unit 6 predators, parasites and other relationships
TRANSCRIPT
Unit 6
Predators, Parasites and Other Relationships
Background introduction
Ecology: the study of the relationship of plants and animals to their physical and biological environment.
• The physical environment includes light and heat or solar radiation, moisture, wind, oxygen, carbon dioxide, nutrients in soil, water, and atmosphere.
• The biological environment includes organisms of the same kind as well as other plants and animals.
• The term ecology was introduced by the German biologist Ernst Heinrich Haeckel in 1866; Modern ecology, in part, began with Charles Darwin. In developing his theory of evolution, Darwin stressed the adaptation of organisms to their environment through natural selection (survival of the fittest).
Ecosystem: a system which relates all the plants, animals and people in an area to their surroundings.
• The term was coined in 1935 by the British plant ecologist Sir Arthur George Tansley.
• Major parts of an ecosystem are (1) the producers (green plants), (2) the consumers (herbivores 草食动物 and carnivores 肉食动物 ), (3) the decomposers 分解体 (fungi and bacteria), and (4) the nonliving, consisting of dead organic matter and nutrients in the soil and water.
Food Web: a set of interconnected food chains by which energy and materials circulate within an ecosystem
Components of a Food Web: Plants 'base' of the food chainHerbivores 草食动物 : feed on plants; many are adapted to l
ive on a diet high in cellulose 纤维素Omnivores 杂食动物 : feed on both plants and animals Carnivores 肉食动物 : feed on herbivores, omnivores & othe
r carnivores • 1st level carnivore - feeds on herbivores• 2nd level carnivore - feeds on 1st level carnivores Decomposers 分解体（分解已败死的原生质之有机体）• the 'final' consumer group • use energy available in dead plants and animals • transform organic material into inorganic material
the animal kingdom
• Birds ( finch 雀）• Birds of prey (vulture 秃鹰 ) • Poultry and game 家禽 (chicken) 和野兽 (tig
er)• Seabirds (seagull 海鸥 )• Primates ( 灵长类： monkey, chimpanzee)• Marsupials ( 有袋类： koala, kangaroo)• Rodents ( 啮齿类： mice, rabbits, squirrel)• Mammals ( 哺乳类： bat, cows, whales)
• ’Pachyderms ( 厚皮动物： hippo, elephant, rhino)
• Insects (bees, butterfly, flea, dragonfly 蜻蜓）• A’rachnids ( 蛛形动物： scorpion, mites,ticks)• Reptiles (snake,crocodiles, turtle ， lizard)• Am’phibians ( 两栖类： toads( 蟾蜍 , newts• ’molluscs( 软体动物： snail, octopus ( 章鱼），
slug 蛞蝓 ( 俗名鼻涕虫 , 吃蔬菜或瓜果的叶子，对农作物有害 )
• Cru’staceans:( 甲壳类： crab,lobster,shrimps)
An overview of technical terms in the text• ecology 生态学• ecosystem 生态系统• biological control 生物控制 vs. chemical control 化学控制• creature 生物• organism 有机体，生物，（尤指）微生物• colony 生物群体• predator 掠食者，捕食性动物 vs. prey 被掠食者 • carnivore 肉食动物 vs. herbivore 草食动物• parasite 寄生生物 vs. host 寄生体• mammal 哺乳动物• symbiosis 共生现象• commensalism 共栖现象• mutualism 互惠互生现象
More on p.106-107
Structure analysis Read the text in 15 minutes and outline th
e synopsis of the text. Term Definition Examples Characteristics
Para 1-4 predators
Para 5-6 parasites
Para 7-9 biological control
Para 10-12 symbiosis
commensalism
mutualism
Text comprehension• Read the text again in 10 minutes, and fill
in the blanks on p.107.
• Now read the text for the third time, and give answers to the following questions.
