This document discusses extinction, both historically and currently. It explores past mass extinction events and examines whether the current extinction rates constitute a sixth mass extinction. While not at the level of past mass extinctions yet, losing threatened species endangers many forms of life. The document also analyzes evidence that early humans drove megafauna to extinction through overhunting. Though human-driven changes can produce artificial selection, species sometimes adapt when released from those pressures. Island ecosystems face especially high extinction risks from human impacts.