Final answer:
An ecological niche is the unique set of resources used by a species. Interspecific competition occurs when the niches of two populations overlap, leading to competitive exclusion.
Step-by-step explanation:
An ecological niche refers to the unique set of resources used by a species, including its interactions with other species. It encompasses the role of a species in its ecosystem, including its food source and how it obtains it.
Interspecific competition can occur when the niches of two populations overlap. When two species compete for the same resources, such as food, water, or space, they may experience competitive exclusion, where one species outcompetes and replaces the other.
For example, let's consider two bird species that occupy the same forest habitat. If both species rely on the same food source, such as insects or berries, they will compete for those resources. The species that is better adapted to obtain the resources will have a competitive advantage and may outcompete the other species, leading to its local extinction.