高中英语外研版 (2019)选择性必修 第二册Unit 5 A delicate world背景图ppt课件

这是一份高中英语外研版 (2019)选择性必修 第二册Unit 5 A delicate world背景图ppt课件，共31页。PPT课件主要包含了Warming up，absorb，rely on，fed on，prey on，break down，release，Speaking等内容，欢迎下载使用。
Using languageEcsystems Listening and speaking
Objectives
At the end f the class, yu will be able t:1. acquire wrds and expressins related t ecsystems2. btain the relatinships between the living things3. get the specific infrmatin and chse the true statements
4. take dwn sme infrmatin and expressins expressing dubt and respnding t dubt 5. act ut a cnversatin abut the ecsystem, using the wrds and expressins yu have learnt
Lk at the diagram n Page 54 and answer the questins.Q1: What des the diagram shw?Q2: What are the relatinships between the living things?
Checking the answers
1. What des the diagram shw?
The diagram shws a fd chain — the cnnectin between the living things.
2. What are the relatinships between the living things?
The living things are clsely cnnected with each ther by the fd they eat. Secndary cnsumers prey n primary cnsumers. Primary cnsumers feed n prducers. Prducers absrb light frm the sun, water and disslved nutrients frm the sil, which are prvided by decmpsers.
In the wdland ecsystem, trees and ther plants are prducers. They water and take in nutrients frm the sil and energy frm the sun.
Cmplete the passage with the crrect frm f the wrds and expressins in Activity 5.
Insects are an example f a primary cnsumer. They the prducers t prvide fdfr them, and are by secndary cnsumers: small mammals and birds.
They the primary cnsumers. Wrms, fungi and bacteria are decmpsers. They animal waste and the remains f living things. The chemicals these decmpsers fertilise the sil and give the plants the nutrients they need t grw.
Read abut bees n Page 55.
What d yu knw abut bees?
1. They have been in existence fr millins f years.
2. They can fly 24 kilmetres per hur. The wings can beat 200 times per secnd.
3. One bee can pllinate 50 —100 flwers.
Listening fr main idea
What will be talked abut? Listen t the cnversatin in Acticity 7 n Page 55, and chse the true statements.
1. Bees are very imprtant t ur fd supply because they prvide hney.2. The bee ppulatin is declining. 3. Withut bees, humans wuld die ut.4. All human crps depend n bees fr pllinatin.5. If bees became extinct, ther insects culd pllinate enugh crps.6. Humans are respnsible fr the decline in the bee ppulatin.
Listening fr detailed infrmatin
Task 1: Listen again and cmplete the flw chart.
A cmbinatin f things damages bee habitats, mainly 1 . The bee ppulatin is 2 . Accrding t statistics, bee numbers in the US 3 in just ne year.
pesticides and climate change
declining very quickly
have fallen by 70%
Withut bees, crps wuld 4 .5 wuld nt be able t cmpensate fr the lss f bees, because 6 f the species f crps. Animals that live n the crps 7 .
be unable t reprduce
Other insects
bees are respnsible fr
pllinating abut 70%
wuld die ut
Task 2. Discuss and talk abut the imprtance f bees.
Bees are very imprtant. Withut bees, crps wuld be unable t reprduce. Meanwhile, ther insects wuld nt be able t cmpensate fr the lss f bees, because bees are respnsible fr pllinating abut 70% f the species f crps.
Withut bees, numerus plants species wuld die ut. As a result, animals that live n the crps wuld disappear, and humans wuld have nthing t eat.
Listening fr speaking
Cmplete the bx in Activity 9 with the useful expressins frm the cnversatin.
Expressing dubt Yu must be kidding! I dn’t believe it! Are yu sure abut
Respnding t dubt It’s a fact!Dn’t frget that it ut fr yurself t statistics ...
Act ut a cnversatin abut what wuld happen t the ecsystem if anther species died ut. Use the wrds and expressins in this sectin.
Criteria fr speaking
cntentlanuage (useful expressins)Prnunciatin &intnatin
Student A: Hey, Mark, what d yu think wuld happen t the ecsystem if wlves died ut?Student B: I dn’t think it has a big impact n the ecsystem.Student A: If wlves died ut, it wuld threaten the planet’s balance.Student B: What?! Yu must be kidding! I dn’t believe it!
Student A: It’s a fact! I watched a nature article abut it. Student B: Hw can that be pssible?Student A: Wlves feed n sheep. Peple capture and kill them t get mre benefits frm sheep, which causes the wlf ppulatin declining quickly. Withut wlves, sheep wuld start breeding, and the number f sheep wuld be larger and larger.Student B: S mre milk, meat, and fur wuld be prvided t peple.
Student A: It sunds reasnable. Dn’t frget that the wild rabbits and cws cmpete fr the grass with sheep. Years later, the number f grass wuld be greatly reduced. In turn, numerus sheep wuld die f starvatin. Even wrse, much f the grassland wuld becme desert.Student B: That’s scary.
Student A: Remember that we are a part f the fd chain, s we wuld be in danger t!Student B: Obviusly, human activity is the main cause.Student A: That’s right.Student B: Well, we’d better d smething befre it’s t late.
1. Sme vcabularies abut a fd chain;2. Relatinships between the living things; 3. Imprtance f bees; 4. Sme useful expressins expressing dubt and respnding t dubt; 5. Cnversatin abut the eclgical impact f the extinctin f a species.
We’ve learned in the lessn: