"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)

　　词汇：

　　cryptic adj．隐蔽的；隐藏的

　　taxon n．(生物的)分类单元

　　biodiversity n．生物多样性

　　taxonomic adj．分类(学)的

　　DNA n．脱氧核糖核酸

　　non-interbreeding a dj．非

　　deoxyribonucleic acid的缩写) 杂交繁殖

　　Biogeographical adi．生morphology n．形态学 物地理学的malaria n．疟疾

　　reptile n．爬行动物sibling n．同胞，同属

　　temperate adj．(气候)温带的

　　注释：

　　1．the Goethe-Universitat in Frankfurt：德国法兰克福大学，即Johann Wolfgang Goethe-Universitat Frankfurt am Main，位于美因和莱茵两河汇流处的法兰克福。

　　2．the University of Guelph：圭尔夫大学。该校成立于1964年，是一所公立的综合性大学。在2005年加拿大综合类大学评比中，圭尔夫大学名列第3名，是全加拿大最著名的高等学府之一。

　　3．Ontario：安大略。加拿大中东部的一个省。

　　4．the World Conservation Union：世界自然保护联盟。全球最大、最重要的自然保护网络机构，它集合了82个国家、1 11个政府机构、800多个非政府组织以及来自181个国家的约1万多名科学家和专家，形成了世界环保领域里独一无二的全球性合作关系。

　　练习：

　　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，研究结果为广泛的研究领域提供启示，包括生物多

　　样性研究，还能帮助我们理解传染疾病及其演变。所以，选项A、B、C都是正确的，它们不是答案。选项D的“适者生存”的内容文章中没有提及，因此是本题的答案。

　　2．D．短之的第二段第二句描述的是科学家目前的研究结果，第j段描述的是科学家住这之前对于cryptic species的理解。本题用的是过上式，问的是过去的状况，因此，答案在第三段中，B和c是答案，所以D是正确选择。

　　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．其意思就是人们目前还不了解。第五段的最后一句也说明r研究者目前对此尚未了解。

　　4．C．答案在第六段中。该段举了非洲大象为例，说明什么是cryptic species。第六段的句子“A 2001 study found the elephants were actually two genetically distinct，non—interbreeding species"是选择C的依据。选项A不对，the WCU并没有杂交繁殖这两种象。选项B不对，短文说这两种象是非杂交物种。选项D的内容短文中找不到。

　　5．A．短文最后一段告诉我们，由于对蚊子种类不了解，20世纪初期疟疾曾肆虐欧洲，最终，科学家才了解到蚊子这一物种不是由一个种类而是由六个种类组成。所以，应该选择A。

　　译文：

第五十篇 “隐种”可能令人惊叹地普遍存在

　　隐蔽性物种，即形态相似但基因距离较远的物种，分布范围远比以前所认为的广。这一发现将为广泛的研究领域提供启示，包括生物多样性的预测、野生动物管理、对传染病及其演变的认识等。

　　随着DNA测序成本的降低，20多年来关于隐蔽性物种的研究报告与日俱增。法兰克福大学的Markus Pfenniger和Klaus Schwen在对已知的隐蔽性物种的数据分析后发现，这些隐蔽性物种跟动物王国的主要分支有同样多的比重并在生物地理学上占有同样多的区域。

　　科学家曾推测，绝大多数的隐种在昆虫与爬行动物中，并多处于热带而非温带。“那些看上去分布很广、数量很大的物种很有可能实际上是一些低种群且高度濒危的隐蔽性物种。”Pfenninger说。

　　在一种分类里面的所有物种的遗传信息没有得到全面研究以前，没有人知道到底存在多少隐蔽性物种。“有可能高达30％。”Pfenniger说。

　　“我真的为他们的发现感到惊奇，”加拿大安大略圭尔夫大学的AlexSmith说，“这真是在呼叫：我们联手起来进行基因研究啊。”

　　科学家们希望在下一个5—10年内完成对所有鱼类和鸟类的取样。一‘旦完成这两个分类，扣任何一个分类的遗传分析，研究者便可以确定动物王国里隐蔽性物种的数量。

　　隐蔽性物种的—个代表是非洲象。g001年的一个研究发现，象其实也有遗传差别，有两个不可杂交种群，分别是非洲丛林象和非洲象。目前世界自然保护联盟将非洲丛林象和非洲象分别列为易受伤害和易受威胁的动物。

　　重新分类并不仅仅是个学术活动。他们把进化上彼此独立并H彼此间的遗传差异有明显的延续性的定义为不同的群体。

　　欧洲20世纪初墓于形态学对蚊子的错误分类影响了对疟疾的控制。这个原以为是一个单—类型的物种竟由6个分类构成，而仅其中的3个分类传播疾病。“生物学的基本单元始终是物种，这是必须要明白的，”Pfenninger说。他还说，以前大部分研究已经不能再用了，闲为它们对于在被研究的物种都没有分清。

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