1. Are all predators carnivores? 2. Can predators like tigers and lions kill at will?
Why not?3. Did the U.S. and Jamaica succeed in controlling
elm spanworms and rats?4. Are scientists confident that some day biological
control could replace insecticides to kill pests?
More on the eco-system
1. predator: an animal living by killing other animals for food 掠食者，捕食性动物
• lion• wolf• robin 知更鸟• frog • fox • tiger• humans
bald eagle
2. carnivore: a flesh-eating animal 肉食动物
• lion
• wolf
• fox
• tiger
3. parasite: a creature depending on another for the necessities of life 寄生生物
• flea 蚤• louse (lice) 虱子• fungus (fungi) 真菌（如木耳）• bacterium (bacteria)• flatworm 扁形虫• insect • tick 扁虱 / 蜱虫 / 吸血寄生虫• mite 螨（状似蜘蛛的微小生物，在动植物，地毯
等上生活）• elm spanworm 榆树尺蠖
Three types of parasites:
• parasites of animals ---protozoan 原生动物 , worm parasites, and arthropod parasites such as mites, ticks, and fleas.
• parasites of humans ---Humans are subjected to numerous protozoan, worm, and insect-related parasites.
• parasites of plants ---Fungi, which cause the majority of plant diseases. The fungus that causes Dutch elm disease is often carried from tree to tree by beetles.
4. mammal: an animal which, when young, feeds on milk from its mother 哺乳动物
• mongoose
• lion
• wolf
• tiger
• fox
• rhinoceros
5. some sea or fresh-water creatures 海洋/ 淡水生物
• shellfish
• shrimp
• sponge
• algae
• remora
• shark
6. some cold-blooded animals that crawl or creep 冷血爬行动物
• lizard
• snake
7. some blood-sucking disease-carrying parasites living on people, animals and birds 吸血带菌寄生生物
• tick
• flea
• louse (lice)
8. symbiosis: living together, a state of two different living things which depend on each other for certain advantages, often with one living on the other’s body 共生现象
• symbiotic relationship: sometimes both species benefit, sometimes one species benefits at the other's expense (the other is harmed) , and in other cases one species benefits and the other is not affected.
• So there are three main types of symbiosis/ symbiotic relationship: mutualism 互惠互生现象 , parasitism 寄生现象 , and commensalism 共栖现象 .
Three examples of mutualism
Example 1:
Hummingbirds 蜂鸟 have a special relationship with certain flowering plants. The flowers provide the hummingbird with nectar 花蜜 for food. When a hummingbird dips its long bill into a flower, the bill becomes dusted with pollen 花粉 , some of which is transferred to the next flower the hummingbird visits. By transferring pollen from one flower to another, the hummingbird assists in plant reproduction.
Example 2:
Certain tropical acacia trees 金合欢树 have large hollow thorns 荆棘 on their branches, which provide homes to a certain species of ant 蚂蚁 . These ants construct their nests and raise young within the shelter of the thorns. The acacia trees secrete a special nutritive fluid on their leaves and a sweet nectar at the bases of the leaves which provide food for the ants. In return, the ants attack any leaf-eating insects which come upon the tree and sting any mammals thinking to make a meal of the acacia’s leaves. The ants also trim away any plants which grow on their host tree, especially vines 藤蔓植物 which could choke 使窒息 it. Studies done with these trees and ants showed that if the ants were experimentally removed from the trees, the trees were soon overrun/spread over with vines and plants and died.
Example 3: clown fish 小丑鱼 and sea anemones 海银莲花
Bright and colorful clown fish live in and amongst the tentacles of the sea anemone, which look like beautiful aquatic 水生的 flowers, but bear poisonous stinging cells. A slime 黏液 layer covering the clownfish make them immune to the stinging cells, and the stinging tentacles of the sea anemone deter/discourage potential predators. The clownfish in turn protect the sea anemone from other fish that would feed on the anemone. Clownfish lay eggs within the sea anemone, which offers protection during their incubation 孵卵期 and development.
