万物简史 第493期:多灾多难的生命进程(13)

 For complex organisms, the average lifespan of a species is only about four million years—roughly about where we are now. 对于复杂动物来说，一个物种的平均寿命只有大约400万年——大致相当于我们人类迄今存在的时间。

Extinction¹ is always bad news for the victims, of course, but it appears to be a good thing for a dynamic planet. 当然，灭绝对于受害者来说总是坏消息，但对于一颗有活力的行星来说似乎是一件好事情。

"The alternative to extinction is stagnation²," says Ian Tattersall of the American Museum of Natural History,  “与灭绝相对的是停滞，”美国自然史博物馆的伊恩·塔特萨尔说，

"and stagnation is seldom a good thing in any realm." “停滞在任何领域都很少是一件好事情。”

(I should perhaps note that we are speaking here of extinction as a natural, long-term process. （我也许应当指出，我们在这里谈论灭绝，指的是一个漫长的自然过程。

Extinction brought about by human carelessness is another matter altogether.) 由于人类的粗心大意而造成的灭绝完全是另一回事。）

Crises in Earth's history are invariably associated with dramatic leaps afterward³. 地球史上的危机总是与随后的大跃进有关系。

The fall of the Ediacaran fauna⁴ was followed by the creative outburst of the Cambrian period. 埃迪亚卡拉动物群的没落之后是寒武纪的创造性爆发。

The Ordovician extinction of 440 million years ago cleared the oceans of a lot of immobile filter feeders 44000万年以前的奥陶纪灭绝为大海清除了大量一动不动而靠过滤来进食的动物，

and, somehow, created conditions that favored darting⁵ fish and giant aquatic⁶ reptiles⁷. 为快速游动的鱼类和大型水生爬行动物创造了有利条件。

These in turn were in an ideal position to send colonists⁸ onto dry land when another blowout in the late Devonian period gave life another sound shaking. 那些动物转而又处于理想地位；当泥盆纪末期又一次灾难给生命又一次沉重打击的时候，它们能把殖民者派上了陆地。

And so it has gone at scattered⁹ intervals¹⁰ through history. 在整个历史上，不时发生这样的事。

If most of these events hadn't happened just as they did, just when they did, we almost certainly wouldn't be here now. 要是这些事件不是恰好以它们发生的方式发生，不是恰好在它们发生的时间发生，现在我们几乎肯定不会在这里。

 

1 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。

2 stagnation   

n. 停滞

参考例句：

• Poor economic policies led to a long period of stagnation and decline. 糟糕的经济政策道致了长时间的经济萧条和下滑。
• Motion is absolute while stagnation is relative. 运动是绝对的，而静止是相对的。

3 afterward   

adv.后来；以后

参考例句：

• Let's go to the theatre first and eat afterward. 让我们先去看戏，然后吃饭。
• Afterward,the boy became a very famous artist.后来，这男孩成为一个很有名的艺术家。

4 fauna   

n.(一个地区或时代的)所有动物，动物区系

参考例句：

• This National Park is an area with unique fauna and flora.该国家公园区域内具有独特的动物种群和植物种群。
• Fauna is a biological notion means all the animal life in a particular region or period. 动物群是一个生物学的概念，指的是一个特定时期或者地区的所有动物。

5 darting   

v.投掷，投射( dart的现在分词 )；向前冲，飞奔

参考例句：

• Swallows were darting through the clouds. 燕子穿云急飞。 来自《现代英汉综合大词典》
• Swallows were darting through the air. 燕子在空中掠过。 来自辞典例句

6 aquatic   

adj.水生的，水栖的

参考例句：

• Aquatic sports include swimming and rowing.水上运动包括游泳和划船。
• We visited an aquatic city in Italy.我们在意大利访问过一个水上城市。

7 reptiles   

n.爬行动物，爬虫( reptile的名词复数 )

参考例句：

• Snakes and crocodiles are both reptiles. 蛇和鳄鱼都是爬行动物。 来自《简明英汉词典》
• Birds, reptiles and insects come from eggs. 鸟类、爬虫及昆虫是卵生的。 来自《现代汉英综合大词典》

8 colonists   

n.殖民地开拓者，移民，殖民地居民( colonist的名词复数 )

参考例句：

• Colonists from Europe populated many parts of the Americas. 欧洲的殖民者移居到了美洲的许多地方。 来自《简明英汉词典》
• Some of the early colonists were cruel to the native population. 有些早期移居殖民地的人对当地居民很残忍。 来自《简明英汉词典》

9 scattered   

adj.分散的，稀疏的；散步的；疏疏落落的

参考例句：

• Gathering up his scattered papers,he pushed them into his case.他把散乱的文件收拾起来，塞进文件夹里。

10 intervals   

n.[军事]间隔( interval的名词复数 )；间隔时间；[数学]区间；（戏剧、电影或音乐会的）幕间休息

参考例句：

• The forecast said there would be sunny intervals and showers. 预报间晴，有阵雨。
• Meetings take place at fortnightly intervals. 每两周开一次会。