An introduction to natural selection

  • describe the differences between continuous and discontinuous variation and explain the genetic basis of continuous (many, additive genes control a characteristic) and discontinuous variation (one or few genes control a characteristic)
  • explain, with examples, how the environment may affect the phenotype of plants and animals
  • use the t-test to compare the variation of two different populations
  • explain why genetic variation is important in selection
  • explain that natural selection occurs as populations have the capacity to produce many offspring that compete for resources; in the ‘struggle for existence’ only the individuals that are best adapted survive to breed and pass on their alleles to the next generation