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
Animals on the Move A)It looked like a scene from "Jaws" but without the dramatic music. A huge shark was lowly swimming through
Animals on the Move A)It looked like a scene from "Jaws" but without the dramatic music. A huge shark was lowly swimming through
admin
2017-02-24
41
问题
Animals on the Move
A)It looked like a scene from "Jaws" but without the dramatic music. A huge shark was lowly swimming through the water, its tail swinging back and forth like the pendulum of a clock.
B)Suddenly sensitive nerve ending in the shark’s skin picked up vibrations of a struggling fish. The shark was immediately transformed into a deadly, efficient machine of death. With muscles taut, the shark knifed through the water at a rapid speed. In a flash the shark caught its victim, a large fish, in its powerful jaws. Then, jerking its head back and forth, the shark tore huge chunks of flesh from its victim and swallowed them. Soon the action was over.
Moving to Survive
C)In pursuing its prey, the shark demonstrated in a dramatic way the important role of movement, or locomotion, in animals.
D)Like the shark, most animals use movement to find food. They also use locomotion to escape enemies, find a mate, and explore new territories. The methods of locomotion include crawling, hopping, slithering, flying, swimming, or walking.
E)Humans have the added advantage of using their various inventions to move about in just about any kind of environment. Automobiles, rockets, and submarines transport humans from deep oceans to as far away as the moon. However, for other animals movement came about naturally through millions of years of evolution. One of the most successful examples of animal locomotion is that of the shark. Its ability to quickly zero in on its prey has always impressed scientists. But it took a detailed study by Duke University marine biologists S. A. Wainwright, F. Vosburgh, and J. H. Hebrank to find out how the sharks did it. In their study the scientists observed sharks swimming in a tank at Marine land in Saint Augustine, Fla. Movies were taken of the sharks’ movements and analyzed. Studies were also made of shark skin and muscle.
Skin Is the Key
F)The biologists discovered that the skin of the shark is the key to the animal’s high efficiency in swimming through the water. The skin contains many fibers that crisscross like the inside of a belted radial tire. The fibers are called collagen fibers. These fibers can either store or release large amounts of energy depending on whether the fibers are relaxed or taut. When the fibers are stretched, energy is stored in them the way energy is stored in the string of a bow when pulled tight. When the energy is released, the fibers become relaxed.
G)The Duke University biologists have found that the greatest stretching occurs where the shark bends its body while swimming. During the body’s back and forth motion, fibers along the outside part of the bending body stretch greatly. Much potential energy is stored in the fibers. This energy is released when the shark’ s body snaps back the other way.
H)As energy is alternately stored and released on both sides of the animal’s body, the tail whips strongly back and forth. This whip-like action propels the animal through the water like a living bullet.
Source of Energy
I)What causes the fibers to store so much energy? In finding the answer the Duke University scientists learned that the shark’s similarity to a belted radial tire doesn’t stop with the skin. Just as a radial tire is inflated by pressure, so, too, is the area just under the shark’s collagen "radials". Instead of air pressure, however, the pressure in the shark may be due to the force of the blood pressing on the collagen fibers.
J)When the shark swims slowly, the pressure on the fibers is relatively low. The fibers are more relaxed, and the shark is able to bend its body at sharp angles. The animal swims this way when looking around for food or just swimming. However, when the shark detects an important food source, some fantastic involuntary changes take place.
K)The pressure inside the animal may increase by 10 times. This pressure change greatly stretches the fibers, enabling much energy to be stored.
L)This energy is then transferred to the tail, and the shark is off. The rest of the story is predictable.
Dolphin Has Speed Record
M)Another fastmarine animal is the dolphin. This seagoing mammal has been clocked at speeds of 32 kilometers(20 miles)an hour. Biologists studying the dolphin have discovered that, like the shark, the animal’ s efficient locomotion can be traced to its skin. A dolphin’ s skin is made up in such a way that it offers very little resistance to the water flowing over it. Normally when a fish or other object moves slowly through the water, the water flows smoothly past the body. This smooth flow is known as laminar flow. However, at faster speeds the water becomes more turbulent along the moving fish. This turbulence muses friction and slows the fish down.
