query: during the permian extinction approximately what percent of all marine species were lost

pos: Permian–Triassic extinction event Permian–Triassic extinction event The Permian–Triassic (P–Tr or P–T) extinction event, colloquially known as the Great Dying, the End-Permian Extinction or the Great Permian Extinction, occurred about 252 Ma (million years) ago, forming the boundary between the Permian and Triassic geologic periods, as well as between the Paleozoic and Mesozoic eras. It is the Earth's most severe known extinction event, with up to 96% of all marine species and 70% of terrestrial vertebrate species becoming extinct. It is the only known mass extinction of insects. Some 57% of all biological families and 83% of all genera became extinct. Because so much

pos: Evolution Earth are now extinct, and extinction appears to be the ultimate fate of all species. These extinctions have happened continuously throughout the history of life, although the rate of extinction spikes in occasional mass extinction events. The Cretaceous–Paleogene extinction event, during which the non-avian dinosaurs became extinct, is the most well-known, but the earlier Permian–Triassic extinction event was even more severe, with approximately 96% of all marine species driven to extinction. The Holocene extinction event is an ongoing mass extinction associated with humanity's expansion across the globe over the past few thousand years. Present-day extinction rates are 100–1000 times greater

pos: Mesozoic Following the Paleozoic, the Mesozoic extended roughly 186 million years, from when the Cenozoic Era began. This time frame is separated into three geologic periods. From oldest to youngest: The lower boundary of the Mesozoic is set by the Permian–Triassic extinction event, during which approximately 90% to 96% of marine species and 70% of terrestrial vertebrates became extinct. It is also known as the "Great Dying" because it is considered the largest mass extinction in the Earth's history. The upper boundary of the Mesozoic is set at the Cretaceous–Paleogene extinction event (or K–Pg extinction event), which may have been caused

pos: Permian dominated by two continents known as Pangaea and Siberia, surrounded by a global ocean called Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, who could better cope with these drier conditions, rose to dominance in place of their amphibian ancestors. The Permian (along with the Paleozoic) ended with the Permian–Triassic extinction event, the largest mass extinction in Earth's history, in which nearly 96% of marine species and 70% of terrestrial species died out. It would take well into the Triassic for life to recover from this catastrophe. Recovery from the Permian–Triassic extinction

pos: Geology of Scotland to drift northwards. Scotland's climate was arid at this time and some fossils of reptiles have been recovered. However, Permian sandstones are found in only a few places - principally in the south west, on the island of Arran, and on the Moray coast. Stone quarried from Hopeman in Moray has been used in the National Museum and Scottish Parliament buildings in Edinburgh. At the close of this period came the Permian–Triassic extinction event in which 96% of all marine species vanished and from which bio-diversity took 30 million years to recover. During the Triassic (252–201 Ma), much of Scotland

pos: Prehistory of the United States near Elmo, Kansas. Massive amphibians were not rare in the southwestern United States but were unable to stray too far from bodies of water. "Seymouria" was a twenty inch long transitional form documenting the origin of reptiles from their amphibian-like forebears from Texas. Reptiles were becoming common during the Permian. Texas was also home to the pelycosaurs "Dimetrodon" and "Edaphosaurus". Late in the Permian therapsids became the dominant large-bodied terrestrial vertebrates. These were the precursors of mammals. The Permian ended with the most destructive mass extinction in all of earths history. Globally up to 96% of all species may have

pos: Michael R. Rampino which the 30-million year oscillation of the Solar System through the dense Galactic plane leads to periodic comet showers on Earth. More recent work has centered on the severe Permian–Triassic extinction event (252 million years ago), with fieldwork in South Africa, Hungary, Japan, India and China, particularly focused on the so-called “fungal event” marking the devastation of Late Permian vegetation. Rampino and colleagues found evidence that the mass extinction of 96% of marine species and much of life on land may have occurred in a brief period of only a few thousand years, suggesting some sort of cataclysm It turns

neg: Paleocontinent complete. Pangea formed roughly 20 million years before the Permian Extinction. During the Permian Extinction over 95% of all marine species were lost and 70% of terrestrial species were lost. The Triassic period of Pangea became a time of recovery from the Permian Extinction. This recovery included the rise of sea levels which created extensive shallow oceanic shelves for large marine reptiles. This recovery period was when terrestrial animals flourished and when land reptiles diversified and flourished, along with the appearance of Dinosaurs. These Dinosaurs would become what characterizes the life forms of the following periods, the Jurassic and Cretaceous.

