万物简史 第495期:多灾多难的生命进程(15)

 Two points need to be kept in mind. 我们需要记住两点。

First, these are all just informed guesses. 第一、这些都仅仅是根据资料作出的推测。

Estimates for the number of animal species alive at the end of the Permian range from as low as 45,000 to as high as 240,000. 据估计，二叠纪结束的时候，活着的动物物种数量从45000-240000种不等。

If you don't know how many species were alive, you can hardly specify¹ with conviction the proportion that perished. 要是你不知道有多少活着的物种，你就不大有把握算出灭绝物种的具体比例。

Moreover, we are talking about the death of species, not individuals. 第二，我们在谈论的是物种的而不是单个动物的死亡。

For individuals the death toll² could be much higher — in many cases, practically total. 就单个动物而言，死亡的数量可能还要多得多——在许多情况下，实际上是全部。

The species that survived to the next phase of life's lottery³ almost certainly owe their existence to a few scarred and limping survivors⁴. 存活下来进入生命下一阶段的物种，几乎肯定都要把自己的存在归功于几个受伤的和残疾的幸存者。

In between the big kill-offs, there have also been many smaller, less well-known extinction⁵ episodes, 在几次大屠杀之间，还有许多较小的、不大知名的灭绝事件，

the Hemphillian, Frasnian, Famennian, Rancholabrean, and a dozen or so others, 亨菲利世事件、弗拉尼世事件、法门尼世事件、兰乔拉布里世事件，以及10多个别的事件，

which were not so devastating⁶ to total species numbers, but often critically hit certain populations. 它们对物种总量的破坏程度不是很大，但对某些种群往往是个沉重的打击。

Grazing animals, including horses, were nearly wiped out in the Hemphillian event about five million years ago. 发生在大约500万年以前的亨菲利世事件中，包括马在内的食草动物差一点儿被一扫而光。

Horses declined to a single species, which appears so sporadically⁷ in the fossil record as to suggest that for a time it teetered on the brink⁸ of oblivion. 马只剩下一个物种，时而出现在化石记录中，表明它一度到了灭绝的边缘。

Imagine a human history without horses, without grazing animals. 请你想像一部没有马、没有食草动物的人类历史。

In nearly every case, for both big extinctions and more modest ones, we have bewilderingly little idea of what the cause was. 对于差不多每种情况，无论是大规模的灭绝还是中等规模的灭绝，我们都感到迷惑不解，不大清楚到底是什么原因。

 

1 specify   

vt.指定，详细说明

参考例句：

• We should specify a time and a place for the meeting.我们应指定会议的时间和地点。
• Please specify what you will do.请你详述一下你将做什么。

2 toll   

n.过路(桥)费；损失，伤亡人数；v.敲(钟)

参考例句：

• The hailstone took a heavy toll of the crops in our village last night.昨晚那场冰雹损坏了我们村的庄稼。
• The war took a heavy toll of human life.这次战争夺去了许多人的生命。

3 lottery   

n.抽彩；碰运气的事，难于算计的事

参考例句：

• He won no less than ￡5000 in the lottery.他居然中了5000英镑的奖券。
• They thought themselves lucky in the lottery of life.他们认为自己是变幻莫测的人生中的幸运者。

4 survivors   

幸存者，残存者，生还者( survivor的名词复数 )

参考例句：

• The survivors were adrift in a lifeboat for six days. 幸存者在救生艇上漂流了六天。
• survivors clinging to a raft 紧紧抓住救生筏的幸存者

5 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。

6 devastating   

adj.毁灭性的，令人震惊的，强有力的

参考例句：

• It is the most devastating storm in 20 years.这是20年来破坏性最大的风暴。
• Affairs do have a devastating effect on marriages.婚外情确实会对婚姻造成毁灭性的影响。

7 sporadically   

adv.偶发地，零星地

参考例句：

• There are some trees sporadically around his house. 他的房子周围零星地有点树木。 来自辞典例句
• As for other aspects, we will sporadically hand out questionnaires. 在其他方面，我们会偶尔发送调查问卷。 来自互联网

8 brink   

n.(悬崖、河流等的)边缘，边沿

参考例句：

• The tree grew on the brink of the cliff.那棵树生长在峭壁的边缘。
• The two countries were poised on the brink of war.这两个国家处于交战的边缘。