综合英语Book IV Unit 6.pptVIP

????? Pre-reading activities 1)Look these words up in a dictionary. -???????predator: a wild animal that lives on other animals by killing and eating them -????????parasite: a plant or animal that lives on or in another and gets food from it -????????ecosystem: a system which relates all the plants, animals and people in an area to their surroundings Group discussion: How elements in the ecosystem function? Words and expressions for reference: Animals, predator, vegetarian, parasite, plants, human beings, micro-biological organism, oxygen, carbon dioxide, prey upon, feed on, the fittest survive, the jungle law, aggressive, die out, endangered, extinction, a large population of , biological control, symbiosis, commensalisms, mutualism, food chain, 3)What’s the text about? -The title of the text strongly suggests that it is an expository piece of writing on ecology (the scientific study of the pattern of relations of plants, animals, and people to each other and to their surroundings). Text analysis ???? -? 1)The main idea --The text explains how living things, like predators and their prey, and parasites and their hosts, affect each other in many ways. 2)????? The supporting details (1)????Predators include lions, wolves, robins, frogs, humans, etc. (1st paragraph) (2)?????Humans are the greatest predators known. (2nd paragraph) (3)??Predators do not really have an easy time killing defenseless prey. (from 3rd para to 4th para) (4)????Parasites often spend an entire lifetime with their hosts. (from 5th para to 6th para) (5)????Man makes use of predators and parasites to control the number of some pests. This is called biological control. (from 7th para to 10th para) (6)??Parasites and their hosts are closely associated with each other, and there are a number of examples of symbiosis. (from 11th para to the last para) 3) Answer comprehensive questions (1) A predator is… (2) A carnivore is … (3)A parasite is … (4) A mammal is …