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
2013-11-20
54
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.
【R4】
选项
答案
the honey-bush
解析
(由文章But when the honey-bush is in bloom.…the rest of the flower.They chew them toextract the nectar and spit out what is left可知。Them指的是the honey-bush。)
转载请注明原文地址:https://kaotiyun.com/show/YMAK777K
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
WhileagreatdealofchangeandmodernizationhastakenplaceinIndiasince1947,thebasiceconomicarrangements,values,and
Howmanypeoplecantheboatcarry?
Howmanypeoplecantheboatcarry?
SupposeyouareafreshmaninDepartmentofComputerScience,youarenotsatisfiedwiththeschoolcanteenservicebecauseoft
BywhomhasMichaelMoralesbeensparedthesecondtimeintwenty-fourhours?
Mostchildrenatthetenderageofsixorsoarefullofthemostimpracticalschemesforbecomingpolicemen,firemenortraind
TheMillenniumSeedBankProjectOneofthelargestconservationprojectseverundertaken;thisinternationalcollaboration
中国经济发展潜力大、优势足、空间广,前景光明。【T1】我们有9亿多劳动力,其中1.7亿多受过高等教育或有专业技能。(非限制性定语从句)每年大学毕业生700多万,中职毕业生500多万。【T2】科技人员数量世界第一,研发投入(R&Dinput)世界第
现在是一个极具变革的年代,你们为迎接新的挑战已经做好了准备。(81)是你们使我们的社会更加强大,我们的家庭更加健康和安全,我们的人民更加富裕。同胞们,我们已经进入了全球信息化时代,这是美国复兴的伟大时代。(82)作为总统,我所做的一切—
随机试题
病人,男,60岁,痰中间断带血丝3个月,渐消瘦,体弱。胸片示右肺门阴影增大及右肺中叶模糊阴影,抗生素疗效差。当病人咳嗽、咳痰时,要特别注意()
在我国最好发的口腔颌面部恶性肿瘤是
记忆内容遗忘最快发生在识记后的
竞价排名是按照效果付费的网络推广方式,由()在国内率先推出。
在黄金外汇储备与货币供应量的关系当中,除黄金外汇储备量影响货币供应量以外,对货币供应量有影响的因素还有()。
()属于动态的员工素质测评。
篮球双手胸前传球技术在球出手后,球在空中飞行。球飞行时的旋转方向为()。
沼气:甲烷:气体
已知X~N(μ,σ12),Y~N(2μ,σ22),x与y相互独立,而且P(X-Y≥1)=,则μ=______·
Despiteyourbestintentionsandefforts,itis【B1】______:Atsomepointinyourlife,youwillbewrong.【B2】_______canbehar
最新回复
(
0
)