资源简介

(共31张PPT)
Unit 5
Unit 5 A delicate world
Ecosystems
To learn something about ecosystems and understand the importance of ecological balance and contribute to the protection of ecosystems
To listen to the conversation and get the detailed information about what makes bee habitats dangerous
To learn to express doubt and respond to doubt
What makes the ecosystem balance
Ecosystems
Ecosystem means all the animals and plants in a particular area, and the way in which they are related to each other and to their environment.
Producer…, primary consumers…, secondary consumers…, decomposers…
Look at the diagram and answer the questions. Pay attention to the words and expressions in bold.
v. 溶解
n. 养分、营养物
n. 真菌
5
1. What does the diagram show
The diagram shows a food chain — the connection between the living things.
2. What are the relationships between the living things
The living things are closely connected with each other by the food they eat. Secondary consumers prey on primary consumers, primary consumers feed on producers, and producers absorb light from the sun, and water and dissolved nutrients from the soil, which are provided by decomposers.
Complete the passage with the correct form of the words and expressions in Activity 5.
In a woodland ecosystem, trees and other plants are producers. They 1_______ water, and take in nutrients from the soil and energy from the sun. Insects are an example of a primary consumer. They 2_________ the producers to provide food for them, and are 3_________ by secondary consumers: small mammals and birds.
absorb
rely on
fed on
absorb, dissolve, nutrient, rely on, provide energy, feed on, prey on, break down, release
6
They 4________ the primary consumers. Fungi and bacteria are decomposers. They 5___________ animal waste and the remains of living things. The chemicals these decomposers 6__________ fertilise the soil and give the plants the nutrients they need to grow.
break down
prey on
release
absorb, dissolve, nutrient, rely on, provide energy, feed on, prey on, break down, release
One of the oldest species in the ecosystem, the honey bee has been in existence for millions of years.
A honey bee can fly as fast as 24 kilometres per hour and its wings can beat 200 times per second.
In just one journey to collect pollen and nectar, one single honey bee can pollinate as many as 50 to 100 flowers.
Bees can provide honey to us. But how Watch the video.
Listening tips
Read the given sentences and guess what you may listen to in the conversation;
Underline the key words in each sentence and pay attention to the words while listening;
Write down the words in blanks while listening, and check your spelling.
Listen to the conversation and choose the true statements.
1. Bees are very important to our food supply because they provide honey.
2. The bee population is declining.
3. Without bees, humans would die out.
4. All human crops depend on bees for pollination.
5. If bees became extinct, other insects could pollinate enough crops.
6. Humans are responsible for the decline in the bee population.
7
n. 植物授粉
Listen again and complete the flow chart.
A combination of things damages bee habitats, mainly 1__________________________.
The bee population is 2____________________. According to statistics, bee numbers in the US 3_________________ in just one year.
pesticides and climate change
declining very quickly
have fallen by 17%
Animals that live on the crops 7____________.
Humans have nothing to eat and die out.
Without bees, crops would 4_____________________. 5___________ would not be able to compensate for the loss of bees, because 6_________________________________________ of the species of crops.
be unable to reproduce
Other insects
bees are responsible for pollinating about 70%
would die out
8
Meg: Hey Ollie, have you heard that the bee population is declining
Ollie: No, I haven’t. But, thinking about it, I hardly ever see bees these days. When I was little, they seemed to be everywhere!
Meg: If bees __________, humans will die out too.
Ollie: What ! __________________! I don’t believe it!
Meg: It's a fact!! I watched a nature documentary all about it the other evening. Bees are very important to our food supply.
Ollie: ______________________ Humans won't die out just because there's no honey!
Listen to the conversation and fill in the blanks.
die out
You must be kidding
How can that be possible
Meg: Bees don't just make honey. Don't forget that bees are also responsible for _______________. Without them, crops would be unable to reproduce.
Ollie: But surely there are other ways of getting these crops to reproduce. Does it have to be bees
Meg: Well, there are other insects that pollinate plants, but it's unlikely that they would be able to fully compensate for the loss of bees. Bees __________________ pollinating about 70% of the species of crops.
