高中英语必修三第四单元课件

feed them.
Put the order of development of life.
• • • • • • • • • • • • 10 （ ）1 Insects and amphibians appeared. （7 ）2 Dinosaurs appeared. （3）3 The earth became a solid ball. （8）4 Small plants grew on the water. （4）5 Reptiles appeared. （9）6 Plants began to grow on dry land. （6）7 The earth was a cloud of dust. （1）8 Water appeared on the earth. （5）9 Shellfish and other fish appeared. （ ）10 The universe began with a “Big Bang”. 2 （ ）11 Clever animals with hands and feet appeared. 12 11 （ ）12 Mammals appeared.
Unit 4
Astronomy: the science of the stars
How much do you know about the universe?
What are the names of the eight planets that circle our sun? What is their order from the sun?
1. A composition about What we can do to take care of the earth? 2. Read and retell the passage to learn the
important and difficult language points.
Early shellfish and all sorts of fish
Some animals (amphibian & insects) came to land.
Reptile appeared.
dinosaurs
mammals
Man had evolved from apes.
human beings Para 5: The arrival of humans and their impact on the earth.
Answer the following questions.
1. What is the original earth’s atmosphere made up of? 2. Why did scientists believe water is fundamental to the development of life? 3. How did water come into being on the earth? 4. Which kind of life-being first appeared on the earth, plants or animals? Why? 5. Why were mammals different from all life forms in the past?
recycle rubbish
prevent desertification
Whether life will continue on the earth depends on human beings.
精讲点拨
• The earth became so violent that it was not clear whether the shape would last or not.
THE SOLAR SYSTEM Earth 地球 ______ Neptune 海王星 _______ Saturn 土星 ________ Uranus 天王星 _______ Venus 金星 ________
Jupiter 木星 ______
Mars 火星 ______ Mercury 水星 ________
Fast reading
Read the passage quickly and find the main idea. A brief introduction on how the universe developed and how life began on the earth.
Careful reading
Read the passage carefully and analyse its structure.
earth, accepted theory about the Para 1: A widely atmosphere and water formation of the universe.
• What many scientists believe is that the continued presence of water allowed the earth to dissolve harmful gases and acids into the oceans . 分析句子：
Homework
Let review the evolution of life on the earth.
After the “Big Bang”, the earth was full of water.
Original cells appeared in the ocean.
The cells in the water began to separate. Small plants came into being.
Very small air-breathing creatures. 4. Do you know what the order for the development of plants and animals is?
Ideas about how life began
reading
How Life Began on the Earth
Free Talk
1. How old is the universe? Several billion years ago. 2. How old is the earth?
Between 4.5 and 3.8 billion years ago. 3. Which were the first creature or plants on earth?
4. Which kind of life-being first appeared on the earth, plants or animals? Why? At first, small plants began to appear on the surface
of the water, they produce oxygen, which
Para 2: The formation of the earth. Para 3: The importance of water for life. life development Para 4: The development of plants and animals on the earth.
Because they are putting too much carbon dioxide into the atmosphere.
The earth may become too hot to live on .
The earth is becoming hotter and hotter!
wenku.baidu.com
1. What is the original earth’s atmosphere made up of? Carbon, nitrogen, water vapour, and other gases.
2. Why did scientist believe water is fundamental to the development of life? Because water allowed the earth to dissolve harmful gases and acids into the oceans and seas to ensure a following chain reaction, which made it possible for life to develop. 3. How did water come into being on the earth? The explosion of the earth produced water vapor, which turned into water when the earth cooled down.
Discussion We are making the world better. We are making the world worse.
What can we do to take care of the earth?
solar energy
purify air
plant trees
save water
encouraged the later development of early shellfish and all sorts of fish. 5. Why were mammals different from all life forms in the past? They were different because they produced their young from within their bodies and produce milk to