The End-Triassic Extinction was a significant event that occurred around 201 million years ago, marking the end of the Triassic Period. This extinction led to the loss of approximately 76% of all species on Earth, including many marine reptiles and large amphibians. It is considered one of the five major mass extinctions in Earth's history. Several factors contributed to this extinction, including massive volcanic eruptions that released large amounts of carbon dioxide and sulfur dioxide into the atmosphere. These eruptions likely caused climate change, ocean acidification, and a decrease in oxygen levels, severely impacting ecosystems and leading to widespread species die-offs.