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
77
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.
Which of the following about the African bush elephant and the African elephant is true?
选项
A、The WCU are interbreeding those elephants.
B、They are interbreeding species.
C、They are two genetically distant species.
D、They depend on each other for survival.
答案
C
解析
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-inter-breeding 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,短文说这两类象是非杂交物种。选项D的内容短文中找不到。
转载请注明原文地址:https://kaotiyun.com/show/HyLd777K
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
DNAFingerprintingDNAisthegeneticmaterialfoundwithinthecellnucleiofalllivingthings.Inmammals(哺乳动物)thestrand
Theoriginalexperimentcannotbeexactlyduplicated.
ManyChildren’sDeathsPreventable:WHOOverfivemillionchildrendieeachyearfromdisease,infectionsandaccidentsrela
AmericanDreamsThereisacommonresponsetoAmericaamongforeignwriters:theUSisalandofextremeswherethebestof
ManyChildren’sDeathsPreventable:WHOOverfivemillionchildrendieeachyearfromdisease,infectionsandaccidentsrela
SingingAlarmsCouldSavetheBlindIfyoucannotsee,youmaynotbeabletofindyourwayoutofaburningbuilding--andtha
Wehavetothinkverycarefullybeforewetakeanyaction,becauseit’saveryserioussituationwehaveencountered.
Morethan89ofthebuildingsinAnnapolis,Maryland,wereerectedbeforetheRevolutionaryWar.
随机试题
剩余价值率是剩余价值与()
根据降水量的不同,我国从东南到西北可以划分为三个等雨量区,植被类型也相应分为三个区,即森林区、______和荒漠区。
关于激光热成像技术胶片成像层各部分的功能,说法不正确的是
【2012年第4题】题6~10:某工程通信机房设有静电架空地板,用绝缘缆线敷设,室内要求有通信设备、网络、UPS及接地设备。请回答下类问题,并写出解题过程。人体与导体内发生放电的电荷达到2×10—7C时就可能受到电击,当人体的电容为100pF,依规范确
关于监护人的说法,正确的有()。
存款乘数比货币乘数更全面。()
在经济领域,效率强调提高产出与投入的比率,扩大不同能力主体之间的财富收益差距,而公平则强调收入分配相对平等,社会成员之间的差距不能过大。二者侧重不同,但又具确一致性,都应以调动劳动者的积极性,促进社会稳定发展为目标。改革开放三十多年来,我们对效率
根据下列资料,回答下列题。关于各年龄段就业人数与失业人数的相关情况,下列说法正确的是:
在Windows2003中,用于显示主机上活动的TCP连接状况的命令是()。
A、Manylanguages.B、Prettywell.C、5languages.D、IcanspeakEnglishfluently.C题目问的是“你会说几种语言?”只有C“五种”是符合题意的,故选C。
最新回复
(
0
)