neg: Permian–Triassic extinction event weedy plant); "Dicroidium" (a seed fern). Prior to the extinction, about two-thirds of marine animals were sessile and attached to the sea floor. During the Mesozoic, only about half of the marine animals were sessile while the rest were free-living. Analysis of marine fossils from the period indicated a decrease in the abundance of sessile epifaunal suspension feeders such as brachiopods and sea lilies and an increase in more complex mobile species such as snails, sea urchins and crabs. Before the Permian mass extinction event, both complex and simple marine ecosystems were equally common; after the recovery from the mass

neg: Hirnantian that took place during this time. In fact, the Hirnantian (also known as the End Ordovician and the Ordovician-Silurian) mass extinction event represents the second largest such event in geologic history. Approximately 85% of marine (sea-dwelling) species died. Only the End Permian mass extinction was larger. Unlike many smaller extinction events, however, the long-term consequences of the End Ordovician event were relatively small. Following the climatic oscillation, the climate returned to its previous state, and the species that survived soon (within two or three million years) evolved into species very similar to the ones that existed before. The Hirnantian was

neg: Hybodontiformes end-Permian extinction. However, recent samples found in Oman suggests that Permian hybodont diversity extended until the end-Permian, suggesting the extinction was more impactful than previously thought. Fossils from the Lower Triassic Vega-Phroso Siltstone Member of the Sulphur Mountain Formation of Alberta, Canada show well preserved specimens of "Wapitiodus aplopagus" which survived the extinction and was abundant in the Early Triassic. Maximum hybodont diversity is observed during the Triassic. During the Triassic and Early Jurassic, hybodontiforms were the dominant selachians in both marine and non-marine environments. A study of Middle Jurassic fossils from England analyzed 20 species from 11 genera suggesting

neg: Late Triassic Many of the first dinosaurs evolved during the Late Triassic, including "Plateosaurus", "Coelophysis", and "Eoraptor". The extinction event that began during the Late Triassic resulted in the disappearance of about 76% of all terrestrial and marine life species, as well as almost 20% of taxonomic families. Although the Late Triassic Epoch did not prove to be as destructive as the preceding Permian Period, which took place approximately 50 million years earlier and destroyed about 70% of land species, 57% of insect families as well as 95% of marine life, it resulted in great decreased in population sizes of many living

neg: Permian–Triassic extinction event event. An older theory, still supported in some recent papers, is that there were two major extinction pulses 9.4 million years apart, separated by a period of extinctions well above the background level, and that the final extinction killed off only about 80% of marine species alive at that time while the other losses occurred during the first pulse or the interval between pulses. According to this theory one of these extinction pulses occurred at the end of the Guadalupian epoch of the Permian. For example, all but one of the surviving dinocephalian genera died out at the end of

neg: Paleocontinent shark species began to diversify, and terrestrial vegetation begun colonizing the continent, as organic soil accumulation can be detected. Amniotic eggs started to evolve as more terrestrial land became available with rising land masses and lowering sea levels. During the Permian extinction, almost all marine species were lost, along with some terrestrial species. This event gave rise to terrestrial species, such as reptiles, dinosaurs, and small mammals. Gondwana experienced a variety of climates as it has been a land mass from 600 million years ago in the Precambrian to the Early Jurassic with the breakup of Pangea. In the Cambrian,

neg: Permian some large members such as "Dimetrodon". The special adaptations of reptiles enabled them to flourish in the drier climate of the Permian and they grew to dominate the vertebrates. Permian amphibians consisted of temnospondyli, lepospondyli and batrachosaurs. The Permian ended with the most extensive extinction event recorded in paleontology: the Permian–Triassic extinction event. 90% to 95% of marine species became extinct, as well as 70% of all land organisms. It is also the only known mass extinction of insects. Recovery from the Permian-Triassic extinction event was protracted; on land, ecosystems took 30 million years to recover. Trilobites, which had thrived

neg: Cartorhynchus enigmatic clade of marine reptiles. Naming author Ryosuke Motani suggested the clade Ichthyosauriformes consisting of the Ichthyopterygia and the more basal "Cartorhynchus". "Cartorhynchus" also indicates that the enigmatic Hupehsuchia were closely related. Motani combined the Ichthyosauriformes and the Hupehsuchia into the Ichthyosauromorpha. The new fossil improves understanding of how rapidly ichthyosaurs arose during the aftermath of the Permian-Triassic extinction event 252 million years ago, in which more than 90 percent of marine species died out. Scientists have long wanted to know how long it took for animals and plants to bounce back after that catastrophic die-off. "Cartorhynchus"'s discovery shows it

neg: Impact event mass extinctions that on average extinguished half of all species. One of the largest mass extinctions to have affected life on Earth was the Permian-Triassic, which ended the Permian period 250 million years ago and killed off 90 percent of all species; life on Earth took 30 million years to recover. The cause of the Permian-Triassic extinction is still a matter of debate; the age and origin of proposed impact craters, i.e. the Bedout High structure, hypothesized to be associated with it are still controversial. The last such mass extinction led to the demise of the dinosaurs and coincided with

neg: Animals of Devonian Michigan Trilobite numbers were declining even further during the Carboniferous and Permian periods, but they were not able to survive the great extinction which killed nearly all life on the planet. Blastoids are small marine echinoderms that originated in Ordovician period and became extinct at the end of the Permian. They were never as diverse as their cousins, the crinoids. They were very similar in anatomy to crinoids, having a stem attached to the seafloor while a head held their internal organs. Their head is what makes them easy to distinguish from crinoids, with a five pointed “star” on their theca.

