Unit 12 Mainly revision知识拓展

发布时间:2016-11-2 编辑:互联网 手机版

How to keep fish

Animals That Help People

Escape from the zoo

Giant Panda

Animals That People Change

Kindness to Animals

Most Successful Animal Alive

Animals that harm people

How People Protect Animals

How to keep fish

Animals That Help People

  People first learned about animals when they hunted them for their food and when some of the animals hunted people for their food. One of the first great steps toward civilization took place when early human beings and dogs became partners. The dog was probably the first tamed animal. Early people used dogs to help hunt the animals they used for food.

   Later, people learned to tame the animals they liked to eat. About 12,000 years ago, cattle were tamed in what is now the southern part of the Russia. In the Far East, the Tibetans domesticated the yak. In Lapland, a region in far northern Europe, the people had herds of tame reindeer. Indians who lived in South America tamed and herded the alpaca and the llama. Goats and sheep, like cattle, were first tamed because their meat was good to eat. Later, people learned to use their fur, skin, and wool to make clothing and shelters. The horse also was first tamed for its meat. People then learned to ride tame horses, and used them to carry burdens and to pull loads. The pig was domesticated about 8,000 years ago during the New Stone Age.

   The camel was tamed for riding and for pulling loads in Arabia and Babylonia. The donkey carried loads in northern Africa about 5,000 years ago. The cat was tamed by the ancient Egyptians, who used it to protect their storehouses of grain from mice and rats.

Pigeons were the first tame birds. About 5,000 years ago, people living near the Mediterranean Sea raised pigeons for food. Chickens were first raised as domesticated jungle fowl in Southeast Asia. Ducks and geese were tamed early in history. Long before Christopher Columbus came to America, Indians were raising turkeys in what is now Mexico.

  Even insects have been put to work for human beings. For hundreds of years, bees have produced honey and have helped pollinate fruit trees in many lands. Several thousand years ago, the people of China began to raise silkworms. The Chinese used the silkworms cocoons to make silk.

  Dogs, guinea pigs, and mice and other rodents are used to increase knowledge about many diseases. Doctors test new drugs on animals before giving the medicines to human beings. Animals also supply many important drugs, such as insulin, that people use to fight disease.

Escape from the zoo

  

Giant Panda

  What animal is black and white and loved all over the world? If you guessed the giant panda, you’re right! The giant panda is also known as the panda bear, bamboo bear, or in Chinese as Daxiongmao, the “large bear cat.” In fact, its scientific name means “black and white cat - footed animal.”

  Giant pandas are found only in the mountains of central China, in small isolated areas of the north and central portions of the Sichuan Province, in the mountains bordering the southernmost part of Gansu Province and in the Qinling Mountains of the Shaanxi Province.

  Ciant pandas live in dense bamboo and coniferous forests at altitudes of 5,000 to 10,000 feet. Tie mountains are shrouded in heavy clouds with torrential rains or dense mist throughout the year.

  Giant pandas have existed since the Pleistocene Era (about 600,000 years ago), when their geographic range extended throughout southern China. Fossil remains also have been found in present - day Burma.

  Giant pandas are bear - like in shape with striking black and white markings. The ears, eye patches, legs and shoulder band are black; the rest of the body is whitish. They have thick, woolly coats to insulate them from the cold. Adults are four to six feet long and may weigh up to 350 pounds, about the same size as the American black bear. However, unlike the black bear, giant pandas do not hibernate and cannot walk on their hind legs.

  The giant panda has unique front paws, one of the wrist bones is enlarged and elongated and is used like a thumb, enabling the giant panda to grasp stalks of bamboo. They also have very powerful jaws and teeth to crush bamboo. While bamboo stalks and roots make up about 95 percent of its diet, the giant panda also feeds on gentians, irises, crocuses, fish, and occasionally small rodents. It must eat 20 to 40 pounds of food each day to survive, and spends ten to sixteen hours a day feeding.