Two examples of parasitism
Example 1: Sea Lamprey 八目鳗 （鱼形脊椎动物） clings to a fish
The sea lamprey, a vertebrate parasite, belongs to the most primitive group of living fish, or jawless 无颚 fish. In this species the lower jaw is missing and the upper jaw is modified into a sucking disk 吸盘 . The lamprey feeds on blood by using this disk to attach to another fish and drilling a small hole into the fish’s side with its small, muscular tongue. The parasitic action rarely kills the host, but wounds caused by lampreys often become infected.
Example 2: Parasitism does not have to be the physical draini
ng of nutrients from the host. There is also the phenomenon of “social parasitism.” One well-known social parasite is the European Cuckoo 布谷鸟 , which lays its eggs in the nests of other birds and leaves its offspring to be cared for by foster parents养父母 of a different species. The baby cuckoo has a shorter incubation 孵化 time than the foster parents’ babies and so hatches first. It then actually flips the foster parents’ eggs or babies from the nest, thus eliminating competition and gaining the full attention and nutrition from the host birds.
Three examples of commensalism
Example 1:
Epiphytes 附生植物 live attached to the bark 树皮 of a tree’s branches. From the height of the branches, they are in a better position to receive more sunlight. They do not obtain nutrition directly from the tree. Instead, they obtain nutrients and water from the dust and minerals in falling rain, from falling and decaying forest debris, ant nests, etc.
Example 2:
Birds and squirrels 松鼠 nesting in trees and shrubs can be thought of as examples of commensalism. The benefits are obvious - shelter from the elements and protection from predators. Host trees and shrubs are not affected by the presence of nests.
Example 3:
remoras 鮣
shark 鲨鱼
Vocabulary exercises
• Try to guess the rough meanings of new words and expressions in text (p.103).
• You may rely on the context of the words, or, if still in a puzzle, turn to an English-English dictionary.
Language points
1. affect, effect, influence • affect v.: to act on sb. (emotions, heal
th condition) or sth. • effect n. : (positive) result, outcome• influence v. & n.: (to exercise) power t
o affect one’s character, thinking, beliefs or actions gradually through example, fear or admiration
Blank filling:1. Don’t be _________ by bad examples.2. The _______ of Chinese medicine in treating the kind of
disease is clear.3. The person who _________ me most deeply in my
childhood was my aunt.4. The amount of fertilizer you use often ______ the size of a
crop.5. Climate has a great ________ on people’s lives. It can
________ the food they eat, the houses they build and the way in which they dress. And weather ______ the way people feel, too. A gloomy day often makes people feel low. On the other hand, a bright sunny day ______ people quite differently.
6. Einstein’s theory of relativity has great ________ on the science.
7. The war has deeply _______ people’s daily life. 8. This disease will not ______ your brain.Key: influenced, effect, influenced, affect, effect, affect, affects,
affects, influence, affected, affect
2. think of...as...: consider/regard/view/see...to be...
e.g. We think of the boy as a naughty one.
rewrite the sentence:
• They thought that the furniture was shoddy and vulgar.
• He always complained that English is too difficult to learn.
3. prey v. prey on/upon(1) take or hunt for food 捕食e.g. • Hawks 鹰 ~ on small birds.• What does a fox ~ upon?• A cat ~s on mice and birds.• Some large birds ~ on smaller birds and animals.(2) steal from; rob 偷袭；抢夺，骗钱 e.g. • Our coasts were ~ed upon by Viking pirates （维
京海盗） .• For many years gangsters ~ed on business of this
suburb.• The man ~s on old, uneducated women.
(3) (fears etc.) trouble greatly 使苦恼；折磨e.g. • His worries ~ on his mind.• Ill health has ~ed on him for years.• Feelings of guilt ~ed on his mind.• Having taken the bribe, fear of being discovered ~e
d upon him.
n. [U](1) animal, bird etc. killed and eaten by another
被捕食之动物 , 猎（获）物e.g. • Mice and birds are the prey of cats. (prey: n. v.)• The lion was hunting for its ~.• The huge bird flew off with its ~ in its claws.
