Food Security (OCR GCSE Biology A (Gateway))

Biological Threats to Food Security

Food Security

• Food security is having enough food to feed a population

• That ‘population’ could represent a group of people on a range of different scales, from a particular family, to a town, to a region or even a whole country

• Food security gives an indication of how much food is available

Biological Factors Threatening Food Security Table

• Sustainable methods of farming and producing food are needed in order to overcome food shortages and help populations whose food security is under threat

• Sustainable food production involves making enough food but ensuring this is done without using resources (such as water and soils) faster than these resources can be renewed and used again

• It is often about finding the right balance, for example:

  • Biofuels, being produced as a renewable alternative to fossil fuels, take up valuable land space for their growth, which previously would have been used for food production

  • It is an important balance between providing renewable biofuels and producing enough food to feed the growing population

  • An increase in the cost of farming methods for food production may become unsustainable for farmers in the future

  • This requires a balance between cost and food provision

Strategies to Maintain Food Supply

Sustainable strategies to maintain food supply

• In order to feed a rapidly growing human population, we are going to need more food

• Agriculture will need to supply that food, using intensive and innovative techniques to increase output

• The following techniques can intensify older, traditional agricultural methods in order to achieve this

Fertilisers & pesticides

• Fertilisers have been used for centuries by farmers, from the times when farmers first realised that spreading animal dung and compost has a benefit to food crops

• Most fertilisers concentrate on returning nutrients containing the elements nitrogen, potassium and phosphorus to the soil

• For a crop planted on agricultural soil, the crop takes the nutrients from the soil via its growth

  • Normal plant death and decay would return these nutrients to the soil but the crop is harvested and taken away, taking the nutrients with it

  • The nutrients need to be replaced if the soil is to remain fertile

• Farmers assess their crop's success by several measures, notably yield

  • Yield is the tonnage of saleable crop produced per unit area of land

  • Measured for example in tonnes per hectare (t ha^-1)

• One drawback of fertilisers is that they have a high cost, both to buy but also the cost of applying them to the soil on a regular basis

• Another drawback is that fertilisers can cause pollution problems

  • If excess fertiliser gets into streams, rivers and lakes, it can cause problems like eutrophication

Hydroponics

• Hydroponics is a type of agriculture that grows plants without soil

• Plants can be grown indoors, in carefully-controlled conditions

• Their roots are suspended into an aqueous solution that contains all the nutrients that they need to grow

• The solution flows around the greenhouse in channels so all the plants are well supplied with nutrients

• Lighting can be via artificial lights or via glass rooves, as in a commercial greenhouse

• Conditions can be monitored carefully and yields improved

  • Yields are not dependent on good weather

• Examples of hydroponically-grown crops are tomatoes, strawberries, cucumbers, lettuces and peppers

Disadvantages of hydroponics

• High setup cost

• There is a high running cost for fertilisers, artificial light and perhaps heat

• Disease can spread quickly around a hydroponic greenhouse and damage a lot of crop in a short space of time

Biological control

• This uses one species to control the population of another species

  • The latter species is typically a pest

• A non-native species is introduced to prey on the pest or to push the pest out of its niche

• Alternatively, a native species that can control the pest is encouraged

Advantages and Disadvantages of Biological Control Table

Gene technology

• Crops can be genetically modified (they are known as GM crops)

• Crop plants, such as wheat and maize, have been genetically modified to contain a gene from a bacterium that produces a poison that kills insects, making them resistant to insect pests such as caterpillars

  • This can improve crop yields

• Crop plants have also been genetically modified to make them resistant to certain herbicides (chemicals that kill plants), meaning that when the herbicide is sprayed on the crop it only kills weeds and does not affect the crop plant

• Some crops have been genetically modified to produce additional vitamins and improved nutritional value

• eg. ‘Golden Rice’ contains genes from another plant and a bacterium which make the rice grains produce a chemical that is turned into vitamin A in the human body, which could help prevent deficiency diseases in certain areas of the world

• Some have been genetically modified to be drought-resistant (to grow better in very dry conditions)

• Genetic modification can also reduce the use of pesticides, which has benefits to other plants

  • Bees pollinate many wild plants and crop plants, so using less insecticide on crops will benefit all species as we need bees to pollinate crops for us

Mycoprotein – the process of creating food from a fungus

• The fungus Fusarium is cultured (grown) on an industrial scale in fermenters

• These fermenters are large vats that can be kept at the optimum pH and temperature for Fusarium to grow

• The fungus is grown in aerobic conditions (it is provided with oxygen) and provided with glucose syrup as a food source

  • Both allow the fungus to respire aerobically

• The fungus grows and multiplies within the fermenter

• The fungal biomass is then harvested and purified to produce mycoprotein

• Mycoprotein is a protein-rich food suitable for vegetarians

• For example, it is used in Quorn^TM products

A diagram of an industrial fermenter used to produce large quantities of microorganisms eg. Fusarium for mycoprotein production