Hello. My name is Brad Permian and I shall be your guide on this most fantastic voyage back in time. Together, we will explore the various flora, fauna, geologic, and ecologic changes through one very tumultuous Period, the Permian. The rise of the Appalachian mountain range, the formation of the super-continent Pangea, and the cataclysmic end-Permian mass extinction. It's enough to make your head spin. So sit back, grab an ice-cold ginger ale, and let get old Brad spin you a yarn that even the most up-to-date Permophile will find difficulty disputing.
The Permian Period is the last geologic Period of the Paleozoic Era and is marked by the greatest mass-extinction ever, the end-Permian extinction. The geologist Roderick Impy Murchison named the Permian Period after the ancient kingdom of Permia, near the Ural mountains in present-day Russia. The end-Permian extinction significantly reduced the number of living species on Earth, paving the way for the age of the Dinosaurs in the Mesozoic Era.
The shift from the Carboniferous to Permian Period was marked by the end of a world-wide glaciation. This is partly due to the most important geologic event of the Permian, the formation of the super-continent Pangea. As continental plates collided into each other, Pangea moved slowly northward, away from the glaciated south pole and nearer the equator.
The end of the Permian is marked by the greatest biotic extinction ever, the end-Permian Extinction. Marine communities (particularly sessile, filter-feeding fauna) were hit much harder than terrestrial organisms. Some speculations state that 95% of all marine fauna species, 75% of all amphibian species, and 80% of all reptile families went extinct during this time. We'll discuss the many theories explaining the end-Permian extinction a little later.
The Permian opened much the same way the Carboniferous ended: massive glaciers gripped the poles, keeping the ends of the Earth (particularly the southern-lying Gondwanaland) locked in a deep-freeze, while the tropical zones consisted of wet, humid, swampy forests of tree-like ferns. The continued northward migration of Pangea toward the equator melted the polar glaciers and affected global warming during the middle of the Permian. Being such an enormous continent, the interior of Pangea suffered substantial seasonal changes (both in temperature and precipitation). Without nearby oceans or other large bodies of water to moderate temperature, Pangea's interior not only went through seasonal fluctations but was marked by a great degree of aridity. In fact, only parts of the interior are even speculated to have received precipitation. Throughout the Permian, things slowly dried amidst the alternating seasons and high aridity.
The early Permian biomes were a continuation of the prevalent Carbinoferous biomes (polar tundra regions and warm tropical swamp forests). However, the previously noted global warming during the Permian Period and the arid interior of Pangea led to a decline of a number of dominant plant groups, including the pteridosperms, the tree ferns, and sphenopsids. The great, wet forests of tall fern-like plants gave way to a variety of new seed plants, the spermatophytes, especially the gymnosperms and conifers. This new ability to house seeds is seen as a trait that adaptively radiated during the end-Permian.
Marine life during the Permian Period consisted mainly of reefal communities. These communities were made up of sessile filter feeders like brachiopods, bryozoans, sponges, and crinoids. There were a few fish and cephalopods, and even fewer bivalves and gastropods. The gastropods that did exist during the permian were mostly herbivors, scavengers, or sessile fiter feeders, whereas today most gastropods are sophisticated, specialized predators.
Since increased aridity dried out tropical, ferny swamps and ponds, amphibians were the hardest hit land vertebrates. Reptiles quickly took advantage of the increased aridity, however, and we see an impressive radiation of reptiles in the later part of the Permian. Although many reptiles thrived in the Permian, the largest, most diverse, and most successful of them were members of the group Synapsida (also called therapsids), reptilian ancestors to mammals. Herbivorous tetrapods began to thrive during Permian, and an extensive radiation by the dicynodont theraspids occurred during the late Permian. These herbivors were successful in foragining close to the ground, burrowing after roots and tubers. Below are three distinct "Dynasties" of Permian reptiles.
Insects continued to diversify during the Permian, particularly herbivorous insects. The group of insects called the Palaeoptera (insects without the ability to fold their wings against their body) lost out to the more novel and modern group of insects called the Neoptera (insects possessing the ability to fold their wings against their body).
Undoubtedly, the most significant geologic event of the Permian period was the combining of Gondwanaland and Laurasia in the formation of the super-continent Pangea. During most of the Paleozoic, the two large continents of Gondwanaland and Laurasia were isolated from each other, Gondwanaland being the "southern" continent and Laurasia being the "northern" continent. After the collision, Panthalassa was the earth's only ocean. A smaller body of water, the Tethys Sea, lie to the east of Pangea.
The collision of Gondwanaland and Laurasia resulted in the rotation of the positions of the continental plates and a northward thrust of the newly formed Pangea. This change in latitude caused the massive glaciers covering Gondwanaland to slowly melt throughout the Permian.
Numerous hypotheses have been presented to explain Earth's most massive extinction ever. Of course, it is not likely that the extinction was the result of a solitary cataclysmic occurence. More appropriately, we should consider the cause of such a biotic catastrophe as involving several concurrent happenings. Below are a few general hypotheses as to the cause of the extinction:
Where in the world are fossils of this time period collected? Who are the major authorities in primary literature on this geologic period?
A list of works cited.