How did feathers evolve? - Carl Zimmer

羽毛如何演化？ - Carl Zimmer

Translator: Andrea McDonough Reviewer: Bedirhan Cinar

譯者: Jephian Lin 審譯者: 盧 曉天

Feathers are some of the most remarkable things

羽毛是動物身上幾件

ever made by an animal.

最奇妙的東西之一

They are gorgeous in their complexity,

羽毛有華麗的交錯樣式

delicate in their construction,

還有精細的結構

and yet strong enough to hold a bird

而且還夠強健

thousands of feet in the air.

好讓鳥類飛上高空

Like all things in nature,

就像其它自然界的東西一樣

feathers evolved over millions of years

羽毛花了幾百萬年

into their modern form.

演化到現在的形式

It could be hard to imagine

可能很難想像

how this could have happened.

這是怎麼發生的

After all, what did the intermediate forms look like?

究竟，中間那 過度的形式是什麼樣子？

What good is half a wing,

有半演化的翅膀

festooned with half-feathers?

還有半演化的羽毛 好處是什麼？

Thanks to science,

由於科學的演進

we now know that birds are living dinosaurs.

我們現在知道 鳥類就像是還活著的恐龍

You can see the kinship in their skeletons.

你可以看到牠們骨骼 類似的地方

Certain dinosaurs share some anatomical details with birds

某些恐龍在身體結構上 和鳥類是一樣的

found in no other animals, such as wish bones.

而且在動物界是獨一無二的， 比如說叉骨（wish bones）

And in the late 1990s,

之後在 1990 年代末期

paleontologists started digging up

古生物學家開始挖掘

some compelling support for that idea:

一些有力的證據

dinosaurs with bits of feathers

身上保有羽毛的恐龍

still preserved on their bodies.

身上保有羽毛的恐龍

Since then, scientists have found

在那之後，科學家發現

dozens of species of dinosaurs

許多種類的恐龍

with remnants of feathers.

身上都有部份的羽毛

Some were as small as pigeons,

有些像鴿子一樣小

and some were the size of a school bus.

有些則跟校車一樣大

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

如果你觀察一下 牠們在族譜上的關係

the evolution of feathers

那要演化出羽毛

doesn't seem quite so impossible.

並不是那麼不可能

The most distant feathered relatives of birds

鳥類最早的 有羽毛的祖先

had straight feathers that looked like wires.

是有像電線般 直條的羽毛

Then these wires split apart,

後來這些電線開始分叉

producing simple branches.

產生比較小的分支

In many dinosaur lineages,

在許多恐龍的世系中

these simple feathers evolved

這些簡單的羽毛

into more intricate ones,

演化成複雜的樣子

including some that we see today on birds.

包含有些我們今日 在鳥類身上看到的那樣

At the same time,

同時

the feathers spread across the bodies of dinosaurs,

羽毛也開始 遍佈恐龍的全身

turning from sparse patches of fuzz

從零散的小塊細毛

into dense plumage,

變成濃密的全身羽毛

which even extended down to their legs.

甚至還長到腳上

A few fossils even preserved some of the molecules

少數的化石甚至 保存了一些

that give feathers color.

造成羽毛有不同顏色 的分子

They reveal a beautiful range of colors:

這些分子透露了 一系列漂亮的顏色

glossy, dark plumage, reminiscent of crows,

光亮、深色的羽毛， 像是烏鴉

alternating strips of black and white,

或是黑白相間的條紋

or splashes of bright red.

還有亮紅色的色斑

Some dinosaurs had high crests on their heads,

有些恐龍頭上有 高高的冠羽

and others had long, dramatic tail feathers.

而有的則是 又長又戲劇化的尾羽

Now, none of these dinosaurs

但是，這些恐龍

could use their feathers to fly -

沒有一隻能夠 靠羽毛飛翔──

their arms were too short

牠們的胳臂太短

and the rest of their bodies were far too heavy.

而身體其它部份又太重

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

但是鳥類的羽毛 並不只用來飛翔

A woodcock uses feathers to blend in perfectly

鷸鳥用羽毛把自己隱藏

with its forest backdrop.

在樹叢的背景中

An ostrich stretches its wings over its nest

駝鳥會伸出牠的翅膀蓋住巢

to shade its young.

來保護牠的幼鳥

A peacock displays its magnificent tail feathers

孔雀用牠那華麗的尾羽

to attract peahens.

來吸引異性

Feathers could have served these functions

羽毛在恐龍身上也可能

for dinosaurs too.

有這些功能

Exactly how feathered dinosaurs took flight

然而有羽毛的恐龍 是如何開始飛翔

is still a bit of a mystery.

還是個謎

But if a small-feathered dinosaur flapped

但是如果羽毛細小的恐龍

its arms as it ran up an incline,

在爬坡時揮動牠的臂膀

its feathers would have provided extra lift

那羽毛還是可以提供一些 向上的力量

to help it run faster.

這讓牠跑得更快

This accident of physics might have led

這項物理的意外收獲 可能導致

to the evolution of longer dinosaur arms,

演化出更長的臂膀和羽毛

which would let them run faster

這會讓牠們跑得更快

and even leap short distances through the air.

甚至可以跳躍置空一小段

Eventually, their arms stretched out into wings.

最後，他們的臂膀 演化成翅膀

Only then, perhaps 50 million years

只有到這時候，大約是第一隻 有羽毛的恐龍

after the first wiry feathers evolved,

出現的五千萬年後

did feathers lift those dinosaurs into the sky.

羽毛才讓恐龍在天空翱翔