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
It’s a classic mystery of the deep. Why does the hammerhead shark (双髻鲨)have the bizarrely shaped head from which it gets its nam
It’s a classic mystery of the deep. Why does the hammerhead shark (双髻鲨)have the bizarrely shaped head from which it gets its nam
admin
2010-01-13
24
问题
It’s a classic mystery of the deep. Why does the hammerhead shark (双髻鲨)have the bizarrely shaped head from which it gets its name?
There have been a variety of suggested explanations. Some simply say that the sharks use their heads to "hammer" and pin down their favourite food. More plausibly, others have speculated that the wide lobes(圆形突出部分)of the hammerhead allow it to have longer electrorecep-tots, the organs that all sharks use to detect the electric fields produced by nearby prey. This might allow hammerheads to sense subtler electric fields from more distant prey than their narrow-headed cousins.
Now it turns out that the shark’s head does indeed help it find and capture prey, but not in the way that zoologists expected. Stephen Kajlura and Kim Holland of the University of Hawaii at Manoa set out to test the conventional theory by tricking young sharks into chasing phantom (虚构的)prey. Using a system of wires on the bottom of a shallow pool, they set up electric fields that mimicked those created by the bottom-dwelling shrimp and fish that form the sharks’ usual diet.
Sure enough, hungry sharks abruptly turned towards an electric field when they detected it. But when the researchers measured the distance at which this happened they found it was the same for 13 young hammerheads as it was for 12 young sandbar sharks(沙堤鲨),which have normal-shaped heads.
The two types of sharks proved equally adept at sensing the electric fields: each was able to detect the source from up to 30 centimetres away. That ruled out any improved sensitivity from the wider head. However, the hammerheads enjoy another more prosaic(平淡无奇的)advantage: their wider heads let them sweep more than twice as wide a swathe of the seafloor as they swim, which must boost their chance of encountering food.
The researchers also found that hammerheads could turn more sharply when they detected the phantom prey. "They’re a much more bendy shark , "says Kajlura, who is now at the University of California at Irvine. In part, that’s because they have more slender bodies than the sandbar sharks. However, Kajiura has other unpublished data that suggests that the hammerheads’ broad heads can act as fins to improve manoeuvrability(机动性).
So far, the researchers have only experimented with young sharks, so adult hammerheads may gain some other advantage from their head shape.
Which of the following is a feature that the hammerhead shark shares with other sharks?
选项
A、They have slender bodies.
B、They have wide lobes.
C、They use electroreceptors to detect prey.
D、They sense electric fields from far away.
答案
C
解析
具体细节题。第2段第3句话中的longer electroreceptors,the organs that all sharks use to detect the electric fields即是该题解题的信息所在。选项D似乎也对,但文中并没有说明它们可以从很遥远的地方感觉电场的存在。
转载请注明原文地址:https://kaotiyun.com/show/Qvmi777K
0
在职申硕(同等学力)英语
相关试题推荐
Lateralthinking(迂回思维),firstdescribedbyEdwarddeBonein1967,isjustafewyearsolderthanEdward’sson.Youmightimagi
Allexpertsagreethatthemostimportantconsiderationwithdietdrugsiscarefully______therisksandbenefits.
Aqualityeducationistheultimateliberator.Itcanfreepeoplefrompoverty,givingthemthepowertogreatlyimprovetheirl
Cananinventivesocietygetbolderasitgrowsolder?Thatquestionaffectspeopleofallages—especiallythoselivingintheU
Thecountryannouncedthatitwouldhaltnucleartestingthisyearandhopedthatothercountrieswouldtakethesameaction.
Iwas(sointerestedin)thevideothatI(watched)it(for)twohoursbeforeI(realized)it.
A:Wouldyoulikesomemoresoup?B:______.Itisdelicious,butI’vehadenough.
It’saclassicmysteryofthedeep.Whydoesthehammerheadshark(双髻鲨)havethebizarrelyshapedheadfromwhichitgetsitsnam
A:Mr.SmithwouldliketorescheduleFriday’sappointmenttonextWednesdayat9O’clock.B:______.
随机试题
女,48岁。间歇上腹隐痛、饱胀不适6年,体检无特殊。胃镜检查胃窦黏膜稍苍白,变薄,可透见黏膜下紫蓝色血管网。最可能的诊断是
A.柴胡疏肝散B.调营饮C.附子理中汤合五苓散D.一贯煎合猪苓汤E.胃苓汤
房屋拆迁管理部门不得作为拆迁人,但可接受拆迁委托。()
编制某工程施工图预算,套用预算定额后得到的人工、甲材料、乙材料、机械台班的消耗量分别为15工日、12m3、0.5m3、2台班,预算单价与市场单价如下表所示。措施费为直接工程费的7%。则用实物法计算的该工程的直接费为()元。
为股票发行出具审计报告、资产评估报告、法律意见书等文件的有关人员,在该股票承销期内,不得购买或者持有该股票,但在该承销期满之后,可以购买或持有该股票。()
16,17,36,111,448,()
纳粹党人,纳粹的,专横的
Whyhasthemancontactedthewoman?
KingJuanCarlosofSpainonceinsisted"kingsdon’tabdicate,theydareintheirsleep."Butembarrassingscandalsandthepop
Thereareseveralpossiblerelationshipsbetweenlanguageandsociety.Oneiswhatsocialstructuremayeitherinfluenceordete
最新回复
(
0
)