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課程來源:TED
     

Nina Jablonski 談打破膚色的錯覺

Breaks the illusion of skin color

 

 

Photo of 

three lions hunting on the Serengeti.

講者:Nina Jablonski

20092月演講,20097月在TED上線

 

翻譯:洪曉慧

編輯:劉契良

簡繁轉換:陳盈

後製:洪曉慧

字幕影片後制:謝旻均

 

影片請按此下載

閱讀中文字幕純文字版本

 

關於這場演講

Nina Jablonski說,不同膚色只是因為我們身體適應不同氣候和紫外線暴露程度。查爾斯‧達爾文不同意這個理論,但她解釋說,那是因為他當時無法獲得NASA(美國國家航空暨太空總署)的資料。

 

關於Nina Jablonski

Nina Jablonski 是《皮膚:一部自然歷史》的作者,本書是對人類皮膚許多非凡特性的詳細觀察:它有色差、它會排汗,以及我們妝點它的事實。

 

為什麼要聽她演講:

「我們對人類的認知很多是來自我們的皮膚」,Nina Jablonski如是說到。她於1981年洞察到這個事實,事件發生在一堂令人神經緊繃的解剖課,當切開屍體皮膚的剎那,她對其產生了興趣。事實證明,皮膚是令人充滿驚奇、會出汗、耐磨損、具社會性-和未被全然瞭解的-器官。她在其著作《皮膚:一部自然歷史》中,收集了許多觀察資料,內容關於什麼使我們的皮膚如此獨特,或許,比我們所意識到的更重要。

 

Nina Jablonski著迷於具有各種顏色,及多重天賦的人類肌膚,她是一位真正兼容並蓄的科學家。她也是古生物學家和靈長類動物學家,由氣候變化和演化的觀點,研究哺乳動物的類型、行為和飲食習慣。她任教於賓州州立大學,最近才挖出世界上最古老的黑猩猩化石。

 

「Nina Jablonski 對於你可能會想知道的,一切關於人體外衣的知識,給了我們最好和最引人入勝的描述」。

-Jared Diamond

 

Nina Jablonski的英語網上資料

首頁:Nina Jablonski

 

[TED科技娛樂設計]
已有中譯字幕的TED影片目錄(繁體)(簡體)。請注意繁簡目錄是不一樣的。

 

Nina Jablonski 談打破膚色的錯覺

 

有趣的是,查理斯.達爾文天生是一位膚色很淺的人,卻成長在一個中等到深膚色的世界中。在他生命過程中,達爾文享有很大的特權。他生於一個相當富裕的家庭中,由非常支持與關心他的父母養大。當他20多歲時,便搭上小獵犬號展開非凡的航程。在這趟航行過程中,他看到了各種奇異的事物,植物、動物,及人類驚人的多樣性。他在這壯觀的旅程中所做的觀察,最終淬煉成精彩的著作,就是《物種起源》,於150年前出版。

 

非常有趣的是,在某種程度上,有點聲名狼藉的是,關於《物種起源》這本書,其中只有一行寫到關於人類的進化,闡明人類的起源及其歷史。直到很久很久以後,達爾文才確實談到及寫到關於人類的事。在他隨小獵犬號航行的歲月中,透過傳聞或探險家和博物學家的敍述,他知道膚色是展現人們差異最重要的一個層面,他多少對膚色的變化有些興趣。他知道深膚色的人可存在於接近赤道處;像他一樣淺膚色的人,會存在於接近兩極處。

 

因此,他對這一切有什麼瞭解呢?他在《物種起源》中,沒有寫到任何與之相關的事。但很久以後,在1871年,他確實說了些與這有關的事,而且是相當奇特的。他說:「在所有人類種族間的差異中,膚色是最顯而易見的,也是最好的標記之一」。他接著說,「這些差異並不與氣候差異一致變化」。他曾遊歷各地,他曾看到不同膚色的人,生活在不同地方。然而,他拒絕了這個想法,就是人類膚色與氣候有關。

 

