Transcript 3.2a-e – Human Impacts

Unit 3 – Life On Earth
Key Area 3.5 - Human Impact
On The Environment
Human Impact On The
Environment
• Man’s Impact on the environment –
research task.
• Follow the instructions on the sheet in the
resources folder.
• Your teacher will give you an impact to
research and prepare a presentation on.
Intensive Farming
• Learning Intention:
• Investigate the effects of an increasing
human population.
• Success Criteria:
• Be able to state that increasing human
population requires an increased food
supply.
• Be able to identify problems with intensive
farming.
Starter
• On a whiteboard from your research task-
• State different impacts that man has on
the environment.
Human Population
• The human population is continuing to
increase.
• Some changes that have contributed
towards this are• Improvements in medical care
• Industrial revolution
• Agricultural revolution
Human Population
• To provide enough food for the increasing
population, methods of increasing food yields
are needed.
• Farming is the main method of producing food.
• A lot of effort has gone into increasing yields
from farms.
• Some of these methods of increasing food
production have negative impacts on biodiversity
as discussed in the last lesson.
Intensive Farming
• This method involves growing single plant
species, e.g wheat, in large fields.
• It allows• Efficient Planting
• Crop treatments
• Harvesting.
Pesticides and Fertilisers
• Fertilisers are used by farmers to replenish
minerals in the soil and improve growth of
the crop, so increasing the yield.
• Pesticides are use to kill a range of pests
that will affect the growth of a crop.
Problems with use of fertilisers
• Fertilisers leach from fields into waterways
such as rivers and ponds.
• This happens due to heavy rain washing
fertilisers into waterways.
• This increases the growth of algae in the
water which creates algal blooms.
• This is a large number of algae in the
water which blocks out sunlight.
Problems with use of fertilisers
• Later in the year nutrients run out and there is
less light for photosynthesis.
• Algae start to die and are broken down by
aerobic bacteria.
• These bacteria increase and use up the oxygen
reducing the oxygen concentration of the water.
• This results in the death of many organisms.
• http://www.twigonglow.com/films/pollution-water1252/
Problems with use of fertilisers
Problems with use of pesticides
• Pesticides are chemicals sprayed on crops
to kill pests.
• Insecticides are sprayed on crops to kill
insects which reduce crop yield.
• Some insecticides kill other insects as well
as the target pests.
• This affects other organisms that feed on
these pests and affect food chains.
Problems with use of pesticides
• Some pesticides are persistent and can
build up in the bodies of organisms higher
up the food chain.
• The levels of pesticide can build up to
concentrations that can cause harm to
organisms.
• This is called Bioaccumulation.
• http://www.youtube.com/watch?v=MXSv0if
vDjc
Intensive Farming
• Learning Intention:
• Investigate the effects of an increasing
human population.
• Success Criteria:
• Be able to state that increasing human
population requires an increased food
supply.
• Be able to identify problems with intensive
farming.
Making Fertilisers
• Learning Intention:
• Investigate the effects of different minerals
on plant growth.
• Success Criteria:
• Be able to state the effect of different
minerals on plant growth.
Making Fertilisers
• In this practical you are going to look at
effects of different levels of minerals on
plant growth.
• Read the background information sheet
and then follow the instructions for the
practical.
Biological Control.
• Learning Intention:
• Investigate the effects of Biological
Control.
• Success Criteria:
• Be able to state that Biological Control
relies on natural solutions to pest
problems.
• Be able to identify Biological Control as an
alternative to intensive farming.
Starter
• From last lesson, on a whiteboard write
down• A description of intensive farming.
• Any two problems associated with use of
fertilisers/pesticides.
Biological Control.
• Biological control involves using natural
predators to control pest numbers.
• This works very well when the pest has
been introduced to the ecosystem and has
no natural predators.
Biological Control.
• The predator species has to be selected
carefully to ensure that it will survive in the
new environment and only attack the pest,
not other species.
• It is also vital they do not carry disease or
become a pest in the new are themselves.
• A trial should be carried out in a controlled
area such as a greenhouse before
releasing the species into the wild.
Biological Control.
• Select two examples from the videos on the
next slides and for each one complete the
tableName of
pest
Name of
species
used as a
control
Basic info
Biological Control.
• Example – The cotton cushion scale insect.
• This insect was accidently introduced to
California from Australia in the late 19th Century.
• It multiplied and destroyed large numbers of
crops.
• So a ladybird beetle, one of the scale insect’s
natural predators was
introduced from Australia.
• This reduced the numbers of
the scale insect to a safe level
allowing both species to coexist.
Biological Control.
• The Use of Barn Owls and Kestrels as
Biological Control Agents (11mins)
• http://www.youtube.com/watch?v=ZJDVoh
cnfHQ&feature=related
Biological Control.
• Biological Control of Greenhouse Pests
• http://www.youtube.com/watch?v=XXDR4I
zOl60
Biological Control.
• Cane Toads: An Unnatural History 1/5what has gone wrong here???
• http://www.youtube.com/watch?v=4mvV8
OT-mmE
Biological Control.
• "The Bugman" - March Biological
Control - How To Use Beneficial
Nematodes - Fly Control http://www.youtube.com/watch?v=on0i
04LPkY4
Biological Control.
• Learning Intention:
• Investigate the effects of Biological
Control.
• Success Criteria:
• Be able to state that Biological Control
relies on natural solutions to pest
problems.
• Be able to identify Biological Control as an
alternative to intensive farming.
Genetically Modified (GM) crops
•
•
•
•
Learning Intention:
Investigate the effects of GM crops.
Success Criteria:
Be able to state that a GM crop has had its
genetic information altered.
• Be able to identify GM crops as an
alternative to intensive farming.
Starter
• Discuss with a partner• What is biological control?
• Any examples of biological control.
Genetically Modified (GM) crops
• http://www.youtube.com/watch?v=JMPE5
wlB3Zk
• http://www.twigonglow.com/films/feedingthe-planet-1263/
Genetically Modified (GM) crops
• You are going to do a research task on
GM crops covering the following points• What are GM crops?
• Examples of GM crops.
• How are GM crops altered?
• Why are GM crops beneficial?
GM Challenge
Your task is to produce an A5 information
booklet about Genetically Modified crops.
You must include…
Answers to the questions on the previous
slide.
You should include…
Examples of using GM crops.
Why GM crops are considered
controversial.
You could include…
A set of five questions at the back of your
booklet about the information inside.
To help you gather information with this task you may use any text book in
the classroom (Int.2, higher) and the books in the library cupboard and box.
and can have 30 minutes per pair on the computers for research.
Genetically Modified (GM) crops
•
•
•
•
Learning Intention:
Investigate the effects of GM crops.
Success Criteria:
Be able to state that a GM crop has had its
genetic information altered.
• Be able to identify GM crops as an
alternative to intensive farming.