Final answer:
The Great Dying, or the Late Permian mass extinction, was likely caused by a combination of factors including a meteorite impact, extensive volcanic activity, and a warming climate.
Step-by-step explanation:
The Great Dying, or the Late Permian mass extinction, which occurred approximately 252 million years ago, is considered the most severe mass extinction event in Earth's history.
This event led to the disappearance of a vast number of species from both land and sea ecosystems. While several hypotheses have been proposed, three main explanations stand out.
Meteorite impact: Similar to the Cretaceous-Paleogene mass extinction, a large meteorite impact is one of the hypothesized causes, possibly resulting in a nuclear winter-like effect that would inhibit photosynthesis and drastically cool the planet.
Volcanic activity: The extensive volcanic eruptions, specifically in Siberia, released a significant amount of ash and gases into the atmosphere, potentially affecting the climate and ocean chemistry drastically.
Warming climate: Apart from the direct effects of volcanic activity, the associated warming of the Earth's climate may also have been a contributing factor, as it would have led to severe environmental changes.
These events could have worked both independently and synergistically to bring about the mass extinction that defines the transition from the Paleozoic to the Mesozoic era.
The Great Dying, unlike the later dinosaur extinction event, may have not been the result of a singular cause but rather a culmination of significant and catastrophic environmental shifts.