Principles of Evolution

The bigger picture

  1. Definition
  2. Examples of evolution in action
  3. A historical perspective

Evidence for evolution comes from:

  1. Fossil record
  2. Biogeography
  3. Comparative anatomy
  4. Comparative embryology
  5. Molecular biology

Mechanism of evolution

  1. Populations have inherent, heritable variation
  2. Populations produce more offspring than the environment can support
  3. Individuals that are better adapted to the environment tend to survive longer and produce more offspring
  4. Traits of the better-adapted individuals are passed on more frequently; populations adapt

Evolution works on populations

  1. Evolution requires variation
  2. Genetic variation arises by
    1. Mutation
    2. Recombination
  3. Evolution acts on a population's gene pool
    1. The sum of all the genes & their alleles
    2. Calculating allele frequencies in a population
      • The Hardy-Weinberg equilibrium
    3. The ratio of alleles tends to stay the same under these conditions:
      • No mutation
      • No gene flow
      • Random mating
      • No genetic drift
      • No selection

Microevolution: changing the gene pool

  1. Genetic drift
  2. Bottleneck effect
  3. Founder effect
  4. Gene flow
  5. Mutation
  6. Natural selection

The origin of species

  1. Defining "species"
  2. Speciation and reproductive barriers
  3. Patterns of speciation
  4. Mechanisms
  5. Tempo of speciation


  1. Biological novelty arises
  2. The changing earth
  3. The diversity of life