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新编大学英语教程第四册Unit 06

时间:2011-09-21 03:52来源:互联网 提供网友:gmeng   字体: [ ]
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    (单词翻译:双击或拖选)

 The living things in an ecosystem1 affect each other in many ways. The consumers that kill other animals for food are called predators3.The word predator2 usually brings to mind pictures of lions and wolves,but such creatures as robins,frogs,and humans are also predators.Some predators,carnivores such as lions,depend entirely4 on animals they kill while many others,such as foxes and humans,eat plant food too.

 
Some people think of predators as "bad",though humans themselves are the greatest predators the world has known.Sometimes individual predators do prey5 upon farm animals,and these individuals have to be controlled.Too often,however,people try to wipe out entire populations of predators,with the mistaken idea that they are doing good.
 
People usually believe that predators have an easy time of it,killing6 defenseless prey.But studies of predators and their prey show that this isn't so .After ovserving tigers in Africa, Dr.George Schaller wrote:"The tiger's seemingly unbeatable array of weapons---its acute senses,great speed (but over short distances only),strength and size ,and formidable claws and teeth--have given many naturalists8 the impression that the tiger can kill at will...My experience shows quite the contrary--the tiger has to work quite hard for its meals...I estimate that ,for every wild prey killed,the tiger makes twenty to thirty unsuccessful attempts."
 
Another biologist made the same observation about wolves.After studying North American wolves for twelve years,Dr.L.David Mech concluded that are either young, old ,sick, weak, injured or diseased.Dr.Mech wrote:"As is true with most predators,the wolf is an opportunist...The predator takes whatever it can catch.If the wolf could capture prime ,healthy prey,it certainly would. But most of the time it cannot,It happens that all they prey species of the wolf are well equipped with superb detection, defense7, and escape systems.As long as these systems are in good working order,a prey animal is usually safe from wolf attack.
 
Predators are usually bigger and fewer in number than the animals they prey upon. The reverse is true of parasites10.These organisms live on or in other living things--their hosts,often spending an entire lifetime with them .In parasitism11 the parasite9 gets food and sometimes shelter, while the host gains nothing and may even suffer in some wya from the relationship.
 
Very few living things are free of parasites ,which are usually smaller and more numerous than their hosts. Indeed ,many parasites have parasites of their own.Jonathan Swift exaggerated only a little when he wrote:
 
So ,naturalists observe,a flea12
 
Hath smaller fleas13 than he on him prey;
 
And these have smaller stilll to bite 'em,
 
And so proceed ad infinitum.
 
Some biologists believed that most of the individual organisms now living are parasites ,since there are many parasitic14 fungi,bacteria,flatworms,insects,ticks,and mites15. Paresites are an important part of all communities, and like predators,often affect the number of other organisms in a community.Man has tried to use this ecological16 knowledge by deliberately17 bringing parasties or predators into an area where they might control the numbers of some pests. Sometimes this works well; often it does not.
 
In the 1870s ,sugar-cane18 planters in Jamaica were losing about a fifth of their crops to rats,and a planter brought mongooses from India in hopes that they would prey on the rats. Within a few years the number of rats had dropped dramatically. The rats became harder to find. Then the mongooses began eating native mammals,ground-nesting birds,snakes, lizards,land crabs,and anything else they could find .They even took to eating sugar cane. Some of the creatures they wiped out had been useful controls on insect numbers, and the insect damage to sugar cane increased. The mongooses themselbes became pest in need of control.
 
In aother instance, house sparrows were brought to the United States from England in hopes that they would help control elm spanworms in New York City's Central Park. The birds did not control the insects and habe spread across most of the nation,crowding out bluebirds and other native birds with which they compete for food and nesting sites.
 
People do learn from their mistakes,and experiences with mongooses,house sparrows, and other introduced organisms led to the passaga of strict laws controlling the importation of plants and animals to the United States. The idea o fusing parasites and predators to control pests has not been abandoned; it is just done with much greater care and advance study.This method of limiting the number of pests is called biological control, and there is hope that it will womeday eliminate the need for many of the insect posons used today.
 
The close association between parasite and host is an example of symbiosis19 which means "living together". There are a number of other examples of symbiosis in nature.In some relationships ,one organism benefits and the other is not affected20 at all.This is called commensalism . Fish called remores attach themselves to sharks. They get a free ride and eat fragments of the sharks' food . There are many other commensal relationships in the sea:practically every worm burrow,shellfish,and sponge contains animals that depend on the host for shelter or food scraps21. A biologist found 13,500animals living within shrimps22, but the total included ninteen species,among them a small fish.
 
