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
47
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."
Which of the following might be the most appropriate title for this passage?
选项
A、How animals see things at night.
B、Moth—the only creature to see things at night.
C、Moths use color to see flowers at night.
D、How many colors can moths see at night.
答案
C
解析
主旨大意题。综合各段的主题句可以看出本文主要是在阐述蛾可以在夜间利用颜色看到花朵,而不是依靠亮度。
转载请注明原文地址:https://kaotiyun.com/show/ocmi777K
0
在职申硕(同等学力)英语
相关试题推荐
Anthropologyisthestudyofhumanbeingsascreaturesofsociety.Itfastensitsattentionuponthosephysicalcharacteristics
Withoutquestion,people’slivesinChinahaveimproveddramaticallyinthepasttwodecades.
TalksonclimatechangeresumedintheGermancityofBonnonJuly16tocombatglobalwarming.
Thebookshiftedheroutlookfromsocialtospiritual,foritsthemewasthatbeforeyouchangeotherpeopleyouhavetochange
Directions:Inthispartyouaretowriteacompositionofnolessthan150wordsaboutWhatDoesPressureDotoU.S.?Youshoul
Imagineaworldinwhichtherewassuddenlynoemotion--aworldinwhichhumanbeingscouldfeelnoloveorhappiness,noterror
Accordingtosociologists,thereareseveraldifferentwaysinwhichapersonmaybecomerecognizedastheleaderofasocialgr
Thefirststepinplanningamarketingstrategyforanewproductistoanalyzethebreakdownofsalesfiguresforcompetitivep
Valentine’sDayisafestivalofromanceandaffection.Theholidayisaninterestingcombinationofpagan(异教徒的)andChristian
ThomasEdison’sofficewasalwaysdisorganizedwithbooksandpapers.
随机试题
银盐法测粮食中的砷时,试样经消化处理后,加入碘化钾和酸性氯化亚锡使五价砷还原为三价砷,然后与新生态氢生成砷化氢,通过()浸泡的棉花取出硫化氢后,与银盐反应生成有色胶态物比色测定。
形成潜影的先决条件是
面积量算的内容包括()。
某新建剧场,设计容纳人数为2800人,按2min内人员疏散完毕的原则设计建筑的安全疏散,每股人流的通过能力为40人/min,该剧场每个出口的最小宽度宜为()m。
对在招股说明书中编造重大虚假内容且发行股票数额巨大、后果严重的,应处以非法募集资金金额()的罚金。
学生具有发展的可能性与()
鲨鱼一般都是肉食性的,但一些科学家称,他们在某海域发现了一种以植物作为食物重要组成部分的窄头双髻鲨鱼。 以下各项如果为真,最能支持这一发现的是:
简述班杜拉的观察学习理论。
Manyobjectsindailyusehaveclearlybeeninfluencedbyscience,buttheirformandfunction,theirdimensionsandappearance
PASSAGEFOUR
最新回复
(
0
)