Biology 242: Lecture 10Spring 2001

Speciation

  1. What is a species?
    1. "Morpho" species concept
      1. Classification based on appearance/anatomical features
      2. Problems
    2. Biological species concept
      1. Classification based on potential to interbreed
      2. Problems
    3. Recognition species concept
    4. Cohesion species concept
    5. Ecological species concept
    6. Evolutionary species concept

  2. Reproductive barriers = genetic isolation
    1. Prezygotic barriers
      1. Habitat isolation
      2. Temporal isolation
      3. Behavioral isolation
      4. Mechanical isolation
      5. Gametic isolation
    2. Postzygotic barriers
      1. Hybrid inviability
      2. Hybrid sterility
      3. Hybrid breakdown

  3. Speciation models
    1. Allopatric speciation
      1. Speciation by geographical isolation
      2. Genetic drift/natural selection in different environments
      3. Adaptive radiation
    2. Sympatric speciation
      1. Speciation without geographical isolation
      2. Polyploidy
      3. Balanced polymorphism + assortative mating

  4. Interpretations of speciation
    1. Gradualism
    2. Punctuated equilibrium


"Character is a victory, not a gift."
Apples of Gold