"Hidden" Species May Be Surprisingly Common

　　Cryptic species- animals that appear identical but are genetically quite distant -may be much more widespread than previously thought. The findings could have major implications in areas ranging from biodiversity estimates and wildlife management, to our understanding of infectious diseases and evolution.

　　Reports of cryptic species have increased dramatically over the past two decades with the advent of relatively inexpensive DNA sequencing technology. Markus Pfenninger and Klaus Schwenk, of the Goethe -Universitat in Frankfurt1, Germany, analyzed all known data on cryptic animal species and discovered that they are found in equal proportions throughout all major branches of the animal kingdom and occur in equal numbers in all biogeographical regions.

　　Scientists had previously speculated that cryptic species were predominantly found in insects and reptiles, and were more likely to occur in tropical rather than temperate regions."Species that are seemingly widespread and abundant could in reality be many different cryptic species that have low populations and are highly endangered," says Pfenninger. Until the genetic information of all species in at least one taxon is thoroughly studied, no one will know just how many cryptic species exist. " It could be as high as 30% ," Pfenninger says.

　　"I'm extremely surprised by their results, " says Alex Smith of the University of Guelph2 in On-tario3 , Canada. "It' s a call to arms to keep doing the broad kind of genetic studies that we are doing. "

　　Sampling as many individuals as possible, scientists hope to cumplete work on all fish and birds in another 5 to 10 years. Once either of these taxonomic groups is completed, Pfenninger says researchers will able to decide how many cryptic species exist throughout the animal kingdom.

　　Examples of cryptic species include the African elephant. A 2001 study found the elephants were actually two genetically distinct, non -interbreeding species, the African hush elephant and the African elephant. The species are currently listed as vulnerable and threatened, respectively, by the World Conservation Union (WCU)4.

　　The reclassifications are more than an academic exercise. They define populations that have evolved independently of each other and whose genetic differences can have significant consequences.

　　In the early 1 900s misidentification of mosquito species based on morphology confused attempts to control malaria in Europe．Ultimately，what was thought to be a single species was actually made up of six sibling species，only three of which transmitted the disease．“The basic unit in biology is always the species，and you have to know what you are dealing with，”Pfenninger says．Much previous research is now no longer used，he says，because it is not clear what species was being studied．(428 words)

　　詞匯：

　　cryptic adj．隱蔽的；隱藏的

　　taxon n．(生物的)分類單元

　　biodiversity n．生物多樣性

　　taxonomic adj．分類(學(xué))的

　　DNA n．脫氧核糖核酸

　　non-interbreeding a dj．非

　　deoxyribonucleic acid的縮寫) 雜交繁殖

　　Biogeographical adi．生morphology n．形態(tài)學(xué) 物地理學(xué)的malaria n．瘧疾

　　reptile n．爬行動物sibling n．同胞，同屬

　　temperate adj．(氣候)溫帶的

　　注釋：

　　1．the Goethe-Universitat in Frankfurt：德國法蘭克福大學(xué)，即Johann Wolfgang Goethe-Universitat Frankfurt am Main，位于美因和萊茵兩河匯流處的法蘭克福。

　　2．the University of Guelph：圭爾夫大學(xué)。該校成立于1964年，是一所公立的綜合性大學(xué)。在2005年加拿大綜合類大學(xué)評比中，圭爾夫大學(xué)名列第3名，是全加拿大最著名的高等學(xué)府之一。

　　3．Ontario：安大略。加拿大中東部的一個省。

　　4．the World Conservation Union：世界自然保護(hù)聯(lián)盟。全球最大、最重要的自然保護(hù)網(wǎng)絡(luò)機(jī)構(gòu)，它集合了82個國家、1 11個政府機(jī)構(gòu)、800多個非政府組織以及來自181個國家的約1萬多名科學(xué)家和專家，形成了世界環(huán)保領(lǐng)域里獨(dú)一無二的全球性合作關(guān)系。

　　練習(xí)：

　　1．Which of the following about the significance of the research on cryptic species is NOT true?

　　A．The results of the research can help the development of many other research areas．

　　B．The results of the research(：an help the development of biodiversity estimates．

　　C．The results of the research can help our understanding of infectious disease evolution．

　　D．The results of the research can help our understanding of“survival of the fittest．”

　　2．What was scientists’understanding of cryptic species?

　　A．They occurred in equal numbers in all biogeographical regions．

　　B．They were mostly f1)und in insects and reptjles．

　　C．They were likely to he in tropical rather than temperate regiOils．

　　D．Both B and C．

　　3．D0 scients know how many cryptic speties exist?

　　A．Not yet．

　　B．Yes，they do．

　　C．They wil一1 know the artswer in another one 0r two years．

　　D．They wil—l never know the answer．

　　4．Which of the following about the African hush elephant flnfl the African elephant is trile?