In some symbiotic23 relationships, both organisms benefit. The most common and widespread example of this mutualism is a team of plants called lichen24. You can find lichens25 clinging to rocks and tree trunks almost anywhere. Part of the lichen is a fungus26. Within it are colonies of green algae27 cells. The fungus provides support and traps water which is used by the algae. The algae make food which is consumed by teh fuges. Thus both kinds of plant benefit.
 
The organisms that make up a lichen couldn't survive long apart. In other cases of mutualism, the two organisms may be together only part of the time. Bires called egrets often perch28 on the backs of African mammals such as rhinoceroses30. The birds feed on lice and ticks in the mammal's skin. This benefits both organisms. Also , the rhinoceros29 may be warned of danger when an egret flies in fright from ites back. But neither species is so dependent on teh other that it can't survive by itself.
 
By Laurence Pringle
 
Slaughter31 of the Elephants 
 
The planned mass slaughter of five thousand elephants in Kenya's Tsavo Game Park cannot be contemplated32 without emotion.Some hunters will refuse to shoot an elephant . It is an understandable attitude . There is something about these great beasts that fills one with fascination33 and awe34, and something akin35 to a deep respect. They are like bisitors from another world, another age. They are the most magnificent of animals. In the animal kingdom the lion is king, yet where the elephant walks the lion fears to tread. 
 
Anyone who has shot an elephant will never forget it . A professional big game hunter in Africa will tell you that the bigger the animal the more terrible seem its death throes. Ther hunter is overcome with the sheer horror of his destruction-- until hours later the hunting instinct exerts itself once more and dulls the dinder thought.
 
This is what is gong to happen in the Tsavo Game Park--five thousand times. Unfortunately there is sufficient justification36 for this massacre37 . And Kenya's is not a unique example. In Zambia the game department is busily engaged in a similar operation--the killing or "cropping" as it is called of 1,500 elephants in teh Luangwa Valley of the Eastern Province. Buffalo38 and hippo are also being thinned out and their meat sold in the butchers'shops of Lusaka and Ndola(elephant meat 1s. 9d. a pound, buffalo 2s. 3d. a pound).
 
In Zambia game officials are using spotter aircraft with air-to -ground radio to plot the position of herds39. Hunters are following up and killing the beasets with dart40 guns, using a fatal drug that kills painlessly and almost instantaneously. It is to be hoped the Kenyans will use an equally humane41 method.
 
Cropping is necessary became wild animals retreating before expanding human populations in Africa no longer have the wide open spaces to roam that they had half a century ago . They are gathering42 with greater density43 in the areas still left to them. More and more attention is being given to conservation of wild life in allocated44 game reserves but as herbs increase in these reserves the food content diminishes.
 
As the herds cannot be permitted to leave their reserves and encroach on farmland to search for food, the only solution for their survival is to limit their numbers to the grazing potential. Elephants pose the biggest problem. They are a tougher breed,live longer than most animals, and are able to adapt themselves to all climates and altitudes. They also have greater appetites and destroy the areas where they feed, pushing over trees to strip off the leaves. The average 6-ton bull elephant eats about 1,000 poungs of food (grass ,leaves, branches ,bushes) every 24 hours and needs about two square miles of grazing land. Tsavo's 8,000 square miles can comfortably accommodate only 4,ooo elephants.
 
The rhino,which competes with the elephant for choice grazing grounds, is being starved out of areas inhabited by elephants.
 
In Tsavo Game Park a year ago Poyal Navy helicopters were used to spray elephants with pink paint from the air in an operation to count their number. I t was learned that there are 15,000 elephants in the pard. That is too many. Several thousand must die.
 
The destruction of a wild beast may seem of little consequence compared with the affairs of men. Yer it has its own poignancy45.Stuart Cloete describes in his book, The Curve and the Tusk,such a scene as two elephants move towards the hunter's gun:" Like battleships, but silent as butterflies, they drifted slowly,eating their way ,resting trunks hand in hand... always silent and unhurried, always with the spoor of the tusked46 elephant in that if his tuskless brother,they came on ,drifting giants as silent as thistledown. Each step brought them nearer to death..."
 
