Natural selection provides the following mechanism for evolution: Some variation in heritable characteristics exists within every species; some of these characteristics give individuals an advantage over others in surviving and reproducing; and the advantaged offspring, in turn, are more likely than others to survive and reproduce. As a result, the proportion of individuals that have advantageous characteristics will increase.
Learning Goal 6a
Natural selection leads to organisms that are well-suited for survival in particular environments.
Learning Goal 6b
Chance alone can result in the persistence of some heritable characteristics having no survival or reproductive advantage or disadvantage for the organism.
Learning Goal 6c
When an environment, including other organisms that inhabit it changes, the survival value of inherited characteristics may change.