Ollie: _________________________ It sounds rather exaggerated.
pollinating plants
are responsible for
Are you sure about that data
Meg: Watch the documentary and _____________________ if you don't believe me. Without bees, numerous plant species would die out. Animals that live on the crops would die out, and we wouldn't have enough to eat.
Ollie: Seriously That's scary! But looking on the bright side, there are millions and millions of bees. They're not going to die out any time soon.
Meg: I'm afraid you're wrong. The bee population is declining very quickly. ____________________, bee numbers in the US have fallen by 17% in just one year.
Ollie: Gosh! What caused that
check it out for yourself
According to statistics
Meg: A combination of things, really, but it's mainly due to damage to their habitats caused by pesticides and climate change.
Ollie: So human activity is the ____________
Meg: That's right.
Ollie: Well, in that case, we'd better do something before it's too late.
main cause
Complete the boxes with the expressions from the conversation.
You must be kidding!
I don't believe it!
It's a fact!
Don't forget that...
Are you sure about...
Check it out for yourself...
According to statistics...
9
You must be kidding!
I don't believe it!
Are you sure about...
It's a fact!
Don't forget that...
Check it out for yourself...
According to statistics...
Expressing doubt
Responding to doubt
Work in pairs. Talk about what would happen to the ecosystem if another species died out. Use the words and expressions in this section.
10
absorb, dissolve, nutrient, rely on, provide energy, feed on, prey on, break down, release
You must be kidding!
I don't believe it!
Are you sure about...
It's a fact!
Don't forget that...
Check it out for yourself...
According to statistics...
Now think about how your knowledge helped you contribute to the discussion.
Can you use some useful words and expressions to give some rough ideas during the discussion
Can you use correct words, expressions and complete sentences to clearly show your ideas during the discussion
Can you use a clear structure with proper words and expressions to show your ideas in a logical way during the discussion
1. Producers absorb water and dissolved nutrients from the soil.
dissolve v. to make a solid become part of a liquid (使)溶解
e.g. Drop two tablets into a glass of water and leave them to dissolve.
Dissolve the salt in water.
dissolve in sth. 溶解于某物
dissolve sth. in sth. 使某物溶解于某物中
2. They feed on green plants.
feed on to eat something 以……为食
e.g. Owls feed on mice and other small animals.
feed … to … 把……喂给……
feed … on/ with 用……喂……
feed…up (用大量食物)养肥，养出
be fed up with= be tired of = be bored with 对……厌烦
feed on “以……为食”，其宾语为食物；
live on“以……主食”“靠……生活”，其宾语为食物、金钱或某人
【语境应用】单句语法填空。
1) The boy is feeding grass __________ the goat. = The boy is feeding goat __________ the grass.
2) She felt exhausted and a bit fed __________ .
3) They feed mostly __________ insects, but also eat fish and frogs.
4) He was already fed up __________ doing the same thing
again and again.
to
on/with
up
on
with
3. Secondary consumers prey on primary consumers, as well as eating other animal matter.
prey on: (of an animal or a bird) to hunt and kill another animal for food 捕食
e.g. Tigers prey on animals like rabbits.
prey on sth. 捕食某物
prey on the weak 弱肉强食
prey on the people 鱼肉百姓
4. Decomposers break down dead animal and vegetable matter into nutrients.
break down: to make a substance separate into parts or change into a different form in a chemical process 分解
e.g. Sugar and starch (淀粉) are broken down in the stomach.
break down (会谈)破裂; 失败; (汽车等)出故障;
(人的健康状况)变得恶劣
break in 闯入; 打岔
break off 中断; 折断
break into 闯入
break out 爆发; 发生
break up 驱散; 分散; 打碎; 终止
break through 突围; 突破
break away (from) 挣脱(束缚); 脱离
【语境应用】用break短语的适当形式填空
1) The worms’ ability to _____________ their everyday food also allows them to break down plastic.
2) The thieves __________ the office and stole some money.
3) If he carries on working like this, he’ll _____________ sooner or later.
4) You should _______________ such bad habits.
break down
break down
break away from
broke into
5) Scientists think they are beginning to _____________ in the fight against cancer.
6) I was still living in London when the war ____________.
break through
broke out
1. Write a short paragraph to describe the diagram in Activity 5.
2. Surf the Internet to find some information about Shennongjia.

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