如果達爾文活在當今,要是達爾文有NASA就好了。NASA所做令人讚歎的其中一件事,就是建造了多種衛星來偵測我們環境中所有有趣的事物。近幾十年來,出現了一系列的TOMS衛星(譯注:TOMS 測繪臭氧總量分光計)收集關於地球表面輻射的資料。TOMS 7號衛星收集的資料顯示在這裏,顯示每年平均地球表面的紫外線輻射。深粉紅色和紅色的區域,是世界上接收最大量紫外線的區域,在這一年的時間中。至於逐步趨冷的顏色,藍色、綠色、黃色,最後是灰色,則標示出紫外線輻射低較多的地區。

 

人類膚色故事的重要性,在於它顯示出北半球有諸多區域處於這些冷灰色地帶,這在我們對人類膚色演化的瞭解上有著巨大的影響。達爾文所無法理解的,也或許他當時並沒有想去理解的。就是有一個基本的關係,存在於紫外線輻射強度和皮膚色素之間,皮膚色素本身就是進化的產物。所以當我們看膚色地圖並預測膚色,如我們現今所知,我們看到的是一個美麗的梯度;從最深的膚色指向赤道,最淺的膚色指向兩極。

 

相當重要的是,最早的人類是在高紫外線環境中發生進化的。在赤道非洲,人類血統中最早的成員,起始人種即是深膚色的。我們共用這個不可思議的遺產。我們原本是深膚色的,在200萬到150萬年前。

 

我們歷史中發生了什麼事?我們先看看紫外線輻射到地球表面的關聯性。在我們進化的早期,看看赤道,我們受到高強度的紫外線輻射襲擊。UVC是能量最高的形式,會被地球大氣層阻擋。但UVB,特別是UVA,能夠穿透大氣層。UVB證明是相當重要的。它非常具有破壞性,但它也催化維生素 D 在皮膚中的產生。維生素 D 是一個分子,我們非常需要它來維持骨骼的強健、免疫系統的健康、以及我們身體許多重要的功能。

 

因此,生活在赤道,我們得到了很多很多的紫外線輻射和黑色素。這個很棒、很複雜、古老的聚合物,在我們皮膚中可作為一種極佳的天然防曬劑。這種聚合物是驚人的,因為它存在於許多不同的有機體中,多種形式的黑色素可能已存在地球上有10億年之久,並藉由進化一次又一次的重現,一直以來都是如此。如果它很有用,為什麼要改變它呢?

 

所以,黑色素被吸收於我們的血統中,特別是進化於我們最早生活在非洲的祖先身上。它成為一種天然防曬劑,在那裏,它保護身體抵抗紫外線輻射的毀壞,或對 DNA 的破壞或損害,及防止一個非常重要的稱為葉酸分子的分解,其有助於供給我們身體細胞生產和再生產的能量。因此,這很棒,我們發展了這個非常具保護作用美妙的黑色素覆蓋物。

 

但隨後我們遷移了。人類四散各處,不只一次,而是兩次。主要的遷移,遠離我們的赤道故鄉,從非洲到舊世界其他地區,近期則進入了新世界。當人類分散到這些高緯度地區,他們面臨了什麼呢?生存環境明顯的較為寒冷,但他們也較不受那麼強的紫外線的統治。

 

因此,如果我們是在北半球某處,看看紫外線輻射的情形。我們仍然會接收到大量的UVA,但所有的UVB,或說幾乎所有的UVB,都消散在厚厚的大氣層中。冬季時,當你到阿爾卑斯山滑雪,你可能會遭受紫外線輻射,但它全都是UVA。顯然的,UVA沒有能力在你的皮膚中製造維生素 D

 

因此,居住在北半球環境中的人們,多年過後便會喪失在他們皮膚中製造維生素 D的潛能。這產生了極大的影響,對人類皮膚色素的演化來說。因為所發生的是,為了確保健康和福祉,這些分散到北半球的人類血統失去了他們的色素。這是天擇,對淺膚色的進化來說。

 

在這裏,我們開始看到演化的分佈,就是這美麗的棕黑色彩虹,這描繪出現在所有人類的特徵。淺膚色的演化不只一次,不只兩次,而可能是三次。不僅在現代人類,在我們一個沒有親緣關係的祖先尼安德塔人身上也是。這是一個非凡的且顯著的證明,對演化的力量來說。人類長期以來一直在遷移,僅在過去5000年,速率的增長即大於距離的拉長。這是一些人類最大的遷移,自願性的遷移,就發生在過去5000年中。