　　A．The WCU are interhreeding those elephants．

　　B．T}1ey are interl)reeding species．

　　C． They are tw0 genetically distant species．

　　D． They depend 0n eaeh 0ther fbr surVival．

　　5．Peoplewereconfusedin theirattemptstocontrolmalariainEuropeintheearly1900s，because scientists

　　A．identified only one mosquito spccies instead of six species．

　　B．thought 0nly three mosquit0 species transmitted disease．

　　C．thought there was 0nly one mosquito species．

　　D．did not know what species was heing studied．

　　1．D．短文的第一段第二句的大意是，研究結(jié)果為廣泛的研究領(lǐng)域提供啟示，包括生物多

　　樣性研究，還能幫助我們理解傳染疾病及其演變。所以，選項A、B、C都是正確的，它們不是答案。選項D的“適者生存”的內(nèi)容文章中沒有提及，因此是本題的答案。

　　2．D．短之的第二段第二句描述的是科學(xué)家目前的研究結(jié)果，第j段描述的是科學(xué)家住這之前對于cryptic species的理解。本題用的是過上式，問的是過去的狀況，因此，答案在第三段中，B和c是答案，所以D是正確選擇。

　　3．A．第三段和第五段提供了答案。第_三段的最后一句中的Until…，no one will know‘lUSl

　　how many cryptic species exist．其意思就是人們目前還不了解。第五段的最后一句也說明r研究者目前對此尚未了解。

　　4．C．答案在第六段中。該段舉了非洲大象為例，說明什么是cryptic species。第六段的句子“A 2001 study found the elephants were actually two genetically distinct，non—interbreeding species"是選擇C的依據(jù)。選項A不對，the WCU并沒有雜交繁殖這兩種象。選項B不對，短文說這兩種象是非雜交物種。選項D的內(nèi)容短文中找不到。

　　5．A．短文最后一段告訴我們，由于對蚊子種類不了解，20世紀(jì)初期瘧疾曾肆虐歐洲，最終，科學(xué)家才了解到蚊子這一物種不是由一個種類而是由六個種類組成。所以，應(yīng)該選擇A。

　　譯文：

第五十篇 “隱種”可能令人驚嘆地普遍存在

　　隱蔽性物種，即形態(tài)相似但基因距離較遠(yuǎn)的物種，分布范圍遠(yuǎn)比以前所認(rèn)為的廣。這一發(fā)現(xiàn)將為廣泛的研究領(lǐng)域提供啟示，包括生物多樣性的預(yù)測、野生動物管理、對傳染病及其演變的認(rèn)識等。

　　隨著DNA測序成本的降低，20多年來關(guān)于隱蔽性物種的研究報告與日俱增。法蘭克福大學(xué)的Markus Pfenniger和Klaus Schwen在對已知的隱蔽性物種的數(shù)據(jù)分析后發(fā)現(xiàn)，這些隱蔽性物種跟動物王國的主要分支有同樣多的比重并在生物地理學(xué)上占有同樣多的區(qū)域。

　　科學(xué)家曾推測，絕大多數(shù)的隱種在昆蟲與爬行動物中，并多處于熱帶而非溫帶。“那些看上去分布很廣、數(shù)量很大的物種很有可能實(shí)際上是一些低種群且高度瀕危的隱蔽性物種。”Pfenninger說。

　　在一種分類里面的所有物種的遺傳信息沒有得到全面研究以前，沒有人知道到底存在多少隱蔽性物種。“有可能高達(dá)30％。”Pfenniger說。

　　“我真的為他們的發(fā)現(xiàn)感到驚奇，”加拿大安大略圭爾夫大學(xué)的AlexSmith說，“這真是在呼叫：我們聯(lián)手起來進(jìn)行基因研究啊。”

　　科學(xué)家們希望在下一個5—10年內(nèi)完成對所有魚類和鳥類的取樣。一‘旦完成這兩個分類，扣任何一個分類的遺傳分析，研究者便可以確定動物王國里隱蔽性物種的數(shù)量。

　　隱蔽性物種的—個代表是非洲象。g001年的一個研究發(fā)現(xiàn)，象其實(shí)也有遺傳差別，有兩個不可雜交種群，分別是非洲叢林象和非洲象。目前世界自然保護(hù)聯(lián)盟將非洲叢林象和非洲象分別列為易受傷害和易受威脅的動物。

　　重新分類并不僅僅是個學(xué)術(shù)活動。他們把進(jìn)化上彼此獨(dú)立并H彼此間的遺傳差異有明顯的延續(xù)性的定義為不同的群體。

　　歐洲20世紀(jì)初墓于形態(tài)學(xué)對蚊子的錯誤分類影響了對瘧疾的控制。這個原以為是一個單—類型的物種竟由6個分類構(gòu)成，而僅其中的3個分類傳播疾病。“生物學(xué)的基本單元始終是物種，這是必須要明白的，”Pfenninger說。他還說，以前大部分研究已經(jīng)不能再用了，閑為它們對于在被研究的物種都沒有分清。

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