The term "extinction" refers to the complete disappearance of a species from Earth. This occurs when a species no longer has any living individuals left, often due to factors like habitat loss, climate change, overexploitation, or the introduction of invasive species. Extinction can have profound impacts on ecosystems, as it disrupts food chains and biodiversity. Understanding extinction is crucial for conservation biology, as identifying at-risk species and implementing protective measures can help prevent further losses in global biodiversity. The threat of extinction highlights the importance of preserving natural habitats and promoting sustainable practices.