 

看看一些主要跨緯度的越界遷移。人們從高UV地區遷移到低UV地區,反向亦然。並非所有這些遷移都是自願的。15201867年間,1200500人已從高UV地區移向低UV地區,在跨大西洋奴隸貿易中。現在這已產生各種遭致不滿的社會後果,但那對人們的健康亦有不利的後遺症。

 

那又怎麼樣呢?我們一直在遷移,我們很聰明,我們能夠克服所有這些表面上的生物障礙。我們往往不知道一個事實,即我們生活其中的環境,是我們皮膚天生所不適應的。一些淺膚色的人居住在高UV地區;一些深膚色的人生活在低UV地區;這些對我們健康都有嚴重影響。

 

我們必須,如果我們是淺膚色,要注意皮膚癌的問題,以及我們身體中葉酸的破壞,全都因為大量的陽光。流行病學家和醫生都很擅於告訴我們要保護我們的皮膚,但他們並不擅告知人們反向的問題,就是那些深膚色居住在高緯度地區的人,或總是在室內工作的人。

 

因為這個問題也同樣嚴重,且情況更險惡。因為維生素 D 的缺乏來自於UVB輻射的缺乏,是一個重大的問題。維生素 D缺乏悄悄的影響人們,並導致他們各種骨骼健康的問題,使免疫系統逐漸衰退,或喪失免疫功能。也可能產生一些問題,影響他們的情緒和健康,以及心理健康。

 

因此,我們膚色擁有的,是它作為演化中一項美妙的產物,至今對我們仍然影響深遠。還有社會影響,如我們所知,是難以想像的深刻。我們生活的這個世界裏,有淺膚色和深膚色的人們彼此相鄰,但往往最初會產生非常令人不快的社會互動結果。我們要怎麼克服這些不悅的互動?我們怎樣才能開始理解呢?演化幫助了我們。

 

達爾文誕生200年後,美國有了第一位膚色「適中」的總統。(掌聲)這多美妙啊?!(掌聲)這人象徵著重大意義,從相當多的層面看來。但我們必須思考,關於他的膚色與地球上的其他人相較之下是如何。他是許多都會和多種族社群的一員,非常具有代表性,混血血統、混合膚色。他很相似於,非常接近那些中等膚色,生活在非洲南部或是東南亞的人們。

 

這些人有極大的潛力曬黑,在他們的皮膚中產生更多色素,這是暴露於太陽下的結果。他們還冒著維生素 D 缺乏的風險,如果他們是在辦公室工作,像這位仁兄一樣。讓我們一起祝福他身體健康,以及他對自己的皮膚色素能有所瞭解。

 

其美妙之處為何?關於人類皮膚色素的進化以及色素沉著的現象,因為它是證明,或說是證據,就是進化因為天擇的關係,且就發生在你的身體上。當有人問你,「進化的證據是什麼?」你不必考慮一些外來的例子,或是化石,只需看看你的皮膚。

 

我想達爾文會理解這個,儘管他排除了氣候變化在色素演化上的重要性,在他的生命過程中。我想,如果他能看看我們今天所擁有的證據,他會瞭解、會贊同的。最重要的是,他還會傳授這些知識。

 

你可以傳授它,你可以觸摸它,你可以理解它。將它帶出這個房間,帶著你的膚色,讚美它,並傳遞這樣常識。你擁有人類物種的進化歷史,擁有它的一部分,就寫在你的皮膚中。瞭解它。欣賞它。讚美它。驕傲的展示它。它這麼美好!這麼美妙!你們是進化的產物,謝謝。(掌聲)

 

以下為系統擷取之英文原文

About this talk

Architecture student Magnus Larsson details his bold plan to transform the harsh Sahara desert using bacteria and a surprising construction material: the sand itself.

