Final answer:
Intraspecific competition occurs between members of the same species, while interspecific competition occurs between members of different species. This competition for resources is a basic factor in natural selection and can lead to the evolution of better adaptations within a species.
Step-by-step explanation:
Intraspecific competition occurs between members of the same species. For example, two male birds of the same species might compete for mates in the same area. This type of competition is a basic factor in natural selection. It leads to the evolution of better adaptations within a species.
Interspecific competition occurs between members of different species. For example, predators of different species might compete for the same prey.