1、选修八 Unit2 CloningPeriod1 ReadingTeaching goals教学目标1. Target language 目标语言a. 重点词汇和短语clone, commercial, producer, undertake, arbitrary, object, forbid, accumulate, cast down, object to, the media, in favour ofb. 重点句子It is a way of.The fact is that.The question that occurred .2. Ability goals能力目标Enable
2、 the students to describe cloning: What is the advantages of cloning？ What is the problems or dangers of cloning？What is your opinion of cloning？3. Learning ability goals 学能目标Help the students learn how to describe cloning.Teaching important points 教学重点 How to describe cloning. Teaching difficult po
3、ints 教学难点Help the students analyze the writing techniques of the article.Teaching methods 教学方法Skimming, task-based method and debate method.Teaching aids 教具准备A recorder, a projector and some slides. Teaching procedures & ways教学过程与方式Step I Lead-inThis topic is difficult for students. So teacher shoul
4、d help the students learn more about it. Do this in the way of asking and answering questions.T: You can imagine how rapidly the modern science and technology develop. I think most of you must know something about space traveling, submarine exploration, robot, maglev train, gene engineering etc. But
5、 in recent years, a hot topic, cloning is often mentioned, especially when the cloning Dolly the sheep appeared. You may have first heard of cloning when Dolly the Sheep showed up on the scene in 1997. Cloning technologies have been around for much longer than Dolly, though. First thing first, what
6、is cloning and a clone? The dictionary says cloning is the technique of producing a genetically identical duplicate of an organism. A clone is said to be all descendants derived asexually from a single individual, as by cuttings, bulbs, by fission, by mitosis, or by parthenogenesis reproduction. It
7、sounds very different and complicated to us. In fact, I mean, in our daily life, this happens often. For example, gardeners take cuttings from growing plants to make new ones. You often see that your mother picks a small branch from a growing plant to make a new one. If she likes this kind of flower
8、s, she can do cloning. Cloning also happens in animals or human beings when twins identical in sex and appearance are produced from the same original egg. The fact is that cloning plants is straightforward but the cloning of animals is more complicated. The possibility of human cloning, raised when
9、Scottish scientists at Roslin Institute created the much-celebrated sheep “Dolly”, aroused worldwide interest and concern because of its scientific and ethical implications. You can give your questions if you are interested in this topic. I am here today one of the scientists who work in this field.
10、 I am ready to answer any of your questions.S: Now we know what is cloning. Are there different types of cloning?T: When the media report on cloning in the news, they are usually talking about only one type called reproductive cloning. There are different types of cloning however, and cloning techno
11、logies can be used for other purposes besides producing the genetic twin of another organism. A basic understanding of the different types of cloning is key to taking an informed stance on current public policy issues and making the best possible personal decisions. The following three types of clon
12、ing technologies will be discussed: (1) recombinant DNA technology or DNA cloning, (2) reproductive cloning, and (3) therapeutic cloning. S: Was Dolly created by what cloning? And why was Dolly so important?T: Reproductive cloning is a technology used to generate an animal that has the same nuclear
13、DNA as another currently or previously existing animal. Dolly was created by reproductive cloning technology. She was the first mammal to be cloned from adult DNA taken from an adult cell. Previously, animals had only been cloned using embryo cells which already have the potential to become a comple
14、te embryo in its own right. The big breakthrough with Dolly was to make a clone from an ordinary, adult cell in this case from a female goats udder.S: Have you seen Jurassic Park? In this feature film, scientists use DNA preserved for tens of millions of years to clone dinosaurs. They find trouble,
15、however, when they realize that the cloned creatures are smarter and fiercer than expected. Could we really clone dinosaurs?T: In theory? Yes. What would you need to do this? A well-preserved source of DNA from the extinct dinosaur, and a closely related species, currently living, that could serve a
16、s a surrogate mother. In reality? Probably not. Its not likely that dinosaur DNA could survive undamaged for such a long time. However, scientists have tried to clone species that became extinct more recently, using DNA from well-preserved tissue samples.More questions about cloning are given in the