(2) a person suffering from other things. 受害的人 (used with ‘a’)
bebecome a prey to — be greatly troubled by... 受…折磨， fall 成…的受害者e.g. • Don’t go out at night, or you may be a ~ to a mugger ( 行
凶抢劫者 ).• The deer fell a ~ to a lion.• Some people with disordered minds become a ~ to fears.• She fell a ~ to disease.(3) used in phrase: beast of prey: an animal that kills and eats others 肉食兽，
猛兽bird of prey: a bird that kills and eats others 猛禽
e.g. • The forest is full of beasts of ~.• An eagle is a bird of ~.
4. have an easy time of it: get what one desires without having to work hard for it; do sth. which requires little effort 日子好过；容易得到想要的东西
e.g.
• As long as the new general manager used to be our department head, we’re expecting to have an easy time of it.
• People think that the boxing champion will have an easy time of it. But beating his opponent might be very hard.
5. do sth. at will: act or do sth. as one wishes
e.g.
• Can you write in English at will?
• Shaka often killed people at will.
• Some big powers in the world bullied small nations at will in the past.
translate:
即使是父母也不能任意安排子女未来的生活。
6. estimate (1) v. to form a judgment about; calculate (the co
st, value, size etc. of sth.) 评定；估计（某物的价钱价值，大小等）
estimate sth.e.g. • It is difficult to ~ his ability.• Let’s ~ the value of the painting.estimate sth. at/as: assess sth. at e.g. • He ~d the crowd at/as ten thousand.• The firm ~d the cost of the new house at £80000.• The police ~ed the number of demonstrators at a
bout 2000.
estimate sb./sth. (+ to be)e.g. I ~ him to be 35 years old.estimate for sth. 为…进行估价；为…估计费用e.g. • We’ll ask an engineer to ~ for the repair of the building.• They asked the firm to ~ for the repair of the roof.estimate that e.g. • We ~ that it would take three months to finish the work.• I ~ that it will take 3 months to build the boat.• Father ~d that the room is five feet wide and six feet long.used in passive form: ‘it’ as the formal subjecte.g. It is ~d that 25 million school lunches are sold each day.be estimated to e.g. The project is ~d to have cost £100000.
(2) n. [C] judgment; approximate calculation (of size, cost etc) 判断，估计（价钱，大小等的）
sb’s estimate of sth.e.g. • His ~ of the length of the fish is wrong.• The teacher’s ~ of the weather is right.form/make an estimate of sth.e.g. • I don’t know enough to form an ~ of his abilities.• It is difficult to make an ~ of the cost of a big buildi
ng.give sb. an estimate of sth.e.g. Can you give me an ~ of the cost of the repair?at a rough estimate 据大致估计e.g. At a rough ~, he must have walked 20 miles.
estimation n. [U] (1) judgment; regard 判断，评价e.g. His ~ of their time of arrival was wrong.in sb’s estimation 据某人估计e.g. • In our ~, he will finish the work at five.• In my ~, it will take us 3 months.• He comes first in my ~.(2) respect 尊敬e.g. The dedicated doctor earned the ~ of his collea
gues.
estimated adj.e.g. The country’s ~d population is 10 million.
7. As is true with sb./sth. • ‘As…’ clause is a non-restrictive relative clause introduce
d by the relative pronoun ‘as’, which is used as the subject in the subordinate clause.
• The antecedent of ‘as’ is the main clause -- the wolf is an ‘opportunist.’ The whole sentence may be reworded as:
The wolf is an opportunist, which is true of most predators.another example:• As will be realized, this is perhaps the biggest problem of a
ll to overcome.
be true with = be true of (more commonly used) 是这种情况
e.g. • What you said about doctors in your lecture is also true wit
h teachers.• You have little money and it is true of me too.
