首页
登录
职称英语
As every schoolboy knows, insects pollinate flowers, while birds and mammals
As every schoolboy knows, insects pollinate flowers, while birds and mammals
游客
2024-08-11
21
管理
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. [br] 【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://tihaiku.com/zcyy/3715942.html
相关试题推荐
Aseveryschoolboyknows,insectspollinateflowers,whilebirdsandmammals
Aseveryschoolboyknows,insectspollinateflowers,whilebirdsandmammals
Aseveryschoolboyknows,insectspollinateflowers,whilebirdsandmammals
Aseveryschoolboyknows,insectspollinateflowers,whilebirdsandmammals
Aseveryschoolboyknows,insectspollinateflowers,whilebirdsandmammals
Aseveryschoolboyknows,insectspollinateflowers,whilebirdsandmammals
Aseveryschoolboyknows,insectspollinateflowers,whilebirdsandmammals
Aseveryschoolboyknows,insectspollinateflowers,whilebirdsandmammals
Aseveryschoolboyknows,insectspollinateflowers,whilebirdsandmammals
Aseveryschoolboyknows,insectspollinateflowers,whilebirdsandmammals
随机试题
清朝是中国的最后一个封建王朝。它由满族人(Manchus)建立,是中国历史上第二个由非汉族人创建的统一王朝。满族人以前也被称为女真(Jurchen),他们居住在
Thepast50yearshaveseenmassiveexpansionofagriculture,withfoodprod
落锤式弯沉仪,简称FWD,由荷载发生装置与车辆牵引系统组成。()
不属于医学伦理学尊重原则的内容是A.保护病人的隐私 B.保守病人的秘密
在证券市场上选择一些具有代表性的证券(或全部证券),通过对证券的交易价格进行平均
酮体包括( )。A.乙酰乙酸、β-羟丁酸和丙酮酸 B.草酰乙酸、β-酮丁酸和
在十八大报告和十八届三中全会通过的《中共中央关于全面深化改革若干重大问题的决定》
下列投资项目经济效果评价指标中,属于动态指标的是()。A.偿债备付率 B
螺杆泵的主要特点是()。A:液体沿轴向移动 B:流量不均匀,脉动大 C:流量
对于一个施工项目而言,其成本计划的编制是一个不断深化的过程。在这过程的不同阶段形
最新回复
(
0
)