足骨化石开启人类进化新认识-凯发k8官网

足骨化石开启人类进化新认识
文章来源:未知 文章作者:enread 发布时间:2012-03-29 06:34 字体: [ ] 
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scientists have obtained a fascinating new insight into the evolution of humans and our ability to walk.

科学家对于人类的进化以及直立行走的能力有了全新的认识。

the eight elements are all from the forefoot
the eight elements are all from the forefoot
it comes from the fossilised bones of a foot that were discovered in ethiopia and dated to be 3.4 million years old.

the researchers say they do not have enough 1 to identify the species of hominin, or human ancestor, from which the right foot came.

but they tell nature journal that just the shape of the bones shows the creature could walk upright at times.

the fossil haul consists of eight elements from the forefoot - bones such as metatarsals(跖骨) and phalanges(趾骨) .

the 2 were pulled from clay 3 at burtele in the central afar region, about 520km north-east of the capital addis ababa.

it is a significant discovery because it demonstrates there was more than one pre-human species living in east africa between three and four million years ago, each with its own method of moving around.

the other creature was the famous "lucy" animal (australopithecus afarensis), whose remains were first identified in the afar in the 1970s.

lucy's body was built for walking. her big toe was 4 with the other four 5 of the foot, and she had a human-like arch that allowed for very efficient 6.

the owner of the partial foot from burtele was not afarensis; that can be said 7.

the fossils indicate it had no arch and the big toe was opposed to the other digits, enabling the animal to grasp branches in a tree.

but the fact this creature could and would walk on the ground is evidenced by the nature of the bone 9. these were arranged such that the foot could push off, or toe-off - something only humans do as they walk, and something flat-footed apes cannot achieve.

"if you look at the 10(侧面的) metatarsal head along with the proximal(临近的) toe bone, the phalanx - that particular 8 is really unique in hominids," explained team member dr bruce latimer of case western reserve university, us.

"you can see it's a very different kind of a joint, because when you toe-off and push forward in that last phase of walking, your toes are highly 11. in order to achieve that, you have to change the base of the phalanx and the metatarsal head - you have to change both sides of the joint. and it's a highly characteristic type of change that we can pick out immediately," he told the bbc.



点击收听单词发音收听单词发音  

1 1kmzty     
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。
2 91fc365099a256001af897127174fcce     
n.样品( specimen的名词复数 );范例;(化验的)抽样;某种类型的人
参考例句:
  • astronauts have brought back specimens of rock from the moon. 宇航员从月球带回了岩石标本。
  • the traveler brought back some specimens of the rocks from the mountains. 那位旅行者从山上带回了一些岩石标本。 来自《简明英汉词典》
3 8b3acb612b624abdf2c2881bc6928565     
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 165f93b99f87c219277d70d866425da6     
adj.对齐的,均衡的
参考例句:
  • make sure the shelf is aligned with the top of the cupboard.务必使搁架与橱柜顶端对齐。
5 a2aacbd15b619a9b9e5581a6c33bd2b1     
n.数字( digit的名词复数 );手指,足趾
参考例句:
  • the number 1000 contains four digits. 1000是四位数。 来自《简明英汉词典》
  • the number 410 contains three digits. 数字 410 中包括三个数目字。 来自《现代英汉综合大词典》
6 48vzm     
n.运动,移动
参考例句:
  • by land,air or sea,birds are masters of locomotion.无论是通过陆地,飞越空中还是穿过海洋,鸟应算是运动能手了。
  • food sources also elicit oriented locomotion and recognition behavior patterns in most insects.食物源也引诱大多数昆虫定向迁移和识别行为。
7 bfa3c9e3e641847693ee64d5d8ab604b     
adv.决定性地,最后地
参考例句:
  • none of the three super-states could be definitively conquered even by the other two in combination. 三个超级国家中的任何一国都不可能被任何两国的联盟所绝对打败。 来自英汉文学
  • therefore, nothing can ever be definitively proved with a photograph. 因此,没有什么可以明确了一张照片。 来自互联网
8 m3lx4     
adj.联合的,共同的;n.关节,接合处;v.连接,贴合
参考例句:
  • i had a bad fall,which put my shoulder out of joint.我重重地摔了一跤,肩膀脫臼了。
  • we wrote a letter in joint names.我们联名写了封信。
9 d97dcffd67eca7255ca514e4084b746e     
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 83ey7     
adj.侧面的,旁边的
参考例句:
  • an airfoil that controls lateral motion.能够控制横向飞行的机翼。
  • mr.dawson walked into the court from a lateral door.道森先生从一个侧面的门走进法庭。
11 703e75e8210e20f0cb60ad926085640e     
adj.[医]曲折的,屈曲v.屈曲( flex的过去式和过去分词 );弯曲;(为准备大干而)显示实力;摩拳擦掌
参考例句:
  • he stretched and flexed his knees to relax himself. 他伸屈膝关节使自己放松一下。 来自辞典例句
  • he flexed his long stringy muscles manfully. 他孔武有力地弯起膀子,显露出细长条的肌肉。 来自辞典例句
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