8. the prey species: the kinds of animals that the wolf prey upon
species [::] (n.) (sing. and pl. are the same)(1) group having some common characteristics 有共同特
点的一群（某类人或物）e.g. • the human ~ (mankind)• The Origin of Species 《物种的起源》 ( 达尔文著 )• He is a rare ~.(2) sort 品种，尤其是某类动植物e.g. • Satire is a ~ of humour. • There are over 200 ~ of fish.• All kinds of apples belong to the same ~.• feel a species of uneasiness
9. The reverse is true of parasites. = The parasites have the opposite characteristics.
the reverse is true of sb./sth.e.g. Han Meimei studies very hard, and the reverse
is true of Li Lei.Cf. it is true with sb./sth.e.g. I like Italian cuisine very much, and it is also tr
ue with my colleagues. rewrite the sentences:• People are confined to skyscraping buildings in t
he city; those living in the countryside is just the opposite.
• Among all the flowers he likes lilies best. His wife loves lilies too.
10. exaggerate v. stretch a description beyond the truth; make st
h seem larger, bigger, better or worse than it really is 夸大
(1) vt. e.g. You always ~ the difficulties.(2) vi. e.g. If you always ~, people will not believe you.exaggeration n. overstatemente.g. • It is a story full of ~s.• There is no ~ to say that in an unfamiliar culture
one may feel like fish out of water.
11. in hopes that...
in the hope that... — hoping that
in hope that...
e.g. The little sinners sat on the morners’ benches in hopes that they could be saved.
complete the sentences:
• When I have no money, I go to my friends’ home in hope that...
• I bought some shares in the hope that...
12. benefit (1) vt. do good toe.g. • The new subway station will ~ this district.• Working together will ~ both of us.benefit from sth.e.g. • People will ~ from the new railway.• We ~s a lot from the lecture delivered by the renowned economist.(2) n. advantage, profit.e.g. • Did you get much ~ from your holiday?• The money is used for the ~ of the poor.do sth. to the benefit of sb.e.g. The government claimed that the reconstruction was done to the ~ of t
he people.beneficial adj. helpful; having good effect be beneficial to sb./sth.e.g. Fresh air and good food are ~ to our health.
13. attach v. (1) fasten or join (one thing to another) 附上，加上，
贴上，系上attach sth. to sth.e.g. • Please ~ the labels to your luggage.• The boy ~ed a rope to his dog’s neck.• She ~ed a document to the letter.• This is a hospital ~ed to the Peking Medical College.
(2) join oneself to 参加，加入attach oneself to sth.e.g. • He ~ed himself to a political party.• The boy ~ed himself to the group of climbers.• We ~ ourselves to the oral English Association.
(3) bind by love or affection 以爱或感情束缚；使深爱 （ usu. passive ）
(sb.) be/become attached to...e.g. • She is deeply ~ed to her young brother.• Naturally one is ~ed to one’s hometown.• She rejected the new position which requires lots of travel
ing, because she was very much ~ed to her home.
(4) consider to have; connect with 认为有；使与…相关联 attach great/little/no importance/significance to sth.e.g. • They ~ed significance to the president’s fireside speech.• The Domestic Security Department had received some re
ports on the terrorist attack, but they simply ~ed no significance to the threat.
attachment n.(1) [U] act of attaching or joining 附着，附属，附带e.g. • The ~ of a label to the luggage is too easy to occupy a colle
ge graduate. • The ~ of another three cabins to the train took three and an
half years. (2) [C] sth. attached to sth larger 附属物，附件• A sewing machine has various ~s. • The ~ to the contract must be signed by two witnesses.(3) [C] affection; friendship 情感，深情，友爱，依恋have an attachment to sb./sth.e.g. She has a great ~ to her sister.rewrite the sentences ( v. n.)It only took the engineer one hour to attach the engine to the tr
ain.
