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?

  The environment can influence characteristics, such as the color of flowers depending on the pH of the soil.
• 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 source of genetic variation in a population?

  The source of genetic variation is mutations.
• What are mutations?

  Mutations are random changes to DNA that occur all the time.
• How do most mutations affect the phenotype?

  Most mutations have no effect at all on the phenotype.
• Can mutations influence the phenotype? Give an example.

  Yes, 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.
• How can a new phenotype be beneficial?

  A new phenotype can be beneficial if the environment changes, leading to rapid change in the species.
• What happened to the wild rabbit population in the UK in the 1950s?

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

  This mutation gave the rabbits a new beneficial phenotype that became widespread in the UK population.
• What are the 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 phenotypes?

  • Most mutations have no effect on phenotype
  • Some mutations can influence phenotype (e.g., tallness)
  • Rarely, mutations can lead to new phenotypes
  • New phenotypes can be beneficial in changing environments