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课件网) Unit7 The natural world Reading 1 1.Master the pronunciation and meaning of key words such as ecosystem, pollution, and oxygen. 2.Be able to grasp the main idea of the passage by skimming and extract key information by scanning. 3.Be able to discuss and express ideas related to ecosystems in English. Learning objectives Can you share some fun facts about ecosystems Revision How many ecosystems are there in the video Lead in They are Oceans Wetlands and Forests Let's explore the three magic lands of the Earth—oceans, wetlands and forests. What do you know about oaceans,wetlands and forests The big three: oceans,wetlands and forests An ecosystem includes all the living and non-living things in an area.Ecosystems can be of different sizes,from small ponds to large grasslands.Each ecosystem has a role to play and helps keep the balance between all its members and the greater environment. The ocean is a very large ecosystemon earth.It covers around71%of theearth's surface and produces about 70% of the earth's oxygen.It holds plenty of salt water,and the water rises to the sky,falls onto the land and then returns to the ocean.This goes on and on,so the ocean is just like the“heart”of the Earth. Wetlands only cover about 6%of the earth's land area.But they are home to about 40%of the world's plants and animals.Plants in wetlands help get rid of pollution and make the water clean. Wetlands can also help prevent floods.During heavy rains,wetlands store water like giant sponges.They act like the "kidneys"of the earth. Forests make up nearly a third of the earth's land area.Plants there take in carbon dioxide from the air and produce oxygen.They also trap harmful things in their leaves and help clean the air. Therefore,people often call forests the "lungs"of the earth. Each of these ecosystems supports millions of plants and animals.They keep the planet healthy and make our world a better place. Read the text and complete the following tasks. Task1 What is an ecosystem An ecosystem includes all the (plants, animals, microorganisms) and_____ (water, air, soil, sunlight) in an area, and they work together to keep balance. living things non-living things Task2 What are the three main ecosystems mentioned What are their nicknames The three main ecosystems mentioned are oceans, wetlands, and forests. Oceans are nicknamed the "heart" of the earth. Wetlands are nicknamed the "kidneys" of the earth. Forests are nicknamed the "lungs" of the earth. Task3 How big are they What can they do for the Earth Oceans The largest ecosystem on Earth, covering 71% of the planet's surface. Forests Large areas dominated by trees, covering nearly one-third of Earth's land. Wetlands Unique ecosystems where water covers the soil for all or part of the year. Task4 Reading for the structure(结构). An ecosystem includes all the living and non-living things in an area. Ecosystems can be of different sizes, from small pon ... ...
