2015考研英语阅读英文原刊《经济学人》：寒武纪大爆发

　　Dr Zhu and his colleagues hope to find out exactly how these environmental changescorrespond to changes in the fossil record.

　　朱博士和他的同事希望从化石记录的变化中发现这个时期环境是如何确切变化的。

　　The animals’ carnival

　　动物狂欢节

　　Fortunately, China’s fossil record for this period is rich.

　　幸运的是，中国在这个时期的化石资料是非常丰富的。

　　Until recently, the only known fossils of Precambrian animals were what is called theEdiacaran fauna—a handful of strange creatures found in Australia, Canada and the EnglishMidlands that lived in the Ediacaran period, between 635m and 541m years ago, and whichbear little resemblance to what came afterwards.

　　直到目前，唯一知道的前寒武纪一少部分化石是埃迪卡拉动物群。它们生活与生活在距今6.35亿年到5.42亿年之间埃迪卡拉纪，在澳大利亚、加拿大、英格兰中部等地区被发现，但是他们和寒武纪的生物相似性很少。

　　In 1998, however, a team led by Chen Junyuan, also of the Nanjing Institute, and another ledby Xiao Shuhai of the Virginia Polytechnic Institute, in America, discovered a 580m-year-oldLagersttte—a place where fossils are particularly well preserved—in a geological formationcalled the Doushantuo, which spreads out across southern China.

　　然而，1998年，一个由同样来自南京所的陈俊元和美国弗吉尼亚理工大学的肖书海共同领导的小组在中国南部一个广泛存在的陡山沱地质构造中发现了一个距今5.8亿年且保存出奇的好的生物群。

　　Portents of the modern world

　　现代世界的前兆

　　This Lagersttte has yielded many previously unknown species, including microscopicsponges, small tubular organisms of unknown nature, things that look like jellyfish but mightnot be and a range of what appear to be embryos that show bilateral symmetry.

　　这个生物群落发现了许多之前不知道的物种，包括微型海绵生物，不知名物种的小管器官，一些似是而非的软体动物，以及一些有对称结构的像是胚胎的生物。

　　What these embryos would have grown into is unclear. But some might be the ancestors ofthe Cambrian megafauna.

　　这些胚胎将会长成什么不得而知，但是他们中的一些可能就是寒武纪大型动物的祖先。

　　To try to link the evolution of these species with changes in the environment, Chu Xueleiof the Institute of Geology and Geophysics in Beijing and his colleagues have been looking atcarbon isotopes in the Doushantuo rocks.

　　为了把这些物种的进化和环境变化联系起来，北京地质与地球物理研究所的储雪雷和他的同事用碳同位素方法测试陡山沱石块。

　　They have found that the proportion of 12C—a light isotope of carbon that is more easilyincorporated by living organisms into organic matter than its heavy cousin, 13C—increasedon at least three occasions during the Ediacaran period.

　　他们发现在埃迪卡拉纪有至少三次12C的增加，而较轻的碳同位素12C相比于它的同胞13C更容易被生物体吸收转化为有机物。

　　They suggest these increases mark moments when the amount of oxygen in seawater wentup, because more oxygen would mean more oxidisation of buried organic matter. Thatwould liberate its 12C, for incorporation into rocks.

　　他们推测这些增长标志当时海水中的氧含量在增长，因为更多的氧气意味着更多的埋藏的有机物的氧化。他们在变成化石的过程中就将释放12C。

　　Each of Dr Chu’s oxidation events corresponds with an increase in the size, complexity anddiversity of life, both plant and animal.

　　褚博士的每个氧化事项都与动植物在其体积，复杂性、多样性上的增加有关。

　　What triggered what, however, is unclear.

　　然而，哪一个引发哪一个却不得而知。

　　There may have been an increase in photosynthesis because there were more algaearound.

　　这有可能因为出现了更多的藻类，光合作用增强，

　　Or eroded material from newly formed mountains may have buried organic matter thatwould otherwise have reacted with oxygen, leading to a build-up of the gas.

　　或者是新形成的山脉上的腐蚀物质埋藏本该和氧气反应的有机物，导致气体的增加。

　　The last—and most dramatic—rise in oxygen took place towards the end of the Ediacaran.

　　最戏剧性的，也是氧气含量最后的增长发生在埃迪卡拉纪末期。

　　Follow-up work by Dr Zhu, in nine other sections of the Doushantuo formation, suggests thissurge started just after the final Precambrian glacial period about 560m years ago, andwent on for 9m years.

　　后续的工作由朱博士完成，有九个其他的陡山沱构造说明这个激增仅仅是在最后一次前寒武纪冰川之后，大约5.6亿年前，并且持续了900万年。

　　These dates overlap with those of signs of oxidation found in rocks in other parts of the world,confirming that whatever was going on affected the entire planet.

　　这些数据和全球其他地方发现的化石中的氧化物一起确定了到底是什么将影响整个星球。

　　Dr Zhu suspects this global environmental shift propelled the evolution of complexanimals.

　　朱博士认为是全球环境的变化促进了复杂动物的进化。

　　Dr Zhu also plans to push back before the Ediacaran period.

　　朱博士还计划回推到埃迪卡拉纪之前。

　　Other researchers have found fossils of algae and wormlike creatures in rocks in northernChina that pre-date the end of the Marinoan glaciation, 635m years ago, which marks theboundary between the Ediacaran and the Cryogenian period that precedes it.

　　其他研究者已经在中国北部的石块中发现了藻类和类似虫子的生物的化石，其年代在6.35亿年之前的圣马力诺冰期末端之前，圣马力诺冰期确定了其之前埃迪卡拉纪和成冰纪之间的边界。

　　Such fossils are hard to study, so Dr Zhu will use new imaging technologies that can look atthem without having to clean away the surrounding rock, and are also able to detect traces offossil organic matter invisible to the eye.

