Food Production Flashcards
Why do you need to increase food yield.
An increasing human population requires an increasing food yield.
How can you increase food yield
Use of fertilisers, pesticides, biological controls or genetically modified crops
How do fertilisers increase crop yield ?
Fertilisers provide chemicals such as nitrates, which increases crop yield.
How do pesticides increase crop yield
Plants and animals which reduce crop yield are killed by pesticides
What is the nitrogen cycle.
The movement of nitrogen between the air, soil compounds and compounds in the bodies of living organisms is called the nitrogen cycle
Describe the nitrogen cycle
-The chemical element nitrogen is important to living organisms because it is a component of all the different amino acids, that are used to make proteins.
-Nitrates dissolved in soil are absorbed into plants by their roots.
-Nitrates are used to produces amino acids, which are synthesised into plant proteins.
-Animals consume plants or other animals to obtain amino acids for protein synthesis.
- Fertilisers can be added to soil to increase the nitrate content of the soil
How can fertilisers become an environmental issue.
-fertilisers can leach into freshwater, adding extra, unwanted nitrates.
-This will increase algal populations which can cause an algal bloom.
-Algal blooms reduce light levels, killing aquatic plants.
-These dead plants, as well as dead algae, become food for bacteria, which greatly increases populations.
-The bacteria use of large quantities of oxygen, reducing the oxygen availability for other organisms.
What can be used to reduce the use of fertilisers.
Genetically modified (G.M) crops and biological controls
What is the issue with pesticides.
Pesticide sprayed onto crops can remain/persist in the bodies of organisms over time. As they are passed along food chains, toxicity increases can reach lethal levels.
- This buildup of toxic substances in living organism is called bio-accumulation
what are biological controls
-Biological controls of pests are introducing a natural predator to prey on pests which reduces the number of pests, and therefore reduces the need for pesticides.
-for example, introducing lady birds to kill aphids.
-Pesticides are rarely selective, biological controls can be.
What are genetically modified crops
G.M crops have received genes from other organisms to improve their characteristics.
This reduces the need for pesticides.
Scientists have introduced genes from bacteria into maize and potatoes, which make them toxic to insects.