neg: Evolutionary history of life contributed to the Late Devonian extinction event. (The long causal chain implied seems to involve the success of early tree archaeopteris (1) drew down CO levels, leading to global cooling and lowered sea levels, (2) roots of archeopteris fostered soil development which "increased" rock weathering, and the subsequent nutrient run-off may have triggered algal blooms resulting in anoxic events which caused marine-life die-offs. Marine species were the primary victims of the Late Devonian extinction.) Ediacara biota appear during the Ediacaran period, while vertebrates, along with most other modern phyla originated about during the Cambrian explosion. During the Permian period, synapsids,

neg: Prehistory of the United States building and volcanic activity were ongoing in the same region. The Triassic saw the Earth's biosphere recovering from the end-Permian mass extinction. After the Permian mass extinction, ammonoids were one of the first groups of marine invertebrates to become abundant and diverse again. During the Middle Triassic the scleractinian corals typical of modern oceans appeared. During the Triassic, corals were rare in North America. Nevertheless, some were present on the west coast, although these corals did not congregate into reefs. Ichthyosaurs were one of the most important groups of marine reptiles during the Triassic. Important ichthyosaur fossils of this age

neg: Permian–Triassic extinction event in speciation. The extinction primarily affected organisms with calcium carbonate skeletons, especially those reliant on stable CO levels to produce their skeletons. These organisms were susceptible to the effects of the ocean acidification that resulted from increased atmospheric CO. Among benthic organisms the extinction event multiplied background extinction rates, and therefore caused maximum species loss to taxa that had a high background extinction rate (by implication, taxa with a high turnover). The extinction rate of marine organisms was catastrophic. Surviving marine invertebrate groups include: articulate brachiopods (those with a hinge), which have undergone a slow decline in numbers since the

neg: Evolution of tetrapods birds; whereas Synapsida would evolve into today's mammals. During the Permian, however, the distinction was less clear—amniote fauna being typically described as either "reptile" or as "mammal-like reptile". The latter (synapsida) were the most important and successful Permian animals. The end of the Permian saw a major turnover in fauna during the Permian–Triassic extinction event: probably the most severe mass extinction event of the phanerozoic. There was a protracted loss of species, due to multiple extinction pulses. Many of the once large and diverse groups died out or were greatly reduced. Life on Earth seemed to recover quickly after the

neg: Pangaea animals. Plants dependent on spore reproduction were largely replaced by the gymnosperms, which reproduce through the use of seeds. Later on, insects (including beetles and cicadas) also thrived, during the Permian period 299 to 252 million years ago. However, the Permian extinction at 252 Mya greatly impacted these insects in mass extinction, being the only mass extinction to affect insects. When the Triassic Period came, many reptiles were able to also thrive, including Archosaurs, which were an ancestor to modern-day crocodiles and birds. Little is known about marine life during the existence of Pangaea. Scientists are unable to find substantial

neg: Olson's Extinction of species alive at that time while the other losses occurred during the first pulse or the interval between pulses. During the 1990s and 2000s researchers gathered evidence on the biodiversity of plants, marine organism and tetrapods that indicated an extinction pulse preceding the Permian–Triassic extinction event had a profound impact on life on land. On land Sahney and Benton showed that even discounting the sparse fossil assemblages from the extinction period, the event can be confirmed by the stages of time bracketing the event since well preserved sections of the fossil record from both before and after the event

neg: Early Triassic is composed of Buntsandstein, a lithostratigraphic unit of continental red beds. The Permian-Triassic extinction event spawned the Triassic period. The massive extinctions that ended the Permian period and Paleozoic era caused extreme hardships for the surviving species. Many types of corals, brachiopods, molluscs, echinoderms, and other invertebrates had completely disappeared. The most common Early Triassic hard-shelled marine invertebrates were bivalves, gastropods, ammonites, echinoids, and a few articulate brachiopods. The most common land vertebrate was the small herbivorous synapsid "Lystrosaurus". Early Triassic faunas lacked biodiversity and were relatively homogenous throughout the epoch due to the effects of the extinction, ecological recovery

