Unit 5 A delicate world Understanding ideas （ppt课件）-新外研版（2019）《高中英语》选择性必修第二册.pptx

1、Macquarie Island:Macquarie Island:from Chaos to Conservationfrom Chaos to ConservationLearning aims1.To learn how the chaos was caused in Macquarie Island and how people tried to conserve(保护)the island.2.To use“cause and effect”structure(因果结构)to describe a story.3.To realize the great effect of huma

2、ns actions on ecology and the importance of ecological balance.（生态平衡）Look at the picture and answer the questions.1.What animals can you see in the picture?2.What kind of changes would take place if cats,rats and rabbits were introduced to an environment like this?They would hunt the birds and eat t

3、he native vegetation,thus upsetting the local ecological balance.Penguins,elephant seals,wild birdsRead for structurePart 1 Para_ Part 2 Paras Part 3 Paras the _ of the islandthe_ of the islandthe _ of the island 1beauty2-3chaos4-6conservationLook through the passage,divide it into three parts,and g

4、et the main idea of each part.Read for detailsRead for detailsthe of the islandlong and thin shapegreen grass and bare rocks_wildwildnaturalnaturalharmoniousharmoniousIn what ways can we find Macquarie island is beautiful?World Heritage SiteWorld Heritage SitebeautyRead part 1(para.1)and answer the

5、question:native inhabitants natural habitat1 I am standing on Macquarie Island,in the Southwest Pacific Ocean,halfway between Australia and Antarctica.Strong winds and stormy seas have helped sculpt its long,thin shape.The green grass and bare rock of its landscape contrast dramatically,giving it a

6、wild and natural beauty.No visitor would think it surprising that the island is a UNESCO World Heritage Site.Nor would they fail to imagine how its native inhabitants,including royal penguins,king penguins,and elephant seals,existed in perfect harmony with their natural habitat for thousands of year

7、s.the of the island1.What was brought to the island?2.What happened after they reached the island?Read Read part 2(paras.2-3)part 2(paras.2-3)and finish the following tasks.and finish the following tasks.Read Read part 2(paras.2-3)part 2(paras.2-3)and finish the following tasks.and finish the follow

8、ing tasks.the of the island1.What was brought to the island?rats&micerats&micecatscatsrabbitsrabbits2.What happened after they reached the island?took over ate attacked ate birdsmultipliedate vegetationdig holessoil erosionmore cats_ birds_ birdsfewerfewer_ _ destructiondestructionlandscapelandscape

9、have a _effect on ecologyhave a _effect on ecologybadbad！humanshumanson purpose?possible results?Humans _ actionsHumans _ actionscarelesscareless2 But the islands more recent history tells a different story.Its a tragic story that began in 1810 when humans arrived on the island.In their ships they u

10、nknowingly brought rats and mice.These small animals quickly took over the island,eating the birds eggs and attacking baby birds.Cats were brought to the island to control the rats and mice.Unfortunately,the cats subsequently developed an appetite for the birds,too.3 Meanwhile,rabbits were introduce

11、d to the island as a source of food for humans.Loose on the island,they did what rabbits do bestthey multiplied rapidly and began eating the native vegetation and digging holes,which caused soil erosion.The exploding rabbit population provided plentiful food for the cats,meaning that the number of c

12、ats also increased.This in turn led to more cats hunting the birds.The end result was that parakeets,once large in number and native to the island,died out in 1891.the of the islandtimemeasure(s)purpose(s)result(s)Read Read part 3(paras.4-6)&postscriptpart 3(paras.4-6)&postscript,and fill in the bla

13、nks.and fill in the blanks.after the 1970sin the 1980safter 2006release_use_drop poisonuse_to removerabbitsto_to remove allfewer_ birdspestfewercatsno _ _rats _rabbitsland collapsemoremore_free in 2014 virustraps&dogsdogskill catsrabbitsproper?to solve it to solve it onceonce and for and for allallH

14、umans_measures may do greater harm to ecology.improperimproperDeeper thinking:Deeper thinking:What do you think is What do you think is to blame for to blame for the chaos in the chaos in Macquarie Island?Macquarie Island?rats&mice?cats?rabbits?humans humans careless careless behaviorsbehaviors huma

15、ns humans improperimproper measures measures“We humans owe it to the island to give it a happy ending.”HumanbeautybeautySummarySummarychaoschaosconservationconservationharmonyharmony4 Even after Macquarie Island became an official nature reserve in the 1970s,the rabbits remained out of control.Exper

16、ts felt it necessary to come up with a plan to remove all the rabbits from the island.With this goal in mind,a virus was released onto the island.But although the virus caused the rabbit population to decrease from 130,000 to around 10,000,it also meant less food for the cats.The cats in consequence

17、 turned their attentionand their stomachsback to the native birds,killing up to 60,000 each year.In the 1980s,traps and dogs were used to catch the cats.The last Macquarie Island cat was caught in 2000.5 But as the saying goes,“While the cats away,the mice will play.”With the departure of the cats f

18、rom the island,the mouse and rat population started to increase.And remember those 10,000 or so rabbits?It turned out that they developed an immunity to the virus,and their numbers exploded once again.Then,in 2006,the rabbits digging caused some land to collapse,and killed a substantial number of pe

19、nguins.This incident made it clear that the rat,mouse and rabbit problem needed solving once and for all.6 So,I am here on Macquarie Island to participate in the programme to tackle this very problem.The first step involved poison being dropped from helicopters.The next step is to remove the last re

20、maining invading species,and thats where I come inwith my dogs.They have been trained to find every last one,without harming the native animals.This intervention is a long,muchdelayed ending to a sad story,but we humans owe it to the island to give it a happy ending.Postscript:In 2014,Macquarie Isla

21、nd was declared pestfree and the islands ecology is finally on the road to recovery.After readingUnderstanding ideas3.Choose the authors purpose in writing the passage and give your reasons.1)To analyse how Macquarie Island was saved from destruction.2)To inform readers of the chaos caused on Macqua

22、rie Island by humans.3)To entertain readers with a funny story about what happened on Macquarie Island.4)To suggest ways in which an ecosystem can be protected.From the title,we know the Island was saved from destruction(from chaos)to conservation.Small action,but big chaos！Protect the nature,and keep ecological balance！