In biology, the scientific term "extinction" refers to the complete disappearance of a species. It occurs when a species can no longer survive in its environment or compete successfully with others, often due to factors like habitat destruction, climate change, or overexploitation. Extinction can happen gradually over time or abruptly. The phenomenon is significant in ecology because once a species becomes extinct, it can lead to ecosystem changes and negatively affect other species dependent on it, resulting in a cascade effect throughout the ecosystem.