发布时间 : 星期五 文章高中英语人教版选修8Unit2CloningReading教案(系列一)更新完毕开始阅读
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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 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 things first, what 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 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 flowers, 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 Scottish scientists at Roslin Institute created the much-celebrated sheep \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. 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 technologies 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 cloning 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 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 complete 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 goat’s
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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, 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 could serve as a surrogate mother. In reality? Probably not. It’s 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 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 the did not know that his son was cloned. So two same young men both claimed that they were the old man’s 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. According 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? Discussion
In this part the students will discuss the relationship between the 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 we 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 them. 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
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social customs. …
Look at pictures
T: Look at the pictures and discuss which ones are 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 a try? S: I think the identical dog is man-made. T: Good Job Step II 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 list 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 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 writer’s opinion?
T: Good job! I think many of you have questions, now let us read the article with the questions.
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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 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 has the same quality as the real human, natural born baby’s quality is higher than his parents.
7. No. The cloned baby also has the disease.
Step III While- reading
Get the students to comprehend the passage quickly and accurately and meanwhile help the students form a good habit of reading.
T: Have you not the answers of your questions? Now please skim the passage fast to obtain a general understanding of 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 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 IV Post-reading
Ask the students to read the passage again to finish three tasks.
T: Now let’s listen to the. While listening, pay more attention 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 old animals and the same goes with the
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