Key phrases• bring sth. to mind• think of sb./sth. as… • prey on/upon• wipe out• have an easy time of it• an array of • do sth. at will• make attempts• As is true with …• It happens that …• be well equipped with• be in good working order• be safe from• the reverse is true of sb./sth.
• be free of • lose A to B• in hopes/hope/the hope that • take to doing sth.• in need of • in another instance• spread across• crowd out • in nature• attach A to B• cling to • perch on • feed on • be warned of• dependent on
Exercise 1: Multiple choice
1. In the Spring Export Commodities Fair the _____of fine china attracted much attention of customers from all over the world.
A. succession
B. array
C. string
D. procession
2. I hope all the precautions against air pollution, ____suggested by the local government, will be seriously considered here.
A. whileB. sinceC. afterD. as
3. Sometimes children have trouble ____right from wrong.
A. to separateB. separatingC. for separatingD. of separating
4. The physicist has made a discovery, ____of great importance to the progress of science and technology.
A. I think which is B. that I think isC. which I think isD. which I think it is
5. Bob was completely ___by the robber’s disguise and lost his money.
A. taken awayB. taken downC. taken to D. taken in
6. Richard doesn’t think he could ever__ what is called ‘free-style’ poetry. As a matter of fact, he hated it.
A. take on
B. take over
C. take to
D. take after
Key: B, D, B, C, D, C
Exercise 2: Blank filling
1. The painting brings ____mind those sweet days.2. The pests in this building must be wiped ____.3. There is an array ____weapons in the museum.4. Very few living things are free ___ parasites.5. I took ___the film at first sight.6. The mongooses themselves became pests ___need of
control.7. The bluebirds compete ___ the sparrows ___food.8. Egrets can warn rhinoceroses ___ the danger. 9. Birds feed ___lice in the mammal’s skin.
Translation exercises1. 李先生是一位很负责任的经理，王先生刚好相反。（ the reverse is tr
ue of… ）2. 他要领导具有 3000 多人的大公司，他的日子不好过。（ have an eas
y time ） 3. 请把这个便条付在文件上。（ attach …to ）4. 去年 5 月他加入了登山队，现在他已爬了五座山。（ attach …to ）5. 据我们估计，这座桥梁可以一年后交付使用。（ estimate ）6. 所有的肉食动物都想捕食健康的猎物 , 但事实上他们所捕食的动物都
是老、弱、伤病动物。（ old, weak, injured or diseased ）7. 他从监狱逃了出来，现在整天害怕再被抓住。（ prey ）8. 我估计这幅油画的价值是 1000美元。（ estimate...at ）9. 他全心全意地做生意，因为他知道他可以从他的生意里得到很大的利益。（ benefit from... ）
10. 他对我们图书馆的藏书的估计是错误的。（ estimate ）11. 把这个零件附在这机器上花了我整整三小时。（ attach …to ）12. 把这发动机装在火车上花了工程师五小时。（ attach …to ）
Suggested key to translation exercises1. Mr. Li is a responsible manager, and the reverse is true of Mr. Wang.2. He is running a big company of more than 3000 people. He doesn’t ha
ve an easy time of it.3. Please attach this note to the document.4. Having attached himself to a mountain climbing team last May, he has
climbed five mountains up till now.5. In our estimates, this bridge will come into use in a year.6. All carnivores want to prey on healthy prey, but what they actually c
apture are those old, weak, injured or diseased.7. Fears of being caught again always prey on him since his escape from
the prison.8. I estimate this painting at $1000.9. He did his business whole-heartedly, for he knew that he could benefit
a lot from it.10. His estimate/estimation of the collection of the books in our library is
wrong.11. The attachment of the spare part to the machine took me three hours.12. It took the engineer five hours to attach the engine to the train.
Essay writing
Tourism
as A Double-edged Sword