1. Human impact on the environment
This next topic looks at the ways that humans have had an impact on the environment.
Human impact on the environment

2. Human impact on the environment
At the end of this topic you should be able to discuss and explain some of the ways that humans have had an impact on the environment.
Human impact on the environment

3. Human impact on the environment
Think back to the work you have previously
completed.
In what ways have you learned that humans had an impact on the environment?
Habitat destruction
Introducing alien species
Overharvesting of resources
Over use of fertilisers
Pollution
Human impact on the environment

4. Human impact on the environment
Many of these are related to supplying the needs of an ever increasing human population.
What is the human population?
Do you know how population numbers for humans have changed over time?
Human impact on the environment

5. Plot this information as a line graph. What do you notice?
Year
Population
in millions 1
200
1000
310
1800
1,000
1927
2,000
1960
3,000
1974
4,000
1987
5,000
1999
6,000
2011
7,000
2025
8,000
2083
10,000
Human population
This table shows how the human population has changed over the last 2,000 years and possible future population numbers.
Plot this information as a
line graph.
What do you notice?
How do you explain it?
Human impact on the environment

6. Human impact on the environment

7. The increasing population requires an ever increasing food yield.
Human population
The increasing population requires an ever increasing food yield.
Some experts believe that there is enough food to go round but it is not being distributed evenly, others do not.
But everyone agrees that food production will need to increase.
Human impact on the environment

8. Human population and food production
Human impact on the environment

9. Farming methods have changed in many countries through:
Food production
Is very important.
Farming methods have changed in many countries through:
Intensive techniques with many monocultures
Increasing use of fertilisers
Increasing use of pesticides
Use of GM crops
Human impact on the environment

10. Fertilisers are used to help with soil fertility.
Sometimes farmers can use too much man made fertiliser.
What is the impact to the environment of over
using fertilisers?
run-off leading to algal blooms and further consequences when the algae decompose
What are the alternatives to using too much man made fertiliser?
organic farming, natural fertilisers,
traditional crop rotation methods
Human impact on the environment

11. Pesticides are used to control pest species of insects.
These chemicals are convenient but can accumulate to toxic levels as they are passed along a food chain.
This is called bioaccumulation.
An example of this includes the use of DDT.
Banned in Britain but used in other countries.
Human impact on the environment

12. Bioaccumulation also occurs when pesticides end up in fresh water ecosystems
Human impact on the environment

13. Genetically modified crops (GM crops) are now being used to:
Produce increased yield
Produce disease resistant crops
Produce drought resistant crops
Produce crops that make new chemicals
If time you could research GM crops
Human impact on the environment

14. Monocultures
This is when farmers grow large areas of the same type of crop (often year after year).
This is advantageous because:
Large machinery can be used
Fertilisers can be applied easily with machines
Pesticides can be applied easily with machines
Profit margins are maximised
Disadvantages are that diseases among the crops spread easily and soil fertility can be reduced.
Human impact on the environment

15. The reintroduction of native species
Another way that humans impact on the environment is the reintroduction of native species.
An example of this is the
European Beaver (Castor fiber)
Research the reintroduction of the beaver into Scotland and make note of the positive and negative impact the beavers have on the environment.
This may be online at Scottish Beavers and find the information that you need from the FAQs or a DVD the class watches
Human impact on the environment

16. Write your notes up for Assessment Standard 2.2 and 2.3
2.2 Describe an application of Biology.
(the reintroduction of native species).
2.3 Describe how the issue effects the environment.
(how does the reintroduction
of beavers effect the
environment)
Human impact on the environment

17. Human impact on the environment
You should be able to discuss and explain some of the ways that humans have had an impact on the environment.
Complete the place mat activity to summarise your group ideas.
Human impact on the environment