VOA标准英语2011--New Species Might be Human Ancestor

New Species Might be Human Ancestor

Fossils found in a South African cave might belong to a new species of early humans that holds a unique place on the evolutionary¹ road to modern man.
On a 2008 mapping expedition in Malapa, South Africa, American paleoanthropologist Lee Berger made a remarkable² discovery: the fossilized bones of a human-like woman and a boy buried in cave sediments³. The two - possibly a mother and her son - lived almost two million years ago, about the time anthropologists believe the first modern humans were beginning to walk the Earth.
The new species, one of a family of non-ape human ancestors known as hominins is called Australopithecus sediba.
Berger says the age of the find is significant.
“The most accurate date that probably has ever been produced for an early hominin site in Africa at 1.977 million years, placing Australopithecus sediba squarely in the potential for being the best candidate for the ancestor leading to the emergence⁴ of the genus homo,” says Berger.
The partial skeletons reveal that the hominins had an ape-sized brain but human-shaped hips⁵ and pelvis. They walked upright on long legs, but also climbed trees with even longer, ape-like arms.
Report co-author Tracy Kivell, with the Max Planck Institute for Evolutionary Anthropology⁶ in Leipzig, Germany, notes in her study of the adult female’s hand that the fossils display a mix of primitive⁷ features and modern traits.
“Just like the rest of the skeleton," Kivell says, "the Sediba hand revealed a surprising mix of features that we wouldn’t have predicted could exist in the same hand.”
Kivell says the hand, which is the most complete in the hominin record, is very modern-looking, with a long thumb and short somewhat curved fingers - a sign of precision gripping.
“By precision grips, I just mean when we move the pad of our thumb towards the pads of our fingers like when we’re holding a pen or using a key.”
And, since primitive stone tools are evident in the archaeological record more than a half-million years before Sediba’s time, Kivell says it’s possible these hominins used their versatile⁸ hands to make tools.
“We think that with this long thumb and short fingers in Sediba that it would have been capable of making those finer movements and manipulating objects in a way that’s similar to humans and later homo.”
Researchers also used a powerful x-ray scanner to create high resolution images of the hominin’s brain case. Kristian Carlson, of the University of Witwatersrand, says that while the brain is ape-sized, the expanded region behind where the olfactory⁹, or smell sensors¹⁰, are located suggests Sediba’s more advanced thinking ability.
“We can’t talk about interconnections of neurons, but what we can say - and maybe that’s very little - is that this expansion could be related to the initial development of these sorts of activities and those are information in coding and retrieval, relational reasoning and multitasking abilities.”
The fossils also include one of the more complete pelvises every discovered and a foot with evidence of a human-like arch and well-defined Achilles tendon. The heel and shin bone appear to be more ape-like.
With its mosaic¹¹ of traits, the Sediba find has sparked a debate over exactly where it belongs on the human family tree.
The consensus¹², as reported in the Journal Science, is that Australopithecus sediba represents a transitional species to the genus Homo, perhaps as ancestor to Homo erectus, which leads to our own species, Homo sapiens.
Although Sediba’s discovery adds an important new chapter to the human story, much more work remains¹³. Team leader Berger says it will take continued finds of quality fossils to fill the remaining gaps in our evolutionary history.

1 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• Life has its own evolutionary process.生命有其自身的进化过程。
• These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。

2 remarkable   

adj.显著的，异常的，非凡的，值得注意的

参考例句：

• She has made remarkable headway in her writing skills.她在写作技巧方面有了长足进步。
• These cars are remarkable for the quietness of their engines.这些汽车因发动机没有噪音而不同凡响。

3 sediments   

沉淀物( sediment的名词复数 )； 沉积物

参考例句：

• When deposited, 70-80% of the volume of muddy sediments may be water. 泥质沉积物沉积后，体积的70-80％是水。
• Oligocene erosion had truncated the sediments draped over the dome. 覆盖于穹丘上的沉积岩为渐新世侵蚀所截削。

4 emergence   

n.浮现，显现，出现，（植物）突出体

参考例句：

• The last decade saw the emergence of a dynamic economy.最近10年见证了经济增长的姿态。
• Language emerges and develops with the emergence and development of society.语言是随着社会的产生而产生，随着社会的发展而发展的。

5 hips   

abbr.high impact polystyrene 高冲击强度聚苯乙烯，耐冲性聚苯乙烯n.臀部( hip的名词复数 )；[建筑学]屋脊；臀围（尺寸）；臀部…的

参考例句：

• She stood with her hands on her hips. 她双手叉腰站着。
• They wiggled their hips to the sound of pop music. 他们随着流行音乐的声音摇晃着臀部。 来自《简明英汉词典》

6 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。

7 primitive   

adj.原始的；简单的；n.原(始)人，原始事物

参考例句：

• It is a primitive instinct to flee a place of danger.逃离危险的地方是一种原始本能。
• His book describes the march of the civilization of a primitive society.他的著作描述了一个原始社会的开化过程。

8 versatile   

adj.通用的，万用的；多才多艺的，多方面的

参考例句：

• A versatile person is often good at a number of different things.多才多艺的人通常擅长许多种不同的事情。
• He had been one of the game's most versatile athletes.他是这项运动中技术最全面的运动员之一。

9 olfactory   

adj.嗅觉的

参考例句：

• He is to develop a sensor to substitute for the olfactory abilities of dogs.克罗克将研制一种传感器用以代替狗的嗅觉功能。
• Based on these findings, Keller suspects that each person has an olfactory blind spot.根据这些发现，凯勒推断，每个人都有一个嗅觉盲区。

10 sensors   

n.传感器，灵敏元件( sensor的名词复数 )

参考例句：

• There were more than 2000 sensors here. 这里装有两千多个灵敏元件。 来自《简明英汉词典》
• Significant changes have been noted where sensors were exposed to trichloride. 当传感器暴露在三氯化物中时，有很大变化。 来自辞典例句

11 mosaic   

n./adj.镶嵌细工的，镶嵌工艺品的，嵌花式的

参考例句：

• The sky this morning is a mosaic of blue and white.今天早上的天空是幅蓝白相间的画面。
• The image mosaic is a troublesome work.图象镶嵌是个麻烦的工作。

12 consensus   

n.(意见等的)一致，一致同意，共识

参考例句：

• Can we reach a consensus on this issue?我们能在这个问题上取得一致意见吗？
• What is the consensus of opinion at the afternoon meeting?下午会议上一致的意见是什么？

13 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。