没用的身体器官，真的没用？
我们都曾发现当我们在洗澡的时候，手指和脚趾会泡的起皱;也曾盯着挂在喉咙上的肉看。我们也曾听患过急性阑尾炎并做了切除手术的人说，“这没关系，阑尾本来就没什么用。”
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.
我们的身体是令人惊奇的机器，我们可能没有注意到某些部位的作用，但人体几乎没什么完全没用的部位。
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.
那些我们不需要的部位又怎么解释呢?它们证明了我们的进化，并且我们在持续进化。
Your appendix
阑尾
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.
人类的阑尾，即挂在结肠上面似乎没什么偶尔还会发炎的奇怪结构，并不仅仅是一个退化器官。
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!
最近有研究发现阑尾对我们的免疫系统有很重要的作用，它能够孕育有用细菌帮助人体对抗感染。小家伙，做得好!
That extra ear hole
耳朵上额外的洞
(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.
如果你仔细盯着你的耳朵看，那么你可能会注意到耳朵旁边有个小洞。
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.
这被称作耳前窦道，只有少数人拥有它们。实际上它是一种很罕见的先天缺陷，最早于1864年为Van Heusinger所记载。
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.
我们不知道为什么会有这些东西，不过芝加哥大学及菲尔德自然史博物馆的进化生物学家Neil Shubin认为它们是一种鱼鳃残留物。
Wrinkly fingers
发皱的手指
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，那么你可能会发现你的手指和脚趾看起来有点像葡萄干。这并不是什么毫无意义的现象。
发表在2013年《生物通信》期刊上的一篇研究认为，在水下环境中，发皱的手指操控物品的能力比没有发皱的手指强。这意味着这一现象是为了方便人类更好地在湿润的表面行走及操控物品。
Junk DNA
无用DNA
We have a lot of DNA in our body that, until recently, didn't really seem to do anything.
我们体内有很多似乎什么事都没做的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.
它不会制造蛋白质，似乎还让我们更容易遭受伤害和疾病的影响，它构成了基因组的重要部分。如果它没什么用，那么进化就会淘汰这些所谓的无用DNA，但它并没有被淘汰。
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.
近来，研究人员们发现了它的功能，它能够将我们的基因组紧紧地粘合在一起。没有这一功能，细胞就会死亡。看起来无用DNA也不是那么无用。
"Useless" immune cells
无用的免疫细胞
We have these immune cells in our bodies that nobody could figure out what they were for.
我们体内有一些免疫细胞，没人能找到它们的作用。
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?
这真是一大难题，因为这些沉默的淋巴细胞大量存在于我们体内，似乎在自身免疫疾病中还会攻击人体。它看起来有点碍事对吧?
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?
但它并不碍事。原来这些细胞代表着人类并不知道的新型免疫力，它们会攻击伪装成人体一部分的危险病原体。这难道不是一种有用的免疫么?
Gut bacteria
肠道细菌
There's a reason that experts have recently suggested that we all start referring to ourselves using the royal "we".
专家建议我们用“我们”这个词来指代我们自己。
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.
近些年来，研究人员们发现住在人体内部的微生物，尤其是住在肠道内部的微生物，与我们是共生关系。它们对我们的作用远超我们想象。
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.
它们涉及多发性硬化、帕金森、癌症以及慢性疲乏综合征等疾病，这意味着它们十分重要。它们在调节其它情况方面也很重要，比如我们的胃口甚至是情绪。
Interstitium
间质组织
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.
原来我们拥有一个包裹着其它器官的器官，它一直藏得很深。这一被人新发现的器官被称作间质组织，先前科学家们以为它是相对不起眼、坚硬的组织，能够填充器官间的缝隙。
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.
实际上它充满了液体，由胶原框架支撑，帮助我们的器官免受外部冲击，类似于跑鞋里的空气垫。
The pink bit in your eye
眼睛里的粉色组织
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.
如果你看着镜子，那么你会在眼睛的角落里看到一点粉色的结膜组织。这被称作半月襞，如今它的主要功能是帮忙排出眼泪、帮助眼球转动。
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.
曾经它是瞬膜，我们称之为第三眼睑，它能够帮助眼球转动并保护眼球，同时还能保留视力。
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.
如果你有一只猫或者一条狗，那么你可能会在它们睡觉的时候见到它们的第三眼睑。人类和大多数其它灵长类动物不再需要这一功能，因此它被淘汰了，但这一组织保留了下来。
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，有医生报告说见到了第二例人类瞬膜。一个九岁的小女孩的左眼长了不能缩回去的瞬膜，后来医生手术切除了这一组织，瞬膜下女孩的眼睛很好。