  The giant panda reaches breeding maturity between four and ten years of age. Mating usually takes place in the spring, and three to five months later, one or two cubs weighing three to five ounces each is born in a sheltered den. Usually only one cub survives. The eyes open at one to two months and the cub becomes mobile at approximately three months of age. At twelve months the cub becomes totally independent. While their average life span in the wild is about fifteen years, giant pandas in captivity have been known to live well into their twenties.

  Scientists have debated for more than a century whether giant pandas belong to the bear family, the raccoon family or a separate family of their own. This is because the giant panda and its cousin, the lesser or red panda, share many characteristics with both bears and raccoons. Recent DNA analysis indicates that giant pandas are more closely related to bears and red pandas are more closely related to raccoons. Accordingly, giant pandas are categorized in the bear family while red pandas are categorized in die raccoon family.

  In 1869, a French missionary and naturalist named Pere Armand David was the first European to describe the giant panda. In 1936, clothing designer Ruth Harkness brought the first live giant panda, named Su - Lin, out of China and to the West. Su - Lin lived at Chicago’s Brookfield Zoo and was a celebrity until he died in 1938. Today, 124 giant pandas are found in Chinese zoos. Only about 20 giant pandas live in zoos outside of China. In 1980, the first giant panda birth outside China occurred at the Mexico City Zoo.

  Until recently, Washington, D.C.’s National Zoo housed Ling- Ling and Hsing- Hsing, perhaps the most well - known giant pandas in North America. A gift from the People’s Republic of China to the people of the United States, they were presented as a gesture of amity and goodwill to President Richard Nixon when he visited China in 1972. Ling- Ling, at age 23, died in December 1992.

  This fact sheet comes courtesy of the United States Fish and Wildlife Service.

Animals That People Change

  People have changed the animal kingdom in several ways. Some kinds of animals have disappeared because people killed so many of them. Other kinds are disappearing because people have taken away their living places. Biological scientists also have developed types of animals that once did not even exist.

  Prehistoric people hunted mammoths and cave bears until so many were killed that they died out. Later, people killed the aurochs, wild oxen that once roamed Europe. In North America, people almost killed off the bison, a shaggy animal that is usually called the buffalo. Buffaloes now live on private ranches and in national parks.

  Many kinds of animals have become rare because people use their former living places for their cities and farms. Such animals include the antelope, elephant, rhinoceros, and zebra.People change many tame animals by breeding them for desirable characteristics. A person carefully picks animals to become parents, so that they will produce offspring that have a certain useful feature. Some types of chickens, for example, have tastier meat than others because of breeding. Other types of chickens lay more eggs. Breeding goats and rabbits results in types of animals with better fur for clothing.

  People also breed many types of pets and working animals for various purposes. Dachshunds were developed to fight badgers, which live in narrow underground tunnels. Sheepdogs were bred from dogs that had great skill in herding sheep. Some cattle are bred to give more milk or more meat than others. Most types of horses are bred for special purposes. Some serve as work animals, and others are used only as race horses.

Kindness to Animals

   It is man’s nature to live together in families and tribes, and cities and nations, and therefore men have learned to prize(珍惜)those qualities in each other which make social life happiest and best.Of these qualities one of the most important is sympathy(同情)-fellow feeling.If a man had no fellow-feeling, we should call him“ inhumane(无人性的)”; he would be no true man.We think so much of this quality that we call a kind man“ humane”-that is, man-like in his conduct, first to other men, and afterwards to all living things.

  If you are cruel to animals, you are not likely to be kind and thoughtful to men; and if you are thoughtful towards men, you are not likely to be cruel and thoughtless towards animals.This is why the wise man of old wrote, “The merciful(仁慈的) man is merciful to his beast.”

What a pleasure it is also to be loved by our pets or domestic animals(家畜);and to feel that we are caring for them and are deserving of their love; or to watch the ways of wild creatures, and gradually to make friends with them!

  Treating animals kindly does not mean that we must never inflict(施加) any pain on them.We ourselves are trained by pains as well as by pleasures; so, too, punishment is sometimes needed to train our dogs and horses to obey us.We endure pain at the hands of the surgeon, to cure some wound or to heal some disease; so, too, animals must submit(承受) to be doctored.

