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.
【R2】
选项
答案
Pollen
解析
(由some animals may help to…directly as the carrier themselves“它们会传递花粉,但是自己却不是直接的传递者”可知答案。)
转载请注明原文地址:https://kaotiyun.com/show/aMAK777K
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
Ivan:IbroughtyouthenewGroovePeopleCD.Dale:WhatgoodisaCDifIhaven’tgotaCDplayer?Ivan:IcanbringyouaCDpl
whichofthefollowingnumbersshouldreplacethequestionmark?
Rearrangethefollowingletterstomakeasinglewordandthenchoosethecategoryinwhichitbelongs.FAREFIG
Everyyearalargenumberofyoungpeopleleaveschoolandbeginwork.Some【21】jobsonfarmsorinindustry.Othersacceptposit
AdvancenoticeisoftenreferredtoinAmericaas"leadtime,"anexpressionwhichissignificantinaculturewhereschedulesa
Normallyastudentmustattendacertainnumberofcoursesinordertograduate,andeachcoursewhichheattendsgiveshimacr
Mostchildrenatthetenderageofsixorsoarefullofthemostimpracticalschemesforbecomingpolicemen,firemenortraind
旅游业是全世界最大的雇主,全球10%的工作岗位都是由旅游业创造的。(accountfor)
【T1】我希望这个新学年成为对我的学生们有益的一年。(want…tobe)他们会在新学年学习很多东西,包括微积分、莎士比亚和失败。没错,就是失败。根据多种流传的说法,梭罗是个失败者。这位哈佛毕业生似乎把自己的大部分时间都用来在瓦尔登湖畔家
(81)具体说,信息化主要是反映在沟通手段的网络化,也就是所谓的网络经济。这网络就是指由卫星、光纤、电缆和电话线路把世界各个角落联系到一起的电脑网络。(82)只要用鼠标一点,在地球另一端的信息马上就会以每秒钟绕地球七周半的光速跑到你的电脑荧光屏上。
随机试题
企业在金融市场上发行股票和债券,从而取得资金的活动是()
2009年3月5日上午9时,第十一届全国人民代表大会第二次会议在人民大会堂开幕,国务院总理温家宝作政府工作报告,审查年度计划报告和预算报告。国际金融危机影响下,2009年中国经济走势如何百姓关注世界瞩目,政府工作报告提出2009年中国经济增长预期目标为()
Ilikethatsonof______.
2014年1月,北京居民李某的一件珍贵首饰在家中失窃后被窃贼带至甲国。同年2月,甲国居民陈某在当地珠宝市场购得该首饰。2015年1月,在获悉陈某将该首饰带回北京拍卖的消息后,李某在北京某法院提起原物返还之诉。关于该首饰所有权的法律适用,下列哪一选项是正确的
以下选项中不属于设备运杂费的是()。
福安公司为一家食品生产企业。2006年,福安公司拟扩大生产经营范围,投资于饮料行业。福安公司管理层在对当时国内饮料行业进行深入调研后发现:已有一批大中型饮料企业从事各类知名品牌的饮用水的生产和销售。有关情况如下:(1)水清公司生产饮用水的历史最长,其生产的
通常情况下,划分货币层次的依据是货币资产的()。
某超市采用促销的手段,凡购买价值200元以上的商品可以优惠20%,那么用320元钱在该超市最多可以买下价值()元的商品。
1919年,法国的“统一学校运动”主要的主张是()
关于χ的方程(m2-m-2)χ=m2+2m-8有无穷多解,则m=().
最新回复
(
0
)