雅思阅读动植物类真题：塔斯马尼亚虎

 雅思阅读动植物类真题：Tasmanian tiger Extinction¹ Is Forever?(塔斯马尼亚虎)

　　Tasmanian tiger Extinction Is Forever?“Danger, “ says the sign on the doorof a laboratory at the Australian Museum in Sydney: “Tasmanian Tiger,Trespassers will be eaten!” The joke is that the Tasmanian tiger—a belovedsymbol of the island state that appears on its license² plate—has been extinctfor nearly seven decades. But researchers behind that door are working to bringthe animal back to life by cloning it, using DNA⁴ extracted from specimenspreserved decades ago. Among other things, the work raises questions about thenature of extinction itself.

　　A

　　The Tasmanian tiger’s Latin designation, Thylacinus cynocephalus, or“dogheaded pouched-dog,” makes it redundantly⁷ clear that the marsupial’s felinenickname is a misnomer⁸. Yet its striped coat was cat-like, which runs nearlyshoulder to tail. The animal had large, powerful jaws⁹, which secured thepredator a place atop the local food chain. Females carried their young inbackward-facing pouches¹⁰. Thylacines, once spread throughout mainland Australiaand as far north as New Guinea, were probably outcompeted for food by thedingoes ( 猎狗) that humans introduced to the area some 4,000 years ago, saysAustralian Museum director Mike Archer³, founder¹¹ of the cloning project.Eventually, thylacines remained only on the dingo-free island of Tasmania, southof the mainland. But with the arrival of European settlers in the 1800s, themarsupial’s days were numbered. Blamed (often wrongly) for killing¹² livestock,the animals were hunted indiscriminately. The government made thylacines aprotected species in 1936, but it was too late; It was a frigid¹³ winter night in1936. A lone¹⁴ Tasmanian tiger huddled¹⁵ in his— or her— open enclosure at HobartZoo. With nowhere to shelter from the cold and no keepers to care, thedelicately striped animal died. When this solitary¹⁶ animal—whose sex was not evenrecorded because of lack of interest—died, so did an entire species, the lastspecimen reportedly died in captivity¹⁷ the same year. What’s more, with thepassing into extinction of the Tasmanian tiger, Thylacinus cynocephalus, it wasthe end of the line for an entire family of marsupials thathad lived inAustralia for millions of years.

　　B

　　The Australian researchers set out to bring the animal back partly to atonefor humanity’s role in its extinction, Archer says. The idea took root 15 yearsago when he saw a pickled thylacine pup in the museum’s collection. “It jarredme and started me thinking,” recalls the 58-year-old paleontologist andzoologist, who received his undergraduate degree from Princeton University andhis doctorate¹⁸ from the University of Western Australia. “DNA is there cipe formaking a creature. So if there is DNA preserved in the specimen⁵, why shouldn’twe begin to use technology to read that information, and then in some way usethat information to reconstruct the animal? I raised the issue with ageneticist. The response was derisive²⁰ laughter.”

　　C

　　Then, in 1996, Dolly the sheep burst onto the scene and, suddenly, Archersays,“cloning wasn’t just a madman’s dream.” Dolly proved that DNA from anordinary animal cell— in her case, a ewe’s udder— could generate a virtuallyidentical copy, or clone, of the animal after the DNA was inserted into atreated egg, which was implanted in a womb and carried to term. Archer’s goal iseven more ambitious: cloning an animal with DNA from long-dead cells,reminiscent of the sci-fi novel and movie Jurassic Park. The challenge? The DNAthat makes up the chromosomes²³ in which genes²⁴ are bundled falls apart after acell dies.

　　D

　　Researchers working with Don Colgan, head of the museum’s evolutionarybiology department, extracted DNA from a thylacine pup preserved in alcohol in1866, and biologist Karen Firestone obtained additional thylacine DNA from atooth and a bone. Then, using a technique called polymerase chain reaction, theresearchers found that the thylacine DNA fragments could be copied. Thescientists next have to collect millions of DNA bits and pieces and create a“library” of the possibly tens of thousands of thylacine genes— a gargantuantask, they concede. Still, an even greater obstacle looms²⁵, that of stitching allthose DNA fragments together properly into functioning chromosomes; thescientists don’t know how many chromosomes a thylacine had, but suspect that,like related marsupials, it had 14. But no scientist has ever synthesized amammalian chromosome²² from scratch. If the Aussie scientists accomplish thosefeats, they may try to generate a thylacine by placing the synthetic²⁶ chromosomesinto a treated egg cell of a related species— say, a Tasmanian devil, anothercarnivorous marsupial—and implant²¹ the egg in a surrogate mother.

