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Evolution of the Neck Gave Brain a Leg up

脖子的演變助大腦進(jìn)化一臂之力

What's in a neck? Well, it's a good place to hang a pendant or a tie. Or to rest your head. Now scientists say that by separating our heads from our bodies, the neck gave our brains a leg up in evolution. Their findings appear in the online journal Nature Communications.

脖子有什么用？嗯，脖子是個(gè)掛項(xiàng)鏈吊墜或打領(lǐng)帶的好地方。當(dāng)然，脖子也一直架著我們腦袋讓它能夠倚靠休息。如今，科學(xué)家們?cè)凇蹲匀煌ㄓ崱肪W(wǎng)絡(luò)版上發(fā)表的研究成果里稱，脖子將腦袋跟軀體分離開(kāi)，從而協(xié)助了我們的大腦進(jìn)化。

Not all animals have necks. A fish's head is pretty much continuous with its body. And a fish gets around just fine. Nerves based in the fish's brain instruct its fins to move, and off it goes.

并不是所有的動(dòng)物都有脖子。魚的腦袋就直接連在軀體上，它們?cè)谒袝r(shí)總是來(lái)去自如。魚的大腦掌控著神經(jīng)來(lái)指揮魚鰭擺動(dòng)，這樣魚兒就能到處游動(dòng)了。

But something happened when our aquatic ancestors first slithered onto the land. The source of the nerve cells that power the animals' forelimbs shifted, from the brain to the spinal cord. That move allowed the body to grow more distant from the head, taking the arms with it. And so the neck was born.

然而，當(dāng)我們的祖先從水中蹣跚著爬上陸地時(shí)，事情就發(fā)生了變化。驅(qū)使動(dòng)物前肢移動(dòng)的神經(jīng)細(xì)胞源從大腦轉(zhuǎn)到了脊髓。這種轉(zhuǎn)變使得軀體長(zhǎng)得離頭部越來(lái)越遠(yuǎn)，同時(shí)還進(jìn)化出前臂來(lái)。這樣，脖子就應(yīng)運(yùn)而生了。

That neck, say the scientists, was more than just a way to keep the head off the shoulders. The anatomical relocation improved dexterity by leaving the arms free to move in new ways. And the resulting flexibility helped shape the evolution of our heads and our hands, and how we can use them together to do all sorts of nifty things -- like tie a perfect Windsor knot.

科學(xué)家們說(shuō)，這個(gè)脖子可不僅僅是讓腦袋從肩膀“獨(dú)立”出來(lái)。這種解剖學(xué)上的重新定位使前臂得以解放并發(fā)展出新的運(yùn)動(dòng)方式，進(jìn)而改進(jìn)了靈活敏捷程度。而且，由此產(chǎn)生的適應(yīng)性反過(guò)來(lái)幫助形成了我們的頭與手的進(jìn)化，而在手腦配合下，我們就可以做出一切巧奪天工的玩意兒來(lái)——比如打出一個(gè)漂亮的溫莎領(lǐng)結(jié)。

-Karen Hopkin

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