VOA标准英语2009年-Scientists Unearth Earliest Pre-Human Skel

By Jessica Berman
Washington
02 October 2009

Anthropologists from around the world have added another million or so years to the history of human evolution. Scientists say the latest fossil find - while not a direct ancestor of modern humans, may offer new insights into the primate¹ family tree. 

 
Probable life appearance of anterior² view of Ardipithecus ramidus "Ardi", ARA-VP 6/500
At 4.4 million years of age, Ardipithecus ramidus, which scientists have nicknamed Ardi, is now the oldest skeleton of a human ancestor since the discovery of Lucy, the 3.2 million-year-old female hominid skeleton discovered in Ethiopia in 1974. 

Until now, Lucy was believed to have shared a common ancestor with prehistoric³ apes and to have evolved from there.

But scientists say their new analysis of the older Ardipithecus skeleton suggests that chimps⁴ and humans evolved separately from an even older common relative.

Owen Lovejoy is a professor of Anthropology⁵ at Kent State University's Biomedical Sciences division in Ohio.

"This was like discovering a time capsule from a period and a place that we knew nothing about," Lovejoy said.

 
Digital representations of the Ar. ramidus cranium and mandible. This image relates to an article in the 02 October 2009 issue of Science.
It took anthropologists 17 years to assemble and analyze⁶ multiple skull⁷, hand, feet, limb and pelvis fragments of Ardipithecus, which were first discovered in ancient lake and stream deposits near the Ethiopian village of Aramis in 1992. 

Researchers say the composite skeleton belonged to an adult female who stood 120 centimeters, or four feet tall and weighed about 50 kilograms. 
 
Ardi had elongated⁸ palms and special joints⁹ and ligaments that allowed it to climb and hang from tree branches. Its bone structure also permitted walking upright on the ground like modern humans. But it lacked the arched feet and smooth gait evident in Lucy and other later hominids.
 
Researchers say that despite its many ape-like features, Ardipithecus was too different from modern chimps for the lineage to be considered direct.

 
Definitions from human, left, Ar. ramidus, middle, and chimpanzee, right, all males. Below are corresponding samples of the maxillary first molar in each.
Scientists note that Ardi's upper canine¹⁰ teeth are more like the stubby ones of modern humans than the long, sharp, pointed¹¹ ones of male chimps and other primates¹². A scientific analysis of the tooth enamel¹³ suggests Ardi enjoyed a diet of fruit and other woodland-based foods such as nuts and leaves.

Tim White, a professor at the Human Evolution Research Center at the University of California at Berkeley says Ardipithecus' mixture of ape and human-like features suggests that our "last common ancestor" may have been much older than anthropologists believe.

"We may have thought that human evolution began somewhat by accident a million years ago with the discovery of tools or 2.5 million years ago with the discovery of the first stone tools," White said. "But in fact, Ardipithecus tells us that we as humans have been evolving toward what we are today for at least six million years."

 
Partial skeleton of Ardipithecus ramidus, a hominid species living about 4.4 million years ago in Ethiopia. Eleven papers from an international team of authors published in print and online in this special issue describe anatomy¹⁴ of this species.
Scientists say they need more fossil finds dating back three to five million years to determine whether Ardipithecus might be even more closely related to early humans than the current evidence suggests.

Ethiopia regards Ardi's fossil remains¹⁵ as a national treasure, and they are on permanent display at the anthropology museum in Addis Ababa.

The discovery of Ardipithecus is detailed¹⁶ in 11 research papers published this week in the journal Science.

