Animal s on the Move
A) It looked like a scenefrom“Jaws”butwithou t the dramat ic music. A huge sharkwas slowly swimmi ng throug h the water, its tail swingi ng back and forthlike the pendul u m of a clock. Sudden ly sensit ive nerveending in the shark‟sskinpicked up vibrat ionsof a strugg lingfish. The sharkwas immedi ately transf ormed into a deadly, effici ent machin e of death. With muscle s taut, the sharkknifed throug h the waterat a rapidspeed. In a fl ashthe sharkcaught its victim, a largefish, in its powerf ul jaws. Then, jerkin g its head b ack and forth, the sharktore huge chunks of fleshfrom its victim and swallo wed them. S oon the action was over.
Moving to Surviv e
B) In pursui ng its prey, the sharkdemons trate d in a dramat ic way the import ant role of moveme nt, or locomo tion, in animal s.Like the shark, most animal s use moveme nt to f ind food.They also use locomo tionto escape enemie s, find a mate, and explor e new territories. The method s of locomo tioninclud e crawli ng, hoppin g, slithe ring, flying, swimmi n g, or walkin g.Humans have the addedadvant age of usingtheirvariou s invent ionsto mov e aboutin just aboutany kind of enviro nment. Automo biles, rocket s, and submar inestra nsp ort humans from deep oceans to as far away as the m
oon.Howeve r, for otheranimal s moveme nt came aboutnatura lly throug h millio ns of yearsof evolut ion. One of the most succes sfulexampl es of animal locomo tionis that of the shark. Its abilit y to quickl y zero i n on its prey has always impres sed scient ists. But it took a detail ed studyby Duke Univer sitymarine biolog istsS. A. Wainwr ight, F. Vosbur gh, and J. H. Hebran k to find out how t he sharks did it. In theirstudythe scient istsobserv ed sharks swimmi ng in a tank at Mari ne land in SaintAugust ine, Fla. Movies were takenof the sharks‟moveme nts and analyz e d. Studie s were also made of sharkskin and muscle.
Skin Is the Key
C) The biolog istsdiscov eredthat the skin of the sharkis the key to the animal‟shigh effici encyin swimmi ng throug h the water. The skin contai ns many fibers that crissc rossl ike the inside of a belted radial tire. The fibers are called collag en fibers. Thesefibers can either storeor releas e largeamount s of energy depend ing on whethe r the fibers are rel axe d or taut. When the fibers are stretc hed, energy is stored in them the way energy is s tored in the string of a bow when pulled tight. When the energy is releas ed, the fibers be come relaxe d.
D) The Duke Univer sitybiolog istshave foundthat the greate st stretc hingoccurs wh erethe sharkbends
its body whileswimmi ng. Duringthebody‟sbackandforthmotion, f ibers alongthe outsid e part of the bendin g body stretc h greatl y. Much potent ial energy is stored in the fibers. This energy is releas ed when the shark‟sbodysnapsback the otherway.
As energy is altern ately stored and releas ed on both sidesof the animal‟sbody, the t ail whipsstrong ly back and forth. This whip-like action propel s the animal throug h the w aterlike a living bullet.
Source of Energy
E) What causes the fibers to storeso much energy? In findin g the answer the Duke Univer sityscient istslearne d that the shark‟ssimila rityto a belted radial tire doesn‟tstopwith the skin. Just as a radial tire is inflat ed by pressu re, so, too, is the area just undert he shark‟scollag en“radial s”. Instea d of air pressu re, howeve r, the pressu re in the sharkmay be due to the forceof the bloodpressi ng on the collag en fibers.
F) When the sharkswimsslowly, the pressu re on the fibers is relati velylow. The fibe rs are more relaxe d, and the sharkis able to bend its body at sharpangles. The animal s wimsthis way when lookin g around for food or just swimmi ng. Howeve r, when the shark detect s an import ant food source, some fantas tic involu ntary change s take place. The pr essu re inside the animal may increa se by 10 times.
This pressu re change greatl y stretc he s the fibers, enabli ng much energy to be stored. This energy is then transf erred to the tai l, and the sharkis off. The rest of the storyis predic table.
Dolphi n Has SpeedRecord
G) Anothe r fast marine animal is the dolphi n. This seagoi ng mammal has been clocked at speeds of 32 kilome ters(20 miles) an hour. Biolog istsstudyi ng the dolphi n have dis cov eredthat, like the shark, the animal‟seffici ent locomo tioncan be traced to its skin. A dolphi n‟sskinismadeupinsuchawaythatitoffers very little resist anceto the waterflo win g over it. Normal ly when a fish or otherobject movesslowly throug h the water, the w aterflowssmooth ly past the body. This smooth flow is knownas lamina r flow. Howeve r, at faster speeds the waterbecome s more turbul ent alongthe moving fish. This turbul enc emusesfricti on and slowsthe fish down.
