3. CHANGING BIOMES
Investigate the human alteration of biomes to produce
food, industrial materials and fibres and the
environmental effects of these alterations
IN THIS PPT
YOU WILL:
● Examine changes to biomes due to human
alterations
● Assess these environmental impacts
● Discuss successful sustainability strategies that
minimise environmental impacts
You will also go on an Excursion to the Wetlands at Bonna
Point as a case study to support this.
HOW WE CHANGE
BIOMES?
Complete Worksheet:
Changing Biomes PreTest Definitions.
CRITICAL THINKING - PHOTO INTERPRETATION ACTIVITY
• Write your answers then share with the class.
Level
Questions
Here
List what you can see in this image.
Describe the topography of the
land.
Hidden
What food crop is grown in this
photograph?
Where might this photograph be
taken?
Head
Why has the topography been
shaped in this way?
What are some benefits and
limitations of living in this region?
PRODUCING FOOD CHANGES BIOMES
• In Yr7 we learn about the four spheres – This is the
biophysical world.
• The production of food, whether from the land or sea,
has the potential to change (human alterations) the
natural environment and, in doing so, increases the
likelihood of food insecurity.
CRITICAL THINKING - MAKE JUDGEMENTS
ABOUT THE EXTENT OF ENVIRONMENTAL IMPACTS
ON FOOD PRODUCTION.
● Use your handout of the following slides.
● Individually, read each slide about the environmental
impacts of human changes to biomes.
● Cut out each slide
● Then rank each impact in order from the most destructive,
to the most not as destructive
This is according to what you think is most to least destructive to
the environment. Don’t talk to anyone else in the class at this
stage.
DEFORESTATION
► Destruction of original forest and vegetation
► Amazon = produces 20% of Earth’s oxygen supply, but a
football field is cleared every second
► Reasons = Palm + Rubber + Soya plantations, grazing
land for cattle ranches, mining, logging, Hydro-electricity,
highways
► Only 5% of trees cut down are actually used for housing,
paper, furniture and timber.
► If deforestation continues at the current rate globally, all
rainforests will be gone in 40 years
► Many ingredients for foods come from rainforests,
including the Kola nut for Coca Cola drinks
► 25% of medicines have ingredients from rainforests
► Destroys natural habitat for unique flora and fauna
► Most notably Orang-utan habitats in places like Indonesia
and Malaysia are replaced with Palm plantations
BIODIVERSITY
► Clearing and draining land creates habitat
destruction
► Pressure to produce food wipes out diverse habitats to
create monocultures (1 type of rice not 20 used)
► Animals and plants are deprived of their natural food
resources = either die, leave, become endangered or
extinct
► New Zealand = before human settlement approx.
1000 years ago, NZ was 85% covered in forests, now
is only 23% covered – natural and man-made fires to
hunt and clear land for growing food.
► With settlement also came introduced species (not
native) = Stoat (NZ weasel) has preyed on and
displaced the native kiwi bird.
► Irrigation, dams and farming pollution have modified
rivers and lakes creating habitat fragmentation =
pockets of isolated ecosystems that replace the once
much larger ecosystems
DYNAMITE FISHING
► Increasing population pressure leads to overexploitation of marine resources
► Kills fish instantly and quickly
► Destroys coral reefs that are crucial for shelter, feeding
and breeding places for marine animals
► Bombs are indiscriminate between fish and other
unwanted sea animals that are thrown back into the
water
► Bombs also kill more fish than can be harvested
► “Dynamite” bombs are sometimes home made with
chemicals and materials that are toxic to pollute the
water
► This practice is still used illegally in places like Tanzania
and the Philippines.
Drainage
► Diverting or taking away excess water off the land
► Drains are built to remove water from waterlogging the soil
and hindering growth of crops and pasture
► With good planning drainage can be effective without
harming the environment
► Drainage is useful if an area is prone to flooding (e.g., near
rivers)
► However, many wetlands are drained to allow for land
development (e.g., houses + farms), destroying the wetland
ecosystems and all the food webs and wildlife reliant on the
water source
► 40-50% of the Macquarie Marshes in Central NSW have
been drained for agriculture – now government protected
because it is crucial for waterbird feeding + breeding
► Approx. 20% of Australian birdlife relies on wetlands, as
well as other migratory birds from the Northern
Hemisphere.
