Variation

• What is the term used to describe differences among organisms of the same species?


  Variation
• Why do organisms of the same species look different?


  Because they exhibit variation within the species
• What are the two types of variation?

  Genetic variation and environmental variation
• What does genetic variation result from?


  Differences in genotype among organisms
• What is genotype?


  All of the genes and alleles that an organism has
• How does an organism's genotype affect its phenotype?


  It determines the characteristics that the organism displays
• How are genes inherited?


  They are passed down from an organism's parents
• What influences an organism's phenotype besides genotype?


  Interactions with its environment
• What would happen to a plant grown in darkness compared to one grown in sunlight?


  The plant in darkness would be tall, spindly, and have yellow leaves
• What determines the maximum height of an animal or plant?

  • Determined by its genes
  • Actual growth depends on environmental factors (e.g., food availability)
• What is a mutation?


  A rare random change in an organism's DNA that can be inherited
• What does a mutation produce?


  A genetic variant, which is a different form of the gene
• How do gene mutations affect proteins?


  They can lead to changes in the protein that the gene codes for
• What is the effect of most genetic variants on an organism's phenotype?


  Most have very little or no effect
• How can a mutation in one of the genes controlling eye color affect phenotype?


  It may change the eye color slightly
• What genetic disorder is caused by a mutation affecting phenotype?


  Cystic fibrosis