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(共20张PPT)
Unit 3 Conservation
Lesson 1 The Sixth Extinction
重点单词
1．____________ n. 物种，种
2．____________ adj. 异常的；不平常的
3．____________ adj. 大量的
4．____________ adj. 各种各样的，形形色色的
5．____________ vi. & vt. 减少 n.减少；减少的量
6．____________ vt. 责怪，指责
7．____________ vt. 影响
8．____________ adj. 濒危的
9．____________ adj. 太阳光（能）的
10．____________ vi. & vt. （使）孵化
11．____________ vt. （使）恢复
species　
unusual　
mass　
varied　
decrease
blame　
affect　
endangered　
solar　
hatch　
restore　　
重点词块
1．at the rate of… ________________
2．be based on… ________________
3．lay eggs ________________
4．be at risk ________________
5．wipe out ________________
6．die out ________________
7．up to… ________________
8．in short ________________
9．according to ________________
10．take steps ________________
11．be to blame ________________
以……的速度/比例　
基于……　
产卵/下蛋　
处境危险；受到威胁　
彻底毁灭　
消失；绝迹；灭绝
高达……　
简而言之　
根据；按照　
采取措施　
把……归咎于　
(　　) 1. How many times up to today has life on Earth almost died out
a. Once. b. Five times. c. More than 10 times.
1.How much do you know about extinction Choose the option based on your knowledge.
(　　) 2. About what percent of all species on Earth became extinct during the mass extinction known as the “Great Dying”
a. Less than 10%. b. Nearly 50%. c. More than 90%.
(　　) 3. What do scientists think will cause the next mass extinction
a. Human activity. b. Natural causes. c. Unknown reasons.
b
c
a
2. Read and explore.
Read a text about extinction. Then check your answers in Activity 1.
①Extinctions, where entire species are wiped out, are not unusual in our Earth’s history. In fact, over 90 percent of all species that ever lived are now extinct. In the last 500 million years, there have been five times when life on Earth has almost ended. These include the third mass extinction, known as the “Great Dying”, which killed 90% to 96% of all species. And the fifth event, which occurred 66 million years ago, caused the death of the dinosaurs. The reasons for extinctions are varied. According to scientists, they include volcanic eruptions, asteroids hitting the Earth from space, changes in sea levels, the decrease of the oxygen content of the sea and global warming. Many scientists say we are now entering the Earth’s sixth mass extinction. This time, human activity will be to blame.
非限制性定语从句
限制性定语从句
限制性定语从句
非限制性定语从句
非限制性定语从句
承上启下
② Although it is not unusual for species to die out naturally, the rate at which this is now happening is cause for concern. A 2015 study by scientists who were based at Brown University and Duke University in the US, looked at how quickly species die out due to natural causes, that is, the “background extinction rate”. They found that human activity is causing species to die out 1,000 times faster than normal. There is a long list of reasons why so many species are dying out: air and water pollution, forests being destroyed, factory farming and overfishing. It is clear that human activity has negatively affected all other species on Earth, including animals and plants.
双重否定,表示肯定
It is adj for sb/sth to do sth
做...对某人/某物来说...
限制性定语从句
限制性定语从句
宾语从句
It is adj that ...
...是怎么样的
If a sixth mass extinction occurs, scientists who have studied the issue believe that up to three quarters of all species on Earth could die out. Of course, as we humans depend on so many species for our survival, we would also be at risk of dying out. Our world and our lives depend on the balance in nature between animals and plants. Without forests, we would have no air to breathe, and without clean water we would be unable to survive.
限制性定语从句
宾语从句
因为
the n between A and B
A和B之间的...
例：the competition between A and B
A和B之间的竞争
Can a sixth extinction be avoided Experts say that it is not yet too late, if we take action now. This would mean we have to significantly change the way we live. For example, we need to take steps to save endangered species, including setting up special areas where plants and animals can be protected. We need to change how we work and travel by using cleaner, more natural sources of energy, such as wind and solar energy. We also need to improve our farming methods to reduce water, air and land pollution. In short, if we want to survive, we need to stop destroying the planet that we live on and start to protect it.
be done(动词的过去分词) 被动语态
限制性定语从句
For instance
表目的
表条件
The Black Robin
Black robins are the birds that humans saved from extinction. In 1980, there were only five black robins left in the world. They all lived on a small island off the coast of New Zealand. Only one of those birds, a female called Old Blue, was able to lay eggs. Wildlife workers began a programme for raising black robin chicks. They protected Old Blue’s eggs, helped them to hatch, and took care of the chicks.（幼鸟） Thanks to their efforts, there are now more than 250 black robins, and the population（数量） is spreading. To help them survive, people are restoring their habitats and removing small animals that hunt them, such as mice and cats from the islands where they live.
