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 the environment cause variation in flowers?

  Color depends on the pH of the soil
• How do alleles influence height?

  They can make individuals likely to grow taller
• What must a diet include for proper height development?

  Enough calcium for bone development
• What causes genetic variation in a population?

  Mutations
• What are mutations?

  Random changes to DNA
• Do most mutations affect the phenotype?

  No, most have no effect
• What can some mutations influence?

  The phenotype of an individual
• How often do mutations lead to a new phenotype?

  Very rarely
• What can a beneficial mutation lead to?

  A rapid change in the species
• What happened to wild rabbits in the UK in the 1950s?

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

  Widespread new phenotype in the population