Food Production

• An increasing human population requires an increasing food yield. This may involve the use of pesticides and fertilisers.
• Fertilisers can help increase the food yield as they provide chemicals such as nitrates which increase crop yield.
• Pesticides can increase crop yield, by killing unwanted animals and plants that would reduce crop yield.
• Nitrates are dissolved in the soil and absorbed by the plants through the roots. Plants use nitrates to produce amino acids which are used to make proteins.
• Animals consume plants or other animals to gain the amino acids needed for protein synthesis.
• Fertilisers can be added to the soil to increase the nitrate concentration.
• Fertilisers can leach into fresh water rivers and streams. This adds unwanted extra nitrates into the water.

  • The algal population increases causing algal blooms
  • Algal bloom on the surface of the water reduces the light, killing aquatic plants
  • Dead plants and dead algae become food for bacteria
  • Bacteria in the water increases
  • Bacteria use up a large quantity of oxygen form the river
  • Reducing the oxygen for other living organisms
  • Decreasing biodiversity
• The use of genetically modified crops can reduce the use of fertilisers and pesticides.
• Pesticides sprayed onto crops can accumulate into the bodies of organisms over time. As they are passed along the food chain, the toxicity increases and can reach lethal levels, decreasing biodiversity
• Bioaccumulation is the build-up of toxic substances in living organisms.
• Biological control is the use of natural predators to a pest and genetically modified crops can reduce the need of pesticides.
• benefits of biological control:

  1. enviromentally friendly
  2. They have a specific targets, which means they are unlikely to attack beneficial species
• Disadvantages of biological control:

  1. introducing a new species always has an effect on biodiversity, this could be negative
• benefits of GM crops:

  1. improved nutritional content
  2. increased crop yields
  3. reduced dependancy of pesticides
• disadvantages of gm crops:

  1. expensive
  2. potential health risks