Natural Selection

• what is the sequence of events leading to natural selection?

  • genetic variation within population (DNA mutation)
  • selection pressure creates competition for survival
  • some individuals possess favourable alleles/characteristics which means they are better adapted to the environment
  • individuals with favourable alleles survive longer and have more offspring (others die)
  • possessors of favourable alleles will pass them onto some offspring
  • repeated over many generations and favourable allele becomes more common in population
• how can selection pressure drive natural selection?

  • antibiotic resistance in bacteria
  • pesticide resistance in pests
  • camouflage/behaviour
  • disease resistance/survival