About Magnus Larsson

Magnus Larsson hopes to build new structures in the desert -- by using bacteria to turn shifting sand into a solid mass. Full bio and more links

Transcript

It's a bit funny to be at a conference dedicated to things not seen, and present my proposal to build a 6,000-kilometer-long wall across the entire African continent. About the size of the Great Wall of China, this would hardly be an invisible structure. And yet it's made from parts that are invisible, or near-invisible to the naked eye, bacteria and grains of sand.

Now, as architects we're trained to solve problems. But I don't really believe in architectural problems; I only believe in opportunities. Which is why I'll show you a threat, and an architectural response. The threat is desertification. My response is a sandstone wall made from bacteria and solidified sand, stretching across the desert.

Now, sand is a magical material of beautiful contradictions. It is simple and complex. It is peaceful and violent. It is always the same, never the same, endlessly fascinating. One billion grains of sand come into existence in the world each second. That's a cyclical process. As rocks and mountains die, grains of sand are born. Some of those grains may then cement naturally into sandstone. And as the sandstone weathers, new grains break free. Some of those grains may then accumulate on a massive scale, into a sand dune.

In a way, the static, stone mountain becomes a moving mountain of sand. But, moving mountains can be dangerous. Let me try and explain why. Dry areas cover more than one third of the Earth's land surfaces. Some are already deserts; others are being seriously degraded by the sand. Just south of the Sahara we find the Sahel. The name means "edge of the desert." And this is the region most closely associated with desertification. It was here in the late '60s and early '70s that major droughts brought three million people to become dependent upon emergency food aid, with about up to 250,000 dying.

This is a catastrophe waiting to happen again. And it's one that gets very little attention. In our accelerated media culture, desertification is simply too slow to reach the headlines. It's nothing like a tsunami or a Katrina: too few crying children and smashed up houses. And yet desertification is a major threat on all continents, affecting some 110 countries and about 70 percent of the world's agricultural drylands.

It seriously threatens the livelihoods of millions of people, and especially in Africa and China. And it is largely an issue that we've created for ourselves through unsustainable use of scarce resources. So, we get climate change. We get droughts, increased desertification, crashing food systems, water scarcity, famine, forced migration, political instability, warfare, crisis. That's a potential scenario if we fail to take this seriously. But, how far away is it?

I went to Sokoto in northern Nigeria to try and find out how far away it is. The dunes here move southward at a pace of around 600 meters a year. That's the Sahara eating up almost one meter a day of the arable land, physically pushing people away from their homes. Here I am -- I'm the second person on the left -- (Laughter) with the elders in Gidan-Kara, a tiny village outside of Sokoto.

They had to move this village in 1997 as a huge dune threatened to swallow it. So, they moved the entire village, hut by hut. This is where the village used to be. It took us about 10 minutes to climb up to the top of that dune. Which goes to show why they had to move to a safer location. That's the kind of forced migration that desertification can lead to. If you happen to live close to the desert border, you can pretty much calculate how long it will be before you have to carry your kids away, and abandon your home, and your life as you know it.

Now, sand dunes cover only about one fifth of our deserts. And still, those extreme environments are very good places if we want to stop the shifting sands. Four years ago, 23 African countries came together to create the Great Green Wall Sahara. A fantastic project, the initial plan called for a shelter belt of trees to be planted right across the African continent, from Mauritania in the west, all the way to Djibouti in the east. If you want to stop a sand dune from moving what you need to make sure to do is to stop the grains from avalanching over its crest. And a good way of doing that, the most efficient way, is to use some kind of sand catcher. Trees or cacti are good for this. But, one of the problems with planting trees is that the people in these regions are so poor that they chop them down for firewood.

Now there is an alternative to just planting trees and hoping that they won't get chopped down. This sandstone wall that I'm proposing essentially does three things. It adds roughness to the dune's surface, to the texture of the dune's surface, binding the grains. It provides a physical support structure for the trees, and it creates physical spaces, habitable spaces inside of the sand dunes. If people live inside of the green barrier they can help support the trees, protect them from humans, and from some of the forces of nature. Inside of the dunes we find shade. We can start harvesting condensation, and start greening the desert from within.

Sand dunes are almost like ready-made buildings in a way. All we need to do is solidify the parts that we need to be solid, and then excavate the sand, and we have our architecture. We can either excavate it by hand or we can have the wind excavate it for us. So, the wind carries the sand onto the sight and then it carries the redundant sand away from the structure for us.

