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• For a long time the measurement of a healthy baby was having 10 fingers and 10 toes. Wait,

長久以來衡量寶寶健康的方式都是看十指是否健全。等等，

• why didn't anybody care about the eyes, nose, or anything else?

為什麼沒有人在乎眼睛、鼻子或是其他東西呢？

• Hey digitals, Lissette here for Dnews. I am the proud owner of 10 fingers and 10 toes,

嗨， 我是DNews的Lissette。我可以很開心的說我有十根手指與腳指

• I can prove half of this just right now. Youll just have to trust me on the 10 toes thing. But,

我可以證明一半給你看，另一半腳趾的部分你只能選擇相信我了。但，

• have you ever wondered why that is? Why don’t we have 12 fingers and 14 toes? Or 6 fingers

你有沒有想過為什麼是十根？為什麼不是12根手指與14根腳指？或者六根手指

• and 1 toe? Well, this may not come as a shocker to you DNews fans out there, but no one really

與一根腳趾？各位 DNews 的忠實粉絲可能不會太意外：但是

• knows. It might all come down to math.

從來沒有人知道切確原因。可能一切得回歸數學來探討

• Mark Changizi, a theoretical neurobiologist, developed a hypothesis called the Limb Law,

Mark Changizi是個神經生物學家，研發了一套「四肢法則」的理論

• first published in the Journal of Theoretical Biology in 2001. It’s a mathematical equation

首次於2001年在生物理論日報出刊，這個數學公式是

• that tries to figure out the correct number of limbs an animal needs in order to connect

用以求出動物為了符合這世界的生活環境，所演化出的四肢切確數量，

• to the world around it based on the length of its limbs relative to it’s body size.

以及與他們的軀幹大小的相對關係

• Okay, wow. The equation looks like this. Confusing, I know. But he used this equation with 190

Okay，哇。這個公式是這樣的。我知道很難理解。這個公式是以190

• different animal species from seven different animal Phyla, and the math seems to check

種動物，分別從七個不同的生物分類法演算出來的。而這數學公式似乎是

• out. Mark thinks this same equation could be used to figure out why humans have five

可行的。Mark認為這個公式可以用來算出為什麼人類一隻手

• fingers on each hand.

有五根手指頭

• The calculation treats our palms as the animal and our fingers as limbs. Also it takes into

在運算中，他們把人類的手掌比擬做動物體，而人類的手指比擬做動物的四肢。也有另一

• account that the whole reason behind having fingers is that theyre able to fold over

重點是，手指的存在是為了彎曲摺疊時能夠

• our entire palm, in order to grasp things. So, first, fingers have to be at least as

覆蓋住整個手掌，以便於抓取東西。所以，手指必須至少跟我們的

• long as our palms, also known as length need to connect to the outside world. When you crunch the

手掌一樣長，並與外界連接，計算出的

• numbers, you'll get 9.42 digits per hand. But, he argues, since our hand is not a free

數字是，每隻手應該要有9.42根手指。但是，我們的手不單單是個

• roaming creature, but is attached to our arm, it doesn't need limbs protruding from all

漂浮的物體。由於手與手臂相連接，因此不需要四面八方都有指頭，

• sides. Hands only need half the total number of limbs. That gets us to 4.71 fingers per

只需要一半的數字就夠了。所以算出一隻手平均會有4.71根

• hand. Just based on math. Pretty amazing.

手指頭。這只是光靠數學公式算出的，蠻讓人驚艷的

• But other explanations are simpler than that. Evolutionary biologists say that we have 10

但有其他的解釋比這個簡單多了。生物演化學家指出我們的十根

• fingers and 10 toes because that’s the best combination for us. If 8 fingers and 8 toes

手指、腳趾恰逢其所。如果八根手指、腳趾

• would have given us an evolutionary advantage, humans would have 4 fingers on each hand.