  We send out our bravest men to face wounds, sickness, and death, for the good of the nation; so, too, we let our horses share the risk of battle.For similar reasons, we cannot hesitate to destroy dangerous creatures like wolves and tigers and poisonous snakes; but to destroy them cruelly only shows senseless ferocity(残忍).It is no excuse to say that these animals deserve to be treated cruelly on account of their own cruelty; they are not really cruel, for they tear and kill not from love of unkindness, but because they must do so in order to live.

Most Successful Animal Alive

   Which is the most successful animal alive today? Is it the lion, yawning(打着呵欠的)and stretching in the midday African sun, or is it some insect in millions, deep in the Amazon rainforest? A good case could be made for humans themselves, of course. But the animal that seems to have made the most of its limited opportunities is the domestic (家养的) sleep, closely followed by the horse, the pig, the cow, the dog, and all the other domesticated creatures.

These animals have hitch-hiked(得免费搭车的机会) a ride with humans on the fast track to development. They have escaped the pressures which would have wiped some of them out and increased their share of the total living matter on earth. In 1860, humans and domesticated animals represented about five percent of all plant and animal life, while today they are about twenty percent, according to biologist Raymond Coppinger of Hampshire College, Massachusetts. “The domestic animals, the dependent animals, the ones that have made themselves fit in with the existence of humans, they are the success stories in the history of animal development,” he says.

This is certain to cause an argument because it denies a central claim(要求)of the animal rights movement. Among those who argue that animals should have the same rights as humans, domestication means humans profiting (得益)from animals; as they see it, humans have simply used animals for their own selfish purposes, using increasingly cruel methods.The idea that domestication (驯化), instead of serving a human purpose, has actually helped animals to survive and develop is revolutionary and will probably make the animal rights movement even angrier. Yet there is evidence to support it.

  But if, as it seems, it was animals that took the first step in the process of domestication, agreeing to live with humans on a voluntary(自愿的) basis. What exactly did they get from it? Biologists argue that the driving force in all animals is the desire to ensure that they and their future generations survive, and if this is right then it is clear where the benefits to animals lay. Wild sheep today have been almost wiped out, wild cows have been wiped out and wild horses would very likely have been wiped out if it were not for domestication.

Animals that harm people

  People have killed off most of the animals that once hunted them. Most wild animals will attack a person only if they cannot run away, or to defend their young.

  A few animals, including lions and tigers, do hunt human beings. Generally, these animals have been injured by hunters, or have grown too old to hunt their usually prey. Or they may simply eat human flesh as part of a normal varied diet. Crocodiles and sharks will seize any meat they can get when they are hungry. Poisonous snakes cause death to people in many parts of the world.

  Certain insects, worms, and other small animals, called parasites, are people's greatest animal enemies. A parasite feeds and lives on or inside other animals or plants. Parasites include bloodsucking insects, such as some mosquitoes and the tsetse fly. Some diseases that are carried by parasites may cause death. Such mosquitoes carry malaria, yellow fever, and other diseases. The tsetse fly carries sleeping sickness, which kills many people. The tsetse fly also carries nag Ana, a disease that is fatal among cattle and horses. Fleas and lice spread such diseases as plague and typhus.

  Parasites small enough to enter the human body cause many diseases. More than a hundred kinds of disease-causing worms can live in human beings, including blood flukes, liver flukes, hookworms, tapeworms, and trichina worms. These worms typically consist of only a few layers

How People Protect Animals

   All the animals that the world will ever have must come from the animals that exist today. Certain species of animals are in danger of becoming extinct. Some of these endangered species have almost been wiped out by too much hunting or fishing. Others no longer have enough space in which to find food or mates.

  To protect animals many nations have set aside areas called wildlife preserves where laws forbid hunting. Elsewhere, laws keep sport and commercial hunters and fishers from killing too many animals.

  The protection of animals plays an important part in preserving the balance of nature. And by protecting animals, people help themselves. For example, as long as coyotes can find mice and jack rabbits to eat, they are unlikely to attack people's herds of sheep. But suppose people kill off the jack rabbits to feed the fur-producing minks on mink farms. The coyotes then may still be hungry after eating all the mice they can find and will probably attack people's sheep.