　　E

　　Such cross-species cloning, as the procedure is called, is no longerfantasy. In 2001, Advanced Cell Technology (ACT) of Worcester, Massachusetts,succeeded in cloning, for the first time, an endangered animal, a rare wild oxcalled a gaur. This past April, scientists from ACT, Trans Ova Genetics of SiouxCenter, Iowa, and the Zoological Society of San Diego announced they had cloneda banteng, an endangered wild bovine²⁷ species native to Southeast Asia, using adomesticated cow as a surrogate mother. Meanwhile, researchers in Spain aretrying to clone an extinct mountain goat, called a bucardo, using cellscollected and frozen before the species’ last member died in 2000. Otherscientists hope to clone a woolly mammoth²⁸ from 20,000-year-old specimens⁶ foundin Siberian permafrost.

　　F

　　Many scientists are skeptical²⁹ of the thylacine project. Ian Lewis,technology development manager at Genetics Australia Cooperative Ltd., inBacchus Marsh³⁰, Victoria, Australia, says the chances of cloning an animalfrom“snippets” of DNA are “fanciful.” Robert Lanza, ACTs medical director andvice president, says cloning a thylacine is beyond existing science. But itmaybe within reach in several years, he adds: “This area of genetics is movingforward at an exponential rate.”

　　G

　　In Australia, critics say the millions of dollars that the thylacineproject will cost would be better spent trying to save endangered species anddisappearing habitats. One opponent, Tasmanian senator and former AustraliaWilderness Society Director Bob Brown, says people might become blase³¹ aboutconservation if they’re lulled³² into thinking a lost species can always beresurrected. The research “feeds the mind-set that science will fix everything,”he says. Another concern touches on the great nature-nurture quandary³³: Would acloned thylacine truly represent the species, given that it would not have hadthe chance to learn key behaviors from other thylacines? For some carnivores,says University of Louisville behavioral ecologist Lee Dugatkin, “it’s clearthat young individuals learn various hunting strategies from parents.” And afosterparent might not fill the gap. Dugatkin asks whether a cloned Tasmaniantiger raised by a surrogate Tasmanian devil would just be a devil in tiger’sclothing.

　　H

　　But Archer says, in effect, a thylacine is a thylacine, however its DNAblueprint is obtained, because much animal behavior, including that ofmarsupials, is genetically³⁴ hardwired or instinctual. We take kittens and raisethem with humans, but they still behave like cats,” he points out. And Archer,who envisions nature preserves populated by cloned thylacines and theiroffspring, says the project is actually a boon³⁵ to conservation: it shows what ittakes just to contemplate³⁶ resurrecting a vanished species. For now, Archer andcoworkers are trying to piece together the thylacine’s exact genetic¹⁹ makeup³⁷.

1 extinction   

n.熄灭，消亡，消灭，灭绝，绝种

参考例句：

• The plant is now in danger of extinction.这种植物现在有绝种的危险。
• The island's way of life is doomed to extinction.这个岛上的生活方式注定要消失。

2 license   

n.执照，许可证，特许；v.许可，特许

参考例句：

• The foreign guest has a license on the person.这个外国客人随身携带执照。
• The driver was arrested for having false license plates on his car.司机由于使用假车牌而被捕。

3 archer   

n.射手，弓箭手

参考例句：

• The archer strung his bow and aimed an arrow at the target.弓箭手拉紧弓弦将箭瞄准靶子。
• The archer's shot was a perfect bull's-eye.射手的那一箭正中靶心。

4 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

5 specimen   

n.样本，标本

参考例句：

• You'll need tweezers to hold up the specimen.你要用镊子来夹这标本。
• This specimen is richly variegated in colour.这件标本上有很多颜色。