neg: Anomodont Anomodont Anomodontia is an extinct group of non-mammalian therapsids containing many species from the Permian and Triassic periods (possibly continuing into the Early Cretaceous), most of which were toothless, possibly endothermic herbivores. Anomodonts were very diverse during the Middle Permian, including primitive forms like "Anomocephalus" and "Patranomodon" and groups like Venyukovioidea, Dromasauria, and Dicynodontia. Of these, only the dicynodonts survived beyond the Middle Permian. Dicynodonts became the most successful and abundant of all herbivores in the Late Permian and Triassic, filling ecological niches ranging from large browsers down to small burrowers. Few dicynodont families survived the Permian–Triassic extinction event, but

neg: Marine reptile low risk for extinction. Marine reptile Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semiaquatic life in a marine environment. The earliest marine reptiles arose in the Permian period during the Paleozoic era. During the Mesozoic era, many groups of reptiles became adapted to life in the seas, including such familiar clades as the ichthyosaurs, plesiosaurs (these two orders were once thought united in the group "Enaliosauria," a classification now cladistically obsolete), mosasaurs, nothosaurs, placodonts, sea turtles, thalattosaurs and thalattosuchians. After the mass extinction at the end of the Cretaceous period, marine reptiles were less

neg: Species estimated that over 99 percent of all species that ever lived on Earth, some five billion species, are now extinct. Some of these were in mass extinctions such as those at the ends of the Permian, Triassic and Cretaceous periods. Mass extinctions had a variety of causes including volcanic activity, climate change, and changes in oceanic and atmospheric chemistry, and they in turn had major effects on Earth's ecology, atmosphere, land surface, and waters. Another form of extinction is through the assimilation of one species by another through hybridization. The resulting single species has been termed as a "compilospecies". Biologists

neg: Ordovician radiation in reefs and deeper water began to take on a character of their own, becoming more clearly distinct from other marine ecosystems. And as ecosystems became more diverse, with more species being squeezed into the food web, a more complex tangle of ecological interactions resulted, promoting strategies such as ecological tiering. The global fauna that emerged during the GOBE went on to be remarkably stable until the catastrophic end-Permian extinction and the ensuing Mesozoic Marine Revolution. The acritarch record (the majority of acritarchs were probably marine algae) displays the Ordovician radiation beautifully; both diversity and disparity peaked in the middle

neg: Atopodentatus Atopodentatus Atopodentatus is an extinct genus of marine reptile, possibly basal sauropterygian, known from the early Middle Triassic (Pelsonian substage, Anisian stage) of Luoping County, Yunnan Province, southwestern China. It contains a single species, Atopodentatus unicus. It is thought to have lived between 247 and 240 million years ago, during the Middle Triassic period, about six million years after the Permian extinction. "Atopodentatus" was an herbivorous marine reptile, although marine reptiles are usually omnivores or carnivores. A near complete skeleton along with a left lateral portion of the skull were discovered near Daaozi village, Yunnan, China. The scientific name derives

neg: Permian–Triassic extinction event the Guadalupian, as did the Verbeekinidae, a family of large-size fusuline foraminifera. The impact of the end-Guadalupian extinction on marine organisms appears to have varied between locations and between taxonomic groups — brachiopods and corals had severe losses. Marine invertebrates suffered the greatest losses during the P–Tr extinction. Evidence of this was found in samples from south China sections at the P–Tr boundary. Here, 286 out of 329 marine invertebrate genera disappear within the final two sedimentary zones containing conodonts from the Permian. The decrease in diversity was probably caused by a sharp increase in extinctions, rather than a decrease

neg: Lepidopteris Lepidopteris Lepidopteris ("pleasant fern") is a form genus for leaves of Late Permian to Late Triassic Period Pteridospermatophyta, or seed ferns, which lived from around 260 to 200 million years ago in what is now Australia, Antarctica, India, South America, South Africa, Russia and China. Nine species are currently recognized. "Lepidopteris" was a common and widespread seed fern, which survived the Permian-Triassic extinction event but succumbed to the Triassic-Jurassic extinction event. "Lepidopteris callipteroides" is especially common between the first two episodes of Permian-Triassic extinction event, and "L. ottonis" forms a comparable acme zone immediate before the Triassic-Jurassic extinction event. In

neg: Endangered species of listed species in the northeastern United States have a recovering or stable population. Currently, 1,556 known species in the world have been identified as near extinction or endangered and are under protection by government law. This approximation, however, does not take into consideration the number of species threatened with endangerment that are not included under the protection of such laws as the Endangered Species Act. According to NatureServe's global conservation status, approximately thirteen percent of vertebrates (excluding marine fish), seventeen percent of vascular plants, and six to eighteen percent of fungi are considered imperiled. Thus, in total, between seven

