Unit 5 A delicate world Starting out & Understanding ideas 课件 -2023-2024学年高二英语外研版（2019）选择性必修第二册

外研选择性必修 第二册 Unit 5 Period 1 Starting out & Understanding ideas (I) 1 2 To understand the idea that humans are part of earth’s ecosystem To learn how the chaos was caused in Macquarie Island and how people tried to conserve the island, then use “cause and effect” structure to describe a story 学习目标 目标一：To understand the idea that humans are part of earth’s ecosystem Activity 1: Watch the video and answer the questions. 1 Are humans part of Earth’s ecosystems? Why? 2 In what ways can humans affect ecosystems? Man is a part of nature. Human activities have become an influence on the stability of the natural environment of all spheres on earth. Degradation of forest and grassland vegetation, loss of biodiversity, soil erosion, pollution aggravating, the greenhouse effect of the atmosphere, and the destruction of the ozone layer, have sounded the alarm for human beings. Activity 2: Look at the satellite images and answer the questions. 1 What is happening to the area according to the satellite images? 2 What do you think a later satellite image would show? 3 What do you think caused these changes? The water area is shrinking. The water area will be smaller. Maybe it's due to over exploitation. Background Information: The Aral Sea Crisis The Aral Sea is situated in Central Asia, between Kazakhstan to the north and Uzbekistan to the south. It was once the world’s fourth largest lake, and contained 10 grams of salt per litre. The rivers flowing into the Aral Sea are the river Syr Darya from the north and the river Amu Darya from the south. In the 1960s, the two rivers were diverted away from the Aral Sea so that people could irrigate the surrounding desert region and focus on cotton production. As a result, the Aral Sea has been decreasing in size, and by 1997, it had shrunk to a tenth of its original size, splitting into four lakes. By 2009, the south-eastern lake had disappeared altogether, and the south-western