The largest extinction event in the world was the Permian-Triassic extinction event, also known as the "Great Dying."
This catastrophic event marked the boundary between the Permian and Triassic geological periods, approximately 252 million years ago. It was significantly more devastating than the extinction event that wiped out the dinosaurs.
Here's a breakdown of its impact:
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Scale of Devastation: The Permian-Triassic extinction event resulted in the extinction of an estimated 96% of marine species and 70% of terrestrial vertebrate species. This means that life on Earth nearly disappeared.
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Specific Losses:
- 53% of marine families died out.
- 84% of marine genera were lost.
- About 81% of all marine species vanished.
- An estimated 70% of terrestrial vertebrate species became extinct.
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Possible Causes: While the exact causes are still debated, leading theories include:
- Massive Volcanic Activity: The Siberian Traps, a large igneous province, experienced massive volcanic eruptions that released enormous amounts of greenhouse gases (like carbon dioxide and methane) into the atmosphere.
- Global Warming: The increase in greenhouse gases led to rapid and dramatic global warming.
- Ocean Anoxia: The warmer temperatures reduced oxygen levels in the oceans, creating anoxic (oxygen-depleted) conditions that were lethal to many marine organisms.
- Release of Hydrates: Methane hydrates, frozen methane trapped in ocean sediments, may have been destabilized and released, further exacerbating global warming.
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Consequences: The "Great Dying" fundamentally reshaped life on Earth. It took millions of years for biodiversity to recover. The ecological niches vacated by the extinct species allowed new groups of organisms to evolve and diversify during the Triassic period, ultimately paving the way for the rise of the dinosaurs.
In summary, the Permian-Triassic extinction event represents the most severe biodiversity crisis in Earth's history, drastically altering the course of evolution.
