Howlifebeganontheearth阅读公开课PPT课件

1、How Life Began on the Earth第1页/共50页Do you know how life began on earth is explained in different religions and cultures? 第2页/共50页Pangu separates the sky from the earth 第3页/共50页God created the world in seven days第4页/共50页Some legends about the beginning of universe.What is the scientific theory about

2、the beginning of life on the earth?That is the topic we are going to talk about.Follow me, We will get it第5页/共50页 第6页/共50页Read the passage quickly to catch the main idea of the passage :Topic:_Key words:_-_-_-_第7页/共50页Key words:1._2._3._4._ Topic: _ How Life Began on the earthairwaterplantsanimals第8

3、页/共50页New words The universebegan with a“Big Bang”.第9页/共50页 Stephen William Hawking,put forward a theory about black holes.理论，学说i:ri：第10页/共50页The most powerful force in the univers is atomic bomb 原子的(adj)atom原子tm第11页/共50页Carbon ,nitrogen,water vapour and other k:bn naitrdn veipgases are to make the

4、earhs atmosphere.tmsfi第12页/共50页 mltiplaiPlants multiplied and filled the oceans and sea with oxgen第13页/共50页amphibiansmfibinAmphibians can live in the water as well as on land.第14页/共50页Reptiles produced young generallybylaying eggsreptail第15页/共50页 mmlMammals like monkeysgave birth to young baby anima

5、ls and produced milk to feed them.第16页/共50页 ,fndmentlWater was to be fundamental to the development of life.be base on第17页/共50页Water allowed the earth to dissove hurmful gases and acids into the oceans. This produced a chain reaction,which made it possible for life to develop.第18页/共50页 k:bn daiksaid

6、They are putting too much carbon dioxide into the atmosphere ,which prevents heat from escaping the earth into space第19页/共50页in time 及时lay eggs 下蛋give birth to 分娩in one turn 轮到某人prevent .from.=stop from第20页/共50页Read the text quickly and match the main idea for each paragraph.第21页/共50页Para. 1 The for

7、mation(形成) of the earth.Para. 2 The importance of water for life.Para. 3 A widely accepted theory about the formation of the universe.Para. 4 The arrival of humans and their impact on the earth. Para. 5 The development of plants and animals on the earth.第22页/共50页 第23页/共50页第24页/共50页第25页/共50页A cloud o

8、f dustA cloud of dustCombine into a Combine into a solidsolid ball ballExplodeExplodewith fire & rockwith fire & rock(produce H(produce H2 2O, COO, CO2,2,OO2, 2, NN2, 2, other gases)other gases) atmosphereatmosphereCool downCool downwater appearedwater appeared Life Life began and began and

9、developeddevelopedplants-animals第26页/共50页Fish and shellfish第27页/共50页amphibians第28页/共50页retiles第29页/共50页dinosaurs第30页/共50页Mammals第31页/共50页human beings第32页/共50页Work in pairs: Put the order of developmentof life into a timeline first according to your common sense, and then according to the reading pas

10、sage. 第33页/共50页10 73 8 4 9 6 1 5 2 12 111. Insects and amphibians appeared.3. The earth became a solid ball.5. Reptiles appeared.7. The earth was a cloud of dust.9. Shellfish and other fish appeared.11. Clever animals with hands and feet appeared.2. Dinosaurs appeared.4. Small plants grew on the wat

11、er.6. Plants began to grow on dry land.8. Water appeared on the earth.10. The universe began with a Big Bang.12. Mammals appeared.第34页/共50页 True (T) or False (F).1. The earth appeared before the Big Bang happened.2. The original atmosphere consisted of nitrogen and oxygen. 3. The main difference bet

12、ween the earth and other planets is that there is water on the earth. 4. Life began in water and then on land.FFTTDiscuss in groups:第35页/共50页5. Mammals appeared before the development of dinosaurs.6. Dinosaurs could give birth to young baby animals and produced milk to feed them. 7. Human beings pro

13、duce too much carbon dioxide which causes the global warming on the earth. 8. According to the text, human beings would disappear in the end. FFTF第36页/共50页1. What was there on the earth before life could begin? 2. Why do scientists think there has never been life on the moon? 3. Why did animals firs

14、t appear in the seas? 4. Why did green plants help life to develop? 5. Why were mammals different from other animals?Answer the following questions :第37页/共50页1. What was there on the earth before life could begin? Water _, carbon _, o_, nitrogen and other gases.vapourdioxideoxygen第38页/共50页2. Why do

15、scientists think there has never been life on the moon? Because there is no _ on the moon.3. Why did animals first appear in the seas? Because water allowed the earth to _into the oceans and seas. waterdissolve harmful gases第39页/共50页4. Why did green plants help life to develop? Because green plants

16、can take _ from the atmosphere and fill the air with _carbon dioxideoxygen.第40页/共50页5. Why were mammals different from other animals? They were different because they gave birth to young baby animals and produced milk to feed them第41页/共50页III. Read the text and fill in the blanks in the following fo

17、rm.TimeWhat happenedBig Bang_ began to form and combine to create stars and other bodies.Atoms第42页/共50页Between 4.5 and 3.8 billion years agoDust settled into a solid and _ globe.The earth exploded to produce its_ .The continued _ of water allowed the earth to dissolve harmful gases and _ into the oc

18、eans and seas.violentatmospherepresenceacids第43页/共50页Many millions of years laterThe first small plants on the surface of the water produced_ .Early _ and all sorts of fish appeared.Green plants began to grow on land. Insects and_ appeared.oxygenshellfishamphibians第44页/共50页Many millions of years later_ appeared and they laid eggs.Dinosaurs developed, laid eggs and _ for more than 140 million years.Mammals rose and _ babies.Reptilesexistedgave birth to第45页/共50页About 2.6 million years agoSome small _ animals with hands and feet appeared and spread al