1. Unit 3 3.1- Food supply, plant growth and productivity
Higher Biology
Unit 3
3.1- Food supply, plant growth and productivity

2. Food security
Food security is the ability of human populations to access food of sufficient quality and quantity
Food security
Quantity
Quality
Access

3. Increasing demand
The demand for food increases as the human population continues to increase
This leads to a need for an increase in food production
In the past this led to an increased use of fertilisers, pesticides and unsustainable farming techniques
This often led to environmental degradation

4. Sustainable Food Production
Attempts are being made to reverse the impact of these unsustainable food production techniques
This is known as sustainability
Sustainable methods of food production do not degrade natural resources such as the land and water supply

5. Biological Sciences in Food Production
The application of techniques such as selective breeding, genetic engineering, and the development of biodegradable pesticides are examples of applications of science being used to support sustainable food production

6. Agricultural Production
All food production depends on the process of photosynthesis
The Earth possesses at least species of edible plants but humans depend on a small number of these to produce 95% of the world’s food supply

7. Main crop species Cereals Root crops Legumes Maize Potato Rice Cassava
Soya bean
Legumes

8. Improving yields
The area to grow crops is limited so food production can only be increased by improving efficiency
The following practices can be employed to improve efficiency:

9. Identify limiting factors
By identifying any factors that are limiting the growth of plants steps can be taken to overcome this limiting factor and increase yield
An example would be identifying a water shortage in soil and using a sprinkler to provide water to the plants

10. Use of higher yield cultivar
Plant crops can be replaced by higher yielding cultivars
These plants will use the same resources and space but will result in a greater yield so are more efficient

11. Crop Protection
Protecting crops from pests, disease and competition can help to improve yield
To ensure this is sustainable minimal doses of biodegradable herbicides, fungicides and pesticides

12. Pest Resistant Crops
Development of pest resistant crops can help to improve yield
This can be achieved through genetic engineering

13. Food chains Food chains are representations of the transfer of energy
Most of the energy obtained by a consumer in an ecosystem is used for growth, movement and thermoregulation
Only about 10% of the energy taken in by an organism is passed to the next level of the food chain

14. Length of food chain
In general, the shorter a food chain is the greater the quantity of energy held in the food
Growing plant crops for human consumption therefore generates far more food per unit area of land than livestock

15. Cereal Plant 1000 kg
Farm Animal 100kg
Human 10 kg

16. Land planted with a crop to feed humans produces far more food than the same land planted with grass to feed livestock
Some habitats are unsuitable for the cultivation of crops but can be used efficiently for livestock production

17. Grassy land on steep hillsides is unsuitable for crop cultivation but can be used for sheep farming.