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1、 安徽省滁州市第二中学高中英语 Unit22 Environmental Protection The Eleventh Period Check your progress教案 北师大版选修8Teaching goals 教学目标1. Target Language目标语言重点词汇和短语overpopulation, flood, earthquake, typhoon, poverty, carry on, take up, put aside, cut down, set up, come up with2. Ability goals 能力目标 Learn why rainforest
2、s are important.3. Learning ability goals学能目标By reading the article students will learn that rainforests play an invaluable role in sustaining life on Earth. Step I RevisionGo over the passive.1. Ask students to read the text in Ex6 on Page 94.2. Ask students to state the reasons for using the passi
3、ve voice in English. Step II A brief introduction of rainforests First make a brief introduction of rainforests. Then students are given seven minutes to read the article to get a main idea of the article.T: In this class we are going to learn something about rainforests. Before reading the text, lo
4、ok at the brief introduction. (Show the following on the PowerPoint.) Teacher asks the questions, students read the materials together. What is a Rainforest?Rainforests are very dense, warm, wet forests. They are havens (安身之处) for millions of plants and animals. Rainforests are extremely important i
5、n the ecology of the Earth. The plants of the rainforest generate much of the Earths oxygen. These plants are also very important to people in other ways; many are used in new drugs that fight disease and illness. Strata of the Rainforest Different animals and plants live in different parts of the r
6、ainforest. Scientists divide the rainforest into strata (zones) based on the living environment. Starting at the top, the strata are: EMERGENTS: Giant trees that are much higher than the average canopy height. It houses many birds and insects. CANOPY: The upper parts of the trees. This leafy environ
7、ment is full of life in a tropical rainforest and includes: insects, birds, reptiles, mammals, and more. UNDERSTORY: A dark, cool environment under the leaves but over the ground. FOREST FLOOR: Teeming with animal life, especially insects. The largest animals in the rainforest generally live here. A
8、nimals of the RainforestsAn incredible number of animals live in rainforests. Millions of insects, reptiles, amphibians, birds, and mammals call them home. Insects are the most numerous animals in rainforests. Tropical rainforests have a greater diversity of plants and animals than temperate rainfor
9、ests or any other biome. In temperate rainforests, most of the animals are ground dwellers and there are fewer animals living in the forest canopy. Where are Rainforests?Tropical rainforests are found in a belt around the equator of the Earth. There are tropical rainforests across South America, Cen
10、tral America, Africa, Southeast Asia and Australia (and nearby islands). Temperate rainforests are found along the Pacific coast of the USA and Canada (from northern California to Alaska), in New Zealand, Tasmania, Chile, Ireland, Scotland and Norway. They are less abundant than tropical rainforests
11、. RainfallIt is almost always raining in a rainforest. Rainforests get over 80 inches (2 m) of rain each year. This is about 1 1/2 inches (3.8 cm) of rain each week. The rain is more evenly distributed throughout the year in a tropical rainforest (even though there is a little seasonality). In a tem
12、perate rainforest, there are wet and dry seasons. During the dry season, coastal fog supplies abundant moisture to the forest. TemperatureThe temperature in a rainforest never freezes and never gets very hot. The range of temperature in a tropical rainforest is usually between 75 F and 80 F (24-27 C
13、). Temperate rainforests rarely freeze or get over 80 F (27 C). The Soil in a RainforestThe soil of a tropical rainforest is only about 3-4 inches (7.8-10 cm) thick and is ancient. Thick clay lies underneath the soil. Once damaged, the soil of a tropical rainforest takes many years to recover. Tempe
14、rate rainforests have soil that is richer in nutrients, relatively young and less prone to damage. The Importance of RainforestsTropical rainforests cover about 7% of the Earths surface and are VERY important to the Earths ecosystem. The rainforests recycle and clean water. Tropical rainforest trees
15、 and plants also remove carbon dioxide from the atmosphere and store it in their roots, stems, leaves, and branches. Rainforests affect the greenhouse effect, which traps heat inside the Earths atmosphere. Some of the foods that were originally from rainforests around the world include cashew nuts,
16、Brazil nuts, Macadamia nuts, bananas, plantains, pineapple, cucumber, cocoa (chocolate), coffee, tea, avocados, papaya, guava, mango, cassava (a starchy root), tapioca, yams, sweet potato, okra, cinnamon, vanilla, nutmeg, mace, ginger, cayenne pepper, cloves, oranges, grapefruit, lemons, limes, passion fruit, peanuts, rice, sugar cane, and coconuts (mostly from coastal areas). People
