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(单词翻译:双击或拖选)
By David McAlary
Scientists have discovered fossils of an ancient, tiny species of human in an isolated1 part of Indonesia. They are bones from what they say is a smaller version of the now extinct immediate2 ancestor to modern humans. Some observers call it a surprising twig3 on our family tree, one that co-existed with modern humans until relatively4 recently, long after their normal-sized archaic5 counterparts disappeared.
The remote eastern Indonesian Island of Flores is an exotic place, with large lizards6 known as Komodo dragons and remains7 of extinct dwarf8 elephants and miniature humans.
It is the discovery of the chimpanzee-sized humans that is causing excitement among scientists. Australian researchers report in the journal Nature that they found the bones of an adult female who stood just one meter tall with a head the size of a grapefruit. Since submitting the paper for publication, they found the remains of five or six more of these wee (small) people, who lived as recently as 12,000 years ago, just before the dawn of civilization.
"In evolutionary9 terms, 12,000 years is just yesterday," this is University of New England researcher, Peter Brown who admits to being flabbergasted when he realized these tiny archaic people had a brain one-fourth the size of modern humans.
"My colleagues reported that when I measured the size of the brain, I went pale and my jaw10 dropped to my knees because people with this brain size were supposed to have become extinct more than three million years ago, but here we had a small-bodied human relative with a very small brain surviving until the relatively recent past, like we have only just missed them," he said.
Mr. Brown says the bones are not those of the three million-year-old pre-humans to which he referred. Rather, they belong to a small newer human thought to be our modern species most immediate ancestor, Homo erectus. But the size of the creature has earned it the right to be its own species. Mr. Brown's team calls it "Flores Man."
But Homo erectus was much larger, so how did Flores Man become small? The Australian team believes the full-sized erectus people arrived on Flores 840,000 years ago, perhaps from Java, after a million-year migration11 out of Africa. This view is based on the dating of stone tools found on Flores in an earlier excavation12.
Mr. Brown believes that over time, the species shrank on the isolated island.
"It underwent similar selection processes which happen to many other mammals on islands," said Peter Brown. "And in the absence of large predators13 and with reduced calories and a heavy covering of rain forest, it became much smaller in body size."
Evidence gathered with Flores Man suggests the tiny species made its own tools and hunted, like Homo erectus. Remains of a dwarf elephant called Stegodon were near the human bones.
But unlike Homo erectus, which died out by at least 40,000 years ago and maybe earlier, Flores Man stayed around a lot longer. The Australians believe a volcano eruption14 finally killed them off 12,000 years ago, as modern humans were populating the Americas. This belief is based on the dating of ash layers with the bones.
Scientific reaction to the discovery has been enthusiastic. "Breathtaking" is the word used by University of Cambridge anthropologist15 Robert Foley. At the Natural History Museum in London, Christopher Stringer calls it remarkable16, not only for the size and duration of Flores Man, but also because early humans managed to get to the remote island.
"This island is a lot further away than Java," said Christopher Stringer. "Humans could have gotten to the island of Java. At times of low sea level, Java was connected to the rest of southeast Asia. But the islands beyond Java, including Flores, are separated by deep water, so it was not thought that ancient humans could have got across that deep water."
That implies that Homo erectus had mastered the technology of boats. As for their diminutive17 descendants, Mr. Stringer says they are another example of the variety of humans that once existed.
"It shows us that human evolution, even in the recent past, was complex," he said. "There were many different species and nature was conducting its own evolutionary experiments with early humans."
The Australian researchers suggest other remote Indonesian islands could be hiding similar surprises and plan to dig on them to find out.
David McAlary ,VOA News, Washington.
注释:
fossil 化石
version 形式
ancestor 祖先
archaic 古代的
Komodo dragon 科摩多龙
dwarf 矮小
chimpanzee 黑猩猩
flabbergaste 使大吃一惊
Java 爪哇(印度尼西亚的一个岛屿)
excavation 出土文物
Stegodon 剑齿象
enthusiastic 热心的
1 isolated | |
adj.与世隔绝的 | |
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2 immediate | |
adj.立即的;直接的,最接近的;紧靠的 | |
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3 twig | |
n.小树枝,嫩枝;v.理解 | |
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4 relatively | |
adv.比较...地,相对地 | |
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5 archaic | |
adj.(语言、词汇等)古代的,已不通用的 | |
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6 lizards | |
n.蜥蜴( lizard的名词复数 ) | |
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7 remains | |
n.剩余物,残留物;遗体,遗迹 | |
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8 dwarf | |
n.矮子,侏儒,矮小的动植物;vt.使…矮小 | |
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9 evolutionary | |
adj.进化的;演化的,演变的;[生]进化论的 | |
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10 jaw | |
n.颚,颌,说教,流言蜚语;v.喋喋不休,教训 | |
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11 migration | |
n.迁移,移居,(鸟类等的)迁徙 | |
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12 excavation | |
n.挖掘,发掘;被挖掘之地 | |
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13 predators | |
n.食肉动物( predator的名词复数 );奴役他人者(尤指在财务或性关系方面) | |
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14 eruption | |
n.火山爆发;(战争等)爆发;(疾病等)发作 | |
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15 anthropologist | |
n.人类学家,人类学者 | |
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16 remarkable | |
adj.显著的,异常的,非凡的,值得注意的 | |
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17 diminutive | |
adj.小巧可爱的,小的 | |
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