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
32
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.
【R5】
选项
答案
intact
解析
(第四段指出87%of flowers with the petals torn off did so,did so指上文提到的left intact。)
转载请注明原文地址:https://kaotiyun.com/show/BeAK777K
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
Tom:Myteamplayedaseriesofgames.Mike:______Tom:Wewonthefirsttwogames,butlostthelastthree.
Televisionsenablesustoseethingshappenalmostattheexactmoment______.
Manyayoungpersontellsmehewantstobeawriter.Ialwaysencouragesuchpeople,butIalsoexplainthatthere’sabigdiff
Almosteveryonewithorwithoutacomputerisawareofthelatesttechnologicalrevolutiondestinedtochangeforeverthewayin
A、Tobuyanewspaper.B、Tofindachemist.C、Topostaletter.B
Ineverycountryinthedevelopedworld,waistlinesareexpandingasprosperitygrows.Aroughguidetonationalincomecanbeo
Thecoursenormallyattracts20studentsperyear,______uptohalfwillbefromorient.
Surfingissomethingpeopleoftengethookedonaftertryingitafewtimes.Formanysurfersitismuchmorethanahobby—they
Mostpeopleconsiderbacteriadangerous.Afterall,thesemicroorganismscauseahostofserioushumandiseases,includingtuber
Mostpeopleconsiderbacteriadangerous.Afterall,thesemicroorganismscauseahostofserioushumandiseases,includingtuber
随机试题
下列药物中,属于厥阴头痛引经药的是()(2010年第65题)
简述行为治疗中阳性强化疗法。
Asurveyhascomeupwithsomeinteresting【B1】______aboutthecostoflivinginourmajorcities.Tokyoisstillthe【B2】____
A、体克B、腹膜刺激征C、两者均有D、两者均无单纯性肠梗阻可出现_______。
医师的下列行为不属于违法违规的是
某ICU护士,毕业工作3年来,基本上是一个人护理某个病人,病人需要的全部护理由她全面负责,实施个体化护理。对ICU的重症病人护理以下错误的是
将830修约到百位数0.2单位。得820。()
关于旅游保险的保险责任,下列说法不正确的是()。
人类社会的物质性表现为()。
下列关于有条件的宏的说法,错误的一项是()。
最新回复
(
0
)