WATER POLLUTION
► Chemical, physical or biological change in water quality –
factories, fertilisers, oil spills, rubbish, sewage, radioactive waste
► 6.5 million tonnes of garbage washes into ocean annually –
mostly plastic
► 3000 children die every year from contaminated water (UNICEF)
► Waste disposed in waterways intentionally by dumping
► Unintentionally through run-off / leaking industrial /
agricultural / domestic waste
► Bodies of water do have capacity to clean themselves by
dissolving pollutants over time
► Excessive pollutants flow downstream to contaminate other
aquatic populations – fish, marine life, birds, wildlife, humans
► The Natural Resources Defence Council (NRDC) in the USA
helps stop water removal from the San Francisco Bay Delta, the
largest estuary on the west coast.
► In 2010 British Petroleum (BP), responsible for massive oil spill
that killed over 1000 animals.
SALINITY
► Changing use of land changes the way water moves through biomes
► Native vegetation cleared on large scale for urban and agricultural development = natural water balance
disrupted
► Groundwater level rises = topsoil becomes very shallow as roots of crops are not as deep as trees, allowing
groundwater to rise without being absorbed by plants.
► Topsoil erosion = removal of vegetation leaves bare topsoil that is easily eroded away, exposing the
subsoils high in sodium (salt or sodic soils) creating hard salt crust and poor soils
► Compacting soils = like when building roads reduces the soil’s ability to soak up water causing groundwater
ponds, evaporation and increase of salt
► Threat to freshwater river systems = marine plants and animals cannot tolerate high salinity levels, meaning
that entire ecosystems are being destroyed.
TEXTILE WASTE
► Biomes that are used to create fibres for clothing, have also been
drawn into the problem of fast fashion = designs from catwalk to
retailers rapidly, changing each season and with a minimum
turnover of new stock in stores
► 12 - 14 million tonnes of clothing ends up landfill every year
► In Australia, 6000 kg of clothing goes to landfill every 10 minutes
► Textile waste also includes household fabrics, carpets, hospital
linen
► Increasing waste due to culture shift toward disposable and
always changing seasonal fashion trends – clothing not kept for a
long time or repaired before being thrown out
► Disposal of all this waste causing land pollution by over-filling
landfill sites
► Chemicals that leach off clothing pollutes groundwater,
decomposing fibres create methane gas contributing to the
greenhouse effect and ammonia which is toxic in land + marine
ecosystems
Reality of Fast Fashion video: https://www.facebook.com/businessoffashion/videos/10154546877897428/
►Now that you have
ranked your impacts
answer the following
question:
►Justify why you think
your choice of impact is
the worst / most
destructive?
GO A LITTLE DEEPER…..
CAN YOU CONVINCE A CLASS
MATE TO CHANGE THEIR MIND?
● Students
move around the room to find students
who agreed with them.
● Each
group now needs to put their argument across
to the class as to why their choice of impact is the
most destructive
● Use examples and stats to support your argument
● After
each group has put forward their argument,
students can move to groups if they have changed
their mind
WRITING TASK
Discuss the environmental impacts of
human activities on biomes (10 lines)
YOUR TURN
Create two columns on your page and label them according to the example below.
Cut out each box and categorise the information from your worksheet into advantages and disadvantages.
Advantages to human
alterations
Disadvantages to human
alterations
SUGGESTED ANSWERS
CASE STUDY: SHOULD WE FARM FISH?
The ocean biome has always been
seen as an unlimited resource of
food for humans. In fact, overfishing
is causing the collapse of many of
our most important marine
ecosystems, and threatens the main
source of protein for over one billion
people worldwide. Aquaculture (fish
farming) is a possible solution but, at
the same time, it contributes to the
decline in fish stocks.
Read sub-topic 4.6
1. What is aquaculture?
2. List three benefits and
three drawbacks of
farming fish
3. Do the benefits of
aquaculture outweigh
the negative impacts on
the environment? Provide
reasons for your answer.
CASE STUDY ACTIVITIES: