1. Food Production and the Environment
The Carbon Cycle

3. Carbon dioxide in the air

4. Carbon dioxide in the air
Green plants use carbon dioxide to make their food

5. Carbon dioxide in the air
Green plants use carbon dioxide to make their food
Green plants are eaten by animals

6. Carbon dioxide in the air
respiration
Green plants use carbon dioxide to make their food
Green plants are eaten by animals

7. carbon dioxide in the air
respiration
green plants use carbon dioxide to make their food
green plants are eaten by animals
dead remains of plants and animals

8. carbon dioxide in the air
respiration
green plants use carbon dioxide to make their food
green plants are eaten by animals
dead remains of plants and animals
decay by fungi and bacteria

9. Decay
Fungi and bacteria are responsible for the decay of dead organisms.

10. Decay In order to be able to carry out decay, fungi and bacteria need:
Oxygen
Moisture
The correct temperature

11. The Nitrogen Cycle

13. nitrogen in the air

14. nitrogen in the air
fertilizers
fertilizers

15. nitrogen in the air fertilizers fertilizers
waste substances e.g. faeces

16. nitrogen in the air lightning fertilizers fertilizers
waste substances e.g. faeces

17. nitrogen in the air lightning fertilizers fertilizers
waste substances e.g. faeces
Nitrogen-fixing bacteria in the soil

18. nitrogen in the air lightning fertilizers fertilizers
waste substances e.g. faeces
Nitrogen-fixing bacteria in the soil
Nitrogen-fixing bacteria in the root nodules of clover

19. nitrogen in the air lightning fertilizers fertilizers
waste substances e.g. faeces
Nitrogen-fixing bacteria in the soil
Nitrogen-fixing bacteria in the root nodules of clover
dead remains of plants and animals

20. nitrogen in the air lightning fertilizers fertilizers
waste substances e.g. faeces
Nitrogen-fixing bacteria in the soil
Nitrogen-fixing bacteria in the root nodules of clover
dead remains of plants and animals
nitrates in the soil

21. lightning fertilizers fertilizers waste substances e.g. faeces
Nitrogen-fixing bacteria in the soil
Nitrogen-fixing bacteria in the root nodules of clover
dead remains of plants and animals
nitrates in the soil
denitrifying bacteria in the soil break down nitrates

22. The nitrogen cycle Living things need nitrogen to make protein.
They can not use the nitrogen in the air
The nitrogen in the air must be changed to nitrates before plants can use it.

23. The nitrogen cycle
Animals get their nitrogen by eating plants.

24. The nitrogen cycle
The roots of some plants (e.g. clover, pea & beans) have swellings called root nodules on them.
Nitrogen-fixing bacteria living in these nodules change nitrogen in the air into nitrates.

25. The nitrogen cycle
The nitrogen-fixing bacteria are essential to maintain the fertility of the soil.
Without them food yields would rapidly fall.