But, by now, you're probably asking how am I planning to solidify a sand dune? How do we glue those grains of sand together? And the answer is, perhaps, that you use these guys, Bacillus pasteurii, a micro-organism that is readily available in wetlands and marshes, and does precisely that. It takes a pile of loose sand and it creates sandstone out of it. These images from the American Society for Microbiology show us the process.

What happens is, you pour Bacillus pasteurii onto a pile of sand, and it starts filling up the voids in between the grains. A chemical process produces calcite, which is a kind of natural cement that binds the grains together. The whole cementation process takes about 24 hours. I learned about this from a professor at U.C. Davis called Jason DeJong. He managed to do it in a mere 1,400 minutes. Here I am, playing the part of the mad scientist, working with the bugs at UCL in London, trying to solidify them.

So, how much would this cost? I'm not an economist, very much not, but I did, quite literally, a back of the envelope calculation -- (Laughter) -- and it seems that for a cubic meter of concrete we would have to pay in the region of 90 dollars. And, after an initial cost of 60 bucks to buy the bacteria, which you'll never have to pay again, one cubic meter of bacterial sand would be about 11 dollars.

How do we construct something like this? Well, I'll quickly show you two options. The first is to create a kind of balloon structure, fill it with bacteria, then allow the sand to wash over the balloon, pop the balloon, as it were, disseminating the bacteria into the sand and solidifying it. Then, a few years afterwards, using permacultural strategies, we green that part of the desert.

The second alternative would be to use injection piles. So, we pushed the piles down through the dune, and we create an initial bacterial surface. We then pull the piles up through the dune and we're able to create almost any conceivable shape inside of the sand with the sand acting as a mold as we go up. So, we have a way of turning sand into sandstone, and then creating these habitable spaces inside of the desert dunes,

But, what should they look like? Well, I was inspired, for my architectural form, by tafoni, which look a little bit like this, this is a model representation of it. These are cavernous rock structures that I found on the site in Sokoto. And I realized that if I scaled them up, they would provide me good spacial qualities, for ventilation, for thermal comfort, and for other things. Now, part of the formal control over this structure would be lost to nature, obviously, as the bacteria do their work. And I think this creates a kind of boundless beauty actually. I think there is really something in that articulation that is quite nice. We see the result, the traces, if you like, of the Bacillus pasteurii being harnessed to sculpt the desert into these habitable environments.

Some people believe that this would spread uncontrollably, and that the bacteria would kill everything in its way. That's not true at all. It's a natural process. It goes on in nature today. and the bacteria die as soon as we stop feeding them. So, there it is -- architectural antidesertification structures made from the desert itself. Sand-stopping devices, made from sand. The world is likely to lose one third of its arable land by the end of the century. In a period of unprecedented population growth and increased food demands, this could prove disastrous. And quite frankly, we're putting our heads in the sand.

If nothing else, I would like for this scheme to initiate a discussion. But, if I had something like a TED wish, it would be to actually get it built, to start building this habitable wall, this very very long, but very narrow city in the desert, built into the dunescape itself. It's not only something that supports trees, but something that connects people and countries together. I would like to conclude by showing you an animation of the structure, and leave you with a sentence by Jorge Luis Borges.

Borges said that, "Nothing is built on stone, everything is built on sand, but we must build as if the sand were stone"

Now, there are many details left to explore in this scheme, political, practical, ethical, financial. My design, as it takes you down the rabbit hole, is fraught with many challenges and difficulties in the real world. But, it's a beginning, it's a vision. As Borges would have it, it's the sand. And I think now is really the time to turn it into stone. Thank you. (Applause)


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英文原文, 似乎誤植.

Anonymous, 2011-10-21 10:19:13
關於翻譯中「進化」一詞
改成演化比較好吧?物種原始講的是最適化的留下來,而不是最進步的。
wengoo, 2010-03-04 04:27:37
課程討論
沒有人要來改嗎?
Anonymous, 2010-02-04 20:37:30
課程討論
翻譯怪怪的
Anonymous, 2010-01-30 20:20:56

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