2. Unit 4 Astronomy: the science of the stars

3. Para.1 Para.2 Para.3 Para.4 Para.5 A________ about how the universe was formed The__________ of the earth The importance of______ for life The_______________ of plants and animals The arrival of _________ and their effects on the earth theory formation water development humans How life began on the earth Before life appeared. Different lives developed.

4. Part1 (para1~3) Before life appeared According to a widely accepted theory, how did the stars form? How did the earth’s atmosphere form? Why was the earth different from the other planets? What a role the water played in the development of life?

5. 1. According to a widely accepted theory, how did the stars form? 2. How did the earth’s atmosphere form? The universe began with a “Big Bang” that threw matter in all directions, then atoms began to form and combine to create stars. The earth was so violent. It exploded loudly with fore and rock to produce carbon, nitrogen, water vapor and other gases, which were to make the atmosphere.

6. 3. Why was the earth different from the other planets? 4. What a role the water played in the development of life? Because the water on other planets had disappeared later. The presence of water allowed the earth to dissolve harmful gases and acids into the oceans and seas. This produce a chain reaction which made it possible for life to develop

7. The earth was just a cloud of dust whose future is _________ after the “Big Bang”. Then the dust began to settle into a _______ ball which is so ________ and _______ loudly with fire and rock, to be in time to produce many things, which make the earth’s ___________. As the earth cooled down, ________ began to appear and people think it is important for the beginning of life. It allowed the earth to dissolve ________ gases. Then life began to develop. uncertain solid violentexploded atmosphere water harmful ︶ ︶ ︵ I felt lonely and life was dull at that time.

8. Part2 (para4~5) How the life developed 1.Make a timeline of the development of life 2.Why did the plants grow before the animals came? 3.Why is it wrong in films and stories to show dinosaurs and people together?

9. 1. 2. 3. 4. 5. 6. small plants On surface of water Early shellfish and all sorts of fish green plants on land land animals insects (on land) amphibian (on land and in water) Mammals--- clever animals forests reptiles (huge animal-- dinosaurs)

10. 3. Why is it wrong in films and stories to show dinosaurs and people together? 2.Why did the plants grow before the animals came? Because plants provide oxygen for animals to breathe. Because dinosaurs died out long before human beings developed on the earth.

11. ︵ ︶ Nobody understood plants were the start of changes. They ___________ and filled the first oceans and seas with oxygen. This encouraged the _____________ of early shellfish and fish. Land animals such as insects, amphibians, reptiles and dinosaurs and so on _________ after the first green plants appeared. Dinosaurs disappeared, which made possible the rise of _____________ on the earth. Then small clever animals ____________ all over the earth. multiplied development spread With so many friends on me, I was happy. followed mammals

12. Humans developed new ________ of growing, hunting and moving around. As time went by they covered the earth. Now _______ carbon dioxide has been putting into the __________, which ________ heat_____ escaping from the earth into space. As a result, the problem of ______________ occurs. Whether life will continue on the earth for millions of years to come will ___________ whether this problem can be solved. means from prevents Now, I’ m worried about the future of myself and humans… depend on ︹ too much atmosphere global warming

13. According to the pictures, have a try to retell the development of life.

17. Suppose you were the earth, what would you advise humans to do? Write a letter to the human being.

18. Para1 1 a widely accepted theory 2 begin with 3 in all directions Para2 1.What it was to become was uncertain until between 4.5 and 3.8 billion years ago when the dust settled into a solid globe. 2.The earth became so violent that it was not clear whether the shape would last or not. 3.What is even more important is that as the earth cooled down, water began to appear on its surface.

19. Para3 1.It was not immediately obvious that water was to be fundamental to the development of life. 2.What many scientists believe is that the continued presence of water allowed the earth to dissolve harmful gases and acid into the oceans and seas. 3 make it possible for life to develop Para4 1 on the surface of the water 2 fill the oceans and seas with oxygen 3 live on land as well as in the water 4 produce young by laying eggs 5 the age of the dinosaurs 6 remain a mystery 7. This disappearance made possible the rise of mammals on the earth.

20. Para5 1 spread 2. They are putting too much carbon dioxide into the atmosphere, which prevents heat from escaping from the earth into space. 3. As a result of this, many scientists believe the earth may become too hot to live on. 4. Whether life will continue on the earth for millions of years to come will depend on whether this problem can be solved.