Variation & Evolution

Variation

• Variation is the differences in the characteristics of individuals in a population. It may be due to:
  • The genes they have inherited: genetic causes (eye colour, blood group)
  • The conditions in which they developed: environmental causes (scars, language, a plant's height depending on light and nutrients)
  • A combination of both (height, weight, skin colour)
• The phenotype develops from the genome interacting with the environment
• There is usually extensive genetic variation within a population
• All variants arise from mutations. Most have no effect on the phenotype; some influence it; very few determine it
• Mutations occur continuously. Very rarely one leads to a new phenotype. If that phenotype is suited to a change in the environment it can lead to relatively rapid change in the species