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經濟學人:不是扁平足而是八字足

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Science and technology

科學與技術
Splay-footed, not flat-footed
不是扁平足而是八字足
A new fossil shows that evolution does not always mean change
新發現的化石顯示,進化并不總意味著變化
Palaeontology
古生物學
Then and now
今與昔
WHEN a coelacanth, a type of lobe-finned fish once considered the missing link between fish and amphibians, was found off the coast of South Africa in 1938, it came as a shock to palaeontologists.
1938年當一種空棘魚目魚類—曾被認為是一種消失的連接魚類和兩棲動物的物種在南非海岸被發現時,古生物學家們為之一驚。
Until then, the most recent traces of such a creature had been in rocks dating from the last days of the dinosaurs, 65m years ago.
至到當時,這種生物最新的蹤跡只出現在可以追溯到距今六千五百萬年前恐龍時代末期的化石中。

It was, in its way, as surprising as if a live Tyrannosaurus had been found hiding in an obscure part of Montana.

其驚人程度就如同在蒙大拿的某個陰暗地方發現了一只躲藏于其中的活體霸王龍。
Now the same experience is hitting palaeontologists again—but this time in reverse.
如今,同樣的事件再次讓古生物學家們感到震驚—但是這次恰恰相反,
Instead of finding a living fossil identical to an ancient beast, they have found a real fossil identical to a modern one.
他們不是發現了一個與遠古生物雷同的活化石,而是發現了一個與現代生物一致的真化石。
The fossil in question, a 100m-year-old specimen from north-east Brazil, belongs to the genus Schizodactylus.
這里所討論的化石中的生物是一個來自巴西東北部距今一億年前的物種,屬于Schizodactylus昆蟲科。
These are large, carnivorous, cricket-like insects whose feet splay out wildly in different directions.
它們是一些大型,蟋蟀狀食肉昆蟲,其足向不同方向伸展。
Modern Schizodactylus use their feet like snowshoes, to help them remain stable as they travel over sandy terrain in search of prey.
當現代Schizodactylus科昆蟲在沙地中搜尋獵物時,其足有如雪鞋可以幫助它們保持穩定。
If the new fossil—whose discovery has just been published in ZooKeys by Sam Heads of the Illinois Natural History Survey and Léa Leuzinger of the University of Fribourg, in Switzerland—were merely similar to modern splay-footed insects, the find would not be particularly surprising: it simply demonstrates a phenomenon called evolutionary stasis, in which a specific type of body form hangs around for a long time.
如果該新發現的化石—它的發掘已經被來自伊利諾亞州自然歷史調查所的山姆.海茲以及來自瑞士夫里堡大學的雷.盧辛格發表在了《Zookeys》雜志上—僅僅是與現代八字足昆蟲相似,那么這一發現也沒有什么大驚小怪的:因為這只顯示了一種叫做進化停止的現象,其間某一特定體態在相當長一段時間內保持不變。
What is surprising is just how static Schizodactylus has been.
然而讓人感到驚奇的是Schizodactylus科昆蟲的進化盡然是如此得緩慢。
Evolutionary stasis is fairly common at the higher levels of the Linnaean system of biological classification.
進化停止在生物分類法的林奈分類體系中的高級別生物里比較常見。
Natural selection hits on a good design.
當自然選擇挑中了一個理想的設計后,
That design is then adopted in slightly different forms by species after species.
一個接一個的物種便以略微不同的形式采納這種設計。
The shelled bodies of turtles, for example, evolved between 250m and 200m years ago, while the body plans of scorpions have been around for more than 400m years.
舉個例子,海龜的甲狀軀殼約在2億5千萬年前至2億年前就已經進化完成,相比之下蝎子的身體構制更是在4億多年內都未有大的變化。
That does not mean, however, that a zoologist would mistake a 200m-year-old turtle or a 400m-year-old scorpion for any species now alive.
然而,這并不意味著一位動物學家可以將一只2億年前的海龜或是一只4億年前的蝎子與現在對應的活體物種混為一談。
What is remarkable about the new find is that it is so similar to modern animals that it can be assigned to an existing genus—the lowest level of Linnaean classification above a species—rather than just to some higher taxonomic group.
而這一新發現令人關注的地方在于化石中的物種與現代對應物種是如此得相似以至于它可以被當作是現代物種的某一現存種類—種類是林奈物種分類法中最低的一級,而不是更高級別的種群。
That is rare indeed.
這的確很罕見。
Even the modern coelacanth, on closer examination, had to be put in a different genus from any known fossil.
經過進一步檢驗,就算是現代空棘魚的種類也有別于任何已知化石中的空棘魚的種類。
Clearly the body plan of Schizodactylus is not merely good, but optimal, at least for the environment the animal lives in.
顯然,Schizodactylus科昆蟲擁有的的身體構制不僅令人滿意,而且是最佳的,至少是為了其所生存的環境而生。
Alas for Schizodactylus, the sandy deserts it prefers have retreated from north-eastern Brazil and its optimality there has vanished.
而讓Schizodactylus科昆蟲感到悲哀的是其所青睞的沙漠在巴西已經消退而它們的最佳身體構制也隨之消失。
But its discovery shows better what this part of the world was like 100m years ago—and also illustrates an important point about evolution that is often forgotten in biologists'understandable focus on the development of novelty.
但是該化石的發現更好地展示了世界的這一地區在1億年前是個什么摸樣---同時也闡明了有關進化的一點重要內容,一個經常在生物學家對于發展的推陳出新所持有的一種可理解的關注中而被遺忘的一點內容。
The first rule of natural selection is: If it ain’t broke, don’t fix it.
自然選擇的第一條規則就是:未損勿修。

重點單詞   查看全部解釋    
environment [in'vaiərənmənt]

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n. 環境,外界

 
slightly ['slaitli]

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adv. 些微地,苗條地

 
phenomenon [fi'nɔminən]

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n. 現象,跡象,(稀有)事件

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identical [ai'dentikəl]

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adj. 相同的,同一的

 
prey [prei]

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n. 被掠食者,犧牲者
vi. 捕食,掠奪,使

 
species ['spi:ʃiz]

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n. (單復同)物種,種類

 
competition [kɔmpi'tiʃən]

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n. 比賽,競爭,競賽

 
amphibian [æm'fibiən]

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adj. 兩棲類的,水陸兩用的 n. 兩棲動物,水陸兩用

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obscure [əb'skjuə]

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adj. 微暗的,難解的,不著名的,[語音學]輕音的

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static ['stætik]

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adj. 靜態的,靜力的,靜止的,靜電的
n.

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