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
2011-02-05
69
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【51】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.【52】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【53】to both species. In Tasmania, the skink lizards chew the red petals of【54】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【55】never did.
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 to extract 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/VDAK777K
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
NOCASH,NOPROBLEMAstechnologycontinuestodevelop,peoplearechangingthewaytheypayforthings.Manyofushavea
SeguenceWhichofthefollowingcontinuestheabovesequence?
Jack’splanistolose5poundsbythissummer.Hewilltrytoexercisemoreand_________eatingsweetthings.
ThefollowingnewsitemiscorrectEXCEPT___________.
【T1】人人都需要朋友,若你在交朋友方面总是失败,就该反省自己,看是否你的个性有什么问题。(if)或许你有些在社交上应该避讳的缺点,比如势力、饶舌、说脏话等,这些都会妨碍你结交新朋友。【T2】无论你有什么社交缺点,都应该正视他们,尽力摒弃。(whateve
Usethefollowingletterstoformawordandcompletethesentence.GIYRHWALTPSShakespeareisoneofthemostfamous________i
RareamongAmericanactors,DepphasmadeanameforhimselfeffortlesslyswitchingbetweenmainstreamHollywoodMoviesandmore
Theleadershippuzzlehasbeenhashedaroundfordecades.Theirabilitieshavebeencomparedtoorchestraconductorswhocan
人们因政府在毒品交易问题上所表现出的漠不关心的态度而感到担心。
Amanis48yearsold.Heaskstheothermanhowoldheis.Theothermananswers;"IamtwiceasoldasyouwerewhenIwasas
随机试题
下列影像学方法,哪个可直接显示脊髓
职业道德常常表现为某一职业特有的道德传统和道德习惯,表现为从事( )的人们道德心理和道德品质。
在国债实物券交易中,禁止欠库行为。因此,证券交易所及其登记结算机构规定,对国债现货交易和回购业务实行()的制度。
关于发行公告,下列说法中,正确的有()
2010年3月8日,某食品厂向某面粉厂购买面粉20吨,货款共计12万元。同日,食品厂向面粉厂出具了以自己为出票人、其开户行A银行为付款人、面粉厂为收款人、票面金额为12万元的见票即付的商业汇票一张,并在该汇票上签章。3月20日,面粉厂向某机械厂购买一台磨面
面对国际金融海啸的冲击,有人说:“就算今晚一片浮云遮住了星光,谁能说明天早晨不会是漫天朝霞呢!”这启示我们()。
“童言无忌”从儿童心理学的角度看是()
待命假日指一些公司要求员工在假日期间“顺便工作”或者保持通讯畅通(比如手机开机、掌上电脑或手提电脑随时联网等),以保证有紧急事务时能够随时找到人,马上投入工作。根据上述定义,下列不属于待命假日的表现的是()。
设A,B均为n阶矩阵,且AB=A+B,则下列命题中:①若A可逆,则B可逆;②若A+B可逆,则B可逆;③若B可逆,则A+B可逆;④A-E恒可逆.正确的个数为()
Filmhaspropertiesthatsetitapartfrompainting,sculpture,novels,andplays.Itisalso,initsmostpopularandpowerful
最新回复
(
0
)