AQA Biology Unit 2: 9 Genetic Diversity


  • Similarities and differences between organisms can be defined in terms of variation of DNA
  • DNA difference leads to genetic diversity

Selective Breeding

  • Also known as artificial selection
  • It uses the desired characteristics from one animal
  • Offspring are produced with the desired characteristic
  • If the offspring doesn't have the characteristic it can be killed or stopped from breeding
  • Alleles for unwanted characteristics are bred out
  • Selective breeding reduces genetic diversity
  • It is carried out to produce high yield plants or animals
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Diversity Cont

The Founder Effect

  • When few individuals from a population colonise a new region
  • The individuals have few alleles
  • When the colony repopulate they have less genetic diversity
  • In time the population may develop into a separate species
  • They are less adapt to changing conditions since they have fewer alleles

Genetic Bottleneck

  • Natural disasters can cause this
  • The survivors will possess smaller variety of alleles then original population
  • When repopulating the genetic diversity will remain restricted
  • The fewer alleles mean they are less adapt to change in conditions
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