17、 appendix. The information above is for reference only. Or you can choose several students and ask them to act out a short play whose main topic is as follows:An old man who was dying left all his fortune to his own son. But he did not know that his son was cloned. So two same young men both claimed
18、 that they were the old mans son. They quarreled and fought with each other; at last they went to the judge. The judge let them check DNA. The result was that their DNA was the same. Now even the judge did not know what to do.In this part the teacher can give the students some advice to act out. Acc
19、ording to this play teacher ask the students several questions: 1. Do you want to be cloned or not? Why? 2. If you are the judge what will you do?3. Can you tell me the advantages of cloning?4. And what is the disadvantage?DiscussionIn this part the students will discuss the relationship between the
20、 development of technology and social customs. T: As the technology develops day by day, it has a more and more important influence on the whole society. Technology affects social customs and ethics, sometimes technology may go against the conventional thinking, then comes the problem that whether w
21、e should stop the development of research or change the ethics.S1: As technology develops in almost every field, a lot of our original customs and ethics changed, either because they are out of time or not so scientific. For example millions of years ago human ate meat of animals without heating the
22、m. Later people used fire and no longer ate raw meat and they also used fire to scare dangerous animals.S2: I think we could not stop the development of technology, for it may develop in the way which is acceptable by social customs.Look at picturesT: Look at the pictures and discuss which ones are
23、natural clones and which ones are man-made. Then explain how they differ.S: I think the twins are natural clones and the Dolly sheep is man-made.T: You are right! Can you explain how they differ?S: The twins were born at the same time, but the Dolly sheep is man-made.T: Anything else? Who want have
24、a try?S: I think the identical dog is man-made.T: Good job!Step Pre-reading Before class, ask the students to search for some information about this topic. Now show your questions on the screen, and then let them discuss with each other.T: Now please work in pairs and discuss about cloning. Then lis
25、t the questions you want to find out. Share your list with your partner.Ss: Yes, sir / madam.Questions about cloning:1. What is a clone?2. How is a clone produced?3. What benefits can humans gain from cloning?4. What problems may arise when humans are cloned?5. Should we clone human?6. Could cloning
26、 replace sex as the means of creating new human life?7. Could a parent clone a child who is dying of a terminal illness?After a few minutes.T: Do you have other questions? Volunteer! S: I have! What is the writers opinion? T: Good job! I think many of you have questions, now let us read the article
27、with the questions.Suggest answers:1. It is a way of making an exact copy of another animal and plant.2. This happens in plants when gardeners take cuttings from growing plants to make new ones, and when small parts of a plant are taken and gown in a laboratory. It also happens in animals when twins
28、 identical in sex and appearance are produced from the same original egg.3. It can help cure disease and can help couples who have no baby to bear a new baby.4. There may be more bad people like Hitler.5. In my opinion, I do not agree, for it may cause many moral problems.6. No. Because cloned human
29、 has the same quality as the real human, natural born babys quality is higher than his parents. 7. No. The cloned baby also has the disease.Step While-readingGet the students to comprehend the passage quickly and accurately and meanwhile help the students form a good habit of reading.T: Have you got
30、 the answers of your questions? Now please skim the passage fast to obtain a general understanding of the whole passage. While reading, divide the whole passage into several parts and find out the main idea of each part.Show the following. Para. 1 Cloning is a way of making an exact copy of another
31、animal and plant.Para. 2 Cloning has two major uses.Para. 3 The problems of Dolly.Para. 4 The effect of Dolly.Para. 5 It is forbidden to clone human being.Step Post-reading Ask the students to read the passage again to finish three tasks. T: Now lets listen to the tape. While listening, pay more att
32、ention to the correct pronunciation and tone. Then read the text by yourselves to get the answers to the three tasks. You can work in groups.T: First, what are the problems or dangers of cloning?S: Let me have a try! First, the cloned animals have the same illness of the old animals and the same goe
33、s with the other species. Second, the cloned animals have short life and can cause moral questions.T: You are right! And what are the advantages of cloning?S: I know! Firstly, gardeners use it all the time to produce commercial quantities of plants. Secondly, it is valuable for research on new plant
