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
As every schoolboy knows, insects pollinate flowers, while birds and mammals disperse seeds by eating fruits or transporting bur
As every schoolboy knows, insects pollinate flowers, while birds and mammals disperse seeds by eating fruits or transporting bur
admin
2016-01-14
43
问题
As every schoolboy knows, insects pollinate flowers, while birds and mammals disperse seeds by eating fruits or transporting burs on their feathers and fur. These are examples of co-evolution, a phenomenon first described by Charles Darwin in The Descent of Man, and Selection in Relation to Sex, published in 1871.
Co-evolution, in which two species have evolved together in response to adaptations that each has imposed on the other, can be extremely subtle. For instance, some animals may help to transfer pollen from one plant to another without acting directly as the carrier themselves. Instead, they make it easier for the pollen to be dispersed by other creatures. Mats Olsson and Richard Shine, of the University of Sydney, and Elisabeth Bak-Olsson, of the University of Gothenburg in Sweden, have discovered, apparently for the first time, such a mutually beneficial arrangement between a reptile and a plant.
For most of the year the Tasmanian snow skink lizard confined to mountain tops in that island is catholic in what it eats. But when the honey-bush is in bloom, the skinks make a point of tearing off the tough, red petals that enclose the rest of the flower. They chew them to extract the nectar and spit out what is left. At first sight, this skink-savaging may not seem all that helpful to the honey-bush. But it is. It exposes the reproductive parts of the flowers, thereby allowing pollinating insects to get at them. Dr. Olsson and his colleagues found that flowers with the petals left intact never produced seed. But, according to their paper in the Biological Journal of the Linnean Society, 87% of flowers with the petals torn off did so.
To check that it was the skinks alone that were the plants’ little helpers, the researchers placed cages around some honey-bushes. Virtually all of the petals were removed from the flowers on bushes without cages. Only 16% of the caged bushes had their petals ripped off, possibly by high winds battering them.
Dr Olsson found no evidence of pollen being carried on a skink and so concluded that the lizards play no role in transporting honey-bush pollen from one flower to another. But he did see a range of insects: wasps, flies, bumble-bees and others feeding from honey-bush flowers that had no petals covering them. Without the petals removed, it was impossible for insects to do any pollinating.
SUMMARY:
Co-evolution is【R1】______described by Charles Darwin in The Descent of Man. In the process of co-evolution, two species may have to respond to adaptations they have imposed on each other. For example, some animals may not carry【R2】______from one plant to another. They may help by making it easier for other creatures to disperse the pollen from one plant to another. Such an arrangement seems【R3】______to both species. In Tasmania, the skink lizards chew the red petals of【R4】______and spit out what is left. In doing so, they expose the reproductive parts of the flower and enable pollinating insects to reach them. It was discovered that 87% of these flowers produced seeds. Conversely, flowers with petals remaining【R5】______never did.
【R3】
选项
答案
beneficial
解析
(由第二段such a mutually beneficial arrangement between a reptile and a plant可知答案。)
转载请注明原文地址:https://kaotiyun.com/show/neAK777K
本试题收录于:
B类竞赛(英语专业本科专科)题库大学生英语竞赛(NECCS)分类
0
B类竞赛(英语专业本科专科)
大学生英语竞赛(NECCS)
相关试题推荐
Televisionsenablesustoseethingshappenalmostattheexactmoment______.
ThenewsmediaintheUnitedStates【21】ofradio,televisionandnewspapers.MostAmericansbegintheirdaybyreadingthenewspa
DuringthelongvacationIwasacceptedasatraineebusconductor.Ifoundthejobfiercelydemandingevenonashortroutewit
Readthefollowingadvertisementandwritealetterofapplicationof120words.Donotwriteyouraddressorname.WANTEDFA
Mostchildrenatthetenderageofsixorsoarefullofthemostimpracticalschemesforbecomingpolicemen,firemenortraind
Resourcescanbesaidtobescarceinbothanabsoluteandrelativesense:thesurfaceoftheearthisfinite,imposingabsolute
A、Histeacher.B、Hisboss.C、Hismother.B
Surfingissomethingpeopleoftengethookedonaftertryingitafewtimes.Formanysurfersitismuchmorethanahobby—they
如果你是一个中等水平的读者,你能够以每分钟300字的速度阅读一本中等水平的书。不过,你必须每天这样坚持下去,否则就无法保持这种水平。【T1】你也不可能以这个速度阅读科学、数学、农业、商业方面的书,或是对你来说内容生疏的书。(Nor…or…)你绝不会以这种速
TherearetworeasonswhyIwantedtocometosouthernGermanytostudy.IwantedtobeatthecentreofEurope,withineasyrea
随机试题
行政给付的内容是赋予被帮助人:()
A、Themajorityofdriversprefertodriveandparkthemselves.B、Humandriversbecomeeasilydistractedortiredwhiledriving.
计算机屏幕显示“Harddiskfailure”,表示()。
《公路桥涵地基与基础设计规范》(JTG3363—2019)将桥涵地基岩土分为()。
某企业以在保险公司存款的利息充抵保险费用的方式向保险公司购买保险。2005年7月初,企业在保险公司的存款为400万元;月末,企业在保险公司的存款为200万元。假设人民银行公布的1年期存款利率为3%,保险公司在7月份应纳的营业税税额为()。
贷款分类需要考虑的因素包括()。
()不属于事前风险控制手段。
下列各项中,注册会计师在确定某项重大错报风险是否为特别风险时,通常无须考虑的是()。
系统方法论是项目评估方法论的理论基石。系统方法论的基本原则不包括()。
Sleepwalkingisadisordercharacterizedbywalkingorotheractivitiesapersonengagedinwhile【C1】______stillasleep.Itis
最新回复
(
0
)