沒用的身體器官，真的沒用？

We've all marvelled at our fingers and toes, wrinkling into prunes in the bath. We've all stared at that weird fleshy appendage hanging down in the back of our throats.We've all known someone - or been that someone - with an emergency appendectomy. "It's fine," they say, "the appendix is completely useless anyway."

我們都曾發(fā)現(xiàn)當(dāng)我們?cè)谙丛璧臅r(shí)候，手指和腳趾會(huì)泡的起皺;也曾盯著掛在喉嚨上的肉看。我們也曾聽患過急性闌尾炎并做了切除手術(shù)的人說，“這沒關(guān)系，闌尾本來就沒什么用。”

But our bodies are amazing machines, and, while we may not need some of its features any more, there's very little in our anatomies with no purpose whatsoever.

我們的身體是令人驚奇的機(jī)器，我們可能沒有注意到某些部位的作用，但人體幾乎沒什么完全沒用的部位。

And about those things we don't need any more? They're evidence of where we've been - and that we continue to evolve even to this day.

那些我們不需要的部位又怎么解釋呢?它們證明了我們的進(jìn)化，并且我們?cè)诔掷m(xù)進(jìn)化。

Your appendix

闌尾

Turns out the human appendix - that weird structure attached to the colon that seemed to have little purpose but to occasionally inflame - isn't just an evolutionary vestige after all.

人類的闌尾，即掛在結(jié)腸上面似乎沒什么偶爾還會(huì)發(fā)炎的奇怪結(jié)構(gòu)，并不僅僅是一個(gè)退化器官。

Recent research has found that it might play a key role in our immune systems by harbouring good bacteria that help fight infection. Good work, little buddy!

最近有研究發(fā)現(xiàn)闌尾對(duì)我們的免疫系統(tǒng)有很重要的作用，它能夠孕育有用細(xì)菌幫助人體對(duì)抗感染。小家伙，做得好!

That extra ear hole

耳朵上額外的洞

(Smooth_O/Wikimedia Commons)If you look carefully at your ears, you might notice you have a tiny additional hole just where the helix meets the side of your head.

如果你仔細(xì)盯著你的耳朵看，那么你可能會(huì)注意到耳朵旁邊有個(gè)小洞。

This is called the preauricular sinus, and only a tiny percentage of people have them. It's actually a rare birth defect first documented by Van Heusinger in 1864.

這被稱作耳前竇道，只有少數(shù)人擁有它們。實(shí)際上它是一種很罕見的先天缺陷，最早于1864年為Van Heusinger所記載。

We don't know why we have them - but evolutionary biologist Neil Shubin of the University of Chicago and the Field Museum of Natural History has hypothesised that they're an evolutionary remnant of fish gills.

我們不知道為什么會(huì)有這些東西，不過芝加哥大學(xué)及菲爾德自然史博物館的進(jìn)化生物學(xué)家Neil Shubin認(rèn)為它們是一種魚鰓殘留物。

Wrinkly fingers

發(fā)皺的手指

If you spend too long in the swimming pool, you're going to notice that your fingers and toes start to look a little like raisins. This might not be pointless, according to a paper published in the journal Biology Letters in 2013.They conducted experiments and found that underwater objects were manipulated much more adroitly by wrinkled fingers than unwrinkled fingers - suggesting that the feature exists to give us improved grip in both handling objects and walking when wet surfaces are involved.

如果你在泳池待得太久，那么你可能會(huì)發(fā)現(xiàn)你的手指和腳趾看起來有點(diǎn)像葡萄干。這并不是什么毫無意義的現(xiàn)象。

發(fā)表在2013年《生物通信》期刊上的一篇研究認(rèn)為，在水下環(huán)境中，發(fā)皺的手指操控物品的能力比沒有發(fā)皺的手指強(qiáng)。這意味著這一現(xiàn)象是為了方便人類更好地在濕潤(rùn)的表面行走及操控物品。

Junk DNA

無用DNA

We have a lot of DNA in our body that, until recently, didn't really seem to do anything.

我們體內(nèi)有很多似乎什么事都沒做的DNA。

It doesn't create proteins, and it seems to make us more susceptible to damage and disease - but it makes up a significant part of our genome. If it wasn't somehow beneficial, evolution would have at least started phasing out this so-called "junk DNA," but that hasn't happened.

它不會(huì)制造蛋白質(zhì)，似乎還讓我們更容易遭受傷害和疾病的影響，它構(gòu)成了基因組的重要部分。如果它沒什么用，那么進(jìn)化就會(huì)淘汰這些所謂的無用DNA，但它并沒有被淘汰。

Recently, researchers may have figured out what it's for - it plays a critical role in holding out genome together by ensuring that chromosomes bundle correctly inside the nuclei if our cells. Without that function, cells die - so it seems like "junk" DNA is not so junky after all.

