Unit 4

Reading

How Life Began On The Earth

Leading-in

This unit is concerned with astronomy and how human beings first evolved on the earth and understand the universe around them. There are many different stories that tell how universe began.There are three statements of the origin of life.

Leading-in1 ．神造说 (God made) 这一假说认为地球上的各种生物

都是由神创造出来的，生命是上帝或神按照一定的目的，一次性地创造出来的。

2. 宇宙生命论 (Life in the universe) 这一假说提倡“一切生命来自生命”的观点，认为地球上最初的生命来自宇宙间的其他星球，即“地上生命，天外飞来”。

3. 非生命物质 (Non-living material) 地球上原本没有生命，生命起源于非生命物质。宇宙大爆炸 (Big Bang ) 后，地球只是一团尘埃，然后形成固体球状。经过后期的动荡，球体爆炸喷出烈火与岩石，并释放出碳、氮气、水蒸气和其他气体，形成地球大气层。地球冷却后，地面就有了水，形成了原始海洋。原始海洋中的有生命特征的蛋白质和核酸等物质凝聚成独立体系 最后 经历漫长、复杂的进化，最终形成原始生命。

After the “Big Bang”, something happened to the earth.

Now let’s turn to passage 25

How Life Began On The Earth

Read through the text quickly, and answer these two questions.

1. What’s the main idea of the text?

2.What is the topic sentence of each paragraph?

Fast readingFast reading

Q1:What’s the main idea of the text? A. how did water begin?

B. how did earth begin ? C. how did man begin ?

D. how did life begin ?

Paragraph 1:

Paragraph 2:

Paragraph 3:

Paragraph 4:

Paragraph 5:

A widely accepted theoryabout the formation of the unive

rse

The formation of the earth

The importance of water for life

The development of plants and animals on the earth

The arrival of humans and their impact on the earth

Q2:

Careful reading

Combine into

Explode with fire and rock to produce carbon, nitrogen, water vapour and other gases.

dissolve harmful gases

Big BangBig Bang a cloud of dusta cloud of dust

a solid globe

Atmosphere Water

oceans and seas

Cool down

Read the first three paragraphs and do this exercise in pairs.

AfterAfterbe still

Come to the last three paragraphs and answer the questions:

1.Which one did begin to appear firstly, animals or plants?

2.Why was it necessary for plants to grow before animals?

A. Animals needed plants to protect them from the sun. B. Animals could hide from hunters in forests. C. It was easier for plants to grow. D. Plants provided oxygen for animals to breathe.

Plants firstly began to appear on the surface of the water.

Small plants in the water

Green plants on land

Insects on land

Mammals on land

1

2

123

Shellfish

and all sorts of fish

Amphibian on land and in water

forests

Reptiles on landDinosaurs on land

lifePlants animals

34 Clever animals on land

Read the last three paragraphs again and then complete the blanks.

Listen to the last paragraphs and fill in the blanks:

Finally about 2.6 ______years ago some small _______animals, now with hands and feet, _________and ______all over the earth. Thus they have, in their_____, become the important animals on the______. But they are not looking after the earth. They are putting too much carbon dioxide into the atmosphere, which ________heat from escaping from the earth into space. As a _____of this, many scientists believe the earth may become too hot to live__.

million

cleverappeared spread

returnplanet

preventsresult

on

10 7 3 8 4 9 6 1 5 2 12 11

1. Insects and amphibians appeared.

3. The earth became a solid ball.

5. Reptiles appeared.7. The earth was a clou

d of dust.9. Shellfish and other fis

h appeared.11. Clever animals with

hands and feet appeared.

2. Dinosaurs appeared.

4. Small plants 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.

Row order

Small plants in the water

Green plants on land

Insects on land

Mammals on land

1

2

123

Shellfish

and all sorts of fish

Amphibian on land and in water

forests

Reptiles on landDinosaurs on land

lifePlants animals

34 Clever animals on land

Have a rest.

Retell the text, and then write a summary (about 100 words) of the text in your own words.

Our universe began in a big bang about15 billion years ago. The Big Bang is the term used to describe a huge explosion which threw matter in all directions, creating our universe.