By Peter Younghusband

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1 ecosystem Wq4xz     
n.生态系统
参考例句:
  • This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
  • We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。
2 predator 11vza     
n.捕食其它动物的动物;捕食者
参考例句:
  • The final part of this chapter was devoted to a brief summary of predator species.本章最后部分简要总结了食肉动物。
  • Komodo dragon is the largest living lizard and a fearsome predator.科摩多龙是目前存在的最大蜥蜴,它是一种令人恐惧的捕食性动物。
3 predators 48b965855934a5395e409c1112d94f63     
n.食肉动物( predator的名词复数 );奴役他人者(尤指在财务或性关系方面)
参考例句:
  • birds and their earthbound predators 鸟和地面上捕食它们的动物
  • The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》
4 entirely entirely     
ad.全部地,完整地;完全地,彻底地
参考例句:
  • The fire was entirely caused by their neglect of duty. 那场火灾完全是由于他们失职而引起的。
  • His life was entirely given up to the educational work. 他的一生统统献给了教育工作。
5 prey g1czH     
n.被掠食者,牺牲者,掠食;v.捕食,掠夺,折磨
参考例句:
  • Stronger animals prey on weaker ones.弱肉强食。
  • The lion was hunting for its prey.狮子在寻找猎物。
6 killing kpBziQ     
n.巨额利润;突然赚大钱,发大财
参考例句:
  • Investors are set to make a killing from the sell-off.投资者准备清仓以便大赚一笔。
  • Last week my brother made a killing on Wall Street.上个周我兄弟在华尔街赚了一大笔。
7 defense AxbxB     
n.防御,保卫;[pl.]防务工事;辩护,答辩
参考例句:
  • The accused has the right to defense.被告人有权获得辩护。
  • The war has impacted the area with military and defense workers.战争使那个地区挤满了军队和防御工程人员。
8 naturalists 3ab2a0887de0af0a40c2f2959e36fa2f     
n.博物学家( naturalist的名词复数 );(文学艺术的)自然主义者
参考例句:
  • Naturalists differ much in determining what characters are of generic value. 自然学者对于不同性状决定生物的属的含义上,各有各的见解。 来自辞典例句
  • This fact has led naturalists to believe that the Isthmus was formerly open. 使许多自然学者相信这个地蛱在以前原是开通的。 来自辞典例句
9 parasite U4lzN     
n.寄生虫;寄生菌;食客
参考例句:
  • The lazy man was a parasite on his family.那懒汉是家里的寄生虫。
  • I don't want to be a parasite.I must earn my own way in life.我不想做寄生虫,我要自己养活自己。
10 parasites a8076647ef34cfbbf9d3cb418df78a08     
寄生物( parasite的名词复数 ); 靠他人为生的人; 诸虫
参考例句:
  • These symptoms may be referable to virus infection rather than parasites. 这些症状也许是由病毒感染引起的,而与寄生虫无关。
  • Kangaroos harbor a vast range of parasites. 袋鼠身上有各种各样的寄生虫。
11 parasitism 322755e65739fbee19aba26b19ae07bb     
n.寄生状态,寄生病;寄生性
参考例句:
  • Gastrointestinal parasitism is characterized gastroenteritis, unthriftiness and anemia. 胃肠道寄生虫病的特征是:胃肠炎,瘦弱和贫血。 来自辞典例句
  • Many biologists think that sex, for example, is a response to parasitism. 比如说许多生物学家认为性就是对寄生病菌的一种反应。 来自互联网
12 flea dgSz3     
n.跳蚤
参考例句:
  • I'll put a flea in his ear if he bothers me once more.如果他再来打扰的话,我就要对他不客气了。
  • Hunter has an interest in prowling around a flea market.亨特对逛跳蚤市场很感兴趣。
13 fleas dac6b8c15c1e78d1bf73d8963e2e82d0     
n.跳蚤( flea的名词复数 );爱财如命;没好气地(拒绝某人的要求)
参考例句:
  • The dog has fleas. 这条狗有跳蚤。
  • Nothing must be done hastily but killing of fleas. 除非要捉跳蚤,做事不可匆忙。 来自《简明英汉词典》
14 parasitic 7Lbxx     
adj.寄生的
参考例句:
  • Will global warming mean the spread of tropical parasitic diseases?全球变暖是否意味着热带寄生虫病会蔓延呢?
  • By definition,this way of life is parasitic.从其含义来说,这是种寄生虫的生活方式。
15 mites d5df57c25d6a534a9cab886a451cde43     
n.(尤指令人怜悯的)小孩( mite的名词复数 );一点点;一文钱;螨
参考例句:
  • The only discovered animals are water bears, mites, microscopic rotifers. 能够发现的动物只有海蜘蛛、螨和微小的轮虫。 来自辞典例句
