Variation

• What is meant by variation in biology?

  Differences in characteristics of individuals
• What are the three main causes of variation?

  Genetic, environmental, and combined causes
• What is an example of genetic variation?

  Hair color
• How do alleles contribute to variation?

  They are inherited genetic factors
• What is an example of environmental variation?

  Flower color depending on soil pH
• How does height in humans illustrate combined variation?

  Height is influenced by genes and diet
• What causes genetic variation in a population?

  Mutations in DNA
• What is a mutation?

  Random changes to DNA
• How do mutations affect phenotypes?

  Most have no effect, some influence traits
• What is a key idea about mutations and phenotypes?

  Rarely, mutations can create new phenotypes
• How can a beneficial mutation affect a species?

  It can lead to rapid change in the species
• What happened to wild rabbits in the UK in the 1950s?

  A virus affected 99% of them
• What was the result of the mutation in rabbits?

  Surviving rabbits became resistant to the virus
• What is a new phenotype in the context of the rabbit mutation?

  Resistance to the virus
• How widespread was the beneficial phenotype in the UK rabbit population?

  It became widespread among the population
• What are the types of variation in a population?

  • Genetic variation
  • Environmental variation
  • Combined variation (genes + environment)
• What are the effects of mutations on phenotypes?

  • Most mutations have no effect
  • Some mutations influence traits
  • Rarely, mutations create new phenotypes
• What is the significance of beneficial mutations in a species?

  • Can lead to rapid changes
  • May enhance survival in changing environments