1. How can we manipulate an ecosystem without destroying it ?
Sustainable Farming
How can we manipulate an ecosystem without destroying it ?
Starter:
Why are the following problems for maintaining a closed loop ecosystem?
Harvesting crops.
Growing fields of 1 species of crop.
Grazing animals.

2. describe how human activity can unbalance natural ecosystems
name and outline examples of unsustainable activities
propose solutions that allow natural resources to be used sustainably

3. Sustainable Fishing
Problem: Fish stocks of some species are falling. Task: make a list of ways we can try to make sure we do not over fish. What might are the potential problems with enforcing your ideas.

4. Idea: have fishing quotas / bans
Problems.
Boats overfish and dump the dead fish back into the sea to get on quota.
Boats move to unprotected waters.
Politicians want to preserve jobs so allow more fishing than recommended.

5. Idea: ban fishing for certain fish
Problems.

6. Idea: have fish farms
Problems: not sustainable (linear system).

7. Intensive Agriculture
California grows 80% of the worlds Almonds. It is a linear system that removes the almonds meaning Farmers have to fertilise the soil.
Just almond trees are grown in over an area of around 243,000 hectares in California.
Thomas Winz/Photolibrary

8. Eutrophication

9. Eutrophication.

10. eutrophication http://www.youtube.com/watch?v=h-zncNp-X-E

11. Complete the cut and stick exercise
Complete the cut and stick exercise. Use it to help you answer the following questions.
Describe in detail how fertilisers from a field can kill the life in a pond. (6 marks)
Which chemical in the fertilisers is the main contributor to eutrophication. Why?
How could farmers fertilise their soils without the use of chemicals?

12. Desertification
Think – Pair- Share Describe what you think desertification is.

13. Task
Complete the card sort to work out the order of events in desertification.
Use this to answer the following question.
Explain the process of desertification outlining the possible causes and the impacts on the ecosystem.

14. Possible Causes Possible Effects Possible Solutions
exposure & erosion of soil by wind & rain
reduced moisture in the atmosphere (less transpiration)
education & consultation with local populations
soil compaction
exposure & erosion of soil by wind & rain
planting legumes to increase soil fertility
burning vegetation
overgrazing
tree planting to make wind breaks & provide fuel wood
increased poverty
loss of vegetation
increased poverty
climate change
reduced biodiversity
death of livestock
climate change (reduced rainfall)
Improved livestock marketing
terracing of slopes to stop run off
rise in human population
vehicle tracks
evaporation followed by salinisation
national & international political discussions & negotiations
digging moisture traps (hollows)
Increase in land conflicts
grazing control or rotational grazing
Increase in tribal conflicts
cutting trees for fuel wood
sand dunes forming on valuable land
trampling of vegetation by large animal herds

15. Task
Describe the possible solutions for desertification and what their limitations might be.

16. Eutrophication or Desertification?
Plenary
Eutrophication or Desertification?
Eutrophication
Desertification
Both

17. Caused by excess nutrients
Plenary
Caused by excess nutrients
Eutrophication
Desertification
Both

18. Can be caused by farming/cultivation
Plenary
Can be caused by farming/cultivation
Eutrophication
Desertification
Both

19. Produces an area with low biodiversity
Plenary
Produces an area with low biodiversity
Eutrophication
Desertification
Both

20. Produces an area with low biodiversity
Plenary
Produces an area with low biodiversity
Eutrophication
Desertification
Both

21. Can be prevented by sustainable farming
Plenary
Can be prevented by sustainable farming
Eutrophication
Desertification
Both