neg: The Lost Worlds of Planet Earth million years ago, were not edible by species at the time and would instead fall over and become carbon-dioxide-rich coal. Some 50 million years later, near the end of the Permian period, volcanic activity would burn the carbonaceous matter, releasing the carbon dioxide and acidic components, creating a sudden greenhouse gas effect that warmed the oceans and released methane from the ocean beds, all leading towards the Permian–Triassic extinction event, killing 90% of the species on Earth. Tyson then explains on the nature of plate tectonics that would shape the landmasses of the world. Tyson explains how scientists like Abraham

neg: Extinction event a land bridge between North and South America). Occasionally continental drift creates a super-continent which includes the vast majority of Earth's land area, which in addition to the effects listed above is likely to reduce the total area of continental shelf (the most species-rich part of the ocean) and produce a vast, arid continental interior which may have extreme seasonal variations. Another theory is that the creation of the super-continent Pangaea contributed to the End-Permian mass extinction. Pangaea was almost fully formed at the transition from mid-Permian to late-Permian, and the "Marine genus diversity" diagram at the top of this

neg: Stenolaemata and in some regions form an abundant component of limestones. Their numbers were greatly reduced during the terminal Permian extinction event, but the order Cyclostomatida survives today. Extant and extinct orders in this class include: Stenolaemata Stenolaemata are a class of marine bryozoans. This class originated in the Ordovician, and members still live today. All extant species are in the order Cyclostomatida. These animals are stationary suspension feeders that live on the ocean floor. The individuals in the colony may be tubular, conical, or sac-shaped. Each individual, or zooid, may extend from the colony at an angle, extending its tentacles

neg: Olson's Extinction Olson's Extinction Olson's Extinction was a mass extinction that occurred in the early Guadalupian of the Permian period and which predated the Permian–Triassic extinction event. Everett C. Olson noted that there was a hiatus and a sudden change in between the early Permian and middle/late Permian faunas. Since then this event has been realized across many groups, including plants, marine invertebrates, and tetrapods. The first evidence of extinction came when Everett C. Olson noted a hiatus between early Permian faunas dominated by pelycosaurs and therapsid dominated faunas of the middle and late Permian. First considered to be a preservational gap

neg: Permian–Triassic extinction event of ammonoid structures was once again reoccupied, but the parameters were now shared differently among clades. The Permian had great diversity in insect and other invertebrate species, including the largest insects ever to have existed. The end-Permian is the only known mass extinction of insects, with eight or nine insect orders becoming extinct and ten more greatly reduced in diversity. Palaeodictyopteroids (insects with piercing and sucking mouthparts) began to decline during the mid-Permian; these extinctions have been linked to a change in flora. The greatest decline occurred in the Late Permian and was probably not directly caused by weather-related floral

neg: Olson's Extinction identified primitive therapsid of the Xidagou Formation (Dashankou locality) in China of Roadian age may provide more information on this topic. Olson's Extinction Olson's Extinction was a mass extinction that occurred in the early Guadalupian of the Permian period and which predated the Permian–Triassic extinction event. Everett C. Olson noted that there was a hiatus and a sudden change in between the early Permian and middle/late Permian faunas. Since then this event has been realized across many groups, including plants, marine invertebrates, and tetrapods. The first evidence of extinction came when Everett C. Olson noted a hiatus between early Permian

neg: Marine regression Marine regression Marine regression is a geological process occurring when areas of submerged seafloor are exposed above the sea level. The opposite event, marine transgression, occurs when flooding from the sea covers previously exposed land. Evidence of marine regressions and transgressions occurs throughout the fossil record, and these fluctuations are thought to have caused or contributed to several mass extinctions, among them the Permian-Triassic extinction event (250 million years ago) and Cretaceous–Paleogene extinction event (66 Ma). At the time of the Permian-Triassic extinction, the largest extinction event in the Earth's history, global sea level fell 250 m (820 ft). A

neg: Eurypterid Silurian genus "Eurypterus" accounts for more than 90% of all known eurypterid specimens. Though the group continued to diversify during the subsequent Devonian period, the eurypterids were heavily affected by the Late Devonian extinction event and would decline in numbers and diversity until they became extinct during the Permian–Triassic extinction event (or sometime shortly before) 251.9 million years ago. Although popularly called "sea scorpions", only the earliest eurypterids were marine, with many later forms living in brackish or fresh water, and they were not true scorpions. Some studies suggest that a dual respiratory system was present, which would have allowed

neg: Triassic called ammonites recovered, diversifying from a single line that survived the Permian extinction. The fish fauna was remarkably uniform, suggesting that very few families survived the Permian extinction. There were also many types of marine reptiles. These included the Sauropterygia, which featured pachypleurosaurus and nothosaurs (both common during the Middle Triassic, especially in the Tethys region), placodonts, and the first plesiosaurs. The first of the lizardlike Thalattosauria (askeptosaurs) and the highly successful ichthyosaurs, which appeared in Early Triassic seas soon diversified, and some eventually developed to huge size during the Late Triassic. Subequatorial saurichthyids have also been described in Early

