万物简史 第498期:多灾多难的生命进程(18)

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probably at just the right angle, at a time when oxygen levels were 10 percent higher than at present and so the world was more combustible¹. 角度很可能恰好合适，当时的氧气浓度又比现在高10%，因此世界比较容易着火。

Above all the floor of the sea where it landed was made of rock rich in sulfur². 尤其是，着落地区的海底是由含硫丰富的岩石构成的。

The result was an impact that turned an area of seafloor the size of Belgium into aerosols³ of sulfuric acid. 结果，那个撞击把一片比利时大小的海底变成了硫酸气雾。

For months afterward⁴, the Earth was subjected to rains acid enough to burn skin. 在此后的几个月里。地球遭受酸雨的袭击，酸的浓度足以烧伤皮肤。

In a sense, an even greater question than that of what wiped out 70 percent of the species that were existing at the time is how did the remaining 30 percent survive? 在某种意义上，还有一个比“是什么毁灭了当时存在的70%的物种？”更大的问题，那就是“剩下的30%是怎么存活下来的？”

Why was the event so irremediably devastating⁵ to every single dinosaur⁶ that existed, while other reptiles⁷, like snakes and crocodiles, passed through unimpeded? 为什么那个事件对每个存在的恐龙是个灭顶之灾，而别的像蛇和鳄这样的爬行动物却能安然度过劫难？

So far as we can tell no species of toad⁸, newt, salamander, or other amphibian⁹ went extinct in North America. 就我们所知，北美的蟾蜍、水螈、蝾螈，以及别的两栖动物没有一个物种灭绝。

"Why should these delicate creatures have emerged unscathed from such an unparalleled disaster?" “为什么这些纤弱的动物能安然无恙地逃过这场空前的灾难？”

asks Tim Flannery in his fascinating prehistory of America, Eternal Frontier. 提姆·弗兰纳里在他精彩的描述史前美国的著作《永久的边疆》里发问。

In the seas it was much the same story. 海洋里的情况十分相似。

All the ammonites vanished, but their cousins the nautiloids, who lived similar lifestyles, swam on. 菊石统统消失了，但它们的表亲鹦鹉螺目软体动物却存活下来，尽管它们有着相似的生活方式。

Among plankton¹⁰, some species were practically wiped out — 92 percent of foraminiferans, for instance 在浮游生物中，有的物种实际上全部覆灭——比如，有孔虫丧失了92%，

while other organisms like diatoms, designed to a similar plan and living alongside, were comparatively unscathed. 而像硅藻这样的别的生物尽管体形相似，还同有孔虫在一起生活，却受伤害较轻。

 

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