How-life-began-on-the-earth-阅读课件(公开课).ppt

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1、How Life Began on the EarthDo you know how life began on earth is explained in different religions and cultures? Pangu separates the sky from the earth God created the world in seven daysSome legends about the beginning of universe.What is the scientific theory about the beginning of life on the ear

2、th?That is the topic we are going to talk about.Follow me, We will get it Read the passage quickly to catch the main idea of the passage :Topic:_Key words:_-_-_-_Key words:1._2._3._4._ Topic: _ How Life Began on the earthairwaterplantsanimalsNew words The universebegan with a“Big Bang”. Stephen Will

3、iam Hawking,put forward a theory about black holes.理论，学说i:ri：The most powerful force in the univers is atomic bomb 原子的(adj)atom原子tmCarbon ,nitrogen,water vapour and other k:bn naitrdn veipgases are to make the earhs atmosphere.tmsfi mltiplaiPlants multiplied and filled the oceans and sea with oxgena

4、mphibiansmfibinAmphibians can live in the water as well as on land.Reptiles produced young generallybylaying eggsreptail mmlMammals like monkeysgave birth to young baby animals and produced milk to feed them. ,fndmentlWater was to be fundamental to the development of life.be base onWater allowed the

5、 earth to dissove hurmful gases and acids into the oceans. This produced a chain reaction,which made it possible for life to develop. k:bn daiksaidThey are putting too much carbon dioxide into the atmosphere ,which prevents heat from escaping the earth into spacein time 及时及时lay eggs 下蛋下蛋give birth t

6、o 分娩分娩in one turn 轮到某人轮到某人prevent .from.=stop fromRead the text quickly and match the main idea for each paragraph.Para. 1 The formation(形成形成) 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

7、their impact on the earth. Para. 5 The development of plants and animals on the earth. A cloud of 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) atmospher

8、eatmosphereCool downCool downwater appearedwater appeared Life Life began and began and developeddevelopedplants-animalsFish and shellfishamphibiansretilesdinosaursMammalshuman beings Work in pairs: Put the order of developmentof life into a timeline first according to your common sense, and then ac

9、cording to the reading passage. 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 plant

10、s grew on the water.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. 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 differ

11、ence between 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: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 prod

12、uce too much carbon dioxide which causes the global warming on the earth. 8. According to the text, human beings would disappear in the end. FFTF1. 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 first appear i

13、n the seas? 4. Why did green plants help life to develop? 5. Why were mammals different from other animals?Answer the following questions :1. What was there on the earth before life could begin? Water _, carbon _, o_, nitrogen and other gases.vapourdioxideoxygen2. Why do scientists think there has n

14、ever 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 gases4. Why did green plants help life to develop? Because green plants can take _ from the atmosphere and fi

15、ll the air with _carbon dioxideoxygen.5. Why were mammals different from other animals? They were different because they gave birth to young baby animals and produced milk to feed themIII. Read the text and fill in the blanks in the following form.TimeWhat happenedBig Bang_ began to form and combine

16、 to create stars and other bodies.AtomsBetween 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 oceans and seas.violentatmospherepresenceacidsMany millions of yea

17、rs 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.oxygenshellfishamphibiansMany millions of years later_ appeared and they laid eggs.Dinosaurs developed, laid eggs and _ for more than

18、 140 million years.Mammals rose and _ babies.Reptilesexistedgave birth toAbout 2.6 million years agoSome small _ animals with hands and feet appeared and spread all over the earth.NowHumans produce too much carbon _, making the earth too hot.cleverdioxideThe development of lifeThe development of lif

19、eA cloud of dust a solid ball presence of water on the water shellfish & other fish plants begin to grow on dry land insects and amphibians appear retiles appear dinosaurs appear mammals appearTheThe development of life development of lifesmall plants growon the water appearshellfish & other fishplants begin to grow on drylandinsects and amphibians appearreptiles appeardinosaurs appearmammals appearThank you very much.Good bye!结束结束