Unit 12 Biodiversity
Part A
Pre-listening Task
Questions for Discussion
1.Do you know anything about biological diversity or biodiversity?
2.Where can we enjoy the beauty of biodiversity?
3.Is biodiversity important? Why?
4.What is meant by “endangered species”? Can you name some species that are endangered?
5.What are the main causes that lead some animals and plants to decline in number or even
disappear completely?
6.What can we do to save species from extinction?
Demo:
1. Do you know anything about biological diversity or biodiversity?
The term “biodiversity”comes from “biological diversity”. It is the variation of life forms within a given ecosystem on the entire Earth. Biodiversity is often used as a measure of the health of biological systems. The biodiversity found on Earth today consists of many millions of distinct biological species. The year 2010 has been declared as the International Year of Biodiversity. Today there is concern that the period since the emergence of humans is part of a mass reduction in biodiversity, caused primarily by the impact humans are having on the environment, particularly the destruction of plant and animal habitats.
Additional Question for Discussion
A famous conservationist once said, “Animal conservation is a war to save the human race from committing suicide.” Do you agree?
Demo:
Y es, I do. As members of the earth’s ecosystem, animals play a major part in maintaining the balanc
e and harmony of the earth’s environment. To a great extent, the human race and other animals rely on one another for survival. The extinction of one species would eventually lead to the extinction of another. If human beings did not protect animals, their own survival would soon be endangered. Therefore, a wise policy for the human race is “live and let live”.
Language Focus
Here are some sentences and structures that you may find useful in discussing the above questions.
●Biodiversity refers to the diversity of living things on Earth and the environments in which
they live.
●Biodiversity is everywhere around us.
●We can enjoy the beauty of biodiversity when we are close to nature.
●Different species of flowers, trees, birds, animals show us the rich diversity of the living
world.
●All species that share the same natural environment depend on / interact with each other.
●All species require a small / minimal amount of habitat for survival.
●Biodiversity is important because all the species that share the same environment, or habitat,
rely on one another for survival.
●Every species, no matter how small, has an important role to play.
●It is this combination that enables the ecosystem to prevent and recover from a variety of
disasters.
●Biodiversity is obviously useful for mankind as a larger number of plant species means a
greater variety of crops.
● A larger number of animal species ensure that the ecosystem is naturally sustained.
●At least 40 per cent of the world’s economy and 80 per cent of the needs of the poor are
derived from biological resources.
星光大道李佳丹●The richer the diversity of life, the greater the opportunity for medical discoveries, economic
development, and adaptive responses to such new challenges as climate change.
●Many species are endangered / threatened. Among these are the panda, the tiger, the sea turtle,
the blue whale, the gray wolf, and the bald eagle.
●Human activities and pollution are important causes of the extinction of species.
●Governments / International organizations / Industries / Individuals should make great efforts
to save endangered species / preserve biodiversity.
●The protection of endangered species and habitats should be a top priority.
●We must find solutions that benefit both humans and non-human species.
Part B
Listening Tasks
Passage 1
Why Is Biodiversity Important?
Word Bank
biodiversity n. variety of living things 生物多样性
philosophical a. of or related to philosophy 哲学的
spiritual a. of the spirit, rather than the body 精神的；心灵的
ecosystem n. all the plants and animals that live in a particular area and the complex床边故事
relationship that exists between them and their environment 生态系统species n. a class of animals or plants whose members are so similar that they can
organism n. a living thing 生物；有机体
regulate v. to control控制；制约
recycle v. to convert (waste) to reusable material 回收利用
pest n. an insect or other animal that harms food supplies or crops 害虫；有害动物（如老鼠等）
raw a. not yet treated for use 未加工过的
medicinal a. of healing 医疗的
Script:pork face
The importance of biodiversity seems obvious to us. We enjoy the beauty of biodiversity when we take a walk in the park, take a trip to the zoo or a wild area, read books or watch TV shows about strange creatures in foreign lands. Some people believe that biodiversity is important simply because it is so wonderful. Some think there are philosophical or spiritual reasons for biodiversity. But there are other reasons why it is so important.
The loss of biodiversity will change the balance of life on Earth. If an ecosystem is destroyed, many species adapted to that ecosystem may very likely be destroyed as well. If that species is what scien
tists call “keystone”, a whole ecosystem may depend on it. Biodiversity is also important in its direct benefits to people. Plants give us the air we breathe; animals and plants supply us with the food we eat; and organisms and microorganisms clean the air, regulate floods, recycle waste, and control pests.
Biodiversity also has economic and health benefits. Both industry and agriculture depend on it for raw material and other things. And medicine is even more dependent on biodiversity. In China, more than 5,000 species of plants are used for medicinal purposes. Many species which were thought “useless” at first are found to be valuable. And this is a further threat from the loss of biodiversity.
Language and Culture Notes
1. Background information
Biodiversity, or biological diversity, refers to the sum total of the different species of animals, plants, and organisms living on Earth and the variety of habitats in which they live. This very broad term is essentially a synonym of “life on Earth”. Scientists estimate that more than 10 million species exist on our planet, but so far only 1.75 million species have been discovered and named. And only a very small number of those have been examined for their value in medicine, agriculture, or industry. In the
meantime, we are losing much of Earth’s biodiversity. Most biologists agree that we are facing the most serious extinction of species since the disappearance of dinosaurs 65 million years ago.
