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(共19张PPT)
Unit 5
When you see the title of this unit, what do you think it is about
Why is our world delicate
Unit 5 A delicate world
To watch a video and answer the questions
To look at the satellite images and talk about their changes
To reflect on the impact of human activities on the planet
View the video and talk about your understanding of the sentence:
We were born from nature,
and we are part of nature.
What is ecosystem
An ecosystem is a geographic area
where plants, animals, and other
organisms, as well as weather and
landscapes, work together to form a bubble of life. When we are talking about the ecosystem, most of us would only think about animals and plants. But the truth is our daily activities are playing a vital (极其重要的) role in nature just like everything else.
1. Are humans part of Earth's ecosystems Why
2. In what ways can humans affect ecosystems
Watch the video and answer the questions.
1
2. In what ways can humans affect ecosystems
Humans can affect ecosystems in positive and negative ways. For example, to have a positive influence on ecosystems, people can plant trees, feed and protect animals, recycle things, etc. However, deforestation, air and water pollution and excessive waste affect ecosystems in a negative way.
1. Are humans part of Earth's ecosystems Why
Yes. Humans are part of Earth’s ecosystems. Because all the living things live in ecosystems and people are living things.
Watch the video again and discuss what we can do to keep the balance of the whole ecosystem.
Look at the satellite images and talk about what you can see in them.
1990: The Aral Sea still appears as a large, dark blue body of water, clearly visible from space.
2000: The sea has shrunk dramatically, especially in the eastern part.
2010: The sea has almost disappeared, with only a thin strip of water remaining.
Look at the satellite images and answer the questions.
1. What is happening to the area according to the satellite images
Aral Sea is becoming smaller and smaller/ shrinking.
2. What do you think a later satellite image would show
The water area will be even smaller.
2
The Aral Sea Crisis
The Aral Sea is situated in Central Asia, between Kazakhstan to the north and Uzbekistan to the south. It was once the world's fourth largest lake, and contained 10 grammes of salt per litre. The rivers flowing into the Aral Sea are the river Syr Darya from the north and the river Amu Darya from the south. In the 1960s, the two rivers were diverted away from the Aral Sea so that people could irrigate the surrounding desert region and focus on cotton production.
As a result, the Aral Sea has been decreasing in size, and by 1997, it had shrunk to a tenth of its original size, splitting into four lakes. By 2009, the south-eastern lake had disappeared altogether, and the south-western lake had been reduced to a thin strip, with a salinity level of more than 110 grammes per litre.
This shrinking of the Aral Sea became known as “one of the planet’s worst environmental disasters”; the decline of the once-thriving fishing industry brings unemployment and economic hardship to the surrounding region.
3. What do you think caused these changes
The Aral Sea began shrinking in the 1960s because the two rivers that fed it—the Amu Darya and the Syr Darya—were diverted to grow cotton and other crops.
Much of the water was lost through leaks and evaporation.
Cities and factories along the rivers use more water, further reducing the amount that can reach the Aral Sea.
What are the environmental impacts of the Aral Sea’s shrinking
How did the shrinking affect the local communities
What efforts are being made / can be made to restore the Aral sea
Earth provides enough to satisfy every man’s needs, but not every man’s greed.
地球提供（的东西）能满足每个人的需求，而不是每个人的贪念。
The world now is trying to act to protect the ecosystem. List some activities you know.
Surf the Internet and collect some information about Macquarie Island.
唯有了解，我们才会关心；
Only if we understand can we care.
唯有关心，我们才会采取行动；
Only if we care will we help.
唯有行动，生命才会有希望。
Only if we help shall all be saved.

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