Fossil and molecular evidence suggests the earliest ancestors of the human family lived in forested areas in equatorial Africa in the late Miocene era some 8 to 10 million years ago, when changes in climate may have increased in distance between food patches. That would have forced our earliest ancestors to travel longer distances on the ground and favored those who could cover more ground using less energy. “This isn’t the complete answer,” Sockol said. “But it’s a good piece of a puzzle humans have always wondered about: How and why did we become human? And why do we alone walk on two legs?” (435 words) 文章主题词：human出现7处，walk出现14处，legs出现7处 )：ancestors出现5处， Chimps(Chimpanzees/黑猩猩)出现10处， 结论：文章将用黑猩猩作为研究对象研究人类祖先用两条腿走路的原因。 2.扫视全文， 挑选出文章中可能设为考点的语句： A team of scientists that studied chimpanzees trained to use treadmills has gathered new evidence suggesting that our earliest apelike ancestors started walking on two legs because it required less energy than getting around on all fours. “When our earliest ancestors started walking on two legs, they took the first steps toward becoming human,” said lead(领导) researcher(研究者) Michael Sockol of UC Davis1. “Our findings help answer why.” Sockol worked for two years to find an animal trainer willing to coax adult chimps to walk on two legs and to “knucklewalk” on all fours on the sort of treadmill found in most gymsThe five chimps(黑猩猩) also wore face masks (面具)used to help the researchers measure oxygen consumption. While the chimps worked out, the scientists collected metabolic and other data that allowed them to calculate which method of locomotion used less energy and why. The team gathered the same information for four adult humans walking on a treadmill. The researchers (研究者)found(发现) that human walking used about 75 percent less energy and burned 75 percent fewer calories than quadrupedal and bipedal2 walking in chimpanzees. They also(也) found that for some but not all of the chimps, walking on two legs was no more costly than knucklewalking. “We were prepared to find that all of the chimps used more energy walking on two legs – but that finding wouldn’t have been as interesting,” Sockol said(说). “What we found was much more telling. For three chimps, bipedalism3 was more expensive, but for the other two chimps, this wasn’t the case. One spent about the same energy walking on two legs as on four. The other used less energy walking upright.” These two chimps had different gaits and anatomy than their knucklewalking peers. Taken together, the findings(研究发现) provide(提供) support(支持) for the hypothesis(假设) that anatomical differences affecting gait existed among our earliest apelike ancestors, and that these differences provided the genetic variation which natural selection could act on when changes in the environment gave bipeds an advantage over quadrupeds. Fossil(化石) and molecular(分子的) evidence(证据) suggests (显示，建议)the earliest ancestors of the human family lived in forested areas in equatorial Africa in the late Miocene era some 8 to 10 million years ago, when changes in climate may have increased in distance between food patches. That would have forced our earliest ancestors to travel longer distances on the ground and favored those who could cover more ground using less energy. “This isn’t the complete answer,” Sockol said. “But it’s a good piece of a puzzle humans have always wondered about: How and why did we become human? And why do we alone walk on two legs?” (435 words) 3.直接解题： 1. What did Michael Sockol and his team(研究小组) find out(发现， 找出) in their study(研究) of chimpanzees(黑猩猩)? A) The evidence(证据) why chimpanzees can be trained (被训练)to use treadmills(踏车， 跑步机). B) The evidence why our apelike (象猿人的)ancestors(祖先) came to (开始)walk on four legs. C )The evidence why our apelike ancestors came to walk on two legs. D) The evidence why chimpanzees can be trained to walk on two legs. 1.C.该题可以利用文章主题内容直接判断答案， 也可以利用问题句及被选项中的特征结构及细节信息结构(加粗字体内容)共同作为答案线索， 在文章中查找答案相关句： (可能的考点句)A team of (一组)scientists (科学家)that studied chimpanzees trained to use treadmills (跑步机)has gathered(收集，集合) new evidence (证据)suggesting(表明)that our earliest (初期的)apelike(象猿人的) ancestors(象猿人的) started(开始) walking on two legs because(因为) it required(需要， 要求) less(较少的) energy(能量)than getting around (到处走动)on all fours(四肢). (一组研究被训练学习使用跑步机的黑猩猩的科学家们发现了一些新的证据：我们的人猿祖先开始直立行走是因为两条腿比四条腿行走省力) “When our earliest ancestors started walking on two legs, they took the first steps toward becoming human,” said lead(领导) researcher(研究带头人) Michael Sockol of UC Davis1. “Our findings help answer why.” Sockol worked for two years to find an animal trainer willing to coax adult chimps to walk on two legs and to “knucklewalk” on all fours on the sort of treadmill found in most gyms. |
