Portal:Permian

Topics Culture Geography Health History Mathematics Nature People Philosophy Religion Society Technology The Permian Portal The Permian is a geologic period and system which extends from 298.9 ± 0.15 to 252.17 ± 0.06 (Million years ago). It is the last period of the Paleozoic Era, following the Carboniferous Period and preceding the Triassic Period of the Mesozoic Era. It was first introduced in 1841 by geologist Sir Roderick Murchison, and is named after the ancient kingdom of Permia. The Permian witnessed the diversification of the early amniotes into the ancestral groups of the mammals, turtles, lepidosaurs and archosaurs. The world at the time was dominated by a single supercontinent known as Pangaea, surrounded by a global ocean called Panthalassa. The extensive rainforests of the Carboniferous had disappeared, leaving behind vast regions of arid desert within the continental interior. Reptiles, who could better cope with these drier conditions, rose to dominance in lieu of their amphibian ancestors. The Permian Period (along with the Paleozoic Era) ended with the largest mass extinction in Earth's history, in which nearly 90% of marine species and 70% of terrestrial species died out. It would take well into the Triassic for life to recover from this catastrophe. (See more…) Template:/box-footer Artist's restoration of Ctenorhabdotus capulus. Ctenophora is a phylum of marine animals characterized by "combs" consisting of cilia they use for swimming. Adults range from a few millimeters to 1.5 m (4 ft 11 in) in size. Their bodies consist of a mass of jelly, with one layer two cells thick on the outside and another lining the internal cavity. Almost all ctenophores consume tiny animal prey. The phylum has a wide range of body forms, including the egg-shaped cydippids with retractable tentacles that capture prey, the flat generally combless platyctenids, and the large-mouthed beroids, which prey on other ctenophores. Despite their soft, gelatinous bodies, fossils thought to represent ctenophores have been found in lagerstätten as far back as the early Cambrian, about 525 million years ago. The position of the ctenophores in the tree of life has long been debated, and the majority view at present, based on molecular phylogenetics, is that ctenophores are more primitive than the sponges, which are more primitive than the cnidarians and bilaterians. A recent molecular phylogenetics analysis concluded that the common ancestor of all modern ctenophores was cydippid-like, and that all the modern groups appeared relatively recently, probably after the Cretaceous–Paleogene extinction event 66 million years ago. Evidence accumulating since the 1980s indicates that the "cydippids" are not monophyletic, in other words do not include all and only the descendants of a single common ancestor, because all the other traditional ctenophore groups are descendants of various cydippids. (see more...) The history of paleontology traces the history of the effort to study the fossil record left behind by ancient life forms. Although fossils had been studied by scholars since ancient times, the nature of fossils and their relationship to life in the past became better understood during the 17th and 18th centuries. At the end of the 18th century the work of Georges Cuvier ended a long running debate about the reality of extinction and led to the emergence of paleontology as a scientific discipline. The first half of the 19th century saw paleontological activity become increasingly well organized. This contributed to a rapid increase in knowledge about the history of life on Earth, and progress towards definition of the geologic time scale. As knowledge of life's history continued to improve, it became increasingly obvious that there had been some kind of successive order to the development of life. After Charles Darwin published Origin of Species in 1859, much of the focus of paleontology shifted to understanding evolutionary paths. The last half of the 19th century saw a tremendous expansion in paleontological activity, especially in North America. The trend continued in the 20th century with additional regions of the Earth being opened to systematic fossil collection, as demonstrated by a series of important discoveries in China near the end of the 20th century. There was also a renewed interest in the Cambrian explosion that saw the development of the body plans of most animal phyla. (see more...) Cross-bedded Permian sandstone deposited in ancient sand dunes.. Cross-bedded Permian Sandstone. These are the remnants of ancient desert sand dunes from around 300 to 350 million years ago. Photo credit: Tony Atkin Methanosarcina barkeri fusaro. ... that the single-celled Methanosarcina (Methanosarcina barkeri fusaro pictured) may have played a significant role in both the evolution of early life and the worst extinction event in history? ... that Gerobatrachus is considered to be a missing link that supports the hypothesis offered by cladistics, that frogs and salamanders had a common ancestor? ... that Arthropleuridea is an extinct class of myriapods which includes, at over 2 meters long, the largest terrestrial arthropods that ever lived? Template:/box-header Epochs - Cisuralian - Guadalupian - Lopingian Ages - Asselian - Sakmarian - Artinskian - Kungurian - Roadian - Wordian - Capitanian -Wuchiapingian - Changhsingian Events - Hunter-Bowen orogeny - Permian–Triassic extinction event Geography - Pangaea - Panthalassa Animals - Ammonoids - Blattopterans - Dicynodonts - Dinocephalians - Fusulinids - Gorgonopsians - Lepospondyls - Pareiasaurs - Pelycosaurs - Temnospondyls - Trilobites Plants - Conifers - Cycads - Ginkgos - Seed ferns Fossil sites - Paleorrota Stratigraphic units - Red Beds of Texas and Oklahoma Researchers - Edward Drinker Cope Culture - Animal Armageddon - The Day The Earth Nearly Died - List of creatures in the Walking with... series - Walking with Monsters Template:/box-footer Template:/box-header Featured Permian articles - Amphibian Good Permian articles - Dimetrodon - Temnospondyli Template:/box-footer ▼ Permian ► Permian life Here are some tasks awaiting attention: Stubs : Permian stubs Current Permian FACs - none currently Template:/box-footer Time Earth sciences Paleontology Extinct and Endangered Species Paleozoic Cambrian Ordovician Silurian Error creating thumbnail: File missing Devonian Carboniferous Permian Mesozoic What are portals? 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