How did feathers evolve? - Carl Zimmer

羽毛如何进化？- 卡尔·齐默

Translator: Andrea McDonough Reviewer: Bedirhan Cinar

翻译人员: Geoff Chen 校对人员: Chencheng Guo

Feathers are some of the most remarkable things

羽毛是动物身上几件

ever made by an animal.

最奇妙的东西之一

They are gorgeous in their complexity,

羽毛构造极为复杂，让人惊叹

delicate in their construction,

还有精细的结构

and yet strong enough to hold a bird

而且还够强壮

thousands of feet in the air.

好让鸟类飞上数千尺的高空

Like all things in nature,

就像其它自然界的东西一样

feathers evolved over millions of years

羽毛耗费了几百万年

into their modern form.

进化到现在的形式

It could be hard to imagine

我们可能很难想像

how this could have happened.

这是怎么发生的

After all, what did the intermediate forms look like?

究竟，中间那 过度的形式是什么样子的呢？

What good is half a wing,

这种在翅膀上

festooned with half-feathers?

覆盖了羽毛的结构究竟好在哪里呢？

Thanks to science,

科学研究发现

we now know that birds are living dinosaurs.

鸟类就像是还活着的恐龙

You can see the kinship in their skeletons.

你可以看到它们骨架非常相似

Certain dinosaurs share some anatomical details with birds

某些恐龙和鸟类一样，都有一些在动物界独一无二的身体结构

found in no other animals, such as wish bones.

比如说叉骨（wish bones）

And in the late 1990s,

之后在 1990 年代末期

paleontologists started digging up

古生物学家开始挖掘出

some compelling support for that idea:

一些有力的证据：

dinosaurs with bits of feathers

有些恐龙身上

still preserved on their bodies.

仍旧保有羽毛

Since then, scientists have found

在那之后，科学家发现

dozens of species of dinosaurs

许多种类的恐龙

with remnants of feathers.

身上都有部份羽毛

Some were as small as pigeons,

有些恐龙像鸽子一样小

and some were the size of a school bus.

有些则跟校车一样大

If you look at how they are related on a family tree,

如果你观察一下 它们在族谱上的关系

the evolution of feathers

那么要进化出羽毛

doesn't seem quite so impossible.

并不是那么不可能

The most distant feathered relatives of birds

鸟类最早的 有羽毛的祖先

had straight feathers that looked like wires.

是一种像电线一般的 直条羽毛

Then these wires split apart,

后来这些电线开始分叉

producing simple branches.

产生比较小的分支

In many dinosaur lineages,

在许多恐龙的世系中

these simple feathers evolved

这些简单的羽毛

into more intricate ones,

进化成更加复杂的样子

including some that we see today on birds.

包括许多我们今日 在鸟类身上看到的那种羽毛

At the same time,

同时

the feathers spread across the bodies of dinosaurs,

羽毛也开始 遍布恐龙的全身

turning from sparse patches of fuzz

从零散的小块细毛

into dense plumage,

演变为浓密的全身羽毛

which even extended down to their legs.

甚至还长到脚上

A few fossils even preserved some of the molecules

少数的化石甚至 保存了一些

that give feathers color.

让羽毛显现出不同颜色 的分子

They reveal a beautiful range of colors:

透过这些分子，我们发现 恐龙羽毛有着一系列漂亮的颜色：

glossy, dark plumage, reminiscent of crows,

光亮、深色的羽毛， 像是乌鸦

alternating strips of black and white,

或是黑白相间的条纹

or splashes of bright red.

还有亮红色的色斑

Some dinosaurs had high crests on their heads,

有些恐龙头上有 高高的冠羽

and others had long, dramatic tail feathers.

而有的则是 相当长的尾羽

Now, none of these dinosaurs

但是，这些恐龙

could use their feathers to fly -

没有一只能够靠羽毛飞翔

their arms were too short

它们的胳臂太短

and the rest of their bodies were far too heavy.

而身体其它部份又太重

But, birds don't just use feathers to fly.

但是鸟类的羽毛除了让它们飞翔之外 还有其他用处。

A woodcock uses feathers to blend in perfectly

鹬鸟用羽毛把自己隐藏于

with its forest backdrop.

树丛的背景中

An ostrich stretches its wings over its nest

驼鸟会伸出它的翅膀盖住巢

to shade its young.

来保护它的幼鸟

A peacock displays its magnificent tail feathers

孔雀用它华丽的尾羽

to attract peahens.

来吸引异性

Feathers could have served these functions

羽毛在恐龙身上也可能

for dinosaurs too.

有这些功能

Exactly how feathered dinosaurs took flight

然而有羽毛的恐龙 是如何开始飞翔

is still a bit of a mystery.

仍然还是个谜

But if a small-feathered dinosaur flapped

但是如果羽毛细小的恐龙

its arms as it ran up an incline,

在爬坡时挥动它的臂膀

its feathers would have provided extra lift

那羽毛还是可以提供一些 向上的力量

to help it run faster.

这让它跑得更快

This accident of physics might have led

这项物理的意外收获 可能导致

to the evolution of longer dinosaur arms,

进化出更长的臂膀和羽毛

which would let them run faster

这会让牠们跑得更快

and even leap short distances through the air.

甚至可以跳跃置空一小段

Eventually, their arms stretched out into wings.

最后，它们的臂膀 进化成翅膀

Only then, perhaps 50 million years

只有到这时候，大约是第一只 有羽毛的恐龙

after the first wiry feathers evolved,

出现的五千万年后

did feathers lift those dinosaurs into the sky.

羽毛才让恐龙在天空翱翔