Myths and misconceptions about evolution - Alex Gendler

對於演化論的迷思與誤解 - Alex Gendler

譯者: Anny Chung 審譯者: Hao-Wei Chang

Myths and misconceptions about evolution.

對於演化論的迷思與誤解

Let's talk about evolution.

讓我們談談演化

You've probably heard

你可能聽說

that some people consider it controversial,

有些人認為它具爭議性

even though most scientists don't.

雖然多數科學家不如此認為

But even if you aren't one of those people

即使你不是反對人士之一

and you think you have a pretty good understanding of evolution,

且認為自己非常瞭解演化

chances are you still believe some things about it

你仍可能相信

ㄧ些不完全正確的觀念

that aren't entirely right,

things like,

像是

"Evolution is organisms adapting to their environment."

「演化是生物個體 適應它們的生存環境」

This was an earlier,

這是一個老舊

now discredited,

現在已被推翻

theory of evolution.

的演化理論

Almost 60 years before Darwin published his book,

在達爾文發表它的巨作的 60 年前

Jean-Baptiste Lamarck proposed

拉馬克提出

that creatures evolve by developing

物種於一生中

certain traits over their lifetimes

可能發展各種特徵

and then passing those on to their offspring.

然後將之傳給後代

For example, he thought

例如：他認為

that because giraffes spent their lives

由於長頸鹿一生都在

stretching to reach leaves on higher branches,

伸長脖子吃樹梢的葉子

their children would be born with longer necks.

牠們的後裔將會擁有更長的脖子

But we know now that's not how genetic inheritance works.

現在我們知道 基因遺傳並不是這樣

In fact, individual organisms don't evolve at all.

事實上，生物個體並不會演化

Instead, random genetic mutations cause

而是基因突變隨機使得

some giraffes to be born with longer necks,

有些長頸鹿 生來就有較長的脖子

and that gives them a better chance to survive

那使牠們生存的機率提升

than the ones who weren't so lucky,

而其它的就沒那麼幸運

which brings us to

這觀念帶我們到

"survival of the fittest".

「適者生存」

This makes it sound like evolution always favors

這聽起來好像演化總是偏好

the biggest,

最大

strongest,

最強壯

or fastest creatures,

或最快的動物

which is not really the case.

事實並不如此

For one thing, evolutionary fitness is just a matter

首先，演化適存度

of how well-suited they are to their current environment.

只反應生物是否適合現在的環境

If all the tall trees suddenly died out

如果所有的樹突然消失

and only short grass was left,

只剩下短草

all those long-necked giraffes

所有的長頸鹿

would be at a disadvantage.

都會處於不利

Secondly, survival is not how evolution occurs,

其次，演化的延續靠的不是生存

reproduction is.

而是生殖

And the world if full of creatures

世界上多的是物種

like the male anglerfish,

像是雄性的鮟鱇魚

which is so small and ill-suited for survival at birth

牠們出生時既小又不適生存

that it has to quickly find a mate before it dies.

必須迅速於死亡前找到配偶

But at least we can say

那這樣我們可以說

that if an organism dies without reproducing,

如果有一個物種沒生殖就死亡

it's evolutionarily useless, right?

那在演化上就沒用，對吧?

Wrong!

錯!

Remember, natural selection happens

記住，天擇並不是

not at the organism level,

針對物種個體

but at the genetic level,

而是在基因層面

and the same gene that exists in one organism

而存在於一個個體中的基因

will also exist in its relatives.

也會存在於其親屬

So, a gene that makes an animal altruistically sacrifice itself

所以使生物犧牲自我

to help the survival and future reproduction

來幫助後代子孫或親屬

of its siblings or cousins,

的生存或生殖的基因

can become more widespread

繁衍的數目可大於

than one that is solely concerned with self-preservation.

只在乎保存自我的基因

Anything that lets more copies of the gene

任何能使更多基因複製

pass on to the next generation

並傳給後代的機制

will serve its purpose,

都可以達到這個目的

except

除了

evolutionary purpose.

演化目的

One of the most difficult things to keep in mind about evolution

演化論其中一個最困難的概念

is that when we say things like,

就是當我們說

"Genes want to make more copies of themselves,"

「基因想要增加自己的數目」

or even,

或甚至

"natural selection,"

「天擇」

we're actually using metaphors.

這些其實都是比喻

A gene doesn't want anything,

基因並不想要作任何事

and there's no outside mechanism

並沒有一個外來的機制

that selects which genes are best to preserve.

選擇哪些基因是最適合保存

All that happens is that random genetic mutations

真正發生的是，隨機基因突變

cause the organisms carrying them

會使得生物個體

to behave or develop in different ways.

產生不同行為或發展

Some of those ways result in more copies

而其中有些行為最後使

of the mutated gene being passed on,

某些突變基因被傳到下一代

and so forth.

如此而已

Nor is there any predetermined plan

並沒有一個使物種演化

progressing towards an ideal form.

並臻至完美的計畫

It's not ideal for the human eye to have a blind spot

例如：人視神經 與視網膜接觸點

where the optic nerve exits the retina,

會產生不完美的盲點

but that's how it developed,

但是人眼就是這樣

starting from a simple photoreceptor cell.

自一個簡單的感光細胞發展出來

In retrospect, it would have been

以現代角度思考

much more advantageous for humans to crave

人類如果能著重 營養和維生素的攝取

nutrients and vitamins

而不單是熱量

rather than just calories.

那該有多好

But over the millenia,

但是在我們祖先

during which our ancestors evolved,

這幾百萬年來的演化過程之中

熱量是很難取得的

calories were scarce,

and there was nothing to anticipate

而沒有任何人能預料

情況將改變得如此快速

that this would later change so quickly.

So, evolution proceeds blindly,

所以演化是盲目的

step

一步

by step

接著

by step,

一步

creating all of the diversity we see in the natural world.

創造我們所見的多樣自然界