Food Production

• Pesticides


  Substance used to prevent, destroy, or repel pests
• Nitrates

  Importance: Fertilisers can be added to soil to increase the nitrate content, which encourages plant growth and increases crop yield
• Increasing human population requires an increased food yield, involving the use of fertilisers and pesticides
• Plants and animals which reduce crop yield can be killed by pesticides
• As pesticides are passed along food chains, toxicity levels can reach lethal levels
• Fertilisers leach into fresh water, adding extra, unwanted nitrates
• Genetically modified crops (GM Crops)


  • Can be used to reduce the use of fertilisers
  • Genetic engineers have managed to create a wide variety of GM crops by inserting a useful gene from some other organism into the cells of a crop plant
• Pesticides sprayed onto crops can prevent, destroy, or repel pests and can build up in the bodies of organisms over time. This is called bioaccumulation
• Algal Blooms

  Nitrates dissolved in soil water are absorbed into plants, used to produce amino acids which are synthesized into plant proteins. Animals consume plants or other animals to obtain amino acids for protein synthesis
• Some pesticides have unintended effects on other populations in the ecosystem
• Fertilisers provide chemicals such as nitrates for plant growth and increased crop yield
• Pesticide alternatives

  • Biological control
  • GM crops
• Ladybirds


  Feed on aphids
• GM crops

  Plants have been genetically modified to be naturally resistant
• Genetic modification eliminates the need for pesticides
• Organisms used in biological control

  • Ladybirds
  • viruses
  • Cactus imoths
• Cactus imoths

  Eat GM crops
• Viruses

  Myxomatosis in rabbits
• Biological control

  Using organisms such as natural predators or parasites to control pest numbers