高中英语选修七Unit3 Under the sea Period 7教案 4页

Period 7　Listening Task，Talking and Writing Teaching aims　　　　　‎ ‎1．Students will be able to find out the reasons why the population of sharks decreases sharply.‎ ‎2．Students will be able to express opinions with the polite expressions like：‎ I don't think it is wise to...‎ It would be better if we... ‎ It is a good idea to...‎ I suppose it is right...‎ I wonder if...‎ ‎3．Students will be able to persuade the local government to protect wildlife in a polite way.‎ Teaching procedures　　　　　‎ Step 1　Before listening Show students a picture of shark and tell them a fact that shark populations are decreasing rapidly.‎ Step 2　During listening Task 1：Tell students Jordon Davies is interviewing the shark expert Don James about the sharks' situation.First read the statements below.Then listen and number these statements in the order that they hear them.‎ ‎□Shark populations grow at a very slow rate.‎ ‎□A lot are killed because of modern fishing technology.‎ ‎□Governments should take action so that the fishing of sharks is slowed down.‎ ‎□Shark attacks get a lot of attention in the news.‎ ‎□Shark populations are decreasing at a serious rate.‎ ‎□Some species need to be protected.‎ ‎□The chance of being bitten by a shark is actually very small.‎ ‎□Millions of sharks are killed each year.‎ Keys：the order：7 4 8 1 5 6 2 3‎ Task 2：Listen again and answer the following questions：‎ ‎1．Should people be afraid of swimming in the sea?‎ ‎2．How many people are killed by sharks each year?‎ ‎3．Do sharks or people need to be protected？Why?‎ ‎4．Why are so many sharks being killed?‎ ‎5．Why does the shark's biology affect shark populations？Complete the sentences blow.‎ A：Age for reproducing young ‎ ‎________________________________________________________________________‎ B：Time for the young to develop ‎ ‎________________________________________________________________________ ‎ C：Number of young ‎ ‎________________________________________________________________________‎ ‎6．How long have shark species been in existence?‎ ‎7．What does Don think will happen if we don't slow down the fishing of sharks?‎ Suggested answers：‎ ‎1．No.‎ ‎2．Only a few.‎ ‎3．Sharks need to be protected as millions are killed each year by human beings，whereas only a few human beings are killed each year by sharks.‎ ‎4．Sometimes they are killed by accident and sometimes on purpose.For example，shark fin soup is a delicacy in some Asian countries.‎ ‎5．15 years；14 months；7－9.‎ ‎6．400 million years.‎ ‎7．Don thinks that many shark species will not be able to survive.‎ Step 3　Post－listening(talking)‎ Ask students to make up a dialogue according to the situation below.‎ Suppose you were a citizen in a coastal city in China，shark hunt is a serious problem in your province.Try to persuade the local government to take action to protect wild life in a polite way with the help of the following expressions：‎ I don't think it is wise to...‎ It would be better if we...‎ It is a good/wise idea to...‎ I suppose it is right...‎ I wonder if...‎ Why not...‎ We'd better...‎ Step 4　Homework Write a persuasive letter to the local government to control the improper hunts.‎ ‎1．Killer Whales ‎ Common name：Killer Whale[来源:学&科&网Z&X&X&K]‎ Scientific name：Orcinus orca[来源:学科网]‎ Size：‎ Females can reach lengths up to 24 feet and weigh between 3000 to ‎8000 lb.Males can reach lengths up to 27 feet and can weigh up to 12 ‎000 lb.Calves are about 8 feet long and 300 to 400 pounds at birth.‎ Where are they found?[来源:Z_xx_k.Com]‎ From the North Pole to the South Pole from the Indian Ocean to the Atlantic，killer whales are found in all oceans of the world.‎ What do they eat?‎ How do they get a name like “killer whale”？Killer whales are one of the top predators in the sea.As a group，killer whales are known to eat fish，squid，seals，sea lions，penguins，even other whales.‎ But，keep in mind，it would be difficult for a killer whale off the coast of California to eat a penguin.Killer whales eat the food(or prey)that's available to them.For example，a killer whale that lives in the northern Pacific can hunt harbor seals，California sea lions，and a variety of fish.A killer whale in the Antarctic could find Weddell seals，leopard seals，and penguins!‎ Researchers studying killer whales in the Northwest Pacific have found that some pods feed primarily on fish and others seem to prefer marine mammals.‎ A killer whale uses its sharp teeth to catch its prey.‎ Killer Whale Highlights：‎ Scientists have determined that killer whales can live a maximum of 35 years.How？By looking at a cross－section of a killer whale's tooth.Killer whales，like other marine mammals，produce a periodic growth layer on the teeth.By counting these layers，scientists can estimate the animal's age.‎ You can tell an adult male from an adult female by the shape of their dorsal fin.This is a male(photo below)，how do we know？A male's fin is very tall(up to 6 feet tall)and triangular shaped.A female is shorter(3 feet)and curves back toward the dorsal fin(see the picture of the mother/calf above)．‎ ‎2．The earth's oceans can reach depths of up to 11 000 meters.That is deep enough to cover Mt.Qomolangma！The oceans are incredibly large and contain several different habitats.To make it easier to describe the various parts of the oceans，marine scientists usually divide the oceans into five zones.Each zone is different mainly as a result of how much sunlight reaches it.‎ Most of the life in the ocean can be found in the first zone，which begins at the surface and goes down about 200 meters.Because there is sunlight at this level，plants are able to grow.Marine animals such as dolphins，sharks，sea turtles and sea lions，and of course a variety of fish，live in the sunlit part of the ocean.It is difficult to hide from other animals in this area.‎ The second zone starts at 200 meters and goes down to about 1000 meters.Some sunlight can reach this level，but it is not enough for plants to grow.Because this zone is relatively dark，many of the creatures that live here are able to make light with their body.The light from these animals makes the water look like a sky with moving stars in it.‎ The third zone of the ocean is dark.This place，about 3000 meters deep，may not seem a likely habitat，but there are more creatures here than one might think.Most of the animals that live here are black or red because of the lack of light.‎ Below 4000 meters，the temperature is near freezing and there is no light at all.In fact，the zone is so dark and empty that scientists named this zone after the Greek word for “no bottom”．There is not much life to be found in this cold and unpleasant part of the ocean，but some small creatures still manage to survive here despite the high water pressure.‎ The very deepest part of the ocean is found 2000 meters further down.At this depth，the water pressure is extremely high and life is very difficult for the few creatures that live here.Compared to the other zones，this one has very little life.Since there is no light here，some of the animals do not have eyes.‎ Next time you look at the ocean from the beach or on a map，remember that what you are seeing is only the surface—only the beginning of the large and varied adventure.‎