6 specimens   

n.样品( specimen的名词复数 )；范例；（化验的）抽样；某种类型的人

参考例句：

• Astronauts have brought back specimens of rock from the moon. 宇航员从月球带回了岩石标本。
• The traveler brought back some specimens of the rocks from the mountains. 那位旅行者从山上带回了一些岩石标本。 来自《简明英汉词典》

7 redundantly   

多余地，冗余地

参考例句：

8 misnomer   

n.误称

参考例句：

• Herbal"tea"is something of a misnomer because these drinks contain no tea at all.花草“茶”是一个误称，因为这类饮料里面根本不含茶。
• Actually," Underground "is a misnomer,because more than half the shops are above ground.实际上，“ 地下 ” 这个名称用之不当，因为半数以上的店铺是在地面上的。

9 jaws   

n.口部；嘴

参考例句：

• The antelope could not escape the crocodile's gaping jaws. 那只羚羊无法从鱷鱼张开的大口中逃脱。
• The scored jaws of a vise help it bite the work. 台钳上有刻痕的虎钳牙帮助它紧咬住工件。

10 pouches   

n.（放在衣袋里或连在腰带上的）小袋( pouch的名词复数 )；（袋鼠等的）育儿袋；邮袋；（某些动物贮存食物的）颊袋

参考例句：

• Pouches are a peculiarity of marsupials. 腹袋是有袋动物的特色。 来自《简明英汉词典》
• Under my eyes the pouches were heavy. 我眼睛下的眼袋很深。 来自《简明英汉词典》

11 Founder   

n.创始者，缔造者

参考例句：

• He was extolled as the founder of their Florentine school.他被称颂为佛罗伦萨画派的鼻祖。
• According to the old tradition,Romulus was the founder of Rome.按照古老的传说，罗穆卢斯是古罗马的建国者。

12 killing   

n.巨额利润；突然赚大钱，发大财

参考例句：

• Investors are set to make a killing from the sell-off.投资者准备清仓以便大赚一笔。
• Last week my brother made a killing on Wall Street.上个周我兄弟在华尔街赚了一大笔。

13 frigid   

adj.寒冷的，凛冽的；冷淡的；拘禁的

参考例句：

• The water was too frigid to allow him to remain submerged for long.水冰冷彻骨，他在下面呆不了太长时间。
• She returned his smile with a frigid glance.对他的微笑她报以冷冷的一瞥。

14 lone   

adj.孤寂的，单独的；唯一的

参考例句：

• A lone sea gull flew across the sky.一只孤独的海鸥在空中飞过。
• She could see a lone figure on the deserted beach.她在空旷的海滩上能看到一个孤独的身影。

15 huddled   

挤在一起（huddle的过去式与过去分词形式）

参考例句：

• We huddled together for warmth. 我们挤在一块取暖。
• We huddled together to keep warm. 我们挤在一起来保暖。

16 solitary   

adj.孤独的，独立的，荒凉的；n.隐士

参考例句：

• I am rather fond of a solitary stroll in the country.我颇喜欢在乡间独自徜徉。
• The castle rises in solitary splendour on the fringe of the desert.这座城堡巍然耸立在沙漠的边际，显得十分壮美。

17 captivity   

n.囚禁；被俘；束缚

参考例句：

• A zoo is a place where live animals are kept in captivity for the public to see.动物园是圈养动物以供公众观看的场所。
• He was held in captivity for three years.他被囚禁叁年。

18 doctorate   

n.(大学授予的)博士学位

参考例句：

• He hasn't enough credits to get his doctorate.他的学分不够取得博士学位。
• Where did she do her doctorate?她在哪里攻读博士？

19 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

20 derisive   

adj.嘲弄的

参考例句：

• A storm of derisive applause broke out.一阵暴风雨般的哄笑声轰然响起。
• They flushed,however,when she burst into a shout of derisive laughter.然而，当地大声嘲笑起来的时候，她们的脸不禁涨红了。

21 implant   

vt.注入，植入，灌输

参考例句：

• A good teacher should implant high ideals in children.好教师应该把高尚理想灌输给孩子们。
• The operation to implant the artificial heart took two hours.人工心脏植入手术花费了两小时。

