外研版（2019）选择性必修第二册Unit 5 A delicate world Understanding ideas 课件(共18张PPT)

(共18张PPT)
Macquarie Island:
from Chaos to Conservation
Learning aims
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 humans’ actions on ecology and the
importance of ecological balance.（生态平衡）
Look at the picture and answer the questions.
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 the native vegetation, thus upsetting the local ecological balance.
Penguins , elephant seals , wild birds
Read for structure
Part 1 Para_____　　
Part 2 Paras　 　
Part 3 Paras　　
the _________ of the island
the_______________ of the island
the ________________ of the island
1
beauty
2-3
chaos
4-6
conservation
Look through the passage, divide it into three parts, and get the main idea of each part.
Read for details
the beauty of the island
long and thin shape
green grass and bare rocks
_________________
_________________
__________________
wild
natural
harmonious
In what ways can we find Macquarie island is beautiful
World Heritage Site
beauty
Read part 1(para.1) and answer the question:
native inhabitants
natural habitat
1 I am standing on Macquarie Island, in the South west 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 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 years.
the chaos of the island
1. What was brought to the island
2. What happened after they reached the island
Read part 2(paras.2-3) and finish the following tasks.
Read part 2(paras.2-3)and finish the following tasks.
the chaos of the island
1. What was brought to the island
rats&mice
cats
rabbits
2. What happened after they reached the island
took over…
ate …
attacked …
ate birds
multiplied
ate vegetation
dig holes
soil erosion
more cats
_______ birds
fewer
____________ destruction
landscape
have a ______effect on ecology
bad
！
humans
on purpose
possible results
Humans __________ actions
careless
2 But the island's more recent history tells a different story. It's a tragic story that began in 1810 when humans arrived on the island. In their ships they unknowingly 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 introduced to the island as a source of food for humans. Loose on the island, they did what rabbits do best—they 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 cats 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 conservation of the island
time
measure(s)
purpose(s)
result(s)
Read part 3(paras.4-6) & postscript, and fill in the blanks.
after the 1970s
in the 1980s
after 2006
release_______
use__________
drop poison
use_______
to remove
rabbits
to_______
to remove all
fewer_________
but_____ birds
pest
fewer
cats
no ____
but ______rats
______rabbits
land collapse
more
more
_____free in 2014
virus
traps &dogs
dogs
kill cats
rabbits
proper
to solve it once and for all
Humans’____________measures may do greater harm to ecology.
improper
Deeper thinking:
What do you think is to blame for the chaos in Macquarie Island
rats&mice
cats
rabbits
human’s careless behaviors
human's improper measures
“We humans owe it to the island to give it a happy ending.”
Human
beauty
Summary
chaos
conservation
harmony
4 Even after Macquarie Island became an official nature reserve in the 1970s, the rabbits remained out of control. Experts 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 turned their attention—and their stomachs—back 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 cat's away, the mice will play.” With the departure of the cats from 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 penguins. 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 remaining invading species, and that's where I come in—with my dogs. They have been trained to find every last one, without harming the native animals. This intervention is a long, much－delayed ending to a sad story, but we humans owe it to the island to give it a happy ending.
Postscript: In 2014, Macquarie Island was declared pest free and the island's ecology is finally on the road to recovery.
After reading
Understanding ideas
3. Choose the author’s 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 Macquarie 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！