We. Love.
我們。喜歡。
Symmetry. It's in our art, and architecture.
對稱。我們的藝術、建築中都有對稱元素。
We even balance equations on it. Our love of symmetry makes sense, because we're symmetrical.
我們甚至以對稱形式保持等式。我們鍾愛於對稱是有道理的，因為我們就是對稱的。
Two eyes, two ears, two arms, and two legs. Bodies that built like paper dolls.
兩個眼睛、兩隻耳朵、兩隻手臂、還有兩條腿。身體塑造得像紙人。
But that outward beauty is superficial. Peel back the curtain, and that symmetry disappears.
但外表的對稱美是膚淺的。拉開幕布，對稱性就消失了。
Your guts are a mess. Unless you're from Gallifrey, you have one heart, on the left side of your body, same as your stomach and spleen, but your liver is on the right.
你的內臟一團糟。如果你不是來自加利弗雷星，那麼你就只有一顆心臟，在你身體的左側，和你的胃和脾臟一樣，但是你的肝臟在右側。
Even organs that look symmetrical at first seem to tip one way or the other. The right lung is divided into three lobes while the left lung has only two.
即使是一開始看起來對稱的器官似乎也會向一個或另一個方向傾斜。右肺分為三個葉，左肺只有兩個葉。
And in your brain, two areas that are needed for speech and language are found only on one lobe, usually the left. Animals as distantly related as starfish show similar internal asymmetry.
而在你的大腦中，講話和語言所需的兩個區域只在一個腦葉上有，通常是在左側。與海星遠親的動物顯示出相似的內部的不對稱性。
The interesting thing isn't that our bodies are asymmetrical in the first place, but that we all have the same asymmetry.Unless you have a case of oppositus. 1 in 20,000 people on Earth have a genetic condition called situs inversus, where the internal organs are inverted left to right.
有趣的不是我們的身體一開始不對稱，而是我們都有一模一樣的不對稱性。除非你有相反的情況。地球上每2萬人中就有1人患有一種稱為Situs Inversus的遺傳病，其內部器官左右顛倒。
These people usually show no negative effects from their reversed innards. Unless their name is Donny Osmond.
這些人通常沒有因他們扭轉的內部結構而表現出負面影響。除非他們是唐尼·奧斯蒙。
In 1972, the singer was checked into the hospital nearly unconscious from a pain in the left side of his abdomen.Sounds like a classic case of appendicitis, except the pain was in the wrong place.
1972年，這位歌手由於腹部左側痛得幾乎失去知覺，被送進醫院。聽起來像是闌尾炎的典型病例，只是疼痛的部位不對。
The doctors operated anyway, and removed his burst appendix with only hours to spare. . . from the opposite side of his body where it should have been. Enrique Iglesias and Catherine O' Hara also have situs inversus. . . maybe one of you do too.
醫生們無論如何都做了手術，把在只有幾個小時情況下，把那破裂的闌尾切除了……從他本來應該切除的另一邊。恩裡克·伊格萊西亞斯和凱瑟琳·奧哈拉也有Situs Inversus症狀…也許你們中的一個也有。
But if people can live happy, healthy lives with inverted organs, why don't half of us have half of us on either half of us? And if it's doesn't hurt to be asymmetrical on the inside, why are we so non-asymmetrical on the outside?
但是，如果器官是扭轉的人都過上幸福、健康的日子，為什麼我們中有一半人的一半都不能擁有我們的一半呢？如果體內不對稱不要緊的話，為什麼我們的外表又如此對稱呢？
One theory says that throughout evolution, when animals are looking to pass their genes on to the next generation, sometimes it is what's on the outside that counts. Female barn swallows seem to choose males based on the symmetry of their long forked tails.
有一種理論認為，在整個進化過程中，當動物希望把他們的基因傳給下一代時，有時最重要的是外部的東西。雌性穀倉燕子似乎是根據它們長而分叉的尾巴的對稱性來選擇雄性的。
Highly symmetrical bodies in animals might signal quality genes, and better offspring. Of course when humans pair up, we display many kinds of symmetry, and we look for a lot more than just balanced bodies.
動物界存在的高度對稱的體型可能代表著高質量的基因、以及更好的後代。當然，當人類配對時，我們表現出多種對稱性，我們追求的不僅是均衡的身體。
I mean, you wouldn't decide to date someone based on where their heart was, as long as it's with you. So how does it get this way?
我的意思是，只要他/她心在你那兒，你不會根據他/她的心臟在哪個位置決定是否和他/他約會。所以它怎麼就是現在這樣的呢？
All we need in order to define left from right is to determine which ends will be the head and tail, and which will be back and belly. But that only sculpts our outer shell.
為了定義左右，我們要做的就是確定哪一端是頭部和尾部，哪一端是背部和腹部。但那隻能塑造我們的外殼。
Maybe the orientation of your organs may just have to go with the flow. In the earliest days of an embryo, left and right are symmetrical.
也許你的器官的方向與血流方向是一致的。在胚胎的早期，左右是對稱。
Last year researchers found that hairlike cilia on this special bunch of cells began to beat in unison, pointing toward what will later become the left side. Like a blender, They wash a current over the outside of the embryo, and sensing that current leads to the expression of a gene that determines the side on every one of your organs will live on.
去年，研究人員發現，這一特殊細胞群上的毛髮狀纖毛開始協調一致地跳動，指向後來會變成左側的部分。就像攪拌器一樣，它們在胚胎外部清洗電流，並感應到電流會導致一個基因的表達，這個基因決定了你每個器官的生存側。？？
It's strange, because it doesn't have to be that way. Our guts could work in either orientation.
這很奇怪，它不必非得這樣。我們的腸胃也以任何一個方向都運作。
But for most of us, it just is that way. Hopefully you've seen the other videos in this series on guts.
但對於我們大多數來說，它就是這樣的。希望你看過這個系列的其他關於腸胃的視頻。
It's obvious that reversing the other axes of the body, where is the back and belly, or the mouth and the anus, would have some serious evolutionary consequences. But left and right seem to be more interchangeable.
顯然，要是改變身體的其他對稱軸，即背部和腹部，或者口腔和肛門，都會帶來一些嚴重的進化後果。但是左和右更可能相互轉換。
But time and time again in the story of our body we have seen the incredible influence of seemingly chance events on the course of evolution. The first animal to put its eyes near its mouth might be the reason you have a brain in your head.
但在關於我們身體的故事中，我們一次又一次地見證了那些看似偶然的事件對進化過程造成的不可思議的影響。動物第一次將眼睛挪近嘴可能就是促使你頭顱內部裡有大腦的原因。
A worm doing the backstroke might be the reason your spine runs down your back. And a tiny molecular propeller, leaning one way or the other might be the reason that your heart is in the right. . . or left place.
那隻做仰泳的蠕蟲可能就是為什麼你的脊椎沿著背部往下的原因。一個微小的分子螺旋槳，偏向一個方向還是另一個方向可能就是為什麼你的心臟在右邊或左邊的原因。
Stay curious. This video is part of a three-part series all about guts.
保持好奇心。這個視頻是一個由三集系列節目中的一集。
If you wanna know more about why your body is organized the way that it is, check out the rest of these videos.
如果你想知道更多為什麼你的身體是現在的組織的方式的原因，看看這些視頻的剩下幾集吧。