22 chromosome   

n.染色体

参考例句：

• Chromosome material with exhibits of such behaviour is called heterochromatin.表现这种现象的染色体物质叫做异染色质。
• A segment of the chromosome may become lost,resulting in a deletion.染色体的一个片段可能会丢失，结果产生染色体的缺失。

23 chromosomes   

n.染色体( chromosome的名词复数 )

参考例句：

• Chromosomes also determine the sex of animals. 染色体也决定动物的性别。 来自《简明英汉词典》
• Each of four chromosomes divide longitudinally. 四种染色体的每一种都沿着纵向分裂。 来自《现代汉英综合大词典》

24 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

25 looms   

n.织布机( loom的名词复数 )v.隐约出现，阴森地逼近( loom的第三人称单数 )；隐约出现，阴森地逼近

参考例句：

• All were busily engaged,men at their ploughs,women at their looms. 大家都很忙，男的耕田，女的织布。 来自《简明英汉词典》
• The factory has twenty-five looms. 那家工厂有25台织布机。 来自《简明英汉词典》

26 synthetic   

adj.合成的，人工的；综合的；n.人工制品

参考例句：

• We felt the salesman's synthetic friendliness.我们感觉到那位销售员的虚情假意。
• It's a synthetic diamond.这是人造钻石。

27 bovine   

adj.牛的；n.牛

参考例句：

• He threw off his pack and went into the rush-grass andand munching,like some bovine creature.他丢开包袱，爬到灯心草丛里，像牛似的大咬大嚼起来。
• He was a gentle,rather bovine man.他是一位文雅而反应迟钝的人。

28 mammoth   

n.长毛象；adj.长毛象似的，巨大的

参考例句：

• You can only undertake mammoth changes if the finances are there.资金到位的情况下方可进行重大变革。
• Building the new railroad will be a mammoth job.修建那条新铁路将是一项巨大工程。

29 skeptical   

adj.怀疑的，多疑的

参考例句：

• Others here are more skeptical about the chances for justice being done.这里的其他人更为怀疑正义能否得到伸张。
• Her look was skeptical and resigned.她的表情是将信将疑而又无可奈何。

30 marsh   

n.沼泽，湿地

参考例句：

• There are a lot of frogs in the marsh.沼泽里有许多青蛙。
• I made my way slowly out of the marsh.我缓慢地走出这片沼泽地。

31 blase   

adj.厌烦于享乐的

参考例句：

• She's very blase about parties.她非常腻烦聚会。
• The film star is blase about endless flattery now.那位电影明星现在对无休无止的吹捧已经厌烦了。

32 lulled   

vt.使镇静，使安静（lull的过去式与过去分词形式）

参考例句：

• They lulled her into a false sense of security. 他们哄骗她，使她产生一种虚假的安全感。 来自《简明英汉词典》
• The movement of the train lulled me to sleep. 火车轻微的震动催我进入梦乡。 来自《简明英汉词典》

33 quandary   

n.困惑，进迟两难之境

参考例句：

• I was in a quandary about whether to go.我当时正犹豫到底去不去。
• I was put in a great quandary.我陷于进退两难的窘境。

34 genetically   

adv.遗传上

参考例句：

• All the bees in the colony are genetically related. 同一群体的蜜蜂都有亲缘关系。
• Genetically modified foods have already arrived on American dinner tables. 经基因改造加工过的食物已端上了美国人的餐桌。 来自英汉非文学 - 生命科学 - 基因与食物

35 boon   

n.恩赐，恩物，恩惠

参考例句：

• A car is a real boon when you live in the country.在郊外居住，有辆汽车确实极为方便。
• These machines have proved a real boon to disabled people.事实证明这些机器让残疾人受益匪浅。

36 contemplate   

vt.盘算，计议；周密考虑；注视，凝视

参考例句：

• The possibility of war is too horrifying to contemplate.战争的可能性太可怕了，真不堪细想。
• The consequences would be too ghastly to contemplate.后果不堪设想。

37 makeup   

n.组织；性格；化装品

参考例句：

• Those who failed the exam take a makeup exam.这次考试不及格的人必须参加补考。
• Do you think her beauty could makeup for her stupidity?你认为她的美丽能弥补她的愚蠢吗？