Unit 5 A Delicate World Using language 课件-2023-2024学年高中英语外研版（2019）选择性必修第二册

Using language 教材分析：单元整体分析 本单元的主题语境是“人与自然”，涉及的主题语境内容是保护我们脆弱的星球。 Starting out呈现了一段与单元主题相关的视频，该视频介绍了生态系统中所有生物之间相互依赖的关系，点明人类是地球生态系统的一部分，从而引发学生思考人类对生态系统的影响。词汇部分通过一组示意图和一个小语篇呈现了生态系统中的食物链及其相关表达，了解食物链中生物的相互制约、相互依存，共生共荣及生态平衡的重要性。听说部分为一段对话，内容为蜜蜂数量的减少对于整个生态系统的潜在影响。 本单元引导学生认识到人类生存必须依赖于良好的自然生态系统，保护生态就是保护人类，加深学生对人与自然和谐共处这一理念的认识。 教学目标 1.带领学生观看视频，感知地球生态系统的多样性及所有生物之间相互依赖的关系。 2.带领学生学习并运用有关食物链的表达，了解生态系统中各食物链中不同物种之间的关系，引导学生认识保护食物链平衡的重要性，鼓励学生为保护生态系统做贡献。 3.引导学生通过完成听力活动，进一步了解生态平衡的重要性，并能够运用所学表达自己的观点。 Starting out Watch the video and answer the questions. 1. How can an ecosystem be successful and healthy? 2. Are humans part of Earth’s ecosystems? Why? Watch the video and answer the questions. 1. How can an ecosystem be successful and healthy? 2. Are humans part of Earth’s ecosystems? Why? Biodiversity Yes. Because all the living things live in ecosystems and humans are living things. Starting out The diagram shows a food chain — the connection between the living things. What does the diagram show? 1. Producers absorb water and dissolved nutrients from the soil. dissolve : v. to mix with a liquid and become part of it. (使)溶解 eg. Salt dissolves in water. Vocabulary 2. Secondary consumers prey on primary consumers, as well as eating other animal matter. prey on: (of an animal ) to hunt and kill another animal for food 捕食 eg Tigers prey on animals like rabbits. 8 3. Decomposers break down dead animal and vegetable matter into nutrients. break down: to make a substance (物质) separate into parts or change into a different form in a chemical process. 分解 eg Sugar and starch (淀粉) are broken down in the stomach. Roles in an ecosystem producer decomposer primary consumer secondary consumer absorb dissolve rely on feed on prey on release break down provide Explain the relationships 2. What are the relationships between the living things? The living things are closely connected with each other by the food they eat. Secondary consumers prey on primary consumers, primary consumers fe