经济学人77:加拿大出土最早动物足迹

 　　Science and Technology Palaeontology Do the locomotion¹

　　科技 古生物学 活动活动

　　The earliest animal tracks yet found have been unearthed² in Canada

　　在加拿大出土了迄今为止发现的最早动物足迹

　　ONE of the greatest mysteries of the history of life is the Cambrian explosion.

　　寒武纪的大爆炸是生命史中最大的谜团之一。

　　Prior to 560m years ago, animal fossils are rare.

　　5.6亿年以前的动物化石寥寥无几。

　　Then, in a geological eyeblink, they become common.

　　然而，只过了地质史上一瞬间的功夫，它们便多得不足为奇了。

　　Shelly creatures such as trilobites and brachiopods, of whose ancestors there is little sign in the rocks, are suddenly everywhere.

　　像三叶虫、腕足动物此般壳类动物的祖先没有在岩层中留下什么痕迹，但它们的遗迹却突然间比比皆是。

　　Biologists would dearly love to know what happened.

　　生物学家们迫不及待地想知道当时到底发生了什么。

　　Recent discoveries at the delightfully³ named Mistaken Point, in Newfoundland, serve to lift the veil slightly.

　　纽芬兰岛上有个地方名字很有趣，叫“错误点”，正是最近在这里的一些发现轻轻掀起了这个神秘面纱的一角。

　　These findings are not of Precambrian animals themselves, but of their tracks. And these, paradoxically, may be more useful.

　　发现的并不是寒武纪前的动物本身，而是它们的足迹。而出人意料的是，这些足迹可能还更有用。

　　Alexander Liu of Oxford⁴ University and his colleagues took an interest in Mistaken Point because it is a site known for so-called Ediacaran fossils, shell-less animals of unknown provenance⁵ that slightly predate the Cambrian.

　　牛津大学的亚历山大?刘和他的同事们之所以对“错误点”产生兴趣，是因为它因埃迪卡拉动物化石而闻名，埃迪卡拉动物是存在于略早于寒武纪时期的缘起不明的无壳动物。

　　As Mr Liu and his team explored the rocks they came across more than 70 markings that looked like tracks—slight impressions in the sediment⁶ with tiny ridges⁷ sticking up along the sides.

　　在刘和他的团队对那里的岩石进行勘察的过程中，他们发现了70多个类似足迹的斑点——在沉淀物中的一些浅痕，其周边有轻微的突起。

　　These markings, they report in Geology, are up to 13mm wide and up to 17cm long.

　　据他们在《地质学》杂志中的报告，这些斑点宽不过13毫米，长不过17厘米。

　　What is most curious about these tracks is that the rock they are in is reckoned to have formed at least a kilometre below sea level.

　　更奇特的是，据估计，这些足迹所在的岩石是在海平面至少一千米以下形成的。

　　Fossil bodies might get into such rock by sinking to the sea floor.

　　化石体倒是可能会沉到海底而进入这块岩石。

　　Tracks, however, must have been made by something that was alive.

　　然而，只有活的东西才能留下足迹。

　　Precambrian animals must therefore have lived at such depths.

　　因此，前寒武纪的动物肯定曾经生活在这么深的地方。

　　The tracks also cast light on what the Ediacarans actually were.

　　这些足迹也使我们了解了埃迪卡拉动物到底是什么。

　　Some palaeontologists think them members of a phylum that is now extinct.

　　有的古生物学家认为它们属于已经绝迹的一门动物。

　　Others, though, believe they were Cnidarians, the group that includes modern sea anemones⁸ and jellyfish.

　　而有的则认为它们是刺胞动物，这是包括现代的海葵和海蜇在内的一门动物。

　　Cnidarians grow from embryos⁹ that have only two layers of cells.

　　刺胞动物是由只有两层细胞的晶胚发展而来的。

　　Most animals, including all the shelly Cambrian ones, grow from three-layered embryos.

　　而包括所有寒武纪壳类动物在内的大多数动物都是由三层细胞的晶胚发展而来。

　　The tracks found by Mr Liu look suspiciously like those left by modern sea anemones which, despite their sedentary appearance, do move around slowly.

　　刘发现的这些足迹疑似现代的海葵的足迹。海葵虽然看起来不怎么活动，但它们确实会慢慢地四处游动。

　　That is not strong evidence that Ediacarans were Cnidarians, but it is something.

　　这虽然不能有力地证明埃迪卡拉动物属于刺胞动物，但它的确是一个重要的发现。

　　Yet if that is the right interpretation¹⁰, it leaves the question of what evolved into the trilobites and their kind as mysterious as ever.

　　不过倘若这样的解释是正确的，三叶虫和它的同类由何而来的问题将仍然神秘晦涩，一如往昔。

1 locomotion   

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。

2 unearthed   

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。

3 delightfully   

大喜，欣然

参考例句：

• The room is delightfully appointed. 这房子的设备令人舒适愉快。 来自《现代汉英综合大词典》
• The evening is delightfully cool. 晚间凉爽宜人。 来自《现代汉英综合大词典》

4 Oxford   

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。

5 provenance   

n.出处；起源

参考例句：

• Kato was fully aware of the provenance of these treasures.加藤完全清楚这些珍宝的来源。
• This plant's provenance is Asiadj.这种植物原产于亚洲。

6 sediment   

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。

7 ridges   

n.脊( ridge的名词复数 )；山脊；脊状突起；大气层的)高压脊

参考例句：

• The path winds along mountain ridges. 峰回路转。
• Perhaps that was the deepest truth in Ridges's nature. 在里奇斯的思想上，这大概可以算是天经地义第一条了。

8 anemones   

n.银莲花( anemone的名词复数 )；海葵

参考例句：

• With its powerful tentacles, it tries to prise the anemones off. 它想用强壮的触角截获海葵。 来自互联网
• Density, scale, thickness are still influencing the anemones shape. 密度、大小、厚度是受最原始的那股海葵的影响。 来自互联网

9 embryos   

n.晶胚；胚，胚胎( embryo的名词复数 )

参考例句：

• Somatic cells of angiosperms enter a regenerative phase and behave like embryos. 被子植物体细胞进入一个生殖阶段，而且其行为象胚。 来自辞典例句
• Evolution can explain why human embryos look like gilled fishes. 进化论能够解释为什么人类的胚胎看起来象除去了内脏的鱼一样。 来自辞典例句

10 interpretation   

n.解释，说明，描述；艺术处理

参考例句：

• His statement admits of one interpretation only.他的话只有一种解释。
• Analysis and interpretation is a very personal thing.分析与说明是个很主观的事情。