近來，研究人員們發(fā)現(xiàn)了它的功能，它能夠?qū)⑽覀兊幕蚪M緊緊地粘合在一起。沒有這一功能，細(xì)胞就會(huì)死亡。看起來無用DNA也不是那么無用。

"Useless" immune cells

無用的免疫細(xì)胞

We have these immune cells in our bodies that nobody could figure out what they were for.

我們體內(nèi)有一些免疫細(xì)胞，沒人能找到它們的作用。

It was a real head-scratcher, because these "silenced" lymphocytes are present in our bodies in large numbers and only seemed to emerge to attack the body in autoimmune diseases. It looks like a liability, right?

這真是一大難題，因?yàn)檫@些沉默的淋巴細(xì)胞大量存在于我們體內(nèi)，似乎在自身免疫疾病中還會(huì)攻擊人體。它看起來有點(diǎn)礙事對(duì)吧?

But it ain't. It turns out that the cells represent a new type of immunity that we didn't know about before - they attack dangerous infections that otherwise evade the immune system by disguising themselves as part of the body. A pretty useful line of defence to have, wouldn't you say?

但它并不礙事。原來這些細(xì)胞代表著人類并不知道的新型免疫力，它們會(huì)攻擊偽裝成人體一部分的危險(xiǎn)病原體。這難道不是一種有用的免疫么?

Gut bacteria

腸道細(xì)菌

There's a reason that experts have recently suggested that we all start referring to ourselves using the royal "we".

專家建議我們用“我們”這個(gè)詞來指代我們自己。

In recent years, research has found that the microbes that live inside of us, especially our intestines (our microbiome), are symbiotic - and they have far more of an effect on our lives than we realised.

近些年來，研究人員們發(fā)現(xiàn)住在人體內(nèi)部的微生物，尤其是住在腸道內(nèi)部的微生物，與我們是共生關(guān)系。它們對(duì)我們的作用遠(yuǎn)超我們想象。

They have been implicated in such illnesses as multiple sclerosis, Parkinson's disease, cancer and chronic fatigue syndrome, which means they may be pretty danged important. But they also seem to play a role in regulating other things, too - such as our appetites, and even our moods.

它們涉及多發(fā)性硬化、帕金森、癌癥以及慢性疲乏綜合征等疾病，這意味著它們十分重要。它們?cè)谡{(diào)節(jié)其它情況方面也很重要，比如我們的胃口甚至是情緒。

Interstitium

間質(zhì)組織

Turns out we may have an organ wrapped around our other organs, and it's been hiding in plain sight for all this time. The newly classified organ is called the interstitium, and previously scientists had just thought it was relatively unremarkable, relatively solid tissue to fill the space between our organs.

原來我們擁有一個(gè)包裹著其它器官的器官，它一直藏得很深。這一被人新發(fā)現(xiàn)的器官被稱作間質(zhì)組織，先前科學(xué)家們以為它是相對(duì)不起眼、堅(jiān)硬的組織，能夠填充器官間的縫隙。

It's actually filled with fluid, supported by a collagen lattice, and it helps protect our organs from external shocks as we move around, much like air cushions in running shoes.

實(shí)際上它充滿了液體，由膠原框架支撐，幫助我們的器官免受外部沖擊，類似于跑鞋里的空氣墊。

The pink bit in your eye

眼睛里的粉色組織

If you look in the mirror, you'll see a little pink bit of conjunctival tissue in the corner of your eye. This is called the plica semilunaris, and these days its primary function is to help with tear drainage and eyeball mobility.

如果你看著鏡子，那么你會(huì)在眼睛的角落里看到一點(diǎn)粉色的結(jié)膜組織。這被稱作半月襞，如今它的主要功能是幫忙排出眼淚、幫助眼球轉(zhuǎn)動(dòng)。

But once upon a time it was a nictitating membrane - what we call a third eyelid, a translucent eyelid that can be drawn over the eye to keep it moist and protected while maintaining a measure of vision.

曾經(jīng)它是瞬膜，我們稱之為第三眼瞼，它能夠幫助眼球轉(zhuǎn)動(dòng)并保護(hù)眼球，同時(shí)還能保留視力。

If you have a cat or a dog, you may have seen their third eyelid while they're sleeping. Humans and most other primates don't need this feature any more, so it evolved away a long time ago - but we still have that vestigial lump of tissue.

如果你有一只貓或者一條狗，那么你可能會(huì)在它們睡覺的時(shí)候見到它們的第三眼瞼。人類和大多數(shù)其它靈長(zhǎng)類動(dòng)物不再需要這一功能，因此它被淘汰了，但這一組織保留了下來。

Last year, doctors reported the second known case of a nictitating membrane in a human. A nine-year-old girl had a persistent membrane across her left eye that could not be retracted. It was surgically excised, and her eye underneath was fine.

去年，有醫(yī)生報(bào)告說見到了第二例人類瞬膜。一個(gè)九歲的小女孩的左眼長(zhǎng)了不能縮回去的瞬膜，后來醫(yī)生手術(shù)切除了這一組織，瞬膜下女孩的眼睛很好。