万物简史 第460期:生命在前进(2)

 Only about one bone in a billion, it is thought, ever becomes fossilized. 据认为，在10亿根骨头当中，只有大约l根能变成化石。

If that is so, it means that the complete fossil legacy¹ of all the Americans alive today—that's 270 million people with 206 bones each, 要是那样的话，这意味着今天所有活着的美国人——即每人都有206根骨头的27000万美国人，

will only be about fifty bones, one quarter of a complete skeleton. 所能留下的全部化石不过是50根左右，即一副完整骨骼的四分之一。

That's not to say of course that any of these bones will actually be found. 当然，这还不等于说，其中任何一块骨头化石将来真的会被发现。

Bearing in mind that they can be buried anywhere within an area of slightly over 3.6 million square miles, 记住，它们可以被埋在930多万平方公里国土的任何地方。

little of which will ever be turned over, much less examined, it would be something of a miracle if they were. 而这些土地只有很小的一部分会被翻动，小得多的部分会被仔细察看。因此，要是这几根骨头的化石能被发现，那简直是个奇迹。

Fossils are in every sense vanishingly rare. 从任何一种意义上说，化石越来越稀有了。

Most of what has lived on Earth has left behind no record at all. 在地球上生活过的生物当中，大多数都已无影无踪。

It has been estimated that less than one species in ten thousand has made it into the fossil record. 据估计，在1万个物种当中，不足1种有化石记录。

That in itself is a stunningly² infinitesimal proportion. 这本身就是个极其微小的部分。

However, if you accept the common estimate that the Earth has produced 30 billion species of creature in its time 然而，要是你接受普遍认为的关于地球产生过300亿种生物的估计，

and Richard Leakey and Roger Lewin's statement (in The Sixth Extinction³ ) that there are 250,000 species of creature in the fossil record, 以及理查德·利基和罗杰·卢因（在《第六次灭绝》一文中）关于25万种生物有化石记录的说法，

that reduces the proportion to just one in 120,000. 那么那个比例就减少到了只有1:120000。

Either way, what we possess is the merest sampling of all the life that Earth has spawned⁴. 无论如何，我们掌握的只是地球所产生的所有生命的最起码的样品。

Moreover, the record we do have is hopelessly skewed. 而且，我们掌握的记录是极不平衡的。

Most land animals, of course, don't die in sediments⁵. 大多数陆生动物当然不会死在沉积物里。

They drop in the open and are eaten or left to rot or weather down to nothing. 它们倒在空旷地方，不是被吃掉，就是任凭腐烂或被风雨剥蚀得一于二净。

The fossil record consequently is almost absurdly biased⁶ in favor of marine⁷ creatures. 结果，化石记录极其有利于海生动物，有利到了近乎荒唐的程度。

About 95 percent of all the fossils we possess are of animals that once lived under water, mostly in shallow seas. 在我们所掌握的化石当中，大约有95%是一度在水底而主要是在浅海里生活的动物的化石，

1 legacy   

n.遗产，遗赠；先人(或过去)留下的东西

参考例句：

• They are the most precious cultural legacy our forefathers left.它们是我们祖先留下来的最宝贵的文化遗产。
• He thinks the legacy is a gift from the Gods.他认为这笔遗产是天赐之物。

2 stunningly   

ad.令人目瞪口呆地；惊人地

参考例句：

• The cooks, seamstresses and other small investors are stunningly vulnerable to reversals. 那些厨师、裁缝及其他的小投资者非常容易受到股市逆转的影响。
• The production cost of this huge passenger liner is stunningly high. 这艘船城造价之高令人惊叹。

3 extinction   

n.熄灭，消亡，消灭，灭绝，绝种

参考例句：

• The plant is now in danger of extinction.这种植物现在有绝种的危险。
• The island's way of life is doomed to extinction.这个岛上的生活方式注定要消失。

4 spawned   

（鱼、蛙等）大量产（卵）( spawn的过去式和过去分词 )； 大量生产

参考例句：

• The band's album spawned a string of hit singles. 这支乐队的专辑繁衍出一连串走红的单曲唱片。
• The computer industry has spawned a lot of new companies. 由于电脑工业的发展，许多新公司纷纷成立。

5 sediments   

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。

6 biased   

a.有偏见的

参考例句：

• a school biased towards music and art 一所偏重音乐和艺术的学校
• The Methods: They employed were heavily biased in the gentry's favour. 他们采用的方法严重偏袒中上阶级。

7 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。