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| This period is part of the Paleozoic era. |
| Permian |
| Carboniferous |
| Devonian |
| Silurian |
| Ordovician |
| Cambrian |
The Permian is a geologic period that extends from about 280 to 248 million years before the present ( mya). As with most older geologic periods, the strata that define the Permian are well identified, but the exact date of the period's start is uncertain by a few million years. The end of the period is marked by a major extinction event that is more tightly dated. The Permian is named from the extensive exposures in the region around the city of Perm in Russia. The Permian follows the Carboniferous ( Pennsylvanian in North America) and is followed by the Triassic. Permian exposures consist largely of continental redbeds and shallow water marine exposures.
The Permian is usually broken into lower (early) and upper (late) subdivisions. The faunal stages from youngest to oldest are:
The Permian ended with the most extensive extinction event recorded in paleontology: the Permian-Triassic extinction eventThe Permian-Triassic extinction event was an extinction event that occurred approximately 252 million years ago (mya), forming the boundary of the Permian and Triassic periods. It was the Earth's most severe extinction event, with about 90 percent of all. 90% to 95% of marine species became extinctIn biology and ecology, extinction is the disappearance of a species or group of species. The moment of extinction is generally considered to be the death of the last individual of that species. In species which reproduce sexually, extinction of a species, as well as 70% of all terrestrial organisms. There is very modest evidence that the extinction could have been caused by climate changeThe term climate change is used to refer to changes in the Earth's climate. In the most general sense, it can be taken to mean changes over all timescales and in all of the components of climate, including precipitation and clouds as well as temperature.s due to impact by a large bolideA bolide is an extraterrestrial body that collides with the Earth. It explodes either on impact with the Earth's surface or at a low altitude above it, creating a large crater. It is a generic term that does not imply the nature of the impacting body, i.. The reduced coastal habitat and highly increased aridity probably also contributed.
TrilobiteAgnostida Redlichiida Corynexochida Lichida Nektaspida? Phacopida Proetida Asaphida Harpetida Ptychopariida Trilobites are extinct arthropods in the class Trilobita . They appeared in the Cambrian era and flourished throughout the lower Palaeozoic befores, which had thrived since CambrianThe Cambrian is a major division of the geologic timescale that begins about 542 million years before the present (BP) at the end of the Proterozoic eon and ended about 490 million years BP with the beginning of the Ordovician period. It is the first peri times, finally became extinct before the end of the Permian.Terrestrial life in the Permian included diverse plantGreen algae land plants (embryophytes non-vascular embryophytes Hepatophyta liverworts Anthocerophyta hornworts Bryophyta mosses vascular plants (tracheophytes seedless vascular plants Lycopodiophyta clubmosses Equisetophyta horsetails Pteridophyta "true"s, large amphibians and large reptiles, including ancestors of the dinosaurs. Permian marine deposits are rich in fossil mollusks, echinoderms, and brachiopods. Fossilized shells of two kinds of inverebrate s are widely used to identify Permian strata and correlate them between sites: fusulinid s, a kind of shelled amoeba-like protist that is one of the foraminiferans, and ammonoids, ancestors of the modern nautilus.
During the Permian, all the Earth's major land masses except portions of East Asia were collected into a single supercontinent known as Pangea. Pangea straddled the equator and extended toward the poles, with a corresponding effect on ocean currents in the single great ocean (" Panthalassa", the "universal sea"). Large continental landmasses create climates with extreme variations of heat and cold (" continental climate") and monsoon conditions with highly seasonal rainfall patterns. Deserts seem to have been widespread on Pangea. Such dry conditions favored gymnosperms, plants with seeds enclosed in a protective cover, over plants such as ferns that disperse spores. The first modern trees ( conifers, ginkgos and cycads) appeared in the Permian.
Three general areas are especially noted for their Permian deposits: the Ural Mountains (where Perm itself is located), China, and the southwest of North America, where the Permian Basin in the U.S. state of Texas is so named because it has one of the thickest deposits of Permian rocks in the world.