Narrator: Listen to part of a lecture in a biology class.

旁白：听一段生物课的讲座。

Professor: I'd like to talk to you today about a principle of evolutionary biology that was first proposed in the 19th century by an American scientist named Edward Cope.

教授：今天我想和你们谈谈一个进化生物学的原则，这个原则是19世纪由一位名叫爱德华·科普的美国科学家首次提出的。

Cope made a scientific examination of fossils and thought he noticed a pattern of increasing sizes within species.

科普对化石进行了科学研究，并认为他注意到物种内大小增加的模式。

He proposed a principle which is usually called Cope’s rule.

他提出了一个通常被称为科普法则的原则。

What Cope said was that evolution was directed towards larger size creatures, and that this can be seen in many, perhaps even in most fossil lineages.

科普所说的是，进化是朝着更大体型生物的方向发展的，这一点可以在许多，甚至可能在大多数化石谱系中看到。

Fossil lineages, we talked about that before, their chronological charts of fossils of a specific species charted over time.

化石谱系，我们之前谈过这个，它们是特定物种化石随时间变化的年表图。

These lineages allowed Cope to compare fossils of different ages, some millions of years older than others, and Cope notes a tendency toward increasing size.

这些谱系使科普能够比较不同年代的化石，有些化石比其他化石早数百万年，科普注意到一种向增大体型的趋势。

Now there are some obvious advantages to being bigger even within the same species, like being bigger can be a deterrent to predators.

现在，即使在同一物种中，体型更大的确有一些明显的优势，比如体型更大可以威慑捕食者。

So, you're less likely to be eaten, more likely to survive if you happen to be bigger.

所以，如果你恰好更大一点，你就不太可能被吃掉，更有可能存活下来。

In certain species, bigger animals are more fuel efficient.

在某些物种中，体型较大的动物更节能。

They need less food per pound to keep themselves going.

它们每磅需要的食物更少来维持生命。

Although of course they need more food overall, because they're bigger.

当然，由于它们体型更大，它们总体上需要更多的食物。

It's the same thing with marine animals in order to maintain body heat, larger whales need less food per pound than smaller whales.

对于海洋动物来说也是一样的，为了维持体温，较大的鲸鱼每磅需要的食物比较小的鲸鱼少。

Also in most species, larger females tend to produce more eggs increasing their chances of passing on their genes.

此外，在大多数物种中，体型较大的雌性往往会产下更多的卵子，从而增加它们传递基因的机会。

Ok, so, these are all good reasons why there might be an evolutionary vantage towards larger size.

好的，所以，这些都是为什么在进化上可能会有向更大体型倾斜的所有好理由。

And Cope's rule was not really questioned much.

而且科普法则并没有受到太多质疑。

It just seemed obvious that such a thing had to be true.

这似乎显而易见，这种事情必须是真的。

And fossil lineages seem to confirm it.

而且化石谱系似乎证实了这一点。

However, in the 1970s and 80s, there was a pretty serious Challenge to Cope rule, mounted primarily by the famous scientist Stephen Jay Gould, who promoted an alternative theory which subsequently gained widespread acceptance by biologists.

然而，在20世纪70年代和80年代，著名科学家斯蒂芬·杰伊·古尔德（Stephen Jay Gould）对科普法则提出了相当严肃的挑战，他提出了一种替代理论，随后这种理论在生物学家中获得了广泛的认可。

Gould thought of evolution as a much more random process than many previous scientists thought.

古尔德认为进化是一个比许多以前的科学家认为的更随机的过程。

He was very much set against theory suggesting that evolution tends to drive in a certain direction, tends to direct towards certain ends.

他非常反对那些认为进化倾向于朝着某个方向发展、倾向于指向某些目标的理论。

Gould felt that such theories like Cope rule are influenced more by the psychology of the scientist.

古尔德认为，像科普法则这样的理论更多地受到科学家心理的影响。

You know, what's on that scientist’s mind, than the actual science and facts regarding the subject.

你知道，科学家脑子里想的东西，而不是关于这个主题的实际科学和事实。

Uh people assumed that bigger had to be better.

呃，人们认为越大就越好。

They tended to look at these fossils that the way Cope did.

他们倾向于像科普那样看待这些化石。

But you know there's a very strong danger of ignoring the evidence of this contrary to your thesis.

但是你知道，忽视与自己论点相悖的证据是非常危险的。

And often, we don't even realize we're doing it.

而且，我们经常甚至没有意识到自己在这样做。

Gould was trouble because Cope did things like he compared the sizes of fossils with others that might be 10 million years older.

古尔德很麻烦，因为科普做了一些事情，比如他将化石的大小与可能早了1000万年的其他化石进行比较。

Gould felt that's, well, it could be a misleading comparison.

古尔德觉得，这样的比较可能会产生误导。

And also, the fossil record is not Complete.

而且，化石记录并不完整。

There are all kinds of gaps and you can interpret the gaps in different ways.

有各种各样的空白，你可以用不同的方式来解释这些空白。

And Gould, for these reasons, he believed that Cope rule might have been not a rule at all, just a human invention.

而古尔德出于这些原因，他认为科普法则可能根本不是一个规则，只是一个人类的发明。

Cope found what he needed in order to support his theory.

科普找到了他所需要的东西来支持他的理论。

But he didn't really prove it.

但他并没有真正证明这一点。

And Gould suggested another rather interesting possibility.

而古尔德提出了另一个相当有趣的可能性。

He claimed, and there's a certain amount of foundation to this, that when a natural disaster wipes out large numbers of individuals in a species, they often tend to wipe out the bigger individuals more quickly.

他声称，而且这有一定的基础，当自然灾害消灭了一个物种中的大量个体时，它们往往会更快地消灭较大的个体。

Let's say it gets really cold.

假设天气变得非常寒冷。

Your food supply is cut off, the smaller creatures which don't need as much food as the larger creatures with smaller creatures may find it easier to survive.

你的食物供应被切断了，较小的生物不需要像较大的生物那样多的食物，较小的生物可能更容易生存。

So, what Gould suggested is that after a natural disaster, evolution, which is random, might not look random.

所以，古尔德所建议的是，在自然灾害之后，进化虽然是随机的，但可能看起来并不随机。

It might look directed, because in effect, there's nowhere to go, but up when only the smallest of a species survive, animals were going to have to get bigger after a disaster, no matter what.

它可能看起来是有方向的，因为实际上，当只有最小的物种幸存时，别无选择，只能向上发展。无论如何，动物在灾难后都必须变得更大。

So, the growing bigger is merely a tendency, not an evolutionary advantage, it's not evolution directing towards larger sizes.

所以，变大的只是一个趋势，而不是一种进化优势，进化并没有朝着更大尺寸的方向发展。

Now there have been other challenges to Cope's rule like why then are there still so many small animals on earth?

现在还有其他对科普法的挑战，比如为什么地球上仍然有这么多小动物呢？

One reason is simple physics.

一个原因是简单的物理学。

You won't see an insect as large as an elephant, because the insect’s exoskeleton simply can't support the weight.

你不会看到像大象一样大的昆虫，因为昆虫的外骨骼根本无法支撑那样的重量。