Biological resources

• Fertilizers


  Used to replace missing minerals / provide more of them for the plant to increase crop yield
• Pesticides


  Poisonous substances to kill pests harmful to plants
• Biological controls


  Using other organisms to reduce pests
• Anaerobic respiration


  Glucose -> Ethanol + Carbon Dioxide + Energy
• Yeast


  Used in bread making, produces carbon dioxide to help dough rise
• Yoghurt making


  1. Equipment sterilised

  2. Milk pasteurised

  3. Lactobacillus bacteria added

  4. Bacteria ferment lactose into lactic acid

  5. Milk clots and solidifies into yoghurt
• Fermentation


  Microorganisms break sugars down to release energy
• Fermenters


  • Air supply for respiration
  • Nutrients for growth
  • Temperature kept at optimum level
  • Water-cooled jacket to prevent overheating
  • Vessels sterilised
  • Aseptic conditions increase product yield
• Selective breeding


  1. Select individuals with best characteristics from existing stock

  2. Breed the best together

  3. Continue the process
• Selective breeding aims for


  • Maximum yield of milk, wool, meat
  • Good health and disease resistance
  • Attractive flowers and nice smell
• Genetic engineering


  Taking a gene from one species and putting it into another
• Genetic engineering process


  1. DNA to be inserted is cut out using restriction enzymes

  2. Vector DNA is cut open using restriction enzymes

  3. Ligase enzymes join the two pieces of DNA to form recombinant DNA
• Transgenic organism


  An organism that has undergone genetic modification
• How beak of the cactus finch has evolved from natural selection?

  • Variation in the population because of mutation
  • Longer beak - reach for nectar in flower
  • More likely to survive and reproduce
  • Pass on their advantage gene
• Mutation


  Only change in the sequence of DNA bases