  • Mites are frequently found on eggs. 螨会经常出现在蛋上。 来自辞典例句
16 ecological IrRxX     
adj.生态的,生态学的
参考例句:
  • The region has been declared an ecological disaster zone.这个地区已经宣布为生态灾难区。
  • Each animal has its ecological niche.每种动物都有自己的生态位.
17 deliberately Gulzvq     
adv.审慎地;蓄意地;故意地
参考例句:
  • The girl gave the show away deliberately.女孩故意泄露秘密。
  • They deliberately shifted off the argument.他们故意回避这个论点。
18 cane RsNzT     
n.手杖,细长的茎,藤条;v.以杖击,以藤编制的
参考例句:
  • This sugar cane is quite a sweet and juicy.这甘蔗既甜又多汁。
  • English schoolmasters used to cane the boys as a punishment.英国小学老师过去常用教鞭打男学生作为惩罚。
19 symbiosis eqVye     
n.共生(关系),共栖
参考例句:
  • They live in a symbiosis with governments that they are financing.他们与他们服务的政府互利共存。
  • The symbiosis between social values and political structure has produced extraordinary achievement.社会价值观念和政治结构的共生现象带来了非凡的成就。
20 affected TzUzg0     
adj.不自然的,假装的
参考例句:
  • She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
  • His manners are affected.他的态度不自然。
21 scraps 737e4017931b7285cdd1fa3eb9dd77a3     
油渣
参考例句:
  • Don't litter up the floor with scraps of paper. 不要在地板上乱扔纸屑。
  • A patchwork quilt is a good way of using up scraps of material. 做杂拼花布棉被是利用零碎布料的好办法。
22 shrimps 08429aec6f0990db8c831a2a57fc760c     
n.虾,小虾( shrimp的名词复数 );矮小的人
参考例句:
  • Shrimps are a popular type of seafood. 小虾是比较普遍的一种海味。 来自《简明英汉词典》
  • I'm going to have shrimps for my tea. 傍晚的便餐我要吃点虾。 来自辞典例句
23 symbiotic FrbwR     
adj.共栖的,共生的
参考例句:
  • Racing has always had a symbiotic relationship with betting.赛马总是与赌博相挂钩。
  • Engineering completely new symbiotic relationship is obviously not an imminent possibility.筹划完全新的共生关系显然是可能性不大。
24 lichen C94zV     
n.地衣, 青苔
参考例句:
  • The stone stairway was covered with lichen.那石级长满了地衣。
  • There is carpet-like lichen all over the moist corner of the wall.潮湿的墙角上布满了地毯般的绿色苔藓。
25 lichens 8ba13422ddec8ecf73fb1d0cb20f495f     
n.地衣( lichen的名词复数 )
参考例句:
  • The only plants to be found in Antarctica are algae, mosses, and lichens. 在南极洲所发现的植物只有藻类、苔藓和地衣。 来自辞典例句
  • Litmus: Mixture of coloured organic compounds obtained from several species of lichens. 石蕊:从几种地衣类植物中获取的带色有机化合物的混合物。 来自互联网
26 fungus gzRyI     
n.真菌,真菌类植物
参考例句:
  • Mushrooms are a type of fungus.蘑菇是一种真菌。
  • This fungus can just be detected by the unaided eye.这种真菌只用肉眼就能检查出。
27 algae tK6yW     
n.水藻,海藻
参考例句:
  • Most algae live in water.多数藻类生长在水中。
  • Algae grow and spread quickly in the lake.湖中水藻滋蔓。
28 perch 5u1yp     
n.栖木,高位,杆;v.栖息,就位,位于
参考例句:
  • The bird took its perch.鸟停歇在栖木上。
  • Little birds perch themselves on the branches.小鸟儿栖歇在树枝上。
29 rhinoceros tXxxw     
n.犀牛
参考例句:
  • The rhinoceros has one horn on its nose.犀牛鼻子上有一个角。
  • The body of the rhinoceros likes a cattle and the head likes a triangle.犀牛的形体像牛,头呈三角形。
30 rhinoceroses 75b06ff1c3ad4bf5e454140a332dce7a     
n.钱,钞票( rhino的名词复数 );犀牛(=rhinoceros);犀牛( rhinoceros的名词复数 );脸皮和犀牛皮一样厚
参考例句:
  • Rhinoceroses and dragons for once will let us walk in peace. 犀牛与龙安歇,让我们能平静地行走。 来自互联网
  • Although the rhinoceroses are very heavy, they can run very fast. 犀牛虽然体型笨重,但仍能以相当快的速度行走或奔跑。 来自互联网
31 slaughter 8Tpz1     
n.屠杀,屠宰;vt.屠杀,宰杀
参考例句:
  • I couldn't stand to watch them slaughter the cattle.我不忍看他们宰牛。
