Essential idea: The diversity of life has evolved and continues to evolve by natural selection
Nature of science:
Use theories to explain natural phenomena—the theory of evolution by natural selection can explain the development of antibiotic resistance in bacteria. (2.1)
- Natural selection can only occur if there is variation among members of the same species.
- Mutation, meiosis and sexual reproduction cause variation between individuals in a species.
- Adaptations are characteristics that make an individual suited to its environment and way of life.
- Species tend to produce more offspring than the environment can support.
- Individuals that are better adapted tend to survive and produce more offspring while the less well adapted tend to die or produce fewer offspring.
- 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.
Applications and skills:
- Application: Changes in beaks of finches on Daphne Major.
- Application: Evolution of antibiotic resistance in bacteria.
- Students should be clear that characteristics acquired during the lifetime of an individual are not heritable. The term Lamarckism is not required.
Theory of knowledge:
- Natural Selection is a theory. How much evidence is required to support a theory and what sort of counter evidence is required to refute it?