For all the trouble they take to assemble and preserve themselves, species crumple and die remarkably routinely. And the more complex they get, the more quickly they appear to go extinct. Which is perhaps one reason why so much of life isn't terribly ambitious.
尽管物种们费了九牛二虎之力聚集起来保存自己，但它们经常崩溃和死亡。它们变得越复杂，好像灭绝得越快。为什么那么多生命没有雄心壮志，这也许是一个原因。
So anytime life does something bold it is quite an event, and few occasions were more eventful than when life moved on to the next stage in our narrative and came out of the sea.
因此，只要生命干出勇敢的事，都是一件大事。我们将要讲到，生命向前迈入另一阶段，离开了海洋。这就是极少的大事之一。

Land was a formidable environment: hot, dry, bathed in intense ultraviolet radiation, lacking the buoyancy that makes movement in water comparatively effortless. To live on land, creatures had to undergo wholesale revisions of their anatomies. Hold a fish at each end and it sags in the middle, its backbone too weak to support it. To survive out of water, marine creatures needed to come up with new load-bearing internal architecture—not the sort of adjustment that happens overnight. Above all and most obviously, any land creature would have to develop a way to take its oxygen directly from the air rather than filter it from water. These were not trivial challenges to overcome. On the other hand, there was a powerful incentive to leave the water: it was getting dangerous down there. The slow fusion of the continents into a single landmass, Pangaea, meant there was much, much less coastline than formerly and thus much less coastal habitat.
陆地是个可怕的环境：炎热、干燥，笼罩在强烈的紫外线辐射之中，没有在水中移动的那种相对轻松的浮力。在陆地上生活，动物们不得不彻底修正它们的结构。要是你用手拿住一条鱼的两端，它的中部就会弯下去，因为它的脊骨不结实，无法支撑自己。为了在离开水以后生存下去，海生动物需要有个新的能够负重的内部架构——这不是一夜之间能调整过来的。尤其重要的，也是最明显的是，任何陆生动物必须学会直接从空气里摄取氧气。而不是从水里过滤氧气。这一些都不是微不足道的困难。都需要克服。另一方面，动物们对于离开水有着强大的动力：水底下的环境正变得越来越危险。大陆渐渐合并成一个陆块：泛古陆，这意味着海岸线比以前少多了，因而沿海的栖息地也少了。