Some of the biggest causes of mass extinctions include:
- Ocean/atmosphere chemistry
- Climate change
- Volcanic activity
- Meteor/asteroid impacts
No matter how far back you look, nature has found its way to reshuffle the deck. Large mammals are at greater risk. For example, giant sloths, mastodons, and saber-toothed tigers became extinct only about 10,000 years ago. They just couldn’t find a way to outmuscle nature.
What were the 5 biggest dying events in history?
|Extinction Event||Major Cause||Groups Affected||Time (Years Ago)|
|Cretaceous-Paleogene Extinction (K-Pg)||Asteroid impact at Chicxulub Crater||Dinosaurs (not birds), pterosaurs, plesiosaurs, mosasaurs and ammonoids||66,000,000|
|Triassic-Jurassic Extinction||Volcano eruptions, climate change and gas hydrate release||Large amphibians, crurotarsans (not crocodiles), insects and conodonts||201,300,000|
|Permian-Triassic Extinction||Unstable climate, ocean oxygen reduction or asteroid/comet impact||Marine invertebrates, land plants, plankton, insects and all life||252,000,000|
|Late Devonian Extinction||Global anoxia (oxygen shortage), forest evolution and reduced carbon dioxide||Coral-sponge reefs in tropics, fish and plankton||375,000,000|
|Ordovician–Silurian Extinction||Massive glaciation and sea level drop||Brachipods, trilobites, graptolites and moss animals||450,000,000|
1. Cretaceous-Paleogene Extinction (K-Pg)
About 66 million years ago, 75% of species became extinct during the Cretaceous–Paleogene Extinction. Rates of extinction broadly swept the land, sea, and air. In the oceans, ammonites disappeared.
All non-avian dinosaurs became extinct. But avian dinosaurs survived because it was birds that descended from theropod dinosaurs. Eventually, mammals emerged as dominant large land animals.
The cause of this extinction event was from an asteroid impact which left an impact called the Chicxulub Crater. Also, giant floor basalts aggravated called Deccan Traps.
2. Triassic–Jurassic Extinction (T-J)
The Triassic–Jurassic Extinction occurred 201.3 Million years ago. This extinction event witnessed acid 70-75% of all terrestrial and marine species go extinct.
Although the effects of this extinction were less disastrous, most amphibians were eliminated. At the end of it, dinosaurs were left with little terrestrial competition.
Possible causes include volcanoes and giant flood basalts. From the sudden release of carbon dioxide, climate change amplified the greenhouse effect.
3. Permian–Triassic Extinction (Great Dying)
Earth’s largest extinction event in history killed 96% of all marine species and an estimated 70% of land species, including insects. The Permian-Triassic Extinction was such a devastating event that it had the nickname of the ”Great Dying” because of its significance.
Actually, it took 30 million years for vertebrates to fully recover. Even the highly successful marine arthropod and trilobite went extinct. There was enormous evolutionary significance in ending the reign of mammal-like reptiles.
It’s difficult to find the underlying cause of the Permian-Triassic Extinction because it happened 252 million years ago. Much of the evidence would have been removed. But the general consensus for the cause of the “Great Dying” is from severe volcanic activity, environmental change, long-term methane release.
4. Late Devonian Extinction (Late D)
The Late Devonian Extinction was less severe than the other mass extinctions. At least 70% of all species went extinct
It occurred 375–360 million years ago at the end of the Frasnian Age and in the Devonian Period. This mass extinction lasted for over 20 million years.
Though opinions vary, the biggest evidence is attributed to global anoxia. The oxygen shortage was possibly triggered by global cooling or oceanic volcanism.
5. Ordovician–Silurian Extinction (O-S)
The Ordovician–Silurian Extinction actually consists of two consecutive mass extinctions. When combined together, O-S is widely considered to be the second most catastrophic extinction event in history.
About 450–440 million years ago, 60% to 70% of all species were vanquished. This included 85% of marine species that died.
The primary cause of the Ordovician–Silurian Extinction is believed to be massive glaciation and sea-level drop. As continental drift carried Gondwana to the South Pole, this locked water into ice caps. Overall, sea levels substantially dropped.