H) In a dolphi n the skin is so flexib le that it bendsand yields to the wavine ss of the water. The waves, in effect, become tuckedintotheskin‟sfolds. This allows the rest of t he waterto move smooth ly by in a lamina r flow. Whereotheranimal s wouldbe slowed b y turbul ent waterat rapidspeeds, the dolphi n can race throug h the waterat record brea ki ng speeds.
OtherAnimal s Less Effici ent
I) Not all animal s move as effici ently as sharks and dolphi ns. Perhap s the greate st lo serin locomo tioneffici encyis the slug. The slug, whichlookslike a snailwithou t a shell, l ays down a slimytrailover whichit crawls. It uses so much energy produc ing the slimymucusand crawli ng over it that a mousetravel ing the same distan ce uses only one twelfth as much energy. Scient istssay that becaus eoftheslug‟sineffi cient use of energy, its l ifest yle must be restri cted. That is, the animal s are forced to confin e themse lvesto small areasfor obtain ing food and findin g proper living condit ions. Have humans ever been fa cedwith this kind of proble m?
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1
1.Accord ing to the passag e, a sharkcan use moveme nt to find food, to avoidbeingcha
sed by its enemie s, and to find a new placeto live.
选择答案：ABCDEF G H I
2.p les of automo biles, rocket s and submar inesare used to show that humaninve nt ionsenable us to travel in almost any kind of enviro nment.
选择答案：ABCDEFGHIJ
3. The skin is the key to the shark‟sswiftlocomo tionin water.
英语四级阅读分值
选择答案：ABCDEF G H I
44(4)cordin g to the Duke Univer sityscient ists, when bendin g its body in swimmi ng, the sharkstretc h its collag en fibers to the greate st extent
选择答案：ABCDEF G H I
5. Becaus e it is also inflat ed by pressu re, the area just underthe shark‟scollag en fibers simila r to a belted radial tire.
选择答案：ABCDEF G H
6. 6A lamina r flow is formed when a fish swimsslowly throug h the water.
选择答案：ABCDEFGH77
77Consuming the equalamount of energy as a slug does, a mousecan travel 12 timesas long as a slug.
选择答案：ABCDEF G H I
8.A sharkfindsits prey by feelin g the vibrat ionsof a strugg lingprey.
选择答案：ABCDEF G H I
9.r dingto the passag e, collag en fibers can be compar ed to the string of
a bow for both of them storeenergy when stretc hed.
选择答案：ABCDEF G H I
10.When the sharkdetect s an import ant food source, some fantas tic involu ntary change s take place.
选择答案：ABCDEF G H I
7[正确答案]B
[您的答案]
本题分值：2.5分您的得分：0分
试题解析:
可以将答案定位在小标题“Moving to Surviv e”下第二段的前两句话，“Liketheshark, most animal s use moveme nt to find food. They also use locomo tionto escape enemie s, find a mate, and explor e now territ ories”。
+我要茬+加入错题+收藏该题评论此题p les of automo biles, rocket s and submar inesare used to show that humaninvent i onsenable us to travel in almost any kind of enviro nment.
[正确答案]B
[您的答案]I
本题分值：2.5分您的得分：0分
试题解析:
题干考查汽车、火箭和潜艇的例子是为了说明可以使人类到达任何环境，其中的“exampl es of automo biles, rocket s and submar ines”是关键词，可以将答案定位在文章小标题“Moving to Surviv e”下这句话，“Humans have the addedadvant age of usingtheirvariou s
invent ionsto move aboutin just aboutany kind of enviro nment. Automo biles, rocket s, and submar inestransp ort humans from deep oceanstoasfarawayasthemoon”。
+我要茬+加入错题+收藏该题评论此题3The skin is the key to the shark‟sswiftlocomo tionin water.
[正确答案]C
[您的答案]I
本题分值：2.5分您的得分：0分
试题解析:
本题考查鲨鱼在水中快速游动的关键是在皮肤。其中的“key”是关键词，可以将答案定位在小标题“SkinIstheKey”下首段的第一句话，“Thebiolog istsdiscov eredthat the skin of the sharkis the key to the animal‟shigheffici encyin swimmi ng throug h the water”，与本题句子完全一致，所以直接选择C即可。
+我要茬+加入错题+收藏该题评论此题r dingto the Duke Univer sityscient ists, when bendin g its body in swimmi ng, the sh arkstretc h its collag en fibers to the greate st extent
[正确答案]D
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