What is meant by extinct species?

Extinct species are those that have completely disappeared from Earth, with no living individuals remaining anywhere in the wild or in captivity. Extinction represents the permanent loss of a species, meaning it can never be recovered or restored naturally. Famous examples include the dodo bird, passenger pigeon, Tasmanian tiger (thylacine), and numerous dinosaur species. Once extinction occurs, the unique genetic information, ecological role, and evolutionary history of that species are lost forever, representing an irreversible gap in biodiversity.

Species become extinct due to various factors including habitat destruction, overhunting, climate change, disease, competition from invasive species, and natural catastrophes. Human activities have dramatically accelerated extinction rates in recent centuries—current extinction rates are estimated to be 100 to 1,000 times higher than natural background rates. Each extinction disrupts food webs and ecosystem functions, as every species plays a role in its environment. Preventing extinction requires urgent conservation action for endangered species through habitat protection, captive breeding programs, anti-poaching measures, and addressing underlying threats like deforestation and pollution.