  • Wholesale slaughter was carried out in the name of progress.大规模的屠杀在维护进步的名义下进行。
32 contemplated d22c67116b8d5696b30f6705862b0688     
adj. 预期的 动词contemplate的过去分词形式
参考例句:
  • The doctor contemplated the difficult operation he had to perform. 医生仔细地考虑他所要做的棘手的手术。
  • The government has contemplated reforming the entire tax system. 政府打算改革整个税收体制。
33 fascination FlHxO     
n.令人着迷的事物,魅力,迷恋
参考例句:
  • He had a deep fascination with all forms of transport.他对所有的运输工具都很着迷。
  • His letters have been a source of fascination to a wide audience.广大观众一直迷恋于他的来信。
34 awe WNqzC     
n.敬畏,惊惧;vt.使敬畏,使惊惧
参考例句:
  • The sight filled us with awe.这景色使我们大为惊叹。
  • The approaching tornado struck awe in our hearts.正在逼近的龙卷风使我们惊恐万分。
35 akin uxbz2     
adj.同族的,类似的
参考例句:
  • She painted flowers and birds pictures akin to those of earlier feminine painters.她画一些同早期女画家类似的花鸟画。
  • Listening to his life story is akin to reading a good adventure novel.听他的人生故事犹如阅读一本精彩的冒险小说。
36 justification x32xQ     
n.正当的理由;辩解的理由
参考例句:
  • There's no justification for dividing the company into smaller units. 没有理由把公司划分成小单位。
  • In the young there is a justification for this feeling. 在年轻人中有这种感觉是有理由的。
37 massacre i71zk     
n.残杀,大屠杀;v.残杀,集体屠杀
参考例句:
  • There was a terrible massacre of villagers here during the war.在战争中,这里的村民惨遭屠杀。
  • If we forget the massacre,the massacre will happen again!忘记了大屠杀,大屠杀就有可能再次发生!
38 buffalo 1Sby4     
n.(北美)野牛;(亚洲)水牛
参考例句:
  • Asian buffalo isn't as wild as that of America's. 亚洲水牛比美洲水牛温顺些。
  • The boots are made of buffalo hide. 这双靴子是由水牛皮制成的。
39 herds 0a162615f6eafc3312659a54a8cdac0f     
兽群( herd的名词复数 ); 牧群; 人群; 群众
参考例句:
  • Regularly at daybreak they drive their herds to the pasture. 每天天一亮他们就把牲畜赶到草场上去。
  • There we saw herds of cows grazing on the pasture. 我们在那里看到一群群的牛在草地上吃草。
40 dart oydxK     
v.猛冲,投掷;n.飞镖,猛冲
参考例句:
  • The child made a sudden dart across the road.那小孩突然冲过马路。
  • Markov died after being struck by a poison dart.马尔科夫身中毒镖而亡。
41 humane Uymy0     
adj.人道的,富有同情心的
参考例句:
  • Is it humane to kill animals for food?宰杀牲畜来吃合乎人道吗?
  • Their aim is for a more just and humane society.他们的目标是建立一个更加公正、博爱的社会。
42 gathering ChmxZ     
n.集会,聚会,聚集
参考例句:
  • He called on Mr. White to speak at the gathering.他请怀特先生在集会上讲话。
  • He is on the wing gathering material for his novels.他正忙于为他的小说收集资料。
43 density rOdzZ     
n.密集,密度,浓度
参考例句:
  • The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
  • The region has a very high population density.该地区的人口密度很高。
44 allocated 01868918c8cec5bc8773e98ae11a0f54     
adj. 分配的 动词allocate的过去式和过去分词
参考例句:
  • The Ford Foundation allocated millions of dollars for cancer research. 福特基金会拨款数百万美元用于癌症研究。
  • More funds will now be allocated to charitable organizations. 现在会拨更多的资金给慈善组织。
45 poignancy xOMx3     
n.辛酸事,尖锐
参考例句:
  • As she sat in church her face had a pathos and poignancy. 当她坐在教堂里时,脸上带着一种哀婉和辛辣的表情。
  • The movie, "Trains, Planes, and Automobiles" treats this with hilarity and poignancy. 电影“火车,飞机和汽车”是以欢娱和热情庆祝这个节日。
46 tusked f3c84b19850c9ea51fdc3078785c821b     
adj.有獠牙的,有长牙的
参考例句:
  • Bogy,brown eyes regarding me,panted happily,pink tongue peeking from tusked20 jaws. 博吉那双棕色眼睛看着我,高兴地喘着粗气,张开长着獠牙的嘴,吐出粉红的舌头。 来自互联网
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TAG标签:   新编大学英语
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