外研版（2019）选择性必修第二册 Unit5 A delicate world Starting out and Underatanding ideas 名师课件(共23张PPT)
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| 名称 | 外研版（2019）选择性必修第二册 Unit5 A delicate world Starting out and Underatanding ideas 名师课件(共23张PPT) |  | |
| 格式 | pptx | ||
| 文件大小 | 32.9MB | ||
| 资源类型 | 教案 | ||
| 版本资源 | 外研版（2019） | ||
| 科目 | 英语 | ||
| 更新时间 | 2023-03-03 23:09:21 | ||
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(共23张PPT)
Unit5 A delicate world
Starting out and understanding ideas
Ⅰ
Ⅱ
Ⅲ
CONTENTS
Starting out
Homework
Understanding ideas
Starting out
Part 1
What is an ecosystem
What is an ecosystem
All the animals and plants in a particular area, and the way in which they are related to each other and to their environment.
Are humans part of Earth’s ecosystems Why
In what ways can humans affect ecosystems
BAD
Good
Let’s enjoy the video!
1 What is happening to the area according to the satellite images
2 What do you think a later satellite image would show
3 What do you think caused these changes
The Aral Sea is shrinking because its water are being used for irrigation.
The Aral Sea was the world’s fourth largest lake up until the third quarter of the 20th century. However, in the 1960s, two rivers, which used to be its main sources of water income, were diverted so that they could irrigate the desert in order to favor agriculture. Although irrigation helped develop agriculture, it destroyed the Aral Sea.
Understanding ideas
Part 2
1 What animals can you see in the picture
Read the passage, then answer the question.
1
2 What kind of changes would take place if cats, rats and rabbits were introduced to an environment like this
Group Discussion
Read the passage, then answer the question.
What happened to Macquarie Island
2
TIMELINE
in 1810
in 1891
in the 1970s
in the 1980s
in 2006
in 2014
pest free
Choose the author’s purpose in writing the passage and give your reasons.
To analyse how Macquarie Island was saved from destruction.
To inform readers of the chaos caused on Macquarie Island by humans.
To entertain readers with a funny story about what happened on Macquarie Island.
To suggest ways in which an ecosystem can be protected.
3
Read the passage again, then answer the question.
Have a discussion in groups, organize information from the passage and complete the flow chart.
4
Pair work
Cats were brought to the island.
Rabbits were introduced to the island.
To prove food for
humans.
A virus was released onto the island.
Traps and dogs were used.
Poison and dogs were
used.
To remove all the rabbits from the island.
To catch the cats.
To remove all the remaining invading species.
The cats developed an appetite for the birds.
Rats and mice were brought there by accident, and they took over the island, eating the birds’ eggs and attacking baby birds.
Rabbits multiplied and caused soil erosion, and the exploding rabbit population provided plentiful food for the cats. This led to more cats hunting the birds. As a result, parakeets died out in 1891.
The island was pest-free and its ecology is on the road to recovery.
The departure of the cats resulted in an increasing population of rats and mice. And the rabbit population exploded once again.
Substantial reduction of rabbit population led to cats killing more native birds.
Talk bout how human interference led to such severe consequences for Macquarie Island.
Homework
Part 3
Homework
Write a summary according to the flow chart in Activity 4.(About 80 words)
Think and share: Q4—What language can you use to talk about cause and effect How would you apply it to your reading and writing
Unit5 A delicate world
Starting out and understanding ideas
Ⅰ
Ⅱ
Ⅲ
CONTENTS
Starting out
Homework
Understanding ideas
Starting out
Part 1
What is an ecosystem
What is an ecosystem
All the animals and plants in a particular area, and the way in which they are related to each other and to their environment.
Are humans part of Earth’s ecosystems Why
In what ways can humans affect ecosystems
BAD
Good
Let’s enjoy the video!
1 What is happening to the area according to the satellite images
2 What do you think a later satellite image would show
3 What do you think caused these changes
The Aral Sea is shrinking because its water are being used for irrigation.
The Aral Sea was the world’s fourth largest lake up until the third quarter of the 20th century. However, in the 1960s, two rivers, which used to be its main sources of water income, were diverted so that they could irrigate the desert in order to favor agriculture. Although irrigation helped develop agriculture, it destroyed the Aral Sea.
Understanding ideas
Part 2
1 What animals can you see in the picture
Read the passage, then answer the question.
1
2 What kind of changes would take place if cats, rats and rabbits were introduced to an environment like this
Group Discussion
Read the passage, then answer the question.
What happened to Macquarie Island
2
TIMELINE
in 1810
in 1891
in the 1970s
in the 1980s
in 2006
in 2014
pest free
Choose the author’s purpose in writing the passage and give your reasons.
To analyse how Macquarie Island was saved from destruction.
To inform readers of the chaos caused on Macquarie Island by humans.
To entertain readers with a funny story about what happened on Macquarie Island.
To suggest ways in which an ecosystem can be protected.
3
Read the passage again, then answer the question.
Have a discussion in groups, organize information from the passage and complete the flow chart.
4
Pair work
Cats were brought to the island.
Rabbits were introduced to the island.
To prove food for
humans.
A virus was released onto the island.
Traps and dogs were used.
Poison and dogs were
used.
To remove all the rabbits from the island.
To catch the cats.
To remove all the remaining invading species.
The cats developed an appetite for the birds.
Rats and mice were brought there by accident, and they took over the island, eating the birds’ eggs and attacking baby birds.
Rabbits multiplied and caused soil erosion, and the exploding rabbit population provided plentiful food for the cats. This led to more cats hunting the birds. As a result, parakeets died out in 1891.
The island was pest-free and its ecology is on the road to recovery.
The departure of the cats resulted in an increasing population of rats and mice. And the rabbit population exploded once again.
Substantial reduction of rabbit population led to cats killing more native birds.
Talk bout how human interference led to such severe consequences for Macquarie Island.
Homework
Part 3
Homework
Write a summary according to the flow chart in Activity 4.(About 80 words)
Think and share: Q4—What language can you use to talk about cause and effect How would you apply it to your reading and writing