英语选择性必修 第二册Unit 5 A delicate world授课课件ppt

这是一份英语选择性必修 第二册Unit 5 A delicate world授课课件ppt，共21页。
1. Are humans part f Earth's ecsystems? Why?2. In what ways can humans affect ecsystems?
Watch the vide and answer the questins.
Humans can affect ecsystems in psitive and negative ways.
A Delicate Wrld
Starting Out
What is an ecsystem?
An ecsystem is a gegraphic area where plants,animals, and ther rganisms, as well as weather and landscape, wrk tgether t frm a bubble f life. Ecsystems cntain bitic r living, parts, as well as abitic factrs, r nnliving parts.Bitic factrs include plants,animals, and ther rganisms. Abitic ( [ˌeɪbaɪ'ɒtɪk]adj.非生物的；与生物无关的)factrs include rcks,temperature, and humidity.Every factr in an ecsystem depends n every ther factr, either directly r indirectly. A change in the temperature f an ecsystem will ften affect what plants will grw there, fr instance.Animals that depend n plants fr fd and shelter will have t adapt t the changes, mve t anther ecsystem, r perish.
Are humans part f Earth’s ecsystems? Why?
Yes. Humans are part f Earth's ecsystems.Because all living things live in ecsystems and peple are living things.
In what ways can humans affect ecsystems?
Psitive: peple can plant trees, feed and prtect animals, recycle things and s n.Negative: The air and water pllutin and excessive waste.
What is happening t the area accrding t the satellite images?
Lcated in Central Asia, between Kazakhstam t the nrth and Uzbekistan t the suth
The furth largest lake (1960s)
Just fur smaller lakes (NOW)
What d yu think a later satellite image wuld shw? Why?
What d yu think caused these changes?
The irrigatin prjectClimate changeVegetatin Damage...
Lk at the diagram and answer the questins. Pay attentin t the expressins in bld.
Prducers absrb water and disslved nutrients frm the sil. They als make their wn fd by absrbing light frm the sun.
Primary cnsumers rely n vegetatin t prvide energy. They feed n green plants.
Secndary cnsumers prey n primary cnsumers, as well as eating ther animal matter.
Decmpsers break dwn dead animal and vegetable matter int nutrients. The disslved chemicals are the released back int the fd chain,t be used by prducers.
1.What des the diagram shw?2.What are the relatinships between the living things?
The diagram shws a fd chain – the cnnectin between the living things.
2 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, and prducers absrb light frm the sun, and water and disslved nutrients frm the sil, which are prvided by decmpsers.
Task 2 Cmplete the passage with the crrect frm f the expressins in Task 1.
5.break dwn
What is happening in the pictures?
What may it cause?
sil ersin and degradatin
Defrestatin affects habitats, bidiversity, air quality, water ways, and nearly every ther part f the natural wrld.
the lss f habitat fr animal species
glbal warming
Negative effects
Phts taken at the same lcatin n Ouli Muntain in Zhangwu cunty, Lianing prvince, in 2018 and 2022 shw a striking transfrmatin frm barren land t a green asis.
Psitive effects
A. T analyse hw Macquarie Island was saved frm destructin.B. T infrm readers f the chas caused n Macquarie Island by humans.C. T entertain readers with a funny stry abut what happened n Macquarie Island.D. T suggest ways in which an ecsystem can be prtected.
Chse the authr’s purpse in writing the passage.