高中英语外研版 (2019)选择性必修 第二册Unit 5 A delicate world授课ppt课件

这是一份高中英语外研版 (2019)选择性必修 第二册Unit 5 A delicate world授课ppt课件，共20页。PPT课件主要包含了 A等内容，欢迎下载使用。
What is happening in the pictures?
Starting ut
extensive defrestatin
1. serius sil ersin;2. desertificatin;3. shrage f freshwater;4. Severe drught
Lk at the satellite images
1. What is happening t the area?
The water area is shrinking.
2. What wuld a later satellite image shw?
The water area will be smaller.
3. What d yu think caused these changes?
Maybe it's due t ver explitatin; r human ver explitatin.
Watch the vide
1. Are humans part f Earth's ecsytems? Why?2. In what ways can humans affect ecsytems?
Reference: A. Man is a part f nature. Human activities have becme an influence n the stability f the natural envirnment f all spheres n earth. B. Degradatin f frest and grassland vegetatin, lss f bidiversity, sil ersin, pllutin aggravating, the greenhuse effect f the atmsphere, and the destructin f the zne layer, have sunded the alarm fr human beings.
Macquarie Island frm Chas t Cnservatin
Understanding ideas
1. Animals in the pictures: ___________________
penguins, a bird
2. What kind f changes wuld take place if cats, rats and rabbits were intrduced t an envirnment like this?
Pssible answers: a. The penguin's habitat will be destryedb. Ecsystems acrss the island will change cmepletely ver time. c.
What happened t Macquarie Island?
Rats ate the birds' eggs.
Cats hunted rats and mice.
Cats hunted birds fr fd.
Keep rabbits fr meat
Rabbits were rampant. and ate the native vegetatin and digging hles.
Parakeets died ut in 1891
A vicius cycle f destrying natural balance
1. Invasive alien species are ne f the biggest causes f bidiversity lss and species extinctin.2. Alien invasive species such as animals, plants r ther rganisms are intrduced t a new native envirnment, which may adversely affect the bidiversity ecsystem service functin r human welfare.
The structure and the theme f the text
Intrduce the present eclgical situatin f the island.
Eclgical chas happened t the island in the past.
A prgram has been made t prtect the island.
Reading cmprehensin
Chse the authr's purpse in writing the passage and give yur reasn. A. T analyse hw Macquarie Island was saved frm destructin. B. T infrm readers f the chas caused n Macquarie Island by humans. C. T entertain readers with a funny abut what happened n Macquarie Island. D. T suggest ways in which an ecsystem can be prtected.
Suggested answer: _____
Lk fr details frm the text
ate birds' eggs and attacked baby birds.
Cats were brught t the island
Cats ate the birds t.
Rabbits were intrduced t the island.
as a surce f fd fr humans
Rabbits multiplies and caused sil ersin, and prvided plentiful fd fr the cats.
A virus was released nt the island.
T remve all the rabbit frm the island.
The rabbit ppulatin decreased.
Pisn was drpped frm helicpters.
T slve the rat, muse and rabbit prblem.
The island's eclgy is n the rad t recvery.
Think & Share
Pst reading
1. What is yur understanding f “ humnas we it t the island t give it a happy ending”?
The destructin f the island's ecsystem was caused by animals that humans had accidentally brught with them. Human interventin has further undermined the island's eclgical balance. S man shuld make an attempt t restre the island's natural balance.
2. D yu think it was right t eradicate the “pest” frm Macquarie Island? Give yur reasns.
1. I think it wrng t eradicate the “pest” there. Here are sme reasns. 2. Withut pests, there wuld be n creatures that feed n them, and cuntless creatures wuld be wiped ut, causing great damage t bidiversity and resulting in a mre serius cnsequence than the existence f these s-called pests.
Think & Share
3. Hw culd similar situatins be avided in the future?
1. The intrductin f bilgical species resurces frm abrad shall be registered r examined and apprved accrding t law, and crrespnding safety cntrl measures shall be taken. 2. The gvernment shuld make the cntinuus imprvement f the existing laws n the intrductin f alien species. 3. Deepening internatinal cperatin, preventin and cntrl f alien species invasin will surely achieve greater results.
Language appreciatin
1. This in turn led t mre cats hunting the birds. The end result was that parakeets, nce large in number and native t the island. •[句式分析] “in turn”: 反过来； “mre cats hunting the birds” 动名词的复合结构作宾语；“that the island”为that引导的表语从句。 •[尝试翻译] 这反过来又导致更多猫捕食鸟类。最终结果是，曾经数量众多，原产于该岛的长尾鹦鹉于1891年灭绝了。
2. Experts felt it necesary t cme up with a plan t remve all the rabbits frm the island. •[句式分析]“felt it necessary”构成动词+it (“it”作形式宾语)+ adj(作宾语补足语)，“t cme up with a plan” 不定式短语为真正主语后置；“t remve all the rabbits frm the island”为不定式短语作后置定语，修饰plan. •[尝试翻译] 专家认为有必要提出一项计划，把所有的兔子从岛上赶走。
3. It turned ut that they develped an immunity t the virus, and their numbers explded nce again. •[句式分析] “It”作形式主语； that引导的主语从句后置；“an immunity t the virus” 意为“对病毒的免疫力”； “nce again”意为“再一次”•[尝试翻译] 结果它们对病毒产生了免疫力，而它们的数量再次激增。
Language pints