評(píng)論
打印
Science and technology
科學(xué)技術(shù)
Human evolution
人類的進(jìn)化
You look familiar
你，似曾相識(shí)
Another piece of humanity's family tree is fitted into place
確定另一支人類譜系
THE opening scene of Mel Brooks's film History of the World: Part One dispenses with human origins in one line:
梅爾布魯克斯的電影世界歷史：第一部一開場(chǎng)就用一句臺(tái)詞概括了人類的起源：
And the ape stood, and became man.
猿猴站立起來了，然后變成了人。
Would that it were that easy for palaeontologists to sort out.
對(duì)古生物學(xué)家來說，要是真能如此解釋，那也未免太容易了。
The transition to humanity is generally agreed to have occurred between Australopithecus, a genus of small-brained,
人們普遍認(rèn)為，人類是在南猿,
bipedal primates whose most famous member is a fossil nicknamed Lucy, and the big-brained species Homo erectus.
和直立猿人之間完成人類進(jìn)化過渡的。
But pinning down when precisely this took place, and which of the various australopithecine species were involved, has been challenging.
但至于這段過渡期確切發(fā)生在什么時(shí)候，又屬于眾多南猿物種的哪一分支，人們眾說紛紜。
Now the most human-like australopithecine found to date is clarifying things—and staking a claim to be the species from which early humans evolved.
而目前發(fā)現(xiàn)的與人類長(zhǎng)得最像的南猿，讓一切變得清晰起來，同時(shí)，它也被確定是后來進(jìn)化為早期人類的物種。
Fossils of the new species, Australopithecus sediba, were discovered in 2008 in a cave in South Africa.
新發(fā)現(xiàn)的物種化石南猿源泉種于2008年在南非一個(gè)山洞中被發(fā)現(xiàn)。
Initial research, led by Lee Berger of the University of the Witwatersrand, in Johannesburg, concluded that the species came too late in the fossil record to be the ancestor of the Homo lineage.
約翰內(nèi)斯堡的威特沃特斯蘭德大學(xué)教授Lee Berger，帶領(lǐng)的研究團(tuán)隊(duì)經(jīng)初步研究發(fā)現(xiàn)，新物種是化石史上最接近猿人譜系的祖先。
This week, however, a range of new research into sediba, again led by Dr Berger, has been published in Science.
本周，科學(xué)雜志發(fā)表了 Berger博士對(duì)源泉種的一系列新發(fā)現(xiàn)，
These studies conclude that sediba did in fact predate Homo erectus and, moreover, that parts of its anatomy are surprisingly similar to modern man.
稱源泉種實(shí)際上要早于直立猿人，并且其結(jié)構(gòu)的某些部分與現(xiàn)代人也極為相似。
The fossils examined in the Science papers are of an adolescent boy and an adult woman.
科學(xué)雜志發(fā)表的論文研究的化石對(duì)象，一個(gè)是少年，一個(gè)是成年女子。
They are well preserved, and encased in sediments that allow uncommonly precise dating.
這兩具化石保存完好，由于是在沉積層出土，所以可以很精確的確定它們的年代。
They lived 1.977m years ago, predating the appearance of Homo erectus by 77,000 years.
他們生活在197,7000年前，比直立猿人早出現(xiàn)7,7000年。
The period is an especially muddled one for palaeontology, being full of fragmentary fossils that are difficult to assign either to Homo or to Australopithecus.
這段時(shí)期令古生物學(xué)家一直很迷惑不解，因?yàn)樗械幕槠茈y確定到底是屬于南猿還是直立猿人。
The sediba fossils, by contrast, have some of the most complete features in the early human record.
相比較而言，源泉種化石具有部分早期人類最完整的特征。
The new studies centre on the most telling bits of anatomy in the story of human evolution:
最新的研究把重點(diǎn)放在研究人類進(jìn)化最有說服力的結(jié)構(gòu)部位：
the brain, pelvis, hands and feet.
