Using LanguageⅡ教学设计第二课时

Teaching Plan Teaching aims: Enable students to understand whether extinct animals can return or not. Teaching difficulties: Enable students to use their own words to discuss which extinct animals are worth restoring by means of cloning. Teaching procedures: Step 1: Lead-in

1. 克隆技术大事记

1938年:德国科学家首次提出克隆想法。

1952年:科学家开始用青蛙进行克隆实验。

1970年:克隆青蛙实验取得突破,青蛙卵发育成了蝌蚪, 但是在开始进食以后死亡。

1981年:科学家进行克隆鼠实验,据称用鼠胚胎细胞培育出了正常的鼠。

1984年:第一只胚胎克隆羊诞生。

1997年2月24日:英国罗斯林研究所宣布克隆羊培育成功。科学家用取自一只6岁成年羊的乳腺细胞培育成功一只克隆羊。

1998年2月23日:英国PPL医疗公司宣布,该公司克隆出一头牛犊“杰弗逊先生”。

1998年7月5日:日本科学家宣布,他们利用成年动物体细胞克隆的两头牛犊诞生。

1998年7月22日:科学家采用一种新克隆技术,用成年鼠的体细胞成功地培育出了第三代共50多只克隆鼠,这是人类第一次用克隆动物克隆出克隆动物。

1999年5月31日:美国夏威夷大学的科学家,利用成年体细胞克隆出第一只雄性老鼠。

1999年6月17日:以美藉华人科学家杨向中为首的研究小组利用一头13岁高龄的母牛耳朵上取出的细胞克隆出小牛。

2000年1月3日:美国著名华人杨向中,用体外长期培养后的公牛耳皮细胞成功克隆出6头牛犊。

2000年1月:美国科学家宣布克隆猴成功,这只恒河猴被命名“泰特拉”。

2000年3月14日:曾参与克隆小羊“多利”的英国PPL公司宣布,他们成功培育

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出5头克隆猪。

2. Please enjoy some pictures about dinosaurs.

Step 2: Reading Listen to the tape and then answer the following questions: 1. Why shouldn’t you clone an extinct animal if there isn’t enough diversity in the group?

2. Why is it wrong to clone an extinct animal if it would have to live in a zoo? Keys: 1. There will not be enough genetic variation in the group to be able to resist new illnesses.

2. It is not a good idea to clone an animal that would have to live in a zoo because it is not a suitable habitat to develop and increase its numbers. The zoo is not a natural environment for a wild animal. Step 3: Careful-reading 主旨大意: 1. The writer of the text_____

A. is excited by the possibility of cloning fierce and extinct animals

B. believes that extinct animals can be brought back to life by cloning C. thinks it impossible or unsuitable to clone extinct animals like dinosaurs

D. dreams of dinosaurs returning to the earth 细枝末节: 2. The film Jurassic Park is popular because _____.

A. people are interested in the subject of cloning

B. all the actors are dinosaurs C. it was directed by a scientist who clones dinosaurs D. it proves very interesting 3. Which of the following is true? ____ A. Mice were cloned in 1981. B. Dolly the sheep was the first cloned animal. C. The name of the cloned cow is “Bison”

D. China was successful in cloning mammals. 4. The reasons why a group of cloned animals all die of the same illness do NOT include____.

A. they have the same arrangement of genes

B. there isn’t enough diversity in the group for it to overcome illnesses C. the illness is a new one D. their arrangement of genes can not resist that new disease 推理判断: 5. We can infer from the text that____

A. scientists are experimenting to clone dinosaurs

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B. dinosaurs will never return to the earth C. cloned animals will only live in the zoo D. the DNA of dinosaurs can only survive 10 000 year True or false: 1. Scientists are still experimenting with cloning mammals because they think it can make money. 2. The animals that have disappeared from the earth, like dinosaurs, can be brought back to life through cloning. 3. If we can clone any extinct animals, we should let them live in a zoo. Step 4: Discussion Which extinct animals are worth restoring by means of cloning? Choose one and use the information to help you argue why this animal should be restored to the earth. Great Auk (1844)

Dodo bird (1755)

Aurochs (1627)

Quagga (1883)

A sample dialogue (P16) : S1: I think the dodo bird should be returned to the earth. It hasn't been extinct very long. So its DNA will still be good enough for cloning. S2: Yes and sailors in the past always described the dodo as being a very friendly animal. So it would make a good pet. It wasn't too large either. I can't see any other extinct animals becoming a pet, can you? S1: No, indeed. I know it's a bird like the Great Auk but neither of them could fly. So if you kept either, it wouldn't escape from a park, a family or its home in the wild. You could also farm a dodo, unlike all the others, and produce many of them as exotic pets.

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S2: And what about its large nutritious eggs? Just one would feed a large family. So there's more than one reason for producing it in commercial numbers. S1: Did you know that its meat is very tasty too! Perhaps it could be farmed like ostriches and

provide a good source of protein. S2: The only problem is that it needs hot climate to survive. But that's easy to provide with all its other advantages. I don't think any of the other animals stands a chance against the dodo. S1: So we both agree that the best extinct animal to be cloned is the dodo bird. S2: Yes. A sample report (P17): The dodo is the most suitable animal to be cloned for several reasons. First, it became extinct fairly recently, so its DNA is still in good condition. Second, it was always described as being a very friendly animal and it would make a good pet. Third, it cannot fly. So it wouldn't escape from a park, a family or its home in the wild.You could farm a dodo and sell it as an exotic pet. Fourth, it produces large nutritious eggs which could feed a large family. Fifth, its meat is very tasty too!

Perhaps it could be farmed like ostriches and provide a good source of protein. Although it needs hot climate to survive, we feel that this can be easily provided. In return the dodo would provide a most useful source of pleasure and food. Step 5: Homework Finish the exercise on the EW.

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