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
You do not usually get something for nothing. Now, a new study reveals that the evolution of an improved learning ability could
You do not usually get something for nothing. Now, a new study reveals that the evolution of an improved learning ability could
admin
2017-06-27
39
问题
You do not usually get something for nothing. Now, a new study reveals that the evolution of an improved learning ability could come at a particularly high price: an earlier death.
Past experiments have demonstrated that it is relatively easy through selective breeding to make rats, honey bees and—that great favourite of researchers—fruit flies a lot better at learning. Animals that are better learners should be competitive and, thus, over time, come to dominate a population by natural selection. But improved learning ability does not get selected amongst these animals in the wild. No one really understands why.
Tadeusz Kawecki and his colleagues at the University of Fribourg in Switzerland have measured the effects of improved learning on the lives of fruit flies. The flies were given two different fruits as egg-laying sites. One of these was laced with a bitter additive that could be detected only on contact. The flies were then given the same fruit but without an additive. Flies that avoided the fruit which had been bitter were deemed to have learned from their experience. Their children were reared and the experiment was run again.
After repeating the experiment for 30 generations, the children of the learned flies were compared with normal flies. The researchers report in a forthcoming edition of Evolution that although learning ability could be bred into a population of fruit flies, it shortened their lives by 15% . When the researchers compared their learned flies to colonies selectively bred to live long lives, they found even greater differences. Whereas learned flies had reduced their life spans, the long-lived flies learned less well than even average flies.
The authors suggest that evolving an improved learning ability may require a greater investment in the nervous system which takes resources away from processes that delay ageing. However. Dr. Kawecki thinks the effect could also be a by-product of greater brain activity increasing the production of Reactive Oxygen Species(ROS), which can increase oxidation in the body and damage health.
No one knows whether the phenomenon holds true for other animals. So, biologists, at least, still have a lot to learn.
The forthcoming report says that______.
选项
A、long-lived flies are better at laying eggs
B、long-lived flies are poorer in learning
C、learned flies have a relatively long life
D、learned flies live as long as average ones
答案
B
解析
细节题。从文章第四段最后一句“Whereas learned flieshad reduced their life spans,the long—lived flies learned less wellthan even average flies.”可知,长命果蝇的学习能力低于普通果蝇,故选B。
转载请注明原文地址:https://kaotiyun.com/show/BwVd777K
本试题收录于:
公共英语三级笔试题库公共英语(PETS)分类
0
公共英语三级笔试
公共英语(PETS)
相关试题推荐
Faces,likefingerprints,areunique.Didyoueverwonderhowitispossibleforustorecognizepeople?Evenaskilledwriterp
WhoStartedtheideaofcreatingthemachine"Walkman"?
Manyteachersbelievethattheresponsibilitiesforlearningliewiththestudent.【C1】______alongreadingassignmentisgiven,
Manyteachersbelievethattheresponsibilitiesforlearningliewiththestudent.【C1】______alongreadingassignmentisgiven,
Onesummernight,onmywayhomefromworkIdecidedtoseeamovie.Iknowthetheaterwouldbeair-conditionedandIcouldn’t
Whena13-year-oldVirginiagirlstartedsneezing,herparentsthoughtitwasmerelyacold.Butwhenthesneezescontinuedfor
Thequestionofwhetherwarisinevitableisonewhichhasconcernedmanyoftheworld’sgreatwriters.Beforeconsideringthis
Whatisthewomandoingatthemoment?
Whatistheman’sfirsttiponaproductiveworkday?
Whatisthewomandoingatthemoment?
随机试题
Itwaswonderfulupthere.Ralphwantedtoreachoutand【21】astar,forthey【22】soclose.Hecouldseetheearthgettingsmaller
胡女士,36岁,初次妊娠7个月,患有妊高症。当妊娠危及胎儿母亲的生命时,可允许行人工引产术,其原则是()
关于医嘱种类的解释,下列哪项不对
关于生理止血机理的叙述,下列哪项是错误的
设该梁承受的扭矩设计值T=15.0kN·m,弯矩设计值M=105kN·m,剪力设计值V=80kN,则以下______项判断正确?
建筑安装工程税金是指国家税法规定的应计入建筑安装工程造价的()。
丁公司最近参与中东某国水坝建设项目投保,在激烈竞争中最终中标。按照当地法律,丁公司必须与当地企业成立投标联合体方可投标,中标后该投标联合体即转为项目公司负责水坝建设。该国政局相对稳定,但实行外汇管制。按照中标通知书及最终签署合同条款约定,对于前期
高楼:庭院
你有一位在编的同事突然去世,其家属悲痛万分。因为这位同事是家里唯一的经济支柱。其家属要求单位让其女儿替岗。如果你是这个单位的工作人员,你会怎么接待这位去世同事的家属?
下列关于局域网设备的描述中,错误的是()。
最新回复
(
0
)