Variation

• Differences in the characteristics of individuals in a population is called variation
• Variation can be due to

  • The genes they have inherited (genetic causes)
  • The conditions in which they have developed (environmental causes)
  • A combination of genes and the environment
• There is usually extensive genetic variation within a population of a species
• Mutations mostly have no effect on the phenotype
• Mutations occur continuously
• Very rarely a mutation will lead to a new phenotype
• If the new phenotype is suited to an environmental change it can lead to a relatively rapid change in the species