首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
"Hidden" Species May Be Surprisingly Common Cryptic species animals that appear identical but are genetically quite distant—
"Hidden" Species May Be Surprisingly Common Cryptic species animals that appear identical but are genetically quite distant—
admin
2011-01-02
107
问题
"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 Frankfurt, 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 biogeographieal 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 Guelph in Ontario, 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 complete work on all fish and birds in another 5 to 10 years. Once either of these taxonomic groups is completed, Pfenninger says researchers will be 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 bush elephant and the African elephant. The species are currently listed as vulnerable and threatened, respectively, by the World Conservation Union (WCU).
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 1900s 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.
What was scientists’ understanding of cryptic species?
选项
A、They occurred in equal numbers in all biogeographical regions.
B、They were mostly found in insects and reptiles.
C、They were likely to be in tropical rather than temperate regions.
D、Both B and C.
答案
D
解析
短文的第二段第二句描述的是科学家目前的研究结果,第三段描述的是科学家在这之前对于cryptic species的理解。本题用的是过去式,问的是过去的状况,因此答案在第三段中,B和C均是答案,所以D是正确选择。
转载请注明原文地址:https://kaotiyun.com/show/WyLd777K
本试题收录于:
职称英语理工类A级题库职称英语分类
0
职称英语理工类A级
职称英语
相关试题推荐
Common-coldSenseYoucan’tbeatit,butyoudon’thavetojoinit.Maybeitgotthename"commoncold"becauseit’smoreco
ScientistsDevelopWaysofDetectingHeartAttackGermanresearchershavecomeupwithanewgenerationofdefibrillators(除颤
AdaptationofLivingThingsCertainanimalsandplantsdevelopcharacteristicsthathelpthemcopewiththeirenvironmentbe
LivingAloneCouldBeGoodforYourWeightGoodnewsforpeoplelivingalone:Aforthcomingpapershowsthatsingleadults—o
Choosingatopicforresearchisimportantinthatyouwillputagreatdealoftimeandenergyintoit.Choosingagoodresear
ManyofnovelistCarsonMcCullers’charactersareisolated,disappointedpeople.
IrradiatingFoodIrradiatingfruits,vegetables,porkandchickentokillinsectsandbacteriahasbeenapprovedbytheFood
IrradiatingFoodIrradiatingfruits,vegetables,porkandchickentokillinsectsandbacteriahasbeenapprovedbytheFood
Thecommitteewasaskedtorenderareportonthehousingsituation.
Agreatdealhasbeendonetoremedythesituation.
随机试题
关于颞下颌关节紊乱综颌征的叙述哪项是错误的
关于蜂窝织炎,说法错误的是
A.饮水呛咳B.声音低钝C.手足抽搐D.声音嘶哑E.失音喉返神经一侧损伤出现
患者,27岁,车祸撞伤右小腿,X线摄片示右胫骨中段粉碎性骨折,行手法复位石膏托外固定后1天,现感右小腿疼痛、麻木。查体:右小腿肿胀,张力增大,足背动脉搏动减弱,足趾青紫、发凉,被动活动足趾剧痛。目前发生的并发症是
女性,30岁,体重50kg,热力烧伤后4小时入院,查体:休克,Ⅰ度烧伤面积20%,Ⅱ度烧伤面积20%,Ⅲ度烧伤面积20%,入院后,第一个24小时内补液总量为
根据《环境影响评价技术导则一大气环境》,下列关于预测因子选择的说法,正确的是()。
外国人在华死亡后,其遗体运回其国内,运输手续和费用原则上均由旅行社承担。()
前工业和信息化部副部长的杨学山曾被记者问及对市场上欣欣向荣的山寨产品有何看法?他表示,山寨产品是知识产权保护里面的一个重要内容。他说,在讨论知识产权问题的时候,始终考虑平衡两个方面的利益,一方面是知识产权的拥有者,另一方面是广大的用户。也就是说,保护知识创
我国的法律体系是中国特色社会主义法律体系。下列关于我国社会主义法律的本质,表述正确的有()
Amongthemostpowerfulenginesofmoderneconomicgrowthhavebeentechnologicalchangesthatraiseoutputrelativetoinputs.
最新回复
(
0
)