5.2 Natural Selection

Nature of Science
1. The theory of evolution by natural selection
  1. TOK
    1. How much evidence is required to support a theory?
    2. What sort of counter evidence is required to refute it?
  2. Adaptations are characteristics that make an individual suited to its environment and way of life
    1. Individuals that are better adapted tend to survive and produce more offspring while the less well adapted tend to die or produce fewer offspring
      1. Species tend to produce more offspring than the environment can support
        Individuals that reproduce pass on characteristics to their offspring
        Natural selection increases the frequency of characteristics that make individuals better adapted and decreases the frequency of other characteristics leading to changes within the species
  3. Characteristics acquired during the lifetime of an individual are not heritable
  4. Examples
    1. Antibiotic resistance
    2. Beaks in the finches on Daphne Major
Variation
1. Natural selection can only occur if there is variation among members of the same species
  1. Sexual reproduction
  2. Mutations
  3. Meiosis

Resource summary

	Created by Steve Harton almost 10 years ago