Summary: The text discusses how mass extinctions have played a significant role in shaping the evolution of life on Earth and how they are often triggered by large-scale environmental perturbations such as volcanic eruptions, asteroid impacts, or climate change. These events have led to the loss of a significant portion of global biodiversity, but they have also paved the way for new species to evolve and dominate the planet. Researchers suggest that five mass extinctions have occurred in the Earth's history, with the most well-known being the Cretaceous-Paleogene extinction event that wiped out the dinosaurs. By studying these past extinctions, scientists hope to gain insights into how ecosystems respond to environmental changes and how they can better predict and potentially mitigate future mass extinction events caused by human activities like habitat destruction and climate change.