Permian period

The Permian period was the last geological period of the Paleozoic era, spanning from approximately 298.9 million to 251.902 million years ago. It is preceded by the Carboniferous period and followed by the Triassic period, the first period of the Mesozoic era. The Permian period is known for its significant geological, climatic, and evolutionary developments.

Geology

During the Permian, all the Earth's major landmasses were collected into a single supercontinent known as Pangaea. This massive continental formation influenced global climate patterns, leading to a more extreme continental climate with very hot summers and cold winters. The formation of Pangaea also resulted in extensive dry inland areas, with significant environmental consequences for terrestrial life.

Climate

The climate of the Permian was characterized by sharp contrasts due to the vast size of Pangaea. The interior regions of this supercontinent experienced severe seasonal fluctuations, and the climate overall was arid, particularly in the interior. These conditions contributed to the decline of swampy, coal-forming forests, which were abundant during the Carboniferous period, and their replacement by gymnosperms, which were better adapted to the drier climate.

Biosphere

The Permian period saw both flourishing and mass extinction of various forms of life. Early in the Permian, the dominant vertebrates were the synapsids, including the famous Dimetrodon. However, by the end of the period, synapsids were largely supplanted by archosaurs and other early diapsids, which would go on to dominate the Mesozoic era.

The Permian is also notable for the diversification of the amniotes, a group that includes most terrestrial vertebrates, including modern reptiles, birds, and mammals. This era also witnessed the evolution of important plant groups, including the Glossopteris flora, which dominated the southern part of Pangaea.

Mass Extinction

The end of the Permian period was marked by the largest mass extinction in Earth's history, known as the Permian-Triassic extinction event. This event, occurring approximately 251 million years ago, eradicated about 90% of all species. The causes of this extinction event are still debated, but likely involved massive volcanic eruptions, climate change, and anoxia in the oceans.

Legacy

The Permian period set the stage for the Mesozoic era, often called the "Age of Reptiles," and had a profound impact on the evolutionary trajectory of life on Earth. The changes that occurred during this period influenced the development of ecosystems that emerged in the Triassic period and beyond.