劍橋雅思閱讀原文翻譯The history of the tortoise

劍橋雅思9 Test1 Passage3閱讀原文翻譯

第1段

If you go back far enough,everything lived in the sea.At various points in evolutionary history,enterprising individuals within many different animal groups moved out onto the land,sometimes even to the most parched deserts,taking their own private seawater with them in blood and cellular fluids.In addition to the reptiles,birds,mammals and insects which we see all around us,other groups that have succeeded out of water include scorpions,snails,crustaceans such as woodlice and land crabs,millipedes and centipedes,spider and various worms.And we mustn’t forget the plants,without whose prior invasion of the land none of the other migrations could have happened.

如果我們回溯的足夠遙遠(yuǎn)，所有東西都生活在海洋之中。在進(jìn)化史的各個(gè)階段，許多不同動(dòng)物群體的富有冒險(xiǎn)精神的個(gè)體搬到陸地上，有時(shí)甚至到最干旱的沙漠里，將自己的海水融入血液和細(xì)胞液中。除了我們在身邊看到的爬行動(dòng)物，鳥類，哺乳動(dòng)物和昆蟲外，其他成功脫離水生生活的群體還包括蝎子，蝸牛，甲殼類動(dòng)物（例如木虱和陸地蟹），千足蟲和蜈蚣，蜘蛛和各種蠕蟲。我們也千萬不要忘記植物，沒有它們事先侵入陸地，其他遷移都不會(huì)發(fā)生。

第2段

Moving from water to land involved a major redesign of every aspect of life,including breathing and reproduction.Nevertheless,a good number of thoroughgoing land animals later turned around,abandoned their hard-earned terrestrial re-tooling,and returned to the water again.Seals have only gone part way back.They show us what the intermediates might have been like,on the way to extreme cases such as whales and dugongs.Whales(including the small whales we call dolphins)and dugongs,with their close cousins the manatees,ceased to be land creatures altogether and reverted to the full marine habits of their remote ancestors.They don’t even come ashore to breed.They do,however,still breathe air,having never developed anything equivalent to the gills of their earlier marine incarnation.Turtles went back to the sea a very long time ago and,like all vertebrate returnees to the water,they breathe air.However,they are,in one respect,less fully given back to the water than whales or dugongs,for turtles still lay their eggs on beaches.

從水到陸地的遷移涉及到包括呼吸和生殖在內(nèi)的生命各個(gè)方面的重大重新設(shè)計(jì)。但是，后來有大量的陸地動(dòng)物轉(zhuǎn)過身去，放棄了來之不易的適應(yīng)陸地生活的器官，并再次回到水里。海豹只是返回了一部分。他們向我們展示了在鯨魚和儒艮等極端情況下的中間體可能是什么樣的。鯨魚（包括我們稱為海豚的小鯨魚）和儒艮，以及它們的近親海牛，完全不再是陸地生物，而是恢復(fù)了其遠(yuǎn)洋祖先的全部海洋習(xí)性。他們甚至不用上岸繁殖。但是，它們確實(shí)仍然需要呼吸空氣，從未進(jìn)化出類似于腮這樣早期海洋生物的器官。海龜很久以前就回到了大海，就像所有返回海域的脊椎動(dòng)物一樣，他們呼吸空氣。但是，從某種意義上講，它們沒有像鯨魚或儒艮一樣完全返回水中，因?yàn)楹｝斎栽诤┥袭a(chǎn)卵。

第3段

There is evidence that all modern turtles are descended from a terrestrial ancestor which lived before most of the dinosaurs.There are two key fossils called Proganochleys quenstedti and Palaeochersis talampayensis dating from early dinosaur times,which appear to be close to the ancestry of all modern turtles and tortoises.You might wonder how we can tell whether fossil animal lived on land or in water,especially if only fragments are found.Sometimes it’s obvious.Ichthyosaurs were reptilian contemporaries of the dinosaurs,with fins and streamlined bodies.The fossils look like dolphins,and they surely lived like dolphines,in the water.With turtles it is a little less obvious.One way to tell is by measuring the bones of their forelimbs.

