5.2: Natural selection

Retrieval practice and prior learning

A2: Evolution of antibiotic resistance in bacteria.

NoS: Use theories to explain natural phenomena—the theory of evolution by natural selection can explain the development of antibiotic resistance in bacteria. (2.1)

Exercise 1: Using the statements in U4-U7 explain how antibiotic resistance in bacteria may have evolved.

U1: Natural selection can only occur if there is variation among members of the same species.

U2: Mutation, meiosis and sexual reproduction cause variation between individuals in a species.

Exercise 3: Outline how mutation, meiosis and sexual reproduction can cause variation within a species.

U3: Adaptations are characteristics that make an individual suited to its environment and way of life.

Exercise 4: Thinking back to the pentadactyl limb and the species that possess it, what adaptations do the different species have that have this limb?

U4: Species tend to produce more offspring than the environment can support.

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.

U6: Individuals that reproduce pass on characteristics to their offspring.

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.

Guidance from the syllabus: Students should be clear that characteristics acquired during the lifetime of an individual are not heritable. The term Lamarckism is not required.