B2U4Wildlifeprotection拓展阅读handouts熊伟3.doc

Handouts for studentsA①The African elephant, the largest land animal remaining on earth, is of great importance to African ecosystem(生态系统). Unlike other animals, the African elephant is to a great extent the builder of its environment. As a big plant-eater, it largely shapes the forest-and-savanna(大草原)surroundings in which it lives, therefore setting the terms of existence for millions of other animals that live in its habitat(栖息地). ②It is the elephant's great desire for food that makes it a disturber of the environment and an important builder of its habitat. In its continuous search for the 300 pounds of plants it must have every day, it kills small trees and underbushes, and pulls branches off big trees. This results in numerous open spaces in both deep tropical forests and in the woodlands that cover part of the African savannas. In these open spaces are numerous plants in various stages of growth that attract a variety of other plant-eaters. ③Take the rain forests for example. In their natural state, the spreading branches overhead shut out sunlight and prevent the growth of plants on the forest floor. By pulling down trees and eating plants, elephants make open spaces, allowing new plants to grow on the forest floor. In such situations, the forests become suitable for large hoofed plant-eaters to move around and for small plant-eaters to get their food as well. paragraphKey wordsMain idea①②③Main idea:1 . What is the passage mainly about? A. Disappearance of African elephants. B. Forests and savannas as habitats for African elephants. C. The effect of African elephants' search for food. D. The eating habit of African elephants. B①With only about 1, 000 pandas left in the world, China is desperately trying to clone the animal and save the endangered species. That’s a move which is similar to what a Texas A & M University researchers have been undertaking for the past five years in a project called “Noah’s Ark”. ②Noah’s Ark is aimed at collecting eggs, embryos(胚胎), semen and DNA of endangered animals and storing them in liquid nitrogen(液氮). If certain species should become extinct(灭绝), Dr. Duane Kraemer, a professor in Texas A & M’s College of Veterinary Medicine, says there would be enough of the basic building blocks to reintroduce the species in the future. ③It is estimated that as many as 2, 000 species of mammals, birds and reptiles will become extinct in over 100 years. The panda, native only to China, is in danger of becoming extinct in the next 25 years. ④This week, Chinese scientists said they grew an embryo by introducing cells from a dead female panda into the egg cells of a Japanese white rabbit. They are now trying to implant(移植) the embryo into a host animal. The entire procedure（程序） could take from three to five years to complete. “The nuclear transfer(核子移植) of one species to another is not easy, and the lack of available panda eggs could be a major problem,” Kraemer believes. “They will probably have to do several hundred transfers to result in one pregnancy (having a baby). It takes a long time and it’s difficult, but this could be groundbreaking science if it works. They are certainly not putting any live pandas at risk, so it is worth the effort,” adds Kraemer, who is one of the leaders of the Project at Texas A & M, the first-ever attempt at cloning a dog. paragraphKey wordsMain idea①②③④Main idea: 2. What is mainly discussed in the text? A. China’s success in panda’s cloning B. The first cloned panda in the world C. A great project named Noah’s Ark D. The research into pandas cloningC①It was a village in India．The people were poor．However, they were not unhappy．After all, their forefathers had lived in the same way for centuries．②Then one day, some visitors from the city arrived．They told the villagers there were some people elsewhere who liked to eat frog's legs．However, they did not have enough frogs of their own, and so they wanted to buy frogs from other places．③This seemed like money for nothing．There were millions of frogs in the fields around, and they were no use to the villagers．All they had to do was catch them．Agreement was reached, and the children were sent into the fields to catch frogs．Every week a truck arrived to collect the catch and hand over the money．For the first time, the people were able to dream of a better future．But the dream didn't last long．④The change was hardly noticed at first, but it seemed as if the crops were not doing so well．More worrying was that the children fell ill more often, and, there seemed to be more insects around lately．⑤The villagers decided that they couldn't just wait to see the crops failing and the children getting weak．They would have to use the money earned to buy pesticides（刹虫剂 ）and medicines．Soon there was no money left．⑥Then the people realized what was。