neg: Prehistory of Colorado neighboring Hall Ranch Open Space areas. Lykins Formation was formed during the Jurassic and Triassic periods 150-250 million years ago. The sediment deposition of wavy layers of muddy limestone and signs of stromatolites that thrived in a smelly tidal flat at present-day Colorado. The Ancestral Rockies were burying themselves while the shoreline was present during the break-up of Pangaea. This formation began right after Earth’s largest extinction 251 million years ago at the Permian-Triassic Boundary. Ninety percent of the planet’s marine life was destroyed and a great deal on land as well. Related sites: Garden of the Gods, Red Rocks

neg: Trilobite of genera limited to shallow-water shelf habitats, coupled with a drastic lowering of sea level (regression) meant that the final decline of trilobites happened shortly before the end of the Permian mass extinction event. With so many marine species involved in the Permian extinction, the end of nearly 300 million successful years for the trilobites would not have been unexpected at the time. Trilobites have no known direct descendants. Their closest living relatives would be the chelicerates. Though horseshoe crabs are often cited as their closest living relatives, they are no closer evolutionarily than other cheliceratans. Trilobites appear to have

neg: Hybodontiformes now called Hybodontiformes includes many species, with examples such as "Hybodus", "Acrodus", "Asteracanthus", "Lonchidion", and "Lissodus". Hybodont samples have been recovered from Permian deposits from Oman, indicating that hybodonts lived in the Neotethys Ocean during the Permian Period. This study combined with others from Texas suggest that hybodonts were well established, and in some places dominant, during the Permian. In general, the Permian record of hybodonts is limited. It was initially hypothesized that hybodont diversity was not significantly impacted by the end-Permian extinction, instead it was thought that diversity of Permian hybodonts declined over the 50 million years before the

neg: Evolution of mammals cynodont "Trirachodon"; the animals are thought to have been drowned by a flash flood. The extensive shared burrows indicate that these animals were capable of complex social behaviors. The catastrophic Permian-Triassic mass extinction slightly more than 250 million years ago killed off about 70 percent of terrestrial vertebrate species and the majority of land plants. As a result, ecosystems and food chains collapsed, and the establishment of new stable ecosystems took about 30 million years. With the disappearance of the gorgonopsians, which were dominant predators in the late Permian, the cynodonts' principal competitors for dominance of the carnivorous niches were

neg: Permian–Triassic extinction event life depletion approached catastrophic levels; however, marine life extinction never reached the rate of the "Big Five" mass extinctions. Pangaea’s effect on extinctions on land is thought to have been less significant. In fact, the advance of the therapsids and increase in their diversity is attributed to the late Permian, when Pangaea’s global effect was thought to have peaked. While Pangaea’s formation is known to have initiated a long period of marine life extinction, the significance of its impact on the "Great Dying" and the end of the Permian is uncertain. A hypothesis published in 2014 posits that a genus

neg: Front Range wavy layers of muddy limestone and signs of stromatolites that thrived in a smelly tidal flat at present-day Colorado. 250 million years ago, the Ancestral Rockies were burying themselves while the shoreline was present during the break-up of Pangaea. This formation began right after Earth’s largest extinction 251 million years ago at the Permian-Triassic Boundary. Ninety percent of the planet’s marine life was destroyed and a great deal on land as well. After 100 million years of deposition, a new environment brought rise to a new formation, the sandstone Morrison Formation. The Morrison Formation contains some of the best fossils

neg: Bobasatrania Bobasatrania Bobasatrania is an extinct genus of prehistoric bony fish that survived the Permian-Triassic extinction event. The genus originated during the late Permian, survived the Permian-Triassic extinction event, and underwent a speciation event during the Triassic (approx 240M years BP) in the shallow coastal waters off the Pangaean supercontinent. Their fossils are therefore found throughout the world, with some of the best examples coming from the Wapiti Lake region of British Columbia, Canada. They have a distinctive diamond-shaped body, forked tail and long thin pectoral fins. The larger Permian species are up to a metre in length, though the Triassic

neg: Lepidopteris callipteroides with well preserved ovulate structures of "Peltaspermum townrovii" and pollen organs of "Permotheca helbyi" in the same deposits The cuticular structure of "Lepidopteris callipteroides" is comparable to that of modern "Ginkgo", and has been used to estimate past atmospheric carbon dioxide of an astounding 7832 ppm from its stomatal index immediately following the largest Permian-Triassic extinction event. Lepidopteris callipteroides Lepidopteris callipteroides is a form species for leaves of Late Permian Pteridospermatophyta, or seed ferns, which lived from around 252 million years ago in what is now Australia, and Madagascar. "Lepidopteris callipteroides" was an immediate survivor of the largest Permian-Triassic extinction