N)In a dolphin the skin is so flexible that it bends and yields to the waviness of the water.
O)The waves, in effect, become tucked into the skin’s folds. This allows the rest of the water to move smoothly by in a laminar flow. Where other animals would be slowed by turbulent water at rapid speeds, the dolphin can race through the water at record breaking speeds.
Other Animals Less Efficient
P)Not all animals move as efficiently as sharks and dolphins. Perhaps the greatest loser in locomotion efficiency is the slug. The slug(鼻涕虫), which looks like a snail without a shell, lays down a slimy(黏滑的)trail over which it crawls. It uses so much energy producing the slimy mucus(黏液)and crawling over it that a mouse traveling the same distance uses only one twelfth as much energy.
Q)Scientists say that because of the slug’s inefficient use of energy, its lifestyle must be restricted. That is, the animals are forced to confine themselves to small areas for obtaining food and finding proper living conditions. Have humans ever been faced with this kind of problem?
The high efficiency in swimming of sharks largely dues to its skin.
选项
答案
F
解析
信息明示题。题干:鲨鱼能够高效游泳主要是因为它的皮肤。题干关键词是high efficiency in swimming和largely dues to its skin。F段提到The biologists discovered that the skin of the shark is the key to the animal’s high efficiency in swimming through the water.与题干吻合,故选F。
转载请注明原文地址:https://kaotiyun.com/show/KVi7777K
0
大学英语四级
相关试题推荐
Aroundtheworldyoungpeoplearespending【B1】______sumsofmoneytolistentorockmusic.ForbesMagazine【B2】______thatatlea
MymotherwasborninasmalltowninnorthernItaly.ShewasthreewhenherparentsimmigratedtoAmericain1926.Theylivedi
Moreandmoreoftheworld’spopulationarelivingintownsorcities.Thespeedatwhichcitiesaregrowinginthelessdevelop
中国武术是中国传统文化的一部分。武术的创立与发展主要是为了用于自卫和生存、打猎及军事训练等需要。中华人民共和国成立以后,武术通常作为中国传统文化,在学校、专门的训练机构和协会里,以体育运动形式教授。中国武术流派众多,通常有以下三种分类的方法:南派与北派;内
Whenyoulookupatthenightsky,whatdoyousee?Thereareother【B1】______bodiesouttherebesidesthemoonandstars.Oneof
Whenyoulookupatthenightsky,whatdoyousee?Thereareother【B1】______bodiesouttherebesidesthemoonandstars.Oneof
Duringthenineteenthcentury,whenlittlewasknownaboutenvironmental-ismandconservation,itwascommontohearpeopleinE
Duringthenineteenthcentury,whenlittlewasknownaboutenvironmental-ismandconservation,itwascommontohearpeopleinE
Youcantelltheageofatreeby【B1】______itsrings,buttheserecordsofatree’slifereallysayalotmore.Scientistsare
信用卡(creditcard)在1985年引入中国。此后,信用卡的发卡量以惊人的速度增长,到2011年达到了2.85亿张。信用卡给消费者带来诸多好处。用卡付账时,持卡人不需要携带大量现金,还会经常得到一些额外的奖励。而且,持卡人还可以从发卡机构获得一定数
随机试题
分析W—G—W和G—W—G’两个流通公式,可以看出()
对药品养护时库房温、湿度的记录要求是
患者,女,28岁,停经4个月,检查子宫体大于停经月份,为鉴别正常、多胎或异常妊娠,最佳方法为()
下列风险事件中,属于人寿保险保险责任的是()。
旅游团住的饭店有蟑螂、臭虫、老鼠等,游客要求换房应如何处理?()。
目前各国都非常重视教育对经济的作用,因此提出了“教育先行”的理念。下列关于“教育先行”说法正确的是()。
1914年7月,孙中山在日本东京组建了()。
WhydomanypeoplecriticizeTVprogramsintheU.S.?
ClarionResponseprovidesrepairsandmaintenanceservicestomorethan125,000homesandispartofClarionHousingGroup,the
A、Shewashomeschooled.B、Shelearnedfrombooksathome.C、ShestudiedwiththehelpoftheInternet.D、Shelearnedfromteache
最新回复
(
0
)