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(隐蔽的;隐藏的)species -- animals that appear identical but are genetically qui
"Hidden" Species May Be Surprisingly Common Cryptic(隐蔽的;隐藏的)species -- animals that appear identical but are genetically qui
admin
2011-01-02
82
问题
"Hidden" Species May Be Surprisingly Common
Cryptic(隐蔽的;隐藏的)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(生物多样性)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 (脱氧核糖核酸) 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 biogeographical(生物地理学的)regions.
Scientists had previously speculated that cryptic species were predominantly found in insects and reptiles(爬行动物), and were more likely to occur in tropical rather than temperate(温带的)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(分类单元)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 (非杂交繁殖的) 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(疟疾)in Europe. Ultimately, what was thought to be a single species was actually made up of six sibling(同胞,同属)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.
Do scientists know how many cryptic species exist?
选项
A、Not yet.
B、Yes, they do.
C、They will know the answer in another one or two-years.
D、They will never know the answer.
答案
A
解析
短文第三段最后一句提到“直到人们对至少一个类群的所有物种的基因信息有了深入研究,没有人能知道究竟有多少隐性物种存在。”故选A。
转载请注明原文地址:https://kaotiyun.com/show/FALd777K
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
Myfatheralwaystakesastrollforawhileaftersupper.
TryingtoFindaPartnerOneofthemoststrikingfindingsofarecentpollintheUKisthatofthepeopleinterviewed,one
CarMaintenanceOnceitwasconsideredgoodpracticetoletthecarengineidleaminuteortwofollowingcoldstarts.Todaywit
Theoldconcernsloseimportanceandsomeofthemvanishaltogether;
Theauthoriskindtothechildrenbecauseshewantedtoplayanimportantroleinthechildren’slives.Aserious-lookingman
OnBritishNewspapersBesidesthedailynewspapers,thereareanumberofSundaynewspapersinBritain.Manyofthemarecon
IrradiatingFoodIrradiatingfruits,vegetables,porkandchickentokillinsectsandbacteriahasbeenapprovedbytheFood
IrradiatingFoodIrradiatingfruits,vegetables,porkandchickentokillinsectsandbacteriahasbeenapprovedbytheFood
MicroelectronicsRevolutionThe1980sarelikelytobeconsideredasamorethansomewhatinterestingdecadefortheUnited
Jackisadiligentstudent.
随机试题
4绝缘电阻表使用中须根据被测对象不同来选择不同的()等级。
在门脉性与坏死后性肝硬化病变的区别中,不包括下列哪一项
治疗急性白血病时要保护静脉的原因是
男,45岁。因“胃窦部溃疡”欲行“胃大部切除术”,其一般情况尚好,血压18.6/12.69kPa(140/90mmHg)。为该患者做术前准备,下列哪项错误
29岁孕妇,妊娠32周,3周内阴道少量流血2次,今晨突然阴道流血多于月经量,无腹痛,血压13.3/10.7kPa,脉率96次/分,宫高30cm,腹围85cm,臀先露,未入盆,胎心清楚,144次/分。应最先考虑的疾病是()
暴发性流脑病情危重,死亡率高,患者、家属均可产生焦虑及恐惧心理,护士进行护理时不妥的做法是()。
分娩第一期护理,哪项是错的
根据所给资料,回答以下问题。2012年,黑龙江省规模以上工企业中,六大战略性新兴产业单位721户,累计实现增加值455.7亿元,比去年增长15.1%,高于全省规模以上工业增加值增速4.6个百分点,占全省规模以上工业企业增加值的9.6%。
ARM处理器如果R1=0x98001200,已知在小端模式下,内存0x98001204中存放数据0x35,0x98001205中存放数据0x36,0x98001206中存放数据0x37,0x98001207中存放数据0x38,在指令LDRR0,[R1,#
Fourmemberswalkedoutofthesession,withtheresultthatthecommitteedidnothavea______andwouldnottakeanydecision
最新回复
(
0
)