34、 species and for medical research on animals. Thirdly, it suddenly opens everyones eyes to the possibility of using cloning to cure serious illnesses, and even producing human beings.T: What is the writers opinion? What do you think is the writers point of view in this reading passage? Is it in favo
35、ur of cloning or against it?S1: I think the writer is in favour of it, because there are many advantages of cloning. It can help people solve many problems in our daily life.S2: I think the writer doesnt agree with it, because if the cloning technology can be used in an evil way, it can cause much t
36、rouble to our society. T: The next question: What is your opinion of cloning? Give the reasons.S1: As a coin has two sides, everything has two aspects. First, if the cloning is used in a correct way it can bring many conveniences to us. Such as: curing serious illnesses and being used to produce com
37、mercial qualities of plants. On the other hand, if the cloning is used in an evil way it can cause much troubles: such as moral questions.S2: My view on cloning and nuclear transfer is that it is ethical. So actually I find no reason to clone presently. I have this opinion currently, because scienti
38、sts are unable to successfully clone using nuclear transfer as of today. S3: I also have a problem with the possible effects of using nuclear transfer on a large scale. This is because I fear that cloning could greatly reduce genetic diversity. I believe if we were to interfere with the genetic dive
39、rsity of an entire population we would undoubtedly fail.S4: As you can see I believe cloning using nuclear transfer should not be used on humans for any reason. I think if we were to use cloning it should be closely monitored as to what dangers are involved in having copies of people. I also think t
40、his technology should not be used until success. S5: I agree that we should develop cloning. Im not afraid of cloning Hitlers or excited to clone Einsteins. I would say the time and the environment produced Hitler, not his DNA. So you do not need DNA from Hitler to produce a Hitler. In fact, there a
41、re Nazis already present. We should make use of cloning to benefit future generations. You can imagine that how happy the people are if they can recover from the serious illness or get back the son who has just lost his life in an accident by cloning.T: Good job! Yes, if we our human beings use the
42、scientific technology properly it can bring many advantages to us!S: Why did Dollys appearance raise a storm of objections and have a great impact on the media and public imagination? T: Because nothing really prepared the world for the 1997 announcement that a group of Scottish scientists had creat
43、ed a cloned sheep named Dolly. Many folks believe that within the next decade, we will hear a more shocking announcement of the first cloned human. Scientists in South Korea have already created human embryonic stem cells through cloning. Until now, the idea of human cloning has only been possible t
44、hrough movie magic, but the natural progression of science is making human cloning a true possibility. Weve cloned sheep, mice and cows, so why not humans? Some countries have set up laws banning cloning, but it is still legal in many countries. Imagine using a piece of your great-grandmothers DNA t
45、o create a clone of her. In a sense, you could be the parent of your great-grandmother. This opens the door to many ethical problems, but its a door that could soon be opened.S: So what happens next?T: Whatever the reasons, the new cloning technologies have sparked many ethical debates among scienti
46、sts, politicians and the general public. Several governments have considered or enacted legislation to slow down, limit or ban cloning experiments outright. It is clear that cloning will be a part of our lives in the future, but the course of this technology has yet to be determined. Cloning could c
47、ause birth defects, but its not going to change society. In the absence of any legislation or regulation, cloning attempts will quietly continue. Eventually, cloning will succeed (if it hasnt happened already), and humankind will have taken another step down the road of biological engineering. You y
48、oung students are the future of the world. You should study hard today, and you will be able to face this difficult problem and know how to deal with it.ExplanationStep HomeworkAsk the students to do the following. 1. Complete the exercises on page 13.2. Recite the key sentences in the text.3. What is Clone? You might not believe it, but there are human clones among us right now. Have you ever wished you could have a clone of yourself to do homework while you hit the skate park or went out with your friends? Imagine if you could really do that. Where would you start?