【雙語(yǔ)閱讀】羽毛化石.

　　眾所周知，化石記錄總是漏洞百出。一個(gè)漏洞就是由于人們無(wú)法找到白堊紀(jì)時(shí)期保存完好的羽毛，因而該時(shí)期羽毛化石的記錄一直處于空白狀態(tài)，白堊紀(jì)是距今1.45億年到6500萬(wàn)年的一段時(shí)期，末期發(fā)生了導(dǎo)致恐龍消失的物種大滅絕。如今，這段空白得到了部分填充。

　　Science and Technology

　　Fossil feathers

　　Not just for the birds

　　A trove of fossils sheds light on the evolution of feathers

　　THE fossil record is, famously, full of holes. One such lacuna has been the absence of well-preserved feathers from the Cretaceous-the period between 145m and 65m years ago that ended with the mass extinction that wiped out the dinosaurs. Now, this gap has been partly filled. In this week&aposs Science, a team led by Ryan McKellar from the University of Alberta report the discovery of eleven feathers preserved in amber from the latter part of the Cretaceous, about 70m-85m years ago. Intriguingly, not all of them seem to come from birds.

　　The origin of feathers is a mystery. The earliest known bird, Archaeopteryx, lived during the Jurassic, the period bore the Cretaceous. But fossils from China suggest the precursors of feathers-simple, filament-like structures possibly used for insulation-evolved in land-lubbing dinosaurs and were only later adapted for flight. The top picture shows similar filaments discovered by Dr McKellar and his team, suggesting flightless dinosaurs sporting such protofeathers were still around in the late Cretaceous.

　　Not all the feathers found by Dr McKellar were so primitive, though. The second picture shows one similar in shape to those sported by modern birds. Modern feathers consist of thousands of fibres held together by tiny hooks. The details of that design can be tweaked to change a feather&aposs characteristics, offering waterproofing, insulation, streamlining and so on.

　　The third picture shows feathers that have just such a specialisation: coiling reminiscent of that seen in the feathers of modern divers. Such coiling allows a feather to absorb water, which streamlines and insulates the owner. These feathers, then, presumably adorned a diving bird-perhaps Hesperornis, a flightless North American diver from precisely this period.

　　The final picture shows pigmentation preserved in a fossil feather. Different feathers have different patterns of colour, suggesting that Cretaceous dinosaurs-flying or otherwise-used their feathers for display. Charles Darwin once said that contemplating a peacock&aposs tail made him sick, such was the difficulty of explaining its complexity. Dr McKellar&aposs finds suggest, at least, that that complexity began to evolve a long time ago.

　　【中文對(duì)照翻譯】

　　科技

　　羽毛化石

　　并非鳥(niǎo)類(lèi)獨(dú)有

　　珍貴羽毛化石的發(fā)現(xiàn)能夠更好地闡釋羽毛的進(jìn)化過(guò)程

　　眾所周知，化石記錄總是漏洞百出。一個(gè)漏洞就是由于人們無(wú)法找到白堊紀(jì)時(shí)期保存完好的羽毛，因而該時(shí)期羽毛化石的記錄一直處于空白狀態(tài)，白堊紀(jì)是距今1.45億年到6500萬(wàn)年的一段時(shí)期，末期發(fā)生了導(dǎo)致恐龍消失的物種大滅絕。如今，這段空白得到了部分填充。本周，瑞安?麥凱樂(lè)領(lǐng)導(dǎo)的研究小組在《科學(xué)》雜志上發(fā)表報(bào)告稱(chēng)，他們發(fā)現(xiàn)了11種白堊紀(jì)后期(距今約7000至8500萬(wàn)年)封存在琥珀里的羽毛。有趣的是，這些羽毛并不都屬于鳥(niǎo)類(lèi)。

　　羽毛的起源一直是個(gè)謎。 人類(lèi)所熟知的最古老鳥(niǎo)類(lèi)始祖鳥(niǎo)生活在白堊紀(jì)時(shí)期之前的侏羅紀(jì)時(shí)期。 中國(guó)出土的化石表明羽毛的前身呈簡(jiǎn)易的絲狀結(jié)構(gòu)，可能具有隔離熱量的功用，這些簡(jiǎn)易絲狀羽毛在陸地恐龍身上不斷進(jìn)化，直至后來(lái)才具備了飛行功能。 上圖所示為麥凱樂(lè)博士及其研究小組發(fā)現(xiàn)的類(lèi)似絲狀的羽毛，表明長(zhǎng)有這些原生羽毛的“非鳥(niǎo)”恐龍?jiān)诎讏准o(jì)后期仍然存活著。

　　不過(guò)，McKellar博士發(fā)現(xiàn)的羽毛并不都是遠(yuǎn)古時(shí)代的。 第二幅圖顯示的羽毛形狀與現(xiàn)代鳥(niǎo)類(lèi)羽毛相似。 現(xiàn)代鳥(niǎo)類(lèi)羽毛由成千上萬(wàn)束靠細(xì)鉤聚攏在一起的纖維構(gòu)成。 通過(guò)改進(jìn)羽毛構(gòu)造的細(xì)節(jié)可改變它的特性，如防水、隔熱、流線造型等功能。

　　第三幅圖顯示的羽毛就具備這樣的特殊功能：螺旋造型與現(xiàn)代潛鳥(niǎo)的羽毛相似。 這種螺旋形狀的羽毛能夠吸水，并使該鳥(niǎo)類(lèi)身形更加精巧同時(shí)起保溫作用。 這些羽毛想必當(dāng)時(shí)是歸潛鳥(niǎo)所有——也許是“黃昏鳥(niǎo)”，一種恰好生活在這一時(shí)期不會(huì)飛翔的北美潛鳥(niǎo)。

　　最后一幅圖顯示了封存在羽毛化石里的色素沉著。 不同的羽毛有不同的顏色樣式，這表明白堊紀(jì)時(shí)期的會(huì)飛恐龍和陸地恐龍都利用羽毛來(lái)炫示自己。 查爾斯?達(dá)爾文曾說(shuō)過(guò)研究孔雀尾讓他有頭暈的感覺(jué)，可見(jiàn)想解釋清楚其復(fù)雜性有多難了。 不過(guò)，麥凱樂(lè)博士的發(fā)現(xiàn)至少表明這種復(fù)雜性在很久以前就開(kāi)始進(jìn)化了。

　　眾所周知，化石記錄總是漏洞百出。一個(gè)漏洞就是由于人們無(wú)法找到白堊紀(jì)時(shí)期保存完好的羽毛，因而該時(shí)期羽毛化石的記錄一直處于空白狀態(tài)，白堊紀(jì)是距今1.45億年到6500萬(wàn)年的一段時(shí)期，末期發(fā)生了導(dǎo)致恐龍消失的物種大滅絕。如今，這段空白得到了部分填充。

　　Science and Technology

　　Fossil feathers

　　Not just for the birds

　　A trove of fossils sheds light on the evolution of feathers

　　THE fossil record is, famously, full of holes. One such lacuna has been the absence of well-preserved feathers from the Cretaceous-the period between 145m and 65m years ago that ended with the mass extinction that wiped out the dinosaurs. Now, this gap has been partly filled. In this week&aposs Science, a team led by Ryan McKellar from the University of Alberta report the discovery of eleven feathers preserved in amber from the latter part of the Cretaceous, about 70m-85m years ago. Intriguingly, not all of them seem to come from birds.

　　The origin of feathers is a mystery. The earliest known bird, Archaeopteryx, lived during the Jurassic, the period bore the Cretaceous. But fossils from China suggest the precursors of feathers-simple, filament-like structures possibly used for insulation-evolved in land-lubbing dinosaurs and were only later adapted for flight. The top picture shows similar filaments discovered by Dr McKellar and his team, suggesting flightless dinosaurs sporting such protofeathers were still around in the late Cretaceous.

　　Not all the feathers found by Dr McKellar were so primitive, though. The second picture shows one similar in shape to those sported by modern birds. Modern feathers consist of thousands of fibres held together by tiny hooks. The details of that design can be tweaked to change a feather&aposs characteristics, offering waterproofing, insulation, streamlining and so on.

　　The third picture shows feathers that have just such a specialisation: coiling reminiscent of that seen in the feathers of modern divers. Such coiling allows a feather to absorb water, which streamlines and insulates the owner. These feathers, then, presumably adorned a diving bird-perhaps Hesperornis, a flightless North American diver from precisely this period.

　　The final picture shows pigmentation preserved in a fossil feather. Different feathers have different patterns of colour, suggesting that Cretaceous dinosaurs-flying or otherwise-used their feathers for display. Charles Darwin once said that contemplating a peacock&aposs tail made him sick, such was the difficulty of explaining its complexity. Dr McKellar&aposs finds suggest, at least, that that complexity began to evolve a long time ago.

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