Variation

• What is meant by variation in biology?


  Variation refers to the differences in the characteristics of individuals in a population.
• What are the three main causes of variation in a population?


  The three main causes of variation are genetic causes, environmental causes, and a combination of both.
• What is an example of genetic variation in humans?


  Examples of genetic variation include hair color and eye color.
• How does the environment cause variation in characteristics?


  Environmental factors can influence characteristics, such as the color of flowers depending on soil pH.
• What is an example of variation caused by a combination of genes and the environment?


  An example is human height, which is influenced by both genetics and diet.
• What is the role of mutations in genetic variation?

  Mutations are random changes to DNA that contribute to genetic variation.
• How do most mutations affect the phenotype?


  Most mutations have no effect at all on the phenotype.
• How can a mutation influence the phenotype of an organism?


  For example, alleles for tallness may lead to tallness if the diet is suitable.
• What is a key idea about mutations and phenotypes?


  Very rarely, a mutation can lead to a new phenotype.
• What can happen if a new phenotype is beneficial in a changing environment?


  A beneficial phenotype can lead to a rapid change in the species.
• What is an example of a beneficial mutation in rabbits?


  A mutation that made some rabbits resistant to a virus in the 1950s.
• What is the significance of the mutation that occurred in the rabbit population in the UK?


  This mutation resulted in a new phenotype that became widespread in the rabbit population.
• What are the main types of variation in a population?

  • Genetic variation (e.g., hair color, eye color)
  • Environmental variation (e.g., flower color due to soil pH)
  • Combination of genetic and environmental factors (e.g., human height)
• What are the effects of mutations on genetic variation?


  • Mutations are random changes to DNA
  • Most mutations have no effect on phenotype
  • Some mutations can influence phenotype
  • Rarely, mutations can lead to new phenotypes
  • Beneficial mutations can lead to rapid changes in species