Human Fossils Dated to 195,000 Years

时间：2009-10-28 05:07:06

（单词翻译:单击）

Researchers determined1 that the specimens3 are around 195,000 years old.
对化石的深入分析使现代人的历史可以追溯到19.5万年以前。

A new analysis of bones unearthed4（采掘出的） nearly 40 years ago in Ethiopia has pushed the fossil record of modern humans back to nearly 200,000 years ago perhaps close to the dawn of the species.

Researchers determined that the specimens are around 195,000 years old. Previously5, the oldest known fossils of Homo sapiens were Ethiopian skulls7 dated to about 160,000 years ago.

Genetic8 studies estimate that Homo sapiens（智人） arose about 200,000 years ago, so the new research brings the fossil record more in line with that, said John Fleagle of Stony9 Brook10 University in New York, an author of the study.

The fossils were found in 1967 near the Omo River in southwestern Ethiopia. One location yielded Omo I, which includes part of a skull6 plus skeletal（骨骼的） bones. Another site produced Omo II, which has more of a skull but no skeletal bones. Neither specimen2 has a complete face.

Although Omo II shows more primitive11（原始的） characteristics than Omo I, scientists called both specimens Homo sapiens and assigned a tentative（试验性质的，暂时的） age of 130,000 years.

Now, after visiting the discovery sites, analyzing12 their geology（地质学） and testing rock samples with more modern dating techniques, Fleagle and colleagues report in Thursday's issue of the journal Nature that both specimens are 195,000 years old, give or take 5,000 years.

Fleagle said the more primitive traits（特征） of Omo II may mean the two specimens came from different but overlapping13 Homo sapiens populations, or that they just represent natural variation within a single population.

To find the age of the skulls, the researchers determined that volcanic14 rock lying just below the sediment15 that contained the fossils was about 196,000 years old. They then found evidence that the fossil-bearing sediment was deposited soon after that time.

Paul Renne, director of the Berkeley Geochronology Center, which specializes in dating rocks, said the researchers made "a reasonably good argument" to support their dating of the fossils.

"It's more likely than not," he said, calling the work "very exciting and important."     


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1 determined duszmP     
adj.坚定的；有决心的
参考例句：
  • I have determined on going to Tibet after graduation.我已决定毕业后去西藏。
  • He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。
2 specimen Xvtwm     
n.样本，标本
参考例句：
  • You'll need tweezers to hold up the specimen.你要用镊子来夹这标本。
  • This specimen is richly variegated in colour.这件标本上有很多颜色。
3 specimens 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》
4 unearthed e4d49b43cc52eefcadbac6d2e94bb832     
出土的（考古）
参考例句：
  • Many unearthed cultural relics are set forth in the exhibition hall. 展览馆里陈列着许多出土文物。
  • Some utensils were in a state of decay when they were unearthed. 有些器皿在出土时已经残破。
5 previously bkzzzC     
adv.以前，先前（地）
参考例句：
  • The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
  • Let me digress for a moment and explain what had happened previously.让我岔开一会儿，解释原先发生了什么。
6 skull CETyO     
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。
7 skulls d44073bc27628272fdd5bac11adb1ab5     
颅骨( skull的名词复数 )； 脑袋； 脑子； 脑瓜
参考例句：
  • One of the women's skulls found exceeds in capacity that of the average man of today. 现已发现的女性颅骨中，其中有一个的脑容量超过了今天的普通男子。
  • We could make a whole plain white with skulls in the moonlight! 我们便能令月光下的平原变白，遍布白色的骷髅！
8 genetic PgIxp     
adj.遗传的，遗传学的
参考例句：
  • It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
  • Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。
9 stony qu1wX     
adj.石头的，多石头的，冷酷的，无情的
参考例句：
  • The ground is too dry and stony.这块地太干，而且布满了石头。
  • He listened to her story with a stony expression.他带着冷漠的表情听她讲经历。
10 brook PSIyg     
n.小河，溪；v.忍受，容让
参考例句：
  • In our room we could hear the murmur of a distant brook.在我们房间能听到远处小溪汩汩的流水声。
  • The brook trickled through the valley.小溪涓涓流过峡谷。
11 primitive vSwz0     
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。
12 analyzing be408cc8d92ec310bb6260bc127c162b     
v.分析；分析( analyze的现在分词 )；分解；解释；对…进行心理分析n.分析
参考例句：
  • Analyzing the date of some socialist countries presents even greater problem s. 分析某些社会主义国家的统计数据，暴露出的问题甚至更大。 来自辞典例句
  • He undoubtedly was not far off the mark in analyzing its predictions. 当然，他对其预测所作的分析倒也八九不离十。 来自辞典例句
13 overlapping Gmqz4t     
adj./n.交迭（的）
参考例句：
  • There is no overlapping question between the two courses. 这两门课程之间不存在重叠的问题。
  • A trimetrogon strip is composed of three rows of overlapping. 三镜头摄影航线为三排重迭的象片所组成。
14 volcanic BLgzQ     
adj.火山的；象火山的；由火山引起的
参考例句：
  • There have been several volcanic eruptions this year.今年火山爆发了好几次。
  • Volcanic activity has created thermal springs and boiling mud pools.火山活动产生了温泉和沸腾的泥浆池。
15 sediment IsByK     
n.沉淀，沉渣，沉积(物)
参考例句：
  • The sediment settled and the water was clear.杂质沉淀后，水变清了。
  • Sediment begins to choke the channel's opening.沉积物开始淤塞河道口。

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