　　这些化石很难去研究，所以朱博士利用可以清晰成像而不用去清除周边石块的新成像技术，并且可以探测不被肉眼可见的化石有机物的踪迹。

　　Besides digging back before the Ediacaran, the new project’s researchers also intend toanalyse the unfolding of the Cambrian explosion itself by taking advantage of otherLagersttten—for China has several that date from the Cambrian.

　　除了研究埃迪卡拉纪之前以外，新项目的研究者还利用其他生物群去分析未解开的寒武纪大爆炸，因为中国有好几个这样寒武纪的群落。

　　Dr Chen, indeed, first made his name in 1984, when he excavated one at Chengjiang inYunnan province.

　　陈博士因为1984年发掘了云南澄江生物群而出名，

　　It dates from 525m years ago, which make it 20m years older than the most famousCambrianLagersttte in the West, the Burgess shale of British Columbia, in Canada.

　　澄江生物群大概在5.25亿年以前，这就使得他比西方著名的加拿大不列颠哥伦比亚的波基斯页岩寒武纪群落早了2000万年。

　　The project’s researchers plan to see how, evolutionarily speaking, the various Lagerst?ttenrelate to one another, to try to determine exactly when different groups of organismsemerged.

　　这个项目的研究者计划从进化学上解释，不同的群落是怎么和其他的群落发生联系，并且试图解决到底什么时候出现了不同的生物分类。

　　They will also look at the chemistry of elements other than carbon and oxygen—particularlynitrogen and phosphorous, which are essential to life, and sulphur, which often indicates theabsence of oxygen and is thus antithetical to much animal life.

　　他们不单单只是观察氧和碳元素，尤其是生命必须的氮和磷，以及经常指示缺少氧且和大部分动物生命对立的硫。

　　Dr Zhu hopes to map changes in the distribution of these chemicals across time and space.

　　朱博士希望绘制这些元素随着时间和空间分布变化图，确认这些变化的关联性，

　　He will assess how these changes correlate, whether they are related to weathering,mountain building and the ebb and flow of glaciers, how they could have affected theevolution of life, and how plants and animals might themselves have altered the chemistryof air and sea.

　　它们是否和天气，造山，冰川的起伏有关，他们怎样影响生命的进化，以及动植物他们自己是如何改变空气和海洋中的化学组成。

　　Most ambitiously, Dr Zhu, Dr Xiao and their colleagues hope to drill right through severalfossiliferous sites in southern China where Ediacaran rocks turn seamlessly into Cambrianones.

　　朱博士，肖博士以及他们的团队很有雄心的希望在中国南部那些无缝连接埃迪卡拉纪和寒武纪的几个含有化石的地方穿凿而过。

　　Such places are valuable because in most parts of the world there is a gap, known as anunconformity, between the Ediacaran and the Cambrian.

　　这些地方都很有价值，世界的大部分地区，埃迪卡拉和寒武纪之间都有空白，这种空白被称为不整合面。

　　Unconformities are places where rocks have been eroded before new ones are deposited,and the widespread Ediacaran-Cambrian unconformity has been a big obstacle tounderstanding the Cambrian explosion.

　　不整合面地方的石块在新的沉积之前已经被侵蚀，埃迪卡拉纪-寒武纪之间广泛的不整合面是了解寒武纪大爆发的一个重大障碍。

　　With luck, then, a mystery first noticed in the Welsh mountains in the early 19th century willbe solved in the Chinese ones in the early 21st.

　　幸运的是，在19世纪早期威尔士群山中发现的神奇事件将被21世纪中国发现的群落所解决。

　　If it is, the origin of the animal kingdom will have become clear, and an important gap in thehistory of humanity itself will have been filled.

　　如果是的话，那动物王国的起源将会变得更清晰，人类历史中一个重要的空白将被填补。

　　词语解释

　　1.hope to 希望

　　That's what I hope to do.

　　这就是我希望要做的事情。

　　The police hope to identify the body by the goldfillings in the teeth.

　　警方希望通过死者牙齿里的黄金填充物来辨认其身份。

　　2.start to 开始

　　New cars start to depreciate as soon as they are on the road.

　　新车一上路就开始贬值。

　　Stay well away from the helicopter when its blades start to rotate.

　　直升机的螺旋桨开始转动时，尽量离远点儿。

　　3.arrive in 抵达,到达

　　Some day soon, a smoker will arrive in london.

　　不久后的某一天，一个吸烟者将到达伦敦。

　　Will it arrive in 2 hours?

　　两个小时内能到账吗?

　　4.plan to 打算,计划

　　Many plan to stomach more risk.

　　许多人计划承担更多的风险。

　　Other countries plan to buy or build more.

　　其他国家也打算购买或建造更多的潜艇。

　　1.hope to 希望

　　That's what I hope to do.

　　这就是我希望要做的事情。

　　The police hope to identify the body by the goldfillings in the teeth.

　　警方希望通过死者牙齿里的黄金填充物来辨认其身份。

　　2.start to 开始

　　New cars start to depreciate as soon as they are on the road.

　　新车一上路就开始贬值。

　　Stay well away from the helicopter when its blades start to rotate.

　　直升机的螺旋桨开始转动时，尽量离远点儿。

　　3.arrive in 抵达,到达

　　Some day soon, a smoker will arrive in london.

　　不久后的某一天，一个吸烟者将到达伦敦。

　　Will it arrive in 2 hours?

　　两个小时内能到账吗?

　　4.plan to 打算,计划

　　Many plan to stomach more risk.

　　许多人计划承担更多的风险。

　　Other countries plan to buy or build more.

　　其他国家也打算购买或建造更多的潜艇。

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