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So there’s a lot of discussion of what might life look like on other planets, if life has evolved there.
人们经常讨论另一个星球上的生命是什么样的 假如那里已经进化出了生命
Will it diversify in a way like the world today?
它会像如今的世界这样丰富多彩吗？
And there’s a lot of speculation about that question.
关于这一点 人们有很多猜测
But we actually don’t need to go to other planets to ask that question.
但其实我们根本就不需要去另一个星球才能问这个问题
And that’s because there are different places on Earth that have had different evolutionary histories.
因为地球上不同的地方有不同的进化史
And so we can ask on different places in the world, has life evolved in the same way under similar conditions?
我们可以问问在地球上的不同地方 生命在相似条件下的进化方式一样吗？
And it turns out that we’re very well set for that, because there are isolated islands that have been their own evolutionary theaters,
事实表明我们有很好的条件来研究这一点 因为有些完全与世隔绝的岛屿保留着自己的进化系统
if you will, that life has evolved very differently or very independently for a long time.
很久以来 那里的生命进化都完全不同或完全独立
The best example of that I think is New Zealand. Now New Zealand broke off from Australia about 80 million years ago.
我觉得最好的例子是新西兰 大约8000万年前 新西兰从澳大利亚脱离
And this was before most modern mammal groups had really diversified.
那时候很多现代的哺乳动物都还没出现呢
And, in fact, today there are no native land mammals on New Zealand.
事实上 如今的新西兰并没有本土陆地哺乳类动物
There are some seals that come ashore on the beach, there are a few species of bats, but there are no rodents, there are no carnivores, and so on,
那里有一些海豹会到沙滩上去 有几种蝙蝠 但是没有啮齿类动物 没有食肉动物等等
except the ones that humans have introduced in the last couple hundred years.
除了人类在过去几百年中引入的一些哺乳动物
So the question is how did New Zealand evolve in the absence of land mammals?
所以问题是没有陆地哺乳动物的新西兰是怎么进化的？
Well it turns out that birds in particular have taken advantage of that and they’ve evolved to do many of the things that mammals do elsewhere in the world.
事实证明鸟类从这一点中受益颇多 那里的鸟儿所做的事情跟世界其他地方的哺乳动物所做的事情一样
And there are carnivores and herbivores and all kinds of birds.
有食肉动物 食草动物和各种鸟类
Now if we thought that evolution is deterministic then we would expect New Zealand,
如果我们认为进化是命运注定的 那么即便新西兰被鸟类主宰着
even though it’s dominated by birds, to have species very similar to those elsewhere in the world.
我们也会觉得那里有与世界其他地方相似的物种
But that’s not at all the case. The best example is the kiwi. Now people know the kiwi, it’s a bird this big.
但事实根本不是这样 最好的例子就是几维 人们都知道几维 是一种鸟 这么大
It turns out that it has no wings. It runs around on the ground.
它没有翅膀 只会在地上跑
It has an extremely good sense of smell, which is very unusual for birds. It also has little whiskers, very similar to mammals.
嗅觉灵敏 这对鸟类来说可是异类 它们还有小小的胡须 跟哺乳动物特别像
Basically a kiwi does the same thing that a hedgehog or maybe a badger or an armadillo does.
几维鸟的行为跟刺猬 獾 或者犰狳一样
It goes around rooting through the leaf litter looking for worms and other invertebrates.
它会四处走动 翻查腐叶 寻找虫子和其他无脊椎动物
Yet it has adapted in a very different way. And, in fact, the entire cast of characters in New Zealand is very different.
它只不过是采取了另一种很不同的方式 其实 新西兰的整体特性别具一格
There are carnivorous parrots, there are parrots that are completely flightless and walk around on the ground looking for seeds.
那里有食肉鹦鹉 有完全不会飞的鹦鹉 只能在地上走动搜寻种子
There was a ten foot tall moa, a land bird that can’t fly, that is the dominant herbivore that looks nothing like a deer or a bison or its ecological equivalence elsewhere.
那里曾经有十英尺高的恐鸟 一种不会飞的陆地鸟 是占统治地位的食草动物 看起来跟鹿 野牛或其他地方的同类生物完全不一样
So New Zealand is an alternative world if you will.
所以如果你愿意的话 可以把新西兰当做另一个世界
Almost an alternative planet in evolutionary terms.
就进化而言 它基本上可以说是另一个星球
What has evolved there is completely different from the rest of the world.
那里进化出来的东西与世界其他地方完全不同
And this is true of other places. Australia in at least some respects is very different.
其他地方也是如此 至少在某种程度上 澳大利亚也是异类
Madagascar – or go back to the age of the dinosaurs. Well the dinosaurs came, they went extinct.
马达加斯加 或者回头看看恐龙时代 恐龙出现了 又灭绝了
If evolution is so deterministic why don’t we have t-rex and brontosaurus-type dinosaurs today?
如果进化是命运注定的 那么为什么今天没有霸王龙和雷龙了呢？
It’s because evolution has gone in a very different direction.
那是因为进化走了一条完全不同的道路
So we don’t need to go to other planets to see how deterministic evolution is.
我们不需要去另一个星球看进化有多么确定
We can just look in different places on Earth and we can see that the outcome often is very different.
我们只需要看看地球上不同的地方 就会发现结果往往出人意料
