So there’s a lot of discussion of what might life look like on other planets, if life has
Will it diversify in a way like the world today?
And there’s a lot of speculation about that question.
But we actually don’t need to go to other planets to ask that question.
And that’s because there are different places on Earth that have had different evolutionary
And so we can ask on different places in the world, has life evolved in the same way under
事实上 大自然都给我们设定好了 因为孤立的岛屿
And it turns out that we’re very well set for that, because there are isolated islands
that have been their own evolutionary theaters, if you will, that life has evolved very differently
or very independently for a long time.
The best example of that I think is New Zealand.
Now New Zealand broke off from Australia about 80 million years ago.
And this was before most modern mammal groups had really diversified.
And, in fact, today there are no native land mammals on New Zealand.
海滩上有海豹 也有几种蝙蝠 但是
There are some seals that come ashore on the beach, there are a few species of bats, but
没有啮齿目动物 没有食肉动物等 除了
there are no rodents, there are no carnivores, and so on, except the ones that humans have
introduced in the last couple hundred years.
因此问题来了 新西兰缺少陆地动物 那它是怎么进化的呢？
So the question is how did New Zealand evolve in the absence of land mammals?
事实上 特别是鸟 它们利用了这一点
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.
因此有了食肉鸟 食草鸟 各种各样的鸟
And there are carnivores and herbivores and all kinds of birds.
如果现在你认为 进化起决定性作用 那么我们就能预期新西兰的物种与世界其他地方的相似
Now if we thought that evolution is deterministic then we would expect New Zealand, even though
it’s dominated by birds, to have species very similar to those elsewhere in the world.
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.
It turns out that it has no wings.
It runs around on the ground.
It has an extremely good sense of smell, which is very unusual for birds.
It also has little whiskers, very similar to mammals.
基本上 刺猬 獾或者犰狳能做的事情 几维鸟
Basically a kiwi does the same thing that a hedgehog or maybe a badger or an armadillo
它到处转悠 翻树叶 寻找虫子和其他无脊椎动物
It goes around rooting through the leaf litter looking for worms and other invertebrates.
Yet it has adapted in a very different way.
And, in fact, the entire cast of characters in New Zealand is very different.
There are carnivorous parrots, there are parrots that are completely flightless and walk around
on the ground looking for seeds.
这里还有10英尺高的恐鸟 不会飞 食草动物
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.
So New Zealand is an alternative world if you will.
Almost an alternative planet in evolutionary terms.
What has evolved there is completely different from the rest of the world.
And this is true of other places.
Australia in at least some respects is very different.
Madagascar – or go back to the age of the dinosaurs.
Well the dinosaurs came, they went extinct.
If evolution is so deterministic why don’t we have t-rex and brontosaurus-type dinosaurs
It’s because evolution has gone in a very different direction.
So we don’t need to go to other planets to see how deterministic evolution is.
We can just look in different places on Earth and we can see that the outcome often is very