how life began on the earth 公开课课件.ppt

1、Unit 4 Astronomy: the science of the stars,We live on the same planet the earth,1. Do you know the origin of life on earth?2. Each religion or culture has its own ideas about how life began on earth.,In Chinese culture,_ separates(分) the sky from the earth.,Pangu 盘古,sky,earth,_ made human beings.,Nu

2、wa (女娲),In western countries: _ created the world and all living things.,God (上帝),Do you know what a scientific idea is?,Background knowledge The Big Bang is the term used to describe a huge explosion that scientists believe happened about 15 billions years ago. Nobody knows what caused the Big Bang

3、. But it was the event that created our universe.,The Big Bang,Pre-reading,The universe began with a Big Bang.,While-reading,Read the passage on P25 quickly, and match the right main idea of each paragraph. How many parts can the text be divided into?,Step 1. Fast reading,How life began on the earth

4、,Para.1 Para.2 Para.3 Para.4 Para.5,A theory about how the universe was formed,The formation(形成） of the earth,The importance of water for life,The development of plants and animals,The arrival of humans and their effects on the earth,Part1: The development of the earth,Part2:The development of life.

5、,( 2 ) Detailed Reading,Part 1(13): The development of the earth,Part1 (para13) The development of the earth,(1) After the Big Bang, what happened? (2) What happened to the solid globe next? (3) What did the water vapour and gases were to make? (4) What appeared after the earth cooled down? (5) What

6、 did the water do?,How did the earth come into being?,(1) After the Big Bang, what happened?,a cloud of dust,a violent solid ball,Settled into,exploded with fire and rock,produced water vapour and gases,(2) What happened to the solid globe next?,In time,(3) What did the water vapour and gases were t

7、o make?,the earths atmosphere,Water appeared on its surface which is important for the beginning of life on the earth.,(4) What appeared after the earth cooled down?,(5) What did the water do?,It allowed the earth to dissolve harmful gases and acids into the oceans and seas.,a cloud of _,Big Bang,a

8、solid _,slowly combine,the earth _ down,it exploded loudly with _ and _,water,the earths _,dust,ball/globe,fire rock,atmosphere,cooled,How did the earth come into being(产生）?,According to the pictures, have a try to retell the development of life.,A cloud of energetic dust,A solid ball,Atmosphere,A w

9、orld full of water,4,1,3,2,dissolve harmful gases,Part 2 (45) The development of life,Part2 (para45) The development of life,Read para4 carefully and make a timeline of the development of life,water,1.,2.,10.,3.,4. insects (on land) 5.,6.,7._ 8. dinosaurs (on land) 9._,11.,small _ in water,_ and all

10、 sorts of fish,green plants on land,_(on land and in water),forests,(on land),(on land),small clever animals with _,plants,shellfish,amphibians,reptiles,mammals,hands and feet,1. a timeline of the development of life,the cleverest animals,The arrival of _ encouraged the _of early _. Many millions of

11、 years later _ began to appear _. Later _ appeared. Some were_. Others called _, were able to live on lands well as _. When the plants grew into forests, _appeared for the first time. After they disappeared, _became more important. They were the last group of animals different from because they _mil

12、k from within their bodies.,development,shellfish and all sorts of fish,on land,land animals,amphibians,dinosaurs,mammals,produced,small plants,the first green plants,insects,in the sea,Read pare5 carefully .find out the answer. 1. What problem is caused by human being?,They caused global warming.,S

13、tep5:discussion,The earth is getting warmer each year.what effects will this have? How to solve this problem?,Suggested Answers: The earth will be so hot that no life will exist（存在）on the earth any more. To solve this problem, people should protect the earth carefully. They must stop putting too much carbon dioxide into the air , reduce pollution, control th