Case Study
robin n. 知更鸟
habitat n. 栖息地
限制性定语从句
定语
多亏，由于
限制性定语从句
练一练
extinction
species
wipe sth out
global warming
die out
a situation in which something no longer exists
in danger of being harmed or lost
the natural environment in which an animal or plant usually lives
a set of animals or plants in which members have similar characteristics to each other
to destroy something completely
a gradual increase in world temperatures caused by gases such as carbon dioxide that are collecting in the air around the Earth and stopping heat escaping into space
to become less common and finally stop existing
endangered
habitat
(　　) 1. How many times up to today has life on Earth almost died out
a. Once. b. Five times. c. More than 10 times.
Activity 1
How much do you know about extinction Choose the option based on your knowledge.
(　　) 2. About what percent of all species on Earth became extinct during the mass extinction known as the “Great Dying”
a. Less than 10%. b. Nearly 50%. c. More than 90%.
(　　) 3. What do scientists think will cause the next mass extinction
a. Human activity. b. Natural causes. c. Unknown reasons.
b
c
a
Activity 2
Extinctions, where entire species are wiped out, are not unusual in our Earth’s history. In fact, over 90 percent of all species that ever lived are now extinct. In the last 500 million years, there have been five times when life on Earth has almost ended. These include the third mass extinction, known as the “Great Dying”, which killed 90% to 96% of all species. And the fifth event, which occurred 66 million years ago, caused the death of the dinosaurs. The reasons for extinctions are varied. According to scientists, they include volcanic eruptions, asteroids hitting the Earth from space, changes in sea levels, the decrease of the oxygen content of the sea and global warming. Many scientists say we are now entering the Earth’s sixth mass extinction. This time, human activity will be to blam
Read a text about extinction. Then check your answers in Activity 1.
Activity 2
Although it is not unusual for species to die out naturally, the rate at which this is now happening is cause for concern. A 2015 study by scientists who were based at Brown University and Duke University in the US, looked at how quickly species die out due to natural causes, that is, the “background extinction rate”. They found that human activity is causing species to die out 1,000 times faster than normal. There is a long list of reasons why so many species are dying out: air and water pollution, forests being destroyed, factory farming and overfishing. It is clear that human activity has negatively affected all other species on Earth, including animals and plants.
Read a text about extinction. Then check your answers in Activity 1.
Activity 2
If a sixth mass extinction occurs, scientists who have studied the issue believe that up to three quarters of all species on Earth could die out. Of course, as we humans depend on so many species for our survival, we would also be at risk of dying out. Our world and our lives depend on the balance in nature between animals and plants. Without forests, we would have no air to breathe, and without clean water we would be unable to survive.
Read a text about extinction. Then check your answers in Activity 1.
Activity 2
Can a sixth extinction be avoided Experts say that it is not yet too late, if we take action now. This would mean we have to significantly change the way we live. For example, we need to take steps to save endangered species, including setting up special areas where plants and animals can be protected. We need to change how we work and travel by using cleaner, more natural sources of energy, such as wind and solar energy. We also need to improve our farming methods to reduce water, air and land pollution. In short, if we want to survive, we need to stop destroying the planet that we live on and start to protect it.
Read a text about extinction. Then check your answers in Activity 1.
The Black Robin
Black robins are the birds that humans saved from extinction. In 1980, there were only five black robins left in the world. They all lived on a small island off the coast of New Zealand. Only one of those birds, a female called Old Blue, was able to lay eggs. Wildlife workers began a programme for raising black robin chicks. They protected Old Blue’s eggs, helped them to hatch, and took care of the chicks. Thanks to their efforts, there are now more than 250 black robins, and the population is spreading. To help them survive, people are restoring their habitats and removing small animals that hunt them, such as mice and cats from the islands where they live.
Case Study
Notes
robin n. 知更鸟
habitat n. 栖息地
People protected Old Blue’s eggs, helped them to hatch, and took care of the chicks.
People are restoring their habitats and removing pests like mice and cats from the islands where they live.
The case study showed that even in desperate situations, we can do something to help. In short, it’s never too late.
4. What did people do in the case study to protect black robins Which claim(s) did the case study support in the text
In the last 500 million years, there have been five mass extinction events on Earth. In the third event, which 1. __________ the “Great Dying”, 90% to 96% of all species 2. _________. Of course, species died out due to many causes. But nowadays, human activity 3. ___________ all types of species that we 4. ___________ for living. We need to 5. ___________ to avoid the sixth mass extinction. We should 6. __________ to save endangered animals and plants, and 7. _______ special areas to 8. ___________ them before the next extinction comes that may 9. _________ the entire species.
die out be known as have affected depend on wipe out
take steps take action set up take care of
Complete the paragraph about extinctions using the correct form of the phrases below.
is known as
died out
has affected
depend on
take action
take steps
set up
take care of
wipe out
Summary
write an essay to express your opinions on the sixth extinction.
Homework
Let her smile
Don’t let her cry.

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