2. loss of biodiversity
The loss of biological diversity may take many forms but at its most fundamental and irreversible it involves the extinction of species. At present species are disappearing at an alarming rate. According to the estimate of the American biologist Edward O. Wilson, we are losing 27,000 species every year. His estimate is accepted by most biologists. Human activities are largely blamed for this. However, as more and more people realize the importance of biodiversity, positive steps have been taken to protect endangered species and to preserve biodiversity. In 1992, at the Convention on Biological Diversity, held in Rio de Janeiro, an agreement was reached by 160 countries, which called on governments to take action to protect plant and animal species.
Exercise 1
Listen to the recording and decide whether the following statements are true or false. If a statement is true, write T in the brackets. If it is false, write F in the brackets and the correct version in the blank.
1. You can see biodiversity in the park. (T)
2. You cannot enjoy the beauty of biodiversity in a foreign country if you don’t go there. (F)
You can enjoy it through reading books and watching TV shows about foreign lands.
3. Biodiversity is a term used to refer to the variety of living things in the world. (T)
4. Scientists think that the importance of biodiversity lies in its presenting us with a wonderful world to enjoy. (F)
Some people think so, but scientists believe that biodiversity is important to us because it is essential to our survival.
5. The loss of a keystone species may destroy some of the living creatures in the natural world. (F) It may destroy an entire ecosystem.
6. In China, over 7,000 species of plants are used for medicinal purposes. (F)
More than 5,000 species of plants are used for medicinal purposes in China.
Exercise 2
Listen again and fill in the following blanks with the missing information.
Biodiversity is everywhere around us. Without doubt, it is important to our life. Why? Below are some of the reasons:
1. Biodiversity gives people a wonderful world to live in.
2. The loss of any one kind of biodiversity will change the balance of life on Earth.
3. Biodiversity brings direct benefits to people. For example, plants give the air we breathe.
4. Biodiversity also has economic and health benefits. It provides industry and agriculture with raw material and other things. It is essential to medicine.
5. Many species were thought useless at first but were later discovered valuable. This is a further threat from the loss of biodiversity.
Passage 2
How Many Species Are There?
Word Bank
galaxy n. one of the large groups of stars in the universe 星系
database n. a very large collection of related data arranged for convenient access, generally in
a computer 数据库
mammal n. a type of animal in which the female gives birth to babies, not eggs, and feeds them on milk from her body 哺乳动物
microbe n. a living thing that is so small that it can’t be seen without a microscope 微生物；
细菌
Panama a country in Central America 巴拿马（中美洲国家）
Script:
Isn’t it surprising that scientists have a better understanding of how many stars there are in the galaxy than how many species there are on Earth? Their estimates of global species diversity vary from 2 to 100 million species. Most people agree on an estimate of somewhere near 10
million and yet only 1.5 million have actually been named. Current knowledge of species diversity is limited. This problem becomes more serious because there is a lack of a central database or list of the world’s species.
New species are still being discovered —even new birds and mammals. On average, about three new species of birds are found each year, and since 1990, 10 new species of monkeys have been discovered. Other groups are still far from being completely described; an estimated 40 percent of freshwater fishes in South America have not yet been classified.
周华健快歌>以吻封缄歌词Scientists were startled in 1980 by the discovery of a huge diversity of insects in tropical forests. In one study of just 19 trees in Panama, 960 new species of beetles were discovered.
As scientists begin investigating other little-known ecosystems, like the soil and the deep sea, “surprising”discoveries of species become commonplace. There is nothing strange about this, though, since as many as a million undescribed species are believed to live in the deep sea. And on
e gram of a small-sized piece of land might hold 90 million bacteria and other microbes. How many species these communities contain is still anyone’s guess.
Language and Culture Notes
1.Background information
We humans have shared our planet with millions of creatures, yet we know very little of our neighbors. It is estimated that there exist 5 to 100 million species on Earth. But according to the latest counts, scientists have so far only described over 1.5 million species of animals, plants and algae. Among those are mammals (5,416), birds (9,956), reptiles (8,240), amphibians (6,199), insects (950,000), flowering plants (258,650), conifers (980), and mushrooms (16,000). The greatest diversity exists among insects, which account for nearly a million of the planet’s species. Mammals make up one of the smallest groups, with just 5,416 members.袁洁莹三级
2. central database
a database that stores all the related information (about species)
3. “surprising” discoveries of species become commonplace
discovering new species (in the soil and the deep sea) becomes quite ordinary
4. anyone’s guess
something that no one knows for sure
Exercise 1
Listen to the passage and choose the right answers to the questions you hear.
1. Which of the following is true?
a. Scientists don’t know much about the number of stars in the galaxy.
b. Scientists have a sound knowledge about the diversity of species.
c. Scientists don’t agree on the number of species in the worl
d.
d. Scientists show more interest in stars in the galaxy than in species on Earth.
2. How many species are there on Earth according to most scientists?
a. About 10 million.
b. 2 million.
c. 100 million.
d. 1.5 million.
3. In which of the following groups is the discovery of new species not mentioned in the passage?
a. Birds.
b. Monkeys.
c. Trees.
d. Freshwater fish.
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