neg: Microposaurus period of the Triassic, the transition from the Permian-Triassic created more aquatic environments for these species to survive. In the Karoo Basin of South Africa, after the extinction, multiple new rivers were created that ran through areas of the continent. Due to the aquatic lifestyle of "Microposaurus", their diet was determined to be piscivorous. For all trematosaurids, most were marine at one point in their life cycles. The normal size of these carnivorous predators was about one to two meters in total body length. Inferred to be eating smaller vertebrates found in their wide range of environments. At the time

neg: Marine reptile Marine reptile Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semiaquatic life in a marine environment. The earliest marine reptiles arose in the Permian period during the Paleozoic era. During the Mesozoic era, many groups of reptiles became adapted to life in the seas, including such familiar clades as the ichthyosaurs, plesiosaurs (these two orders were once thought united in the group "Enaliosauria," a classification now cladistically obsolete), mosasaurs, nothosaurs, placodonts, sea turtles, thalattosaurs and thalattosuchians. After the mass extinction at the end of the Cretaceous period, marine reptiles were less numerous, but there was

neg: Dresbachian in southeastern Minnesota on the Mississippi River. The Dresbachian is defined by four trilobite zones: "Cedaria"-, "Crepicephalus"-, "Aphelaspis"- and "Dunderbergia" trilobite zones. The Dresbachian extinction event during the Late Cambrian was the second of two severe extinctions during the first period of the Paleozoic era; the first being the End-Botomian extinction event during the Middle Cambrian. According to data on extinction intensity (see below), both extinction events slashed approximately 40 percent of marine genera. However, the two are poorly documented due to a paucity of fossil evidence so early in the evolution of life. Dresbachian The Dresbachian is a Maentwrogian

neg: Trilobite Trilobite Trilobites (; meaning "three lobes") are a group of extinct marine arachnomorph arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period (), and they flourished throughout the lower Paleozoic era before beginning a drawn-out decline to extinction when, during the Devonian, all trilobite orders except the Proetids died out. Trilobites disappeared in the mass extinction at the end of the Permian about 252 million years ago. The trilobites were among the most

neg: Trilobite Trilobite Trilobites (; meaning "three lobes") are a group of extinct marine arachnomorph arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period (), and they flourished throughout the lower Paleozoic era before beginning a drawn-out decline to extinction when, during the Devonian, all trilobite orders except the Proetids died out. Trilobites disappeared in the mass extinction at the end of the Permian about 252 million years ago. The trilobites were among the most

neg: Lystrosaurus Assemblage Zone Permian-Triassic extinction event caused the extinction of all gorgonopsians and almost all dicynodont species except for "Lystrosaurus" and a select few other species such as "Myosaurus gracilis". Therocephalian species experienced a Lilliput Effect where only smaller species survived and thrived after the extinction event. "Moschorhinus", for example, was one of the larger therocephalians to survive the initial extinction event, however, fossil occurrences of this species cease above the lower Katberg Formation. This is also true of "Lystrosaurus" where only the smaller species thrived in the Triassic. By the upper sections of the biozone, ecological niches began to recover as evidenced

neg: Ordovician–Silurian extinction events Silurian, thus including the extinction period. This event was the first of the big five Phanerozoic events and was the first to significantly affect animal-based communities. Almost all major taxonomic groups were affected during this extinction event. Extinction was global during this period, eliminating 49-60% of marine genera and nearly 85% of marine species. Brachiopods, bivalves, echinoderms, bryozoans and corals were particularly affected. Before the late Ordovician cooling, temperatures were relatively warm and it is the suddenness of the climate changes and the elimination of habitats due to sea-level fall that are believed to have precipitated the extinctions. The falling

neg: Elasmobranchii the sharks underwent a period of diversification, with many new forms evolving. Many of these became extinct during the Permian, but the remaining sharks underwent a second burst of adaptive radiation during the Jurassic, around which time the skates and rays first appeared. Many surviving orders of elasmobranch date back to the Cretaceous, or earlier. Elasmobranchs are mostly a marine taxon, but we know several species that live in freshwater environment (approximately 60 species which represent only 5% of the 1154 described species). They can be divided into two groups. The euryhaline elasmobranchs, which are marine species that may survive

neg: Permian–Triassic extinction event the reduction observed in species diversity (of 50%) may be mostly due to taphonomic processes. However, a massive rearrangement of ecosystems does occur, with plant abundances and distributions changing profoundly and all the forests virtually disappearing; the Palaeozoic flora scarcely survived this extinction. At the P–Tr boundary, the dominant floral groups changed, with many groups of land plants entering abrupt decline, such as "Cordaites" (gymnosperms) and "Glossopteris" (seed ferns). Dominant gymnosperm genera were replaced post-boundary by lycophytes—extant lycophytes are recolonizers of disturbed areas. Palynological or pollen studies from East Greenland of sedimentary rock strata laid down during the extinction period

