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
188
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
ManyChildren’sDeathsPreventable:WHOOverfivemillionchildrendieeachyearfromdisease,infectionsandaccidentsrela
EarBreakthroughNewresearchpublishedinthejournalCurrentBiologyhasaddedsignificantlytounderstandingofhowthee
SomeSundaynewspapersmaybelongtothesamepublishingcompanybutarenoteditedbythesamegroupofpeople.Itisobvious
SingingAlarmsCouldSavetheBlindIfyoucannotsee,youmaynotbeabletofindyourwayoutofaburningbuilding--andtha
Hundredsofyearsagocloveswereusedtoremedyheadaches.
Anumberoftheorieshavebeenproposedtoexplainthesituation.
Duringthepasttenyearstherehavebeendramaticchangesintheinternationalsituation.
SuperconductingCeramic(陶瓷)Anundergroundrevolutionbeginsthiswinter.Withtheflip(轻击)ofaswitch,30,000homesinon
Theseareourmotivesfordoingit.
Theseareourmotivesfordoingit.
随机试题
构成传染过程必须具备的因素是
A、PRPPB、PAPSC、FH4D、NAD+E、SAM一碳单位的载体
按照石墨的形状特征,铸铁可分为()三大类。
减少截流难度的主要技术措施是()。
信用风险缓释应遵循的原则有合法性原则、有效性原则、安全性原则、一致性原则、独立性原则。()
(2018年)2017年7月1日,某企业向银行借入一笔生产用周转资金200万元,期限为6个月,到期一次归还本金,年利率为6%,利息按季支付、分月预提。下列各项中,关于2017年9月30日该企业支付借款利息相关科目的会计处理结果正确的是()。
个体自我意识产生的标志是()。
举例说明怎样控制消极情绪,保持良好的心境。
风筝:风:飞翔
居民苏女士在菜市场看到某摊位出售的鹌鹑蛋色泽新鲜、形态圆润,且价格便宜,于是买了一箱。回家后发现有些鹌鹑蛋打不破,甚至丢到地上也摔不坏,再细闻已经打破的鹌鹑蛋,有一股刺鼻的消毒液味道。她投诉至菜市场管理部门,结果一位工作人员声称鹌鹑蛋目前还没有国家质量标准
最新回复
(
0
)