The Competitive Exclusion Principle states that two species competing for the same resources cannot coexist indefinitely. When two species have identical needs, one will outcompete the other, leading to the decline or extinction of the less competitive species. This principle highlights the importance of resource availability in ecosystems. This concept is crucial in understanding biodiversity and species interactions. It explains why different species often occupy distinct niches, allowing them to coexist by utilizing different resources or habitats. The principle is foundational in ecology and helps scientists predict the outcomes of species competition in various environments.