Variation

• Variation

  Differences in characteristics of individuals in a population
• Main causes of variation

  • Alleles
  • Inherited
  • Environment
  • Both genes and environment
• Alleles inherited

  • Hair and eye colour
• Environment

  • Language in animals
  • pH in the soil for plants, affecting their colour
• Both genes and environment

  • Height, through calcium and genes
• In any population of a species, there is a massive amount of genetic variation
• Genetic variation

  Due to mutations, random changes to DNA
• Most mutations have no effect on the phenotype, however some can influence the phenotype
• A small number of mutations can determine phenotype
• Very rarely, mutations can lead to a new phenotype, which can be beneficial if the environment changes. This can lead to a rapid change in species
• Virus spread in the UK in 1950s

  • Killed 99% of rabbits, however the remaining ones survived due to variation making them resistant
• This virus resistance is beneficial to the rabbit species