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  • This is the microraptor,

    這是一隻小盜龍

  • a carnivorous four-winged dinosaur that was almost two-feet long,

    是隻有四翼的肉食性恐龍 將近兩呎長

  • ate fish,

    以吃魚為生

  • and lived about 120 million years ago.

    活在 1 億 2 千萬年前的世界

  • Most of what we know about it comes from fossils that look like this.

    我們對牠的資訊大多是從 像這樣的化石來的

  • So, is its coloration here just an artist's best guess?

    那麼,這些顏色只是畫家的猜測嗎?

  • The answer is no.

    答案是否定的

  • We know this shimmering black color is accurate

    我們知道這閃爍的黑色是正確的

  • because paleontologists have analyzed clues contained within the fossil.

    因為古生物學家分析了 在化石之中的線索

  • But making sense of the evidence requires careful examination of the fossil

    但要搞懂這些証據 必須小心檢驗這些化石

  • and a good understanding of the physics of light and color.

    並了解光與色的物理原理

  • First of all, here's what we actually see on the fossil:

    首先,這是我們實際上在化石看到的:

  • imprints of bones and feathers that have left telltale mineral deposits.

    骨頭和羽毛的刻痕 顯示有礦物沉澱物質

  • And from those imprints,

    從這些刻痕

  • we can determine that these microraptor feathers

    我們可以斷定小盜龍的羽毛

  • were similar to modern dinosaur, as in bird, feathers.

    和現代恐龍 ─ 也就是鳥類 ─ 的羽毛相似

  • But what gives birds their signature diverse colorations?

    但是甚麼讓鳥類有這麼多不同的顏色?

  • Most feathers contain just one or two dye-like pigments.

    多數羽毛只有一兩種類似染料的色素

  • The cardinal's bright red comes from carotenoids,

    北美红雀的鮮紅來自類胡蘿蔔素

  • the same pigments that make carrots orange,

    也就是讓紅蘿蔔呈現橘色的色素

  • while the black of its face is from melanin,

    而牠臉上的黑色來自黑色素

  • the pigment that colors our hair and skin.

    就是讓我們頭髮和皮膚產生顏色的色素

  • But in bird feathers, melanin isn't simply a dye.

    但鳥羽的黑色素不單單是色素

  • It forms hollow nanostructures called melanosomes

    鳥羽內會形成許多 中空奈米結構,稱為「黑色素體」

  • which can shine in all the colors of the rainbow.

    在彩虹的所有顏色下 都會顯得閃閃發光

  • To understand how that works,

    要了解為甚麼會這樣

  • it helps to remember some things about light.

    要先回憶一下有關光的一些知識

  • Light is basically a tiny electromagnetic wave traveling through space.

    基本上,光是在宇宙中穿梭的微小電磁波

  • The top of a wave is called its crest

    波的最高點叫波峰

  • and the distance between two crests is called the wavelength.

    兩波峰之間的距離叫做波長

  • The crests in red light are about 700 billionths of a meter apart

    紅光的波長大約 700 奈米 (700 乘以10 的 負 9 次方公尺)

  • and the wavelength of purple light is even shorter,

    而紫光的波長就更短了

  • about 400 billionths of a meter, or 400 nanometers.

    大約只有 400 奈米 (400 乘以10 的 負 9 次方公尺)

  • When light hits the thin front surface of a bird's hollow melanosome,

    當光射到這隻鳥中空的 黑色素體的前面薄層表面時

  • some is reflected and some passes through.

    有的被反射,而有的穿透過去

  • A portion of the transmitted light then reflects off the back surface.

    部份穿透過去的光 又被後面表面反射回來

  • The two reflected waves interact.

    兩道反射波相互作用

  • Usually they cancel each other out,

    通常會相互抵消

  • but when the wavelength of the reflected light

    但當後面反射光的波長

  • matches the distance between the two reflections,

    和前面反射光的波長相等時

  • they reinforce each other.

    他們就會互相增強

  • Green light has a wavelength of about 500 nanometers,

    綠光波長約 500 奈米

  • so melanosomes that are about 500 nanometers across

    所以寬 500 奈米的黑色素體

  • give off green light,

    會散發綠光

  • thinner melanosomes give off purple light,

    比較細的黑色素就會散發紫光

  • and thicker ones give off red light.

    比較粗的就會散發紅光

  • Of course, it's more complex than this.

    當然,實際情況會更為複雜

  • The melanosomes are packed together inside cells, and other factors,

    黑色素體是成堆擠在細胞裡面, 所以其他因素

  • like how the melanosomes are arranged within the feather, also matter.

    像羽毛裡面的黑色素體 的排列方式也很重要

  • Let's return to the microraptor fossil.

    讓我們回到小盜龍的化石

  • When scientists examined its feather imprints under a powerful microscope,

    當科學家在高倍顯微鏡下 檢視羽毛刻痕時

  • they found nanostructures that look like melanosomes.

    他們發現長得像黑色素體的奈米結構

  • X-ray analysis of the melanosomes further supported that theory.

    透過 X 光分析再次支持這個理論

  • They contained minerals that would result from the decay of melanin.

    它們含有黑色素衰變後的礦物

  • The scientists then chose 20 feathers from one fossil

    接著,科學家在同一個化石 選了 20 根的羽毛

  • and found that the melanosomes in all 20 looked alike,

    發現這 20 根羽毛的 黑色素體都長相一樣

  • so they became pretty sure this dinosaur was one solid color.

    所以他們非常確定這隻恐龍是單一顏色

  • They compared these microraptor melanosomes to those of modern birds

    他們把小盜龍的黑色素體 和現代鳥類做比較

  • and found a close similarity, though not a perfect match,

    發現它和水鴨翅膀閃亮藍綠色羽毛的 黑色素體十分接近,雖然不是完全吻合

  • to the iridescent teal feathers found on duck wings.

    接著再檢視黑色素體的 實際大小和排列方式

  • And by examining the exact size and arrangement of the melanosomes,

    科學家便確定小盜龍羽毛 是閃閃發光的黑色

  • scientists determined that the feathers were iridescent black.

    由於我們已能檢測出 已變成化石的羽毛的顏色

  • Now that we can determine a fossilized feather's color,

    古生物學家在尋找更多 保存良好的黑色素體

  • paleontologists are looking for more fossils with well-preserved melanosomes.

    並已發現許恐龍,像是迅猛龍

  • They've found that a lot of dinosaurs, including velociraptor,

    可能也有羽毛

  • probably had feathers,

    代表某些電影可能 沒有那麼精確符合生物學

  • meaning that certain films might not be so biologically accurate.

    真聰明!

  • Clever girls.

    翻譯:nr Chan

This is the microraptor,

這是一隻小盜龍

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B2 中高級 中文 美國腔 TED-Ed 羽毛 黑色 化石 奈米 黑色素

【TED-Ed】我們如何知道恐龍原來的顏色? (How do we know what color dinosaurs were? - Len Bloch)

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    Lin 發佈於 2016 年 02 月 05 日
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