有證據(jù)表明，所有現(xiàn)代海龜均來自同一陸地祖先。它生活在比大多數(shù)恐龍還要遙遠(yuǎn)的時(shí)代。兩個(gè)關(guān)鍵的化石，Proganochleys quenstedti和Palaeochersis talampayensis，可以追溯到恐龍時(shí)代早期。它們似乎與所有現(xiàn)代烏龜和海龜?shù)淖嫦仁纸咏?。您可能想知道我們?nèi)绾畏直婊械膭?dòng)物究竟是生活在陸地上還是在水里，特別是如果僅發(fā)現(xiàn)碎片的時(shí)候。有時(shí)這很明顯。帶有鰭和流線型身體的魚龍是生活在恐龍時(shí)代的爬行動(dòng)物。其化石看起來像海豚，它們也肯定像海豚一樣生活在水中。對于海龜來說，這一點(diǎn)并不那么明顯。一種判斷方法是測量前肢的骨頭。

第4段

Walter Joyce and Jacques Gauthier,at Yale University,obtained three measurements in these particular bones of 71 species of living turtles and tortoises.They used a kind of triangular graph paper to plot the three measurements against one another.All the land tortoise species formed a tight cluster of points in the upper part of the triangle;all the water turtles cluster in the lower part of the triangular graph.There was no overlap except when they added some species that spend time both in water and on land.Sure enough,these amphibious species show up on the triangular graph approximately halfway between the‘wet cluster’of sea turtles and the‘dry cluster’of land tortoises.The next step was to determine where the fossils fell.The bones of P.quenstedti and P.talampayensis leave us in no doubt.Their points on the graph are right in the thick of the dry cluster.Both these fossils were dry-land tortoises.They come from the era before our turtles returned to the water.

耶魯大學(xué)的Walter Joyce和Jacques Gauthier對71種現(xiàn)存烏龜和海龜?shù)倪@些特殊骨骼進(jìn)行了三項(xiàng)測量。他們使用一種三角形方格紙對比這三項(xiàng)測量數(shù)據(jù)。所有陸龜物種在三角形的上部形成了緊密的點(diǎn)簇。所有的水生烏龜都聚集在三角形的下部。除了部分同時(shí)生活在水中和陸地上的物種外，它們沒有任何重疊。而不出意料的是，這些兩棲物種在三角形中處于海龜和陸龜所形成的點(diǎn)簇的中間部分。下一步是確定這兩個(gè)化石處于圖中何種位置。P.quenstedti和P.talampayensis的骨頭沒有給我們留下疑惑。它們在圖中的點(diǎn)正好位于干燥點(diǎn)群的中心位置。這兩個(gè)化石都是陸生烏龜。它們來自我們的海龜回到水中之前的時(shí)代。

第5段

You might think,therefore,that modern land tortoises have probably stayed on land ever since those early terrestrial times,as most mammals did after a few of them went back to the sea.But apparently not.If you draw out the family tree of all modern turtles and tortoises,nearly all the branches are aquatic.Today’s land tortoises constitute a single branch,deeply nested among branches consisting of aquatic turtles.This suggests that modern land tortoises have not stayed on land continuously since the time of P.quenstedti and P.talampayensis.Rather,their ancestors were among those who went back to the water,and they then re-emerged back onto the land in(relatively)more recent times.

因此，你可能會(huì)認(rèn)為，自陸地時(shí)代早期以來，現(xiàn)代陸龜就可能一直待在陸地上，就像大多數(shù)哺乳動(dòng)物在一些同伴回到海中之后所做的那樣。但顯然不是。如果你繪制所有現(xiàn)代陸龜和海龜?shù)募易V，則幾乎所有分支都是水生的。如今的陸龜組成一個(gè)獨(dú)立的分支，深深地嵌套在由水龜組成的分支之間。這表明，從P.quenstedti和P.talampayensis的時(shí)代以來，現(xiàn)代陸龜并沒有一直待在陸地上。相反，它們的祖先是那些回到水中，但隨后又在近期（相對意義上來講）再次回到陸地上的那些。

第6段

Tortoises therefore represent a remarkable double return.In common with all mammals,reptiles and birds,their remote ancestors were marine fish and before that various more or less worm-like creatures stretching back,still in the sea,to the primeval bacteria.Later ancestors lived on land and stayed there for a very large number of generations.Later ancestors still evolved back into the water and became sea turtles.And finally they returned yet again to the land as tortoises,some of which now live in the driest of deserts.

因此，烏龜代表了引人注目的雙重回歸。與所有哺乳動(dòng)物，爬行動(dòng)物和鳥類一樣，它們的遠(yuǎn)古祖先是海洋魚類，在此之前是各種或多或少的蠕蟲狀生物，再往前延伸是原始的細(xì)菌。后來的祖先居住在土地上，并在此繁衍了許多世代。在此之后，一些祖先仍然進(jìn)化回水中，成為海龜。而最后它們再次回到了陸地，成為陸龜，其中一些現(xiàn)在居住在最干旱的沙漠里。

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