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 the first cause of variation?

  Inherited alleles
• How does language in humans demonstrate variation?

  It is influenced by environmental factors
• How do genetics and diet interact to affect height?

  Genetics influences height, diet affects growth
• What causes genetic variation in a population?

  Mutations in DNA
• What are mutations?

  Random changes to DNA
• What is the effect of most mutations on phenotype?

  Most have no effect at all
• How can some mutations influence phenotype?

  By affecting traits like tallness
• What is a key idea about mutations and phenotypes?

  Very rarely can lead to a new phenotype
• How can a mutation be beneficial?

  If it helps survival in a changing environment
• What happened to the rabbit population in the UK in the 1950s?

  A mutation made rabbits resistant to a virus
• What is the significance of the beneficial phenotype in rabbits?

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

  • Genetic variation (inherited alleles)
  • Environmental variation (influenced by surroundings)
  • Combined variation (interaction of genes and environment)
• What are the effects of mutations on phenotypes?

  • Most mutations have no effect
  • Some mutations can influence traits
  • Rarely, mutations can lead to new phenotypes