What caused Earth’s first mass extinction?
16th Nov, 2021
A recently published paper has come up with a ‘new reason’ behind the first mass extinction, also known as the Late Ordovician mass extinction.
What’s the new finding?
- The article notes that the cooling climate likely changed the ocean circulation pattern.
- This caused a disruption in the flow of oxygen-rich water from the shallow seas to deeper oceans, leading to a mass extinction of marine creatures.
What is mass extinction?
- Mass extinctions are defined as any substantial increase in the amount of extinction (lineage termination) suffered by more than one geographically wide-spread higher taxon during a relatively short interval of geologic time, resulting in an at least temporary decline in their standing diversity.
Major mass extinction events in the geological history of Earth:
- Ordovician-Silurian extinction 485 to 444 million years ago: killed about 85% of all species.
- Late Devonian extinction - 383-359 million years ago: wiped out about 75% of the world’s species.
- Permian-Triassic extinction - 252 million years ago: also known as the Great Dying caused the extinction of over 95% of all species.
- Triassic-Jurassic extinction - 201 million years ago: eliminated about 80% of Earth’s species, including some dinosaurs.
- Cretaceous-Paleogene extinction - 66 million years ago
What’s leading to the extinction?
- destruction and fragmentation of habitats
- direct exploitation like fishing and hunting
- chemical pollution
- invasive species
- human-caused global warming
- Uncontrolled human population
- Overexploitation of resources