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 thro
Animals on the Move A)It looked like a scene from "Jaws" but without the dramatic music. A huge shark was lowly swimming thro
admin
2018-02-08
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?
A dolphin’ s skin has very little resistance to flowing water.
选项
答案
M
解析
信息明示题。题干:海豚的皮肤对水流几乎没有阻力。题干关键词是very little resistance to flowing water。M段提到A dolphin’s skin is made up in such a way that it offers very little resistance to the water flowing over it.与题干吻合,故选M。
转载请注明原文地址:https://kaotiyun.com/show/1ra7777K
0
大学英语四级
相关试题推荐
A、HiredErictotakecareofthepets.B、HiredMargarettolookafterthehouse.C、AskedMr.Cohentotakecareofthechildren.
A、Hethinksitisuseless.B、Hewillthinkaboutitlater.C、Hethinksitmightwork.D、Hehasnoideaaboutit.C细节题。根据对话可知男士认可
A、French.B、Italian.C、Ranch.D、Germany.C侍者说,点炸鸡排送一份沙拉,并问女士用什么样的沙拉调料。女士从侍者给出的四种调料中选了Ranch,故C正确。
A、Theyenjoyloudmusic.B、Theyseldomlosetheirtemper.C、Theywanttohavechildren.D、Theyenjoymoderndances.B文中提到“我轻易不会生
A、Athleticandrecreational.B、Foodandtransportation.C、Bookstoreandpostoffice.D、Medicalandaudio-visual.B文中详细通知了interca
A、Updatingtheirinformationfrequently.B、Postinghatefulthingsregularly.C、Usingmultipleaccounts.D、Suspendingsomeofthe
A、Theeducationproblems.B、Thediscriminationproblems.C、Thepopulationproblems.D、Thedebtproblems.D
Ifyouhaveheartproblems,youmightwanttopluginthatiPodorpopinaCDofmellowsongs.Hospitalpatientswithcoronary
A、Theyaregoingtoaverycoldplace.B、Theirplanewilltakeoffinonehour.C、Thewomanisgoingtobringmorethanonecase
A、Youwillbedelighted.B、Youwillnotbeaffected.C、Youmayfeeldepressed.D、Youwillfeellonely.A短文提到,有一个真正快乐的人在身边能让你心情愉快
随机试题
(2008年4月)采用大规模流水生产组织形式的家电企业在编制生产作业计划时应采取______。
A.B内酰胺类B.氨基糖苷类C.大环内酯类D.喹诺酮类E.四环素类氨苄西林钠为
“肾为气之根”主要指
A、肝、胃、大肠经B、肝、脾、肾经C、肺、胃、膀胱经D、肺、脾、肾经E、肝、脾、膀胱经地榆的归经是()
设计概算审查通常采用()的方式。
防洪高水位至防洪限制水位之间的水库容积叫做()。
入境货物报检单所列各栏必须填写完整、准确、清晰,没有内容填写的栏目应以()表示,不得留空。
根据2010年第六次全国人口普查数据显示,东部地区中北京市常住人口为1961,24万人,上海市常住人口为2301.91万人;中部地区中河南省常住人口为9402.36万人,山西省常住人口为3571.21万人;西部地区中重庆市常住人口为2884.62万人,
Whybotherwiththestudyofhistory?Whatpossibleconnectionsexistbetweenanincreasinglyremotepastandourownpredicamen
ItisimpossibletomeasuretheimportanceofEdisonbyaddinguphisspecificinventions.Actually,hisname【B1】______morethan
最新回复
(
0
)