Mass extinctions are periods of time when an alarmingly large and diverse variety of species become extinct in a comparatively short period of time These events have drastically changed the course of life on Earth, both through the loss of species, as well as the emergence of new species to take their place. Mass extinctions are often seen as the result of drastic changes in the environment, such as dramatic climate change, major volcanic activity, or a major asteroid impact.
The five best examples of mass extinctions are: the end-Permian extinction, the end-Triassic extinction, the end-Cretaceous extinction, the Late Devonian extinction, and the Ordovician-Silurian extinction.
The end-Permian Extinction, sometimes referred to as the Great Dying, is the most severe mass extinction event in the history of life on Earth. Between 252 and 260 million years ago, an unprecedented 95% of all species went extinct. This event is believed to have been caused by a combination of massive volcanic activity in Siberia and a great drop in sea levels, along with numerous other events, such as climate change and a loss of oxygen in the seas.
The end-Triassic Extinction, which occurred around 200 million years ago, was the second-most severe extinction event in Earth’s history. This mass extinction was likely caused by massive volcanic eruptions in the Central Atlantic Magmatic Province (CAMP), which is believed to have drastically disrupted the planet’s climate and caused great changes in the environment.
The end-Cretaceous Extinction, which occurred 66 million years ago, is likely one of the most well-known mass extinctions, as it marks the end of the age of dinosaurs. This extinction is believed to have been due to an asteroid impact, which caused massive damage to the environment.
The Late Devonian Extinction occurred about 375 million years ago, and is thought to be the result of a major drop in sea level, as well as large volcanic eruptions. This event wiped out almost half of all of the species on Earth.
The Ordovician-Silurian Extinction, which occurred about 443 million years ago, is the third-most severe extinction event in Earth’s history. This event is believed to have been caused by a combination of a severe glaciation event and a major drop in sea levels.
Overall, there have been several mass extinction events throughout the history of life on Earth, each of which has had drastic consequences on the environment and the species that live in it. These events have allowed for the emergence of new species, as well as the loss of existing species, thus dramatically changing the course of life.