Essential idea: The diversity of life has evolved and continues to evolve by natural selection.
The image above shows the changes of beak shape in the Galapagos finch to suit the different food sources available on different islands in the archipelago. Natural selection has caused one species to evolve into different, distinct species.
Understandings, applications and skills
|5.2.U1||Natural selection can only occur if there is variation among members of the same species.|
|5.2.U2||Mutation, meiosis and sexual reproduction cause variation between individuals in a species.|
|5.2.U3||Adaptations are characteristics that make an individual suited to its environment and way of life.|
|5.2.U4||Species tend to produce more offspring than the environment can support.|
|5.2.U5||Individuals that are better adapted tend to survive and produce more offspring while the less well adapted tend to die or produce fewer offspring.|
|5.2.U6||Individuals that reproduce pass on characteristics to their offspring. [Students should be clear that characteristics acquired during the lifetime of an individual are not heritable. The term Lamarckism is not required.]|
|5.2.U7||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.|
|5.2.A1||Changes in beaks of finches on Daphne Major.|
|5.2.A2||Evolution of antibiotic resistance in bacteria.|
[Text in square brackets indicates guidance notes]
Presentation and notes
The presentation is designed to help your understanding. The notes outline is intended to be used as a framework for the development of student notes to aid revision.
Use the Cornell style template to collate your own notes for Topic 5.2 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)
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?
Watch the video to the right to understand what is meant by the term Theory as it is used in Science.