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
考研
A nocturnal(夜间活动的)moth has become the first animal known to see colours in the dead of night. The moth uses this visual talent t
A nocturnal(夜间活动的)moth has become the first animal known to see colours in the dead of night. The moth uses this visual talent t
admin
2010-01-13
75
问题
A nocturnal(夜间活动的)moth has become the first animal known to see colours in the dead of night. The moth uses this visual talent to find yellow, nectar-packed flowers in the dark, but the finding suggests that other, species also use colour vision at night.
Nocturnal moths were thought to find flowers by looking for bright petals against a darker, leafy background. This difference in brightness explains why a yellow flower stands out from green leaves on a black and white photo.
To test this idea, researchers at Lund University in Sweden trained nocturnal elephant hawkmoths(豆天蛾)to pick out yellow or blue artificial flowers from eight other flowers of varying shades of grey. They then made moths perform the trick in conditions as dark as a starry but moonless night.
The researchers expected the moths to do badly, but to their surprise the insects picked the correct flower 90 per cent of the time. But the moths could not distinguish between lighter and darker shades of a coloured flower, even though they could still tell both from grey. "This tells us it’s not a brightness-related cue,” says Almut Kelber, the sensory biologist leading the Lund team. "They could only have used the spectral(光谱的)composition of the signals—which we call colour."
The moths use three separate colour receptors: blue, green and ultraviolet. At night, that leaves so little light per receptor that the insects should be almost blind. But hawkmoths have a host of adaptations to compensate. One is a mirror-like structure at the base of the eye, which reflects the light across the photoreceptors for a second time. The structure of the compound eye also allows each facet to supplement the light that strikes it with light from as many as 600 others.
Kelber suspects that many other insects, and some higher animals, also use colour vision at night. She plans to look for the ability in nocturnal frogs and toads that use colour to choose their mate. "Why not? she asks. "At night there are just as many colours as during the day."
According to the passage, which of the following statements is true?
选项
A、Moths are blind insects at daytime.
B、Moths use their color receptors only at night.
C、Moths have special structure at the base of the eye.
D、Moths can see color only at night.
答案
C
解析
在第5段中明确提到“At night,that leaves so little light per receptor that the insects should be almost blind.But hawkmoths have a host of adaptations to compensate.”在夜间,普通昆虫的感光接收器几乎不能感应到光亮,但是hawkmoths却有其他调节机制来弥补这一缺陷,所以选C。
转载请注明原文地址:https://kaotiyun.com/show/K0mi777K
0
在职申硕(同等学力)英语
相关试题推荐
A.患肢短缩、髋屈曲内收内旋畸形B.患肢短缩、髋屈曲内收外旋畸形C.患肢短缩、髋屈曲外展内旋畸形D.患肢短缩、髋屈曲外展外旋畸形E.患肢增长、髋伸直外展外旋畸形股骨颈骨折内收型可有
正常情况下,体表面积为1.73m2的成年人,其肾小球滤过率为
服务市场营销组合中除了产品(product)、价格(price)、地点或渠道(place)、促销(promotion)外,还包括()。
Formillionsofyearsbeforetheappearanceoftheelectriclight,shiftwork,all-nightcableTVandtheInternet,theEarth’s
Thearchitecturaldifferencesmay______confusionordiscomfortfortheforeigntravelers.
Experiencedbaseballfielderscantellhowfaraballisgoingtotraveljustbylisteningtothecrackofthebat.Iftheydidn
TheAmericans______GeorgeWashingtonasthefatheroftheircountry.
Successfulleaders______eventsratherthanreacttothem.
Americansnolongerexpectpublicfigures,whetherinspeechorinwriting,tocommandtheEnglishlanguagewithskillandgift.
随机试题
DNA结合区结构形式有
A、单纯疱疹B、地图舌C、伪膜型白色念珠菌病D、慢性唇炎E、白色角化病病损常变换位置
心源性哮喘最主要的临床表现是:
32岁孕妇,因前置胎盘行剖宫手术,术后即发现阴道内部有液体流出。为明确诊断。首先应采取()。
某项目的投标总价为4500万元,投标保证金不得超过()万元。
基金信息披露方面要求披露的信息应当以客观事实为基础体现了()。
3,5,10,21,(),91
地球磁场发生磁暴的周期性经常与太阳黑子的周期一致。随着太阳黑子数目的增加,磁暴的强度增大。当太阳黑子的数目减少时,磁暴的强度降低。所以,科学家推测,太阳黑子的出现可能是磁暴的原因。下列的哪一项与上面所使用的方法最为类似?
某省会市人民政府为保护当地酒类生产,决定限制外地酒类进入本市,于是制定了《关于外地酒类运输车辆管理规定》。该规定要求,一切运输外地酒类的车辆在进城前,必须向市酒类专卖局设在各路口的检查站交纳运输管理费500元,不交者将不准进城。许多外地货车司机认为这项规定
假设(SP)=0100H,(SS)=2000H,执行PUSH BP指令后,栈顶的物理地址是( )。
最新回复
(
0
)