Great Dying

Definition

The Great Dying refers to the catastrophic decline in biodiversity during the end-Permian extinction, approximately 252 million years ago. This event is notable for being the most severe mass extinction in Earth's history, wiping out around 90% of marine species and 70% of terrestrial vertebrate species. The Great Dying fundamentally reshaped ecosystems, leading to significant evolutionary changes and paving the way for the dominance of the dinosaurs in the Mesozoic Era.

5 Must Know Facts For Your Next Test

1. The Great Dying is estimated to have resulted in the extinction of approximately 96% of all marine species and about 70% of terrestrial vertebrate species.
2. The event is believed to have been caused by a combination of factors, including massive volcanic eruptions in what is now Siberia, climate change, and ocean anoxia.
3. After the Great Dying, ecosystems were drastically altered, allowing for new species to evolve and fill ecological niches left vacant by extinct species.
4. Fossil evidence suggests that recovery from the Great Dying took millions of years, with significant evolutionary innovations occurring during the Triassic period.
5. The Great Dying set the stage for the dominance of reptiles, particularly dinosaurs, in subsequent geological periods.

Review Questions

• How did the Great Dying impact marine and terrestrial ecosystems differently?
  • The Great Dying had a more pronounced effect on marine ecosystems compared to terrestrial ones. While around 96% of marine species went extinct due to factors like ocean anoxia and habitat loss from volcanic activity, terrestrial ecosystems experienced a slightly lesser decline with about 70% of vertebrate species lost. This catastrophic event led to significant changes in food webs and community structures in both environments, ultimately shaping future biodiversity.
• Evaluate the potential causes of the Great Dying and their interconnections in contributing to this mass extinction event.
  • The Great Dying was likely caused by multiple interrelated factors including extensive volcanic eruptions that released large amounts of carbon dioxide, resulting in climate change and ocean acidification. Additionally, these eruptions may have led to a decrease in oxygen levels in oceans (anoxia), further stressing marine life. This complex interplay between geological and climatic changes created conditions that were detrimental to both marine and terrestrial life, culminating in one of Earth's most severe extinction events.
• Synthesize how the effects of the Great Dying influenced evolutionary pathways for subsequent life forms on Earth.
  • The effects of the Great Dying fundamentally altered evolutionary trajectories by clearing ecological niches and allowing new groups of organisms to emerge. After this mass extinction, ecosystems began to recover slowly, leading to diversification among surviving species. The empty niches paved the way for reptiles to thrive and eventually dominate during the Mesozoic Era. This shift not only impacted biodiversity but also set the stage for significant evolutionary developments, such as the rise of mammals later on.

Related terms

Mass Extinction: A widespread and rapid decrease in the biodiversity on Earth, characterized by the loss of a significant number of species in a relatively short period.

Permian Period:

The final period of the Paleozoic Era, which lasted from approximately 299 to 252 million years ago, preceding the Mesozoic Era.

Triassic Period: The first period of the Mesozoic Era, occurring after the Permian, known for the recovery of life and the rise of dinosaurs following the end-Permian extinction.