有利於演化，則人類就會一手有四根手指

• Cliff Tabin, a Harvard Medical school geneticist focusing on limb development in vertebrates,

哈佛遺傳學家Cliff Tabin則是著重在脊椎動物的四肢演化

• pointed out that our motor skills come down to our thumb and index finger, and that another

他指出，我們之所以如此靈巧是由於大拇指與食指的存在，若是生長出

• small, 6th finger wouldn’t really change anything. And if we ever did grow a 6th finger,

第六跟小指頭，則不會對人類有什麼改變。而若我們真的有第六根指頭

• Tabin argues, it would probably grow out of our wrists, like panda’s . It gives

Tabin認為，第六根應該會長在我們的手腕內側，就像熊貓一樣。這讓

• them extra support when gripping bamboo, which gives them an evolutionarily advantage. So,

熊貓們在抓竹子的時候有更多的支撐力量，這也有利於熊貓的演化。所以

• basically, we'd have six if people with six fingers got an advantage.

基本來說如果人類有六根手指頭是有利於演化的話，我們就會有六根手指頭了

• Then, there is this more complicated science answer to why we have the number of digits

除此之外，還有更複雜的科學解釋我們五根手指的原因

• we do. James Sharpe from the Centre for Genomic Regulation in Barcelona discovered

位於巴賽隆納染色體編號規則中心的James Sharp發現

• it all comes down to three molecules in our body. Bmp, Wnt and Sox9. Theyre responsible

我們身體中的三個分子Bmp、Wnt 跟 Sox9 負責

• for marking out in an embryo where fingers will go and how far apart theyll grow.

胎兒生長時手指該長的方向與間隙

• And for the most part it marks out space for five fingers on each hand and five toes on

還有最大的功用是那些分子決定了指頭的分隔

• each foot. But of course sometimes things can go wrong, resulting in the gaps between

但當然有時候可能會出錯，造成手指間的空隙

• fingers being bigger and only having room for four fingers. Or, sometimes it screws

太大而只容得下四根手指；或者有時候也會搞砸

• up and you have room for an extra finger. Oh and fun fact, the basis for this discovery

而使你多長出一根指頭。有趣的是，首先提出這個理論的人是

• was a theory first proposed by Alan Turing back in 1952 about how animals get their spots and

是Alan Turing，他在1952年研究動物為什麼有斑紋

• stripes. Love you, Alan.

或者是線條。愛你，Alan

• So why 10 fingers and 10 toes? Again, were still not entirely sure. But it all seems

所以為什麼有十根手指、腳趾？再一次說明，我們仍然不確定原因。但似乎

• to come down to because that’s exactly the number of fingers and toes we need. Sometimes

結論是因為十根手指、腳恰恰符合需求。有時候，

• it’s best to just trust evolution and be thankful we don’t have hoofs. Amirite?

直接信任演化的結果就好了呀！而且得心存感激我們有手指而非蹄，對吧？

• So that’s hands. But what about feet?

這是講到手，那腳呢？

• When did they evolve and why do they look

腳是什麼時候演化的？而且為什麼腳看起來

• different from hands? Julia walked a mile in those shoes, here.

跟手差那麼多？Julia深入探討了一番

• Toes likely evolved from the same bones that became fins, wings and hoofs in other species.

演化出腳趾的骨頭跟演化初鰭、翅膀、蹄的骨頭相同。

• The dominating scientific theories are that fingers and toes are exclusive features of tetrapods.

較有說服力的科學理論是，手指根腳趾是四足類動物的身體特徵

• Or vertebrates with limbs.

還有有四肢的脊椎動物

• But according to one study toes may evolve even before our fishy ancestors left the ocean.

但一份研究顯示，腳趾的演化或許比魚類祖先離開海洋的時間還早

• Why do you think we have 10 fingers and toes? Would you rather have more or less?

你覺得為什麼我們有十根手指、腳趾？你想要更多還是更少呢？

• Let us know on the comments and remember to subscribe to DNews for more episodes everyday.

在下面留言處跟我們說你的想法，並且不要忘記訂閱DNews，可以看到更多的節目喔

• Thanks for watching, guys.

謝謝收看

For a long time the measurement of a healthy baby was having 10 fingers and 10 toes. Wait,

# 有想過為什麼我們有十根腳趾手指嗎？(Why Do We Have 10 Fingers and 10 Toes?)

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Angela Hsu 發佈於 2016 年 05 月 26 日