骆驼化石时,这让科学家们大吃一惊的是他们的位置,故选C.
29.B;细节理解题.根据文中"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,古代的巨型骆驼不得不面对漫长而又苦涩的冬天,温度低于冰点.可能会有暴风雪和大约六个月的黑暗),可知古代的巨型骆驼在恶劣的条件下挣扎求生.故选B.
30.A;细节理解题.根据文中"Their size suggested that the animal was about 30% larger than today's camels"(他们的尺寸表明,这只动物比今天的骆驼大30%),可知与现代骆驼相比,古老的巨型骆驼更高大.故选A.
31.A;推理判断题.根据文中"in terms of camels being adapted to warm desert-like environments,could have actually originated through adaptation to quite the opposite cold"(在骆驼被适应温暖的沙漠的环境中,实际上可能是通过适应相对于相反的寒冷而产生的),可以推断出巨大的骆驼对极地生活有特殊的适应能力.故选A.
点评 本文考察学生的细节理解和推断能力以及细心程度,只要抓住文章的关键词,采用寻读的方法查找细节,就能找到正确答案.