One of the most interesting geologic periods of the Earth's history, the Permian period is best known for the largest mass extinction on the planet. It is also referred to as the 'Age of Amphibians', as fossils reveal that these cold-blooded vertebrates were found in abundance on the planet during this period. The Permian period was the last period of the Paleozoic Era. It was preceded by the Carboniferous period and succeeded by the Triassic period, with the Triassic being the first period of the Mesozoic Era that followed.
Facts about the Permian Period
The Permian was the last period of the Paleozoic Era, which lasted from 290 to 248 million years ago (mya). This geologic period was marked by the presence of 'Pangaea'―a super-continent made up of all the existing continents on the planet, except for a part of east Asia which was a separate geological entity back then. The continent was surrounded by an ocean called 'Panthalassa' and also had a sea, known as 'Tethys', to its east. The movement of this super-continent, which was located along the equator back then, was one of the predominant features of the Permian period. This period didn't just mark the end of Permo-Carboniferous glaciation, but also created some geological structures, which exist even today; the Appalachian mountain range is perhaps the best example of the same.
Even though the Permian period started with an ice age, the climate eventually changed, and most of the parts of the Pangaea continent turned into arid regions. Until mid-Permian period, the Earth's climate was primarily cold, as the glaciers of Permo-Carboniferous glaciation were still receding. As these glaciers melted, the climate changed and became arid, especially in the interiors. According to the paleontologists, this was the hottest period of the last 500 million years on the planet. As time elapsed, the climatic conditions became more diverse in different parts and often oscillated between episodes of warm and cold periods.
During this period, the flora was dominated by the presence of ferns and seed-ferns. While plants like conifers and ginkgos became more prominent, water-loving species like Lycopods and Sphenopsids became pretty rare. These changes were attributed to decline in swamp forests on the planet. The presence of Glossopteris fossils in various parts of the world including Africa, South America, Antarctica, and Australia is the most prominent evidence of the existence of Pangaea―the supercontinent which eventually broke apart to form different continents of the world.
There was a great deal of diversity in the fauna of this period, which consisted of a wide variety of marine and terrestrial animals. One of the most prominent feature of this period was the evolution for large reptiles. While the marine life of this period was mainly marked by the presence of mollusks, echinoderms, and brachiopods, the terrestrial life was characterized by arthropods and tetrapods, which were found in abundance. Around 90 percent of the insects that existed during this period resembled cockroaches, owing to their similar anatomy. The predators of these insects were large air-borne insects―the dragonflies.
The Permian also marked the evolution of beetles and flies on the Earth alongside the first large herbivores and carnivores. While the early Permian was dominated by pelycosaurs and amphibians, the middle Permian was dominated by therapsids (such as dinocephalia) and the late Permian by advanced therapsids (such as dicynodonts).
The great deal of biodiversity that this period boasted of, finally came to an end with the Permian-Triassic extinction―the largest mass extinction on Earth, wherein around 95 percent of the total species on the planet were wiped off. While some experts argue that there was only one extinction event, others argue that there were two extinction events―one after the other―both of which together resulted in such a high number of extinctions. Almost all the species on the planet were affected by this extinction event, but marine organisms were the most affected.
Almost all the marine invertebrates which thrived on the planet became extinct as a result of this mass extinction. Even those animals which survived this extinction were never able to become dominant in terms of numbers. This extinction and depletion in number of marine and terrestrial species of the Permian paved way for evolution of various Triassic animals; most notable among which were the dinosaurs.
In 1841, this geologic period was assigned the name 'Permian' by the renowned Scottish geologist, Roderick Murchison who played a pioneering role in establishing the Permian archaeological period as well as various other geological time periods in the history of the Earth.