What is the largest known extinction event in Earth’s history?

The Permian-Triassic extinction, often referred to as the "Great Dying," is recognized as the largest known extinction event in Earth's history, occurring approximately 252 million years ago. This catastrophic event led to the extinction of about 96% of all marine species and around 70% of terrestrial vertebrate species. The scale of biodiversity loss and the rapidity of these changes had long-lasting effects on the evolution of life on Earth.

The causes behind this mass extinction are believed to be complex and multifaceted, involving significant volcanic activity, climate changes, ocean anoxia (lack of oxygen), and possibly asteroid impacts. The extinction paved the way for the rise of the dinosaurs in the following Mesozoic Era, fundamentally altering the course of biological evolution.

Understanding this event is crucial for grasping the dynamics of Earth's biological history and the impact of environmental changes on species survival and diversification. It also serves as a critical reminder of the vulnerability of ecosystems to catastrophic changes.