1 primate   

n.灵长类（目）动物，首席主教；adj.首要的

参考例句：

• 14 percent of primate species are highly endangered.14%的灵长类物种处于高度濒危状态。
• The woolly spider monkey is the largest primate in the Americas.绒毛蛛猴是美洲最大的灵长类动物。

2 anterior   

adj.较早的；在前的

参考例句：

• We've already finished the work anterior to the schedule.我们已经提前完成了工作。
• The anterior part of a fish contains the head and gills.鱼的前部包括头和鳃。

3 prehistoric   

adj.（有记载的）历史以前的，史前的，古老的

参考例句：

• They have found prehistoric remains.他们发现了史前遗迹。
• It was rather like an exhibition of prehistoric electronic equipment.这儿倒像是在展览古老的电子设备。

4 chimps   

（非洲）黑猩猩( chimp的名词复数 )

参考例句：

• Chimps are too scarce, and too nearly human, to be routinely slaughtered for spare parts. 黑猩猩又太少，也太接近于人类，不可以作为人器官备用件说杀就杀。 来自英汉非文学 - 生命科学 - 医学的第四次革命
• And as nonprimates, they provoke fewer ethical and safety-related concerns than chimps or baboons. 而且作为非灵长类，就不会产生像用黑猩猩或狒狒那样的伦理和安全方面的顾虑。 来自英汉非文学 - 生命科学 - 医学的第四次革命

5 anthropology   

n.人类学

参考例句：

• I believe he has started reading up anthropology.我相信他已开始深入研究人类学。
• Social anthropology is centrally concerned with the diversity of culture.社会人类学主要关于文化多样性。

6 analyze   

vt.分析，解析 (=analyse)

参考例句：

• We should analyze the cause and effect of this event.我们应该分析这场事变的因果。
• The teacher tried to analyze the cause of our failure.老师设法分析我们失败的原因。

7 skull   

n.头骨；颅骨

参考例句：

• The skull bones fuse between the ages of fifteen and twenty-five.头骨在15至25岁之间长合。
• He fell out of the window and cracked his skull.他从窗子摔了出去，跌裂了颅骨。

8 elongated   

v.延长，加长( elongate的过去式和过去分词 )

参考例句：

• Modigliani's women have strangely elongated faces. 莫迪里阿尼画中的妇女都长着奇长无比的脸。
• A piece of rubber can be elongated by streching. 一块橡皮可以拉长。 来自《用法词典》

9 joints   

接头( joint的名词复数 )； 关节； 公共场所（尤指价格低廉的饮食和娱乐场所） （非正式）； 一块烤肉 （英式英语）

参考例句：

• Expansion joints of various kinds are fitted on gas mains. 各种各样的伸缩接头被安装在煤气的总管道上了。
• Expansion joints of various kinds are fitted on steam pipes. 各种各样的伸缩接头被安装在蒸气管道上了。

10 canine   

adj.犬的，犬科的

参考例句：

• The fox is a canine animal.狐狸是犬科动物。
• Herbivorous animals have very small canine teeth,or none.食草动物的犬牙很小或者没有。

11 pointed   

adj.尖的，直截了当的

参考例句：

• He gave me a very sharp pointed pencil.他给我一支削得非常尖的铅笔。
• She wished to show Mrs.John Dashwood by this pointed invitation to her brother.她想通过对达茨伍德夫人提出直截了当的邀请向她的哥哥表示出来。

12 primates   

primate的复数

参考例句：

• Primates are alert, inquisitive animals. 灵长目动物是机灵、好奇的动物。
• Consciousness or cerebration has been said to have emerged in the evolution of higher primates. 据说意识或思考在较高级灵长类的进化中已出现。

13 enamel   

n.珐琅，搪瓷，瓷釉；(牙齿的)珐琅质

参考例句：

• I chipped the enamel on my front tooth when I fell over.我跌倒时门牙的珐琅质碰碎了。
• He collected coloured enamel bowls from Yugoslavia.他藏有来自南斯拉夫的彩色搪瓷碗。

14 anatomy   

n.解剖学，解剖；功能，结构，组织

参考例句：

• He found out a great deal about the anatomy of animals.在动物解剖学方面，他有过许多发现。
• The hurricane's anatomy was powerful and complex.对飓风的剖析是一项庞大而复杂的工作。

15 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

16 detailed   

adj.详细的，详尽的，极注意细节的，完全的

参考例句：

• He had made a detailed study of the terrain.他对地形作了缜密的研究。
• A detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。