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课件网) Unit 6 Period 4 Reading 新 课 导 入 1 Look at the infographic below and answer the questions. Facts about DDT: DDT was first produced in 1874 and was later used as pesticide. It stays in the environment. It is highly poisonous to living organism, including humans. Now banned in many countries, it is still used in some for malaria control. 1 How does DDT reach the human body in the food chain 2 What harm does DDT cause 1 How does DDT reach the human body in the food chain 2 What harm does DDT cause When DDT is sprayed onto plants in order to kill insects, it is absorbed by the plants and subsequently consumed by animals; humans in turn eat those animals. DDT also leaks through the soil and into rivers and lakes, where it contaminates fish consumed by humans. DDT is highly poisonous to living organism, including humans. 课 堂 学 习 2 Read the book review on Silent Spring, a book that led to the banning of DDT. Predict what will be mentioned in the passage. Silent Spring 1 There was a strange stillness. The birds, for example - where had they gone Many people spoke of them, puzzled and disturbed. The feeding stations in the backyards were deserted. The few birds seen anywhere were moribund; they trembled violently and could not fly. It was a spring without voices. On the mornings that had once throbbed with the dawn chorus of robins, catbirds, doves, jays, wrens, and scores of other bird voices there was now no sound; only silence lay over the fields and woods and marsh. Now read the passage and check your prediction. 2 Rachel Carson was a scientist by profession, but these lines from the opening chapter of her 1962 book Silent Spring,“A Fable for Tomorrow”, show her talent as a writer. By imagining a world without birds, she aimed to alert not only the scientific community but also the general public to the damaging effects of human activity on natural ecosystems - in particular, to the harmful use of pesticides, such as DDT. She believed that the chemical industry was knowingly causing harm to plants, animals and even humans, and wished to see pesticides used in a more responsible, limited and carefully monitored way. 3 Carson urged people to make themselves aware of the facts and do something about the situation. Silent Spring contains a lot of scientific research and case studies. The book details the gypsy moth eradication programme, which killed birds, in addition to gypsy moths. Another case study was the fire-ant programme that killed cows, but not fire ants. The book also gives dozens of other examples of eradication programmes that did nothing to reduce the problems they were originally designed to solve. The 50 or so pages at the end of the book list Carson's sources, showing how thorough and precise she was as a scientist. 4 Carson's message was very alarming, causing a great increase in environmental awareness. Its impact was immediate and far reaching: the use of DDT wa ... ...
