Final answer:
The largest extinction event in Earth's history, known as the Great Dying, occurred at the end of the Permian period, leading to the loss of a vast majority of marine and terrestrial species.
Step-by-step explanation:
The largest extinction in the history of life occurred at the end of the Permian period. The end-Permian extinction, often referred to as the Great Dying, resulted in the loss of approximately 96 percent of all marine species and 70 percent of terrestrial species. This catastrophic event is attributed to prolonged and widespread volcanic activity, leading to elevated global temperatures, anoxic oceans, and massive losses in biodiversity.
Trilobites, which had survived previous mass extinction events, were completely eradicated during this period. The aftermath of the end-Permian extinction was so severe that terrestrial tetrapod diversity required around 30 million years to recover, making the Permian extinction a defining point in Earth's evolutionary history.