Populations

• Species


  One or more populations of organisms of the same species occupying a particular space at a particular time that can potentially interbreed
• Population


  A group of organisms of the same species occupying a particular space at a particular time that can potentially interbreed
• Gene pool


  The total number of alleles that are present in a population
• Allelic frequency


  Expresses as a decimal or percentage the proportion of a certain allele in a gene pool
• Hardy-Weinberg equation


  1. Calculates the frequency of alleles, genotypes & phenotypes in a population

  2. Predicts that allele frequencies will not change from generation to generation
• Assumptions for Hardy-Weinberg principle

  • No mutations occur to create new alleles
  • No movement of alleles into or out of the population by migration
  • The population is large
  • No selection, so every allele has an equal chance of being passed to the next generation
  • Mating is random
• Hardy-Weinberg equation


  • p + q = 1
  • p² + 2pq + q² = 1
  • p = frequency of the dominant allele
  • q = frequency of the recessive allele
  • p2 = frequency of homozygous dominant
  • 2pq = frequency heterozygous
  • q2 = frequency of homozygous recessive