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
"How the zebra got his stripes" sounds like the title of one of Rudyard Kipling’s "Just So" stories. Sadly, it isn’t, so the que
"How the zebra got his stripes" sounds like the title of one of Rudyard Kipling’s "Just So" stories. Sadly, it isn’t, so the que
admin
2012-12-01
258
问题
"How the zebra got his stripes" sounds like the title of one of Rudyard Kipling’s "Just So" stories. Sadly, it isn’t, so the question has, instead, been left to zoologists. But they, too, have let their imaginations rip. Some have suggested camouflage. Others suggest they are a way to display an individual’s fitness. Irregular stripes would let potential mates know that someone was not up to snuff. One researcher proposed that stripes are to zebra what faces are to people, allowing them to recognise each other, since every animal has a unique stripe-print. Another even speculated that predators might get dizzy watching a herd of stripes gallop by. There is, however, one other idea: that stripes are a sophisticated form of fly repellent. It was originally dreamed up in the 1980s, but never proved. Now, a team of investigators led by Gabor Horvath of Eotvos University in Budapest report in the Journal of Experimental Biology that they think they have done so.
The original suggestion was that stripes repel tsetse flies. These insects carry sleeping sickness, which is as much a bane of ungulates as it is of people. But tsetses are not the only dipteran foes of zebra and, since they are rarely found in the meadows of Hungary, Dr Horvath plumped for studying an almost equally obnoxious alternative: the horsefly. Horseflies, too, transmit disease. They also bite incessantly, thus keeping grazing beasts from their dinner. Indeed, previous research has shown that fly attacks on horses and cattle reduce their body fat and milk production. Such research has also shown something odd: horseflies attack black horses in preference to white ones. That fact got Dr Horvath wondering how they would react to a striped horse—in other words, a zebra.
Actual zebra are hard to experiment on. They insist on moving around and swishing their tails. The team therefore conducted their study using inanimate objects. Some were painted uniformly dark or uniformly light, and some had stripes of various widths. Some were plastic trays filled with salad oil. Some were glue-covered boards. And some were actual models of zebra. They put these objects in a field infested with horseflies and counted the number of insects they trapped.
Their first discovery was that stripes attracted fewer flies than solid, uniform colours. As intriguingly, though, they also found that the least attractive pattern of stripes was precisely those of the sort of width found on zebra hides. Zebra stripes do, therefore, seem to repel horseflies. Exactly why is unclear. But Dr Horvath thinks it might be related to a horsefly’s ability to see polarised light, which imposes a sense of horizontal and vertical on an image. Horseflies are known to prefer horizontal polarised light. Possibly, the mostly vertical stripes on a zebra confuse the fly’s tiny brain and thus stop it seeing the animal.
Another obvious question, though, is why other species have not evolved this elegant form of fly repellent, and what the consequences would have been if they had. If humans, for example, were black-and-white striped then the history of intercommunal violence the species has suffered when different races have met might not have been quite as bad. One for Kipling to have pondered, perhaps?
Which of the following adjectives best describes the author’s attitude of the topic?
选项
A、Positive.
B、Negative.
C、Ambivalent.
D、Objective.
答案
D
解析
推断题。文中一直以叙述各种实验为主,作者很少发表自己的观点,因此其态度因为客观性的。
转载请注明原文地址:https://kaotiyun.com/show/phaO777K
0
专业英语八级
相关试题推荐
ThetasteoftheEnglishinthecultivationofland,andinwhatiscalledlandscapegardening,isunrivalled.Theyhavestudied
AboutWetlandsintheU.S.A.Peopleenjoyafamoussoup(SHE-CRABSOUP)inNorthCarolinabecausethedaysoftheregionalsoup
Undoubtedly,ourworldhaschangedalotwiththedevelopmentofscienceandtechnology.Somepeoplethinkthattechnologyhasm
A、discusshowtopromoteinternationaleconomicgrowthB、setpolicydirectionforInternationalMonetaryFundC、talkabouthowt
Withregardtoitssize,Australiais______countryintheworld.
Forme,scientificknowledgeisdividedintomathematicalsciences,naturalsciencesdealingwiththenaturalworld(physicalan
Concernwithmoney,andthenmoremoney,inordertobuytheconveniencesandluxuriesofmodernlife,hasbroughtgreatchanges
AlthoughChopinlaterattendedtheLyceumwherehisfathertaught,hisearlytrainingbeganathome.Thisincludedreceivingpia
Duringthetraditionalweddingceremony,thebridalcouplepromiseseachotherlifelongdevotion.Yet,aboutoneoutoffour【M1】
Telecom:TheMergerIstheMessageLastyearendedwithabangintelecom.Duringthefinalthreemonths,Cingularclosedits
随机试题
公安工作的对象决定了公安工作具有打击与保护的双重特点。()
枳实消痞丸的功用为
宜用五加皮治疗的病症是
《宪法重大信条十九条》
对于钢筋混凝土房屋.当必须设置防震缝时,其宽度应根据哪些因素确定?Ⅰ.结构类别;Ⅱ.房屋高度;Ⅲ.设防烈度;Ⅳ.场地类别
下列关于人类性别决定与伴性遗传的叙述,正确的是()
ForthepeoplewhohavenevertraveledacrosstheAtlanticthevoyageisafantasy.Butforthepeoplewhocrossitfrequentlyo
请在【答题】菜单下选择【进入考生文件夹】命令,并按照题目要求完成下面的操作。注意:以下的文件必须都保存在考生文件夹下。小赵是一名参加工作不久的大学生。他习惯使用Excel表格来记录每月的个人开支情况,在2013年底,小赵将每个月各类支出
71.Therewasabigpileofbricksonthetopofatallbuildingandamanhadtobringthemdowntotheground.Hehadalongr
1 Peoplehavebeenpaintingpicturesforatleast30,000years.Theearliestpictureswerepaintedbypeoplewhohuntedanimals
最新回复
(
0
)