neg: Moschorhinus in the earliest Triassic beds in the Karoo basin, showing that "Moschorhinus" did survive the Permian-Triassic extinction event, but disappeared soon afterwards. Although smaller than their Permian predecessors, Triassic "Moschorhinus" were the largest therocephalian predators of their time. An examination of the change in size between "Moschorhinus" fossils from before and after the mass extinction at the end of the Permian provides an excellent study of the Lilliput effects observable in species known to have survived an environmental catastrophe such as an extinction event. Its name is derived from the Ancient Greek words μόσχος (mos'-khos) "moschos" for calf or young

neg: Early Triassic on land took 30M years. The climate during the Early Triassic epoch (especially in the interior of the supercontinent Pangaea) was generally arid, rainless and dry and deserts were widespread; however the poles possessed a temperate climate. The relatively hot climate of the Early Triassic may have been caused by widespread volcanic eruptions which accelerated the rate of global warming and possibly caused the Permian-Triassic extinction event. Until recently the existence of an extinction event about 3 million years following the end-Permian extinctions was not recognised, possibly because there were few species left to go extinct. However, studies on conodonts

neg: Bobasatrania species are considerably smaller. The structure of their teeth suggests they fed on small shelled animals. Bobasatrania Bobasatrania is an extinct genus of prehistoric bony fish that survived the Permian-Triassic extinction event. The genus originated during the late Permian, survived the Permian-Triassic extinction event, and underwent a speciation event during the Triassic (approx 240M years BP) in the shallow coastal waters off the Pangaean supercontinent. Their fossils are therefore found throughout the world, with some of the best examples coming from the Wapiti Lake region of British Columbia, Canada. They have a distinctive diamond-shaped body, forked tail and long thin

neg: Triassic Triassic strata. Groups of terrestrial fauna, which appeared in the Triassic period or achieved a new level of evolutionary success during it include: The Permian–Triassic extinction devastated terrestrial life. Biodiversity rebounded as the surviving species repopulated empty terrain, but these were short-lived. Diverse communities with complex food-web structures took 30 million years to reestablish. Temnospondyl amphibians were among those groups that survived the Permian–Triassic extinction; some lineages (e.g. trematosaurs) flourished briefly in the Early Triassic, while others (e.g. capitosaurs) remained successful throughout the whole period, or only came to prominence in the Late Triassic (e.g. plagiosaurs, metoposaurs). As for other

neg: Gigantoproductus giganteus the water. Reproduction was likely to have involved release of gametes into the water column. "Gigantoproductus giganteus", like the vast majority of other brachiopod species, may have become extinct after a catastrophic event known as the Permian–Triassic extinction event which occurred about 252 million years ago. Gigantoproductus giganteus Gigantoproductus giganteus is an extinct species of brachiopods in the family Monticuliferidae, known only from its fossil remains. It was a marine invertebrate found on the seabed in shallow seas. It probably evolved during the Devonian period and it is believed to be the largest brachiopod that has ever existed. "Gigantoproductus giganteus"

neg: Permian–Triassic extinction event the earth’s major continental plates were joined, forming a supercontinent called Pangaea, which was surrounded by the superocean, Panthalassa. Oceanic circulation and atmospheric weather patterns during the mid-Permian produced seasonal monsoons near the coasts and an arid climate in the vast continental interior of Pangaea. The extent of biologically diverse and ecologically productive coastal areas shrank as the supercontinent formed. The elimination of shallow aquatic environments exposed formerly protected organisms of the rich continental shelves to increased environmental volatility. After the formation of Pangaea (see the diagram "Marine genus biodiversity" at the top of this article), the rate of marine

neg: Permian–Triassic extinction event anemones, from which modern corals evolved. Animals with high metabolic rates, well-developed respiratory systems, and non-calcareous hard parts had negligible losses—except for conodonts, in which 33% of genera died out. This pattern is consistent with what is known about the effects of hypoxia, a shortage but not a total absence of oxygen. However, hypoxia cannot have been the only killing mechanism for marine organisms. Nearly all of the continental shelf waters would have had to become severely hypoxic to account for the magnitude of the extinction, but such a catastrophe would make it difficult to explain the very selective pattern

neg: Permian–Triassic extinction event indicate dense gymnosperm woodlands before the event. At the same time that marine invertebrate macrofauna declined, these large woodlands died out and were followed by a rise in diversity of smaller herbaceous plants including Lycopodiophyta, both Selaginellales and Isoetales. Later, other groups of gymnosperms again become dominant but again suffered major die offs. These cyclical flora shifts occurred a few times over the course of the extinction period and afterwards. These fluctuations of the dominant flora between woody and herbaceous taxa indicate chronic environmental stress resulting in a loss of most large woