7.2 Natural Selection

Describe the importance of phenotypic variation in a population.

• Natural selection acts on phenotypic variations in populations.
• Environments change and apply selective pressures to populations.
• Some phenotypic variations can increase or decrease the fitness of an organism in particular environments.

Explain how variation in molecules within cells connects to the fitness of an organism.

• Variation in the number and types of molecules within cells can provide populations a greater ability to survive and reproduce in different environments.