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
110
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.
In this experiment, scientists observed that______.
选项
A、some flies avoided the fruit without an addictive
B、some flies preferred the fruit with an addictive
C、the eggs of the flies were not damaged
D、the impact on the flies did not last long
答案
A
解析
推断题。从文章第三段第五句“Flies that avoided the fruitwhich had been bitter were deemed to have learned from their expe—rience.”可知,那些果蝇通过学习能力的提升能够避开带有添加剂的水果,由此可以推断,果蝇已经有经验,看见同种水果也会避开,所以果蝇也会避开没有添加剂的同种水果,故选A。
转载请注明原文地址:https://www.kaotiyun.com/show/6wVd777K
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
Whatwillthewomanprobablydo?
Faces,likefingerprints,areunique.Didyoueverwonderhowitispossibleforustorecognizepeople?Evenaskilledwriterp
Whendidthetwopeopleseeeachotherlasttime?
Themessageof【C1】______suchasthisis【C2】______naturalsystemsarecomplex,unpredictable:understandingthem【C3】______patien
Onesummernight,onmywayhomefromworkIdecidedtoseeamovie.Iknowthetheaterwouldbeair-conditionedandIcouldn’t
Onesummernight,onmywayhomefromworkIdecidedtoseeamovie.Iknowthetheaterwouldbeair-conditionedandIcouldn’t
Whena13-year-oldVirginiagirlstartedsneezing,herparentsthoughtitwasmerelyacold.Butwhenthesneezescontinuedfor
Americanarchitectureisatitsbestwhenitisconcernedwithbuildingsthathaveapracticalpurpose.Factories,officebuildi
Americanarchitectureisatitsbestwhenitisconcernedwithbuildingsthathaveapracticalpurpose.Factories,officebuildi
Whatisthewomandoingatthemoment?
随机试题
A.呆小症B.巨人症C.侏儒症D.阿狄森病幼年期甲状腺激素分泌不足可引起
在正常人和各种心脏病患者中,最为常见的心律失常为
男,55岁,间歇性全程无痛肉眼血尿2个月。静脉尿路造影可见右肾盂充盈缺损。首先考虑的疾病是
估价上的折旧注重的是()。
在工程设计中通常根据生产机械的负荷类型及工作制选用不同的电动机与之配套。生产机械的负载转矩T随转速n而变化的特性T=f(n)称为负载特性。图中所示四组曲线为不同生产机械的负载曲线。风机、水泵负载,随叶轮的转动,介质对叶片的阻力在一定转速范围内大致与转
图示结构在水平杆AB的B端作用一铅直向下的力P,各杆自重不计,铰支座A的反力RA的作用线应该是( )。
防火门是由门板、门框、锁具、闭门器、顺序器、五金件、防火密封件以及电动控制装置等组成,符合耐火完整性和隔热性等要求的防火分隔物。下列有关防火门的选型、外观、安装质量和系统功能等不符合现行国家消防技术标准的要求的是()。
竹片:刻刀:文字
用划线法分析下边的多重复句长城当然也非常伟大,不管孟姜女们如何痛哭流涕,站远了看,这个苦难的民族竟用人力在野山荒漠间修了一条万里屏障,为我们生存的星球留下了一种人类意志的骄傲。
[*]
最新回复
(
0
)