英国出土欧洲最古老的现代人颚骨-凯发k8官网

英国出土欧洲最古老的现代人颚骨
文章来源:未知 文章作者:enread 发布时间:2011-11-06 03:44 字体: [ ] 
(单词翻译:双击或拖选)

a piece of jawbone 2 from a 3(史前的) cave in england is the earliest evidence for modern humans in europe, according to an international team of scientists. the bone first was believed to be about 35,000 years old, but the new research study shows it to be significantly older -- between 41,000 and 44,000 years old, according to the findings that will be published in the journal nature. the new dating of the bone is expected to help scientists pin down how quickly the modern humans spread across europe during the last ice age. it also helps confirm the much-debated theory that early humans coexisted with neanderthals. beth shapiro, the shaffer associate professor of biology at penn state university and a member of the research team, explained that the fragment of maxilla(上颌骨) -- the upper 1 -- containing three teeth was 4 in 1927 in a prehistoric 5 cave called kent's 6 in southwestern england. records from the original 8, undertaken by the torquay natural history society located in devon, england, indicate that the jawbone was discovered 10 feet 6 inches beneath the surface and was sealed by stalagmite(石笋) deposits. "in 1989, scientists at 9 university dated the bone as being about 35,000 years old. however, doubts were later raised about the 10 of the date because traces of modern glue, which was used to 11 the bone after discovery, were found on the surface," shapiro said. "we knew we were going to have to do additional testing to re-date the bone." because the remaining uncontaminated area of bone was deemed too small to re-date, the research team searched through the 7 archives and collections in the torquay museum to obtain samples of other animal bones from recorded depths both above and below the spot where the maxilla was found.

members of the research team then obtained radiocarbon dates for the bones of wolf, deer, cave bear, and woolly 12, all of which were found close to the maxilla, and all of which could be dated at between 50,000 and 26,000 years old. using a bayesian statistical-modelling method, the scientists then were able to calculate an age for the maxilla. the new date indicates that the bone is between 41,000 and 44,000 years old.

tom higham, deputy director of oxford university's radiocarbon accelerator unit and a member of the research team, said "radiocarbon dating of ancient bones is very difficult to do. because the initial date from this fragment of jawbone was 13 by traces of modern glue, the initial measurement made in 1989 was too young. the new dating evidence we have obtained allows us, for the first time, to 14 the real age of this key 15. we believe this piece of jawbone is the earliest direct evidence we have of modern humans in northwestern europe."

shapiro explained that the new and more-accurate date is especially important because it provides clearer evidence about the coexistence of neanderthals and anatomically(结构上) modern humans. "if the jawbone is, in fact, 41,000 to 44,000 years old, that means it was from a time when neanderthals were still present in europe, so we first had to confirm that the bone was from an anatomically modern human, and not a neanderthal," shapiro said. shapiro and her team first tried to extract mitochondrial 16 from one of the teeth, but there were 17 amounts for 18 dna sequencing. eventually, team members were able to use a virtual three-dimensional model based on a ct scan of the jawbone to carry out a 19 analysis of the fossil. they compared the external and internal shapes of the teeth with those of modern human and neanderthal fossils from a number of different sites. they found early modern human characteristics in all but three of the 16 dental characteristics.



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1 5xgy9     
n.颚,颌,说教,流言蜚语;v.喋喋不休,教训
参考例句:
  • he delivered a right hook to his opponent's jaw.他给了对方下巴一记右钩拳。
  • a strong square jaw is a sign of firm character.强健的方下巴是刚毅性格的标志。
2 3cafdb6f7c26ffe41daf7aa353505858     
v.挖掘( excavate的过去式和过去分词 );开凿;挖出;发掘
参考例句:
  • the site has been excavated by archaeologists. 这个遗址已被考古学家发掘出来。
  • the archaeologists excavated an ancient fortress. 考古学家们发掘出一个古堡。 来自《简明英汉词典》
3 spvxq     
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 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 w3xyj     
n.石灰石
参考例句:
  • limestone is often used in building construction.石灰岩常用于建筑。
  • cement is made from limestone.水泥是由石灰石制成的。
6 ec2yo     
n.洞穴,大山洞
参考例句:
  • the cavern walls echoed his cries.大山洞的四壁回响着他的喊声。
  • it suddenly began to shower,and we took refuge in the cavern.天突然下起雨来,我们在一个山洞里避雨。
7 rikzy     
n.挖掘,发掘;被挖掘之地
参考例句:
  • the bad weather has hung up the work of excavation.天气不好耽误了挖掘工作。
  • the excavation exposed some ancient ruins.这次挖掘暴露出一些古遗迹。
8 185c90d3198bc18760370b8a86c53f51     
n.挖掘( excavation的名词复数 );开凿;开凿的洞穴(或山路等);(发掘出来的)古迹
参考例句:
  • the excavations are open to the public. 发掘现场对公众开放。
  • this year's excavations may reveal ancient artifacts. 今年的挖掘可能会发现史前古器物。 来自辞典例句
9 wmmz0a     
n.牛津(英国城市)
参考例句:
  • at present he has become a professor of chemistry at oxford.他现在已是牛津大学的化学教授了。
  • this is where the road to oxford joins the road to london.这是去牛津的路与去伦敦的路的汇合处。
10 qvexf     
n.可靠性,确实性
参考例句:
  • we mustn't presume too much upon the reliability of such sources.我们不应过分指望这类消息来源的可靠性。
  • i can assure you of the reliability of the information.我向你保证这消息可靠。
11 vyryp     
vt.保存,保护,节约,节省,守恒,不灭
参考例句:
  • he writes on both sides of the sheet to conserve paper.他在纸张的两面都写字以节省用纸。
  • conserve your energy,you'll need it!保存你的精力,你会用得着的!
12 txxxw     
n.犀牛
参考例句:
  • the rhinoceros has one horn on its nose.犀牛鼻子上有一个角。
  • the body of the rhinoceros likes a cattle and the head likes a triangle.犀牛的形体像牛,头呈三角形。
13 tzuzg0     
adj.不自然的,假装的
参考例句:
  • she showed an affected interest in our subject.她假装对我们的课题感到兴趣。
  • his manners are affected.他的态度不自然。
14 xnexl     
vt.准确地确定;用针标出…的精确位置
参考例句:
  • it is difficult to pinpoint when water problems of the modern age began.很难准确地指出,现代用水的问题是什么时候出现的。
  • i could pinpoint his precise location on a map.我能在地图上指明他的准确位置。
15 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。
16 4u3z1l     
(缩)deoxyribonucleic acid 脱氧核糖核酸
参考例句:
  • dna is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
  • gene mutations are alterations in the dna code.基因突变是指dna密码的改变。
17 l5vxu     
adj.(for,of)不足的,不够的
参考例句:
  • there was insufficient evidence to convict him.没有足够证据给他定罪。
  • in their day scientific knowledge was insufficient to settle the matter.在他们的时代,科学知识还不能足以解决这些问题。
18 eicwm     
adj.有确实根据的;有效的;正当的,合法的
参考例句:
  • his claim to own the house is valid.他主张对此屋的所有权有效。
  • do you have valid reasons for your absence?你的缺席有正当理由吗?
19 xunzms     
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。
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