北师大版（2019） 选择性必修第一册 Unit 3 Conservation Lesson 1 The Sixth Extinction 课件13张

(共13张PPT)
Lesson 1
The Sixth Extinction
How much do you know about extinction
1 How many times up to today has life on Earth almost died out
a Once.
b Five times.
c More than 10 times.
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.
Match the main idea to each paragraph.
Para.1
Para.2
Para.3
Para.4
the main reasons of the sixth extinction
ways to avoid it
background history about extinction
the potential influence of the sixth extinction
96%
dinosaurs
asteroids
sea levels
oxygen content
Para1
Scientists found that human activity is causing species to die out 1,000 times faster than normal.
Para2
the main reasons of the sixth extinction
1. What did scientists find out in 2015
2. What are the main reasons
Air and water pollution
Forests being destroyed
Factory farming
Overfishing
Up to_________ quarters of all species on Earth could be wiped out, including ___________________ .
Para 3
the potential influence of the sixth extinction
1. What is the potential influence
human beings
three
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.
Para 3
the potential influence of the sixth extinction
Para 4
ways to avoid it
1. How to avoid the sixth extinction
take steps to save endangered species,including setting up special areas where plants and animals can be protected
change how we work and travel by using cleaner water,more natural sources of energy,such as wind and solar energy
improve our farming methods to reduce water,air and land pollution
Complete the paragraph about extinctions using the correct form of the phrases below.
die out be known as have affected
depend on wipe out take steps
take action set up take care of
die out be known as have affected
depend on wipe out take steps
take action set up take care of
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.
was known as
died out
has affected
depend on
die out be known as have affected
depend on wipe out take steps
take action set up take care of
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.
take steps
take action
set up
take care of
wipe out