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  • This is the microraptor, a carnivorous four-winged dinosaur that was almost two-feet long, ate fish, and lived about 120 million years ago.

    這是小盜龍,牠是隻有四片飛翼的肉食性恐龍,體長將近兩英呎,以吃魚為生,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.

    我們對牠的瞭解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.

    並非如此。

  • We know this shimmering black color is accurate because paleontologists have analyzed clues contained within the fossil.

    我們知道牠的顏色確實是黑得發亮的原因,是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 and a good understanding of the physics of light and color.

    但為了搞懂這些証據,必須要小心檢驗這些化石,並了解光線與色彩的物理原理。

  • First of all, here's what we actually see on the fossil: imprints of bones and feathers that have left telltale mineral deposits.

    首先,這是我們實際上在化石看到的:留下礦物沉澱物質的骨頭和羽毛的刻痕。

  • And from those imprints, we can determine that these microraptor feathers were similar to modern dinosaur, as in bird, feathers.

    從這些刻痕我們可以斷定小盜龍的羽毛和現代恐龍 ─ 也就是鳥類 ─ 的羽毛相似。

  • But what gives birds their signature diverse colorations?

    但是為什麼鳥類能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, the same pigments that make carrots orange, while the black of its face is from melanin, the pigment that colors our hair and skin.

    北美红雀的鮮紅來自類胡蘿蔔素,也就是讓紅蘿蔔呈現橘色的色素。而牠臉上的黑色來自黑色素,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只是色素而已。

  • It forms hollow nanostructures called melanosomes which can shine in all the colors of the rainbow.

    鳥羽內會形成許多稱為「黑色素體」的中空奈米結構,讓羽毛能夠在展現出五彩繽紛的色澤。

  • To understand how that works, it helps to remember some things about light.

    要了解為什麼羽毛能如此鮮豔,我們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,光就是在宇宙中穿梭的微小電磁波。

  • The top of a wave is called its crest and the distance between two crests is called the wavelength.

    波的最高點叫波峰,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 and the wavelength of purple light is even shorter, about 400 billionths of a meter, or 400 nanometers.

    紅光的波長大約 700 奈米 (700 乘以 10 的 負 9 次方公尺),而紫光的波長就更短了,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, some is reflected and some passes through.

    當光線射入鳥羽內中空黑色素體的前表面薄層時,有的光線會被反射,而有的則會穿透過去。

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

    部份穿透過去的光在之後又會被後表面反射回來。

  • The two reflected waves interact.

    這兩道反射波便會相互作用。

  • Usually they cancel each other out, but when the wavelength of the reflected light matches the distance between the two reflections, they reinforce each other.

    它們通常會相互抵消,但當後面反射光的波長和前面反射光的波長相等時,它們就會互相增強。

  • Green light has a wavelength of about 500 nanometers, so melanosomes that are about 500 nanometers across give off green light, thinner melanosomes give off purple light, and thicker ones give off red light.

    綠光波長約 500 奈米,所以寬 500 奈米的黑色素體會散發綠光,而比較細的黑色素就會散發紫光,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, like how the melanosomes are arranged within the feather, also matter.

    黑色素體會成堆地擠在細胞裡面, 所以如羽毛裡面黑色素體的排列方式等的其他因素也很重要。

  • Let's return to the microraptor fossil.

    讓我們回到小盜龍的化石這邊。

  • When scientists examined its feather imprints under a powerful microscope, they found nanostructures that look like melanosomes.

    當科學家在高倍顯微鏡下檢視羽毛刻痕時,他們發現了長得像黑色素體的奈米結構。

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

    之後對黑色素體進行 X 光分析後更進一步地支持了這個理論。

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

    它們含有黑色素衰變後所產生的礦物。

  • The scientists then chose 20 feathers from one fossil and found that the melanosomes in all 20 looked alike, so they became pretty sure this dinosaur was one solid color.

    接著,科學家在同一個化石中選出了 20 根的羽毛,並發現這 20 根羽毛的黑色素體外觀一致,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 and found a close similarity, though not a perfect match, to the iridescent teal feathers found on duck wings.

    他們把小盜龍的黑色素體和現代鳥類做比較後,發現它和水鴨翅膀閃亮藍綠色羽毛的黑色素體雖然不是完全吻合,卻十分接近。

  • And by examining the exact size and arrangement of the melanosomes, scientists determined that the feathers were iridescent black.

    藉由檢視黑色素體的實際大小和排列方式,科學家便確定小盜龍羽毛是閃閃發光的黑色。

  • Now that we can determine a fossilized feather's color, paleontologists are looking for more fossils with well-preserved melanosomes.

    既然現在我們能從羽毛化石中判斷顏色了,古生物學家於是開始尋找更多黑色素體保存完好的化石。

  • They've found that a lot of dinosaurs, including velociraptor, probably had feathers, meaning that certain films might not be so biologically accurate.

    他們已經已發現包含迅猛龍的許多恐龍很可能也有羽毛,而這代表某些電影可能沒有那麼精確符合生物學。

  • Clever girls.

    真聰明!

This is the microraptor, a carnivorous four-winged dinosaur that was almost two-feet long, ate fish, and lived about 120 million years ago.

這是小盜龍,牠是隻有四片飛翼的肉食性恐龍,體長將近兩英呎,以吃魚為生,活在 1 億 2 千萬年前的世界 。

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B2 中高級 中文 美國腔 TED-Ed 羽毛 黑色 奈米 化石 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 2021 年 07 月 21 日
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