腦，骨盆，手和腳。
The brain itself does not fossilise, but the inside of the cranium retains an impression of its contours.
腦部分本身是不會(huì)變成化石的，但在頭蓋骨內(nèi)部卻還保留著腦的輪廓。
The researchers mapped these with high-powered X-ray beams to create a three-dimensional model of the surface of sediba's brain.
研究人員借助高功率X射線，描繪出了源泉種腦表面的三維模型。
They found that its size was on a par with other australopithecines,
他們發(fā)現(xiàn)源泉種的腦尺寸與其它南猿一樣，
but its shape was more like that of a human brain.
但是其形狀則更像人類的大腦。
Specifically, the frontal lobes, which are the seat in modern humans of higher cognitive functions such as abstract reasoning,
特別是大腦前庭部分，它使現(xiàn)代人具有較高的認(rèn)知能力—例如抽象推理的能力，
looked more humanlike in sediba's brain than they do in the brains of other australopithecines.
而相比較南猿來說，源泉種的大腦前庭更像人類。
That suggests the neurological changes which gave rise to humanity may have predated the brain's expansion—an event that had, hitherto, been regarded as crucial to the emergence of humans.
這表明，人類產(chǎn)生所依賴的大腦神經(jīng)上的變化，有可能在大腦變大之前就已經(jīng)出現(xiàn)，這也是迄今為止被認(rèn)為是人類誕生的關(guān)鍵因素。
The hands, feet and pelvis of sediba indicate that it both climbed trees and walked upright, though with a different gait from that of humans or chimpanzees.
從源泉種的手、腳和骨盆來看，源泉種既能爬樹又能直立行走，但步態(tài)與人類或是猩猩有點(diǎn)不一樣。
The species may have been a toolmaker, as its hand allowed for a human-like grip.
這種物種有可能也會(huì)制作工具，因?yàn)樗氖挚梢韵袢祟愐粯幼ト|西。
Sediba's pelvis, an upright butterfly shape, is likewise reminiscent of the human one.
源泉種的骨盆，呈垂直蝴蝶形，同樣讓人看到人類骨盤的影子。
It therefore sheds light on a longstanding debate:
這也使長(zhǎng)期的爭(zhēng)論變得清晰起來：
whether it was bipedalism or giving birth to babies with large heads that drove changes in the shape of the human pelvis.
是否這種物種是用兩只腳行走，或是它所生的后代頭比較大，使其骨盆發(fā)生了改變，和人類的骨盆形狀一樣。
Adult sediba had small heads, which indicates that walking upright was the advantage brought by the modern pelvis.
成年的源泉種頭比較小，這也表明，南猿在骨盆進(jìn)化之后，直立行走才變?yōu)榭赡堋?/p>
All of which makes sediba more similar to modern humans than are other australopithecines—and more similar, even, than Homo habilis, until now seen as one of the earliest humans.
所有這些使得源泉種比其它南猿，甚至比能人更像現(xiàn)代人類，直到現(xiàn)在有人把源泉種視為最早的人類成員之一。
The consensus had been that habilis was a transitional form between Australopithecus and Homo erectus.
普遍認(rèn)為，能人是介于南猿與直立猿人之間。
Dr Berger posits that sediba may have evolved directly into Homo erectus, leaving habilis as an evolutionary sideline, and not even part of the genus Homo.
而Berger博士認(rèn)為，源泉種有可能直接進(jìn)化為直立猿人，而能人卻是進(jìn)化過程中的一個(gè)分支，甚至和源泉種不屬于一個(gè)類別。
Slowly, then, the origin of the strange assemblage of characters that makes a human being human is emerging.
之后，一些奇特的人類特征才開始慢慢出現(xiàn)。
As the oracle said, the beginning of wisdom is: know thyself.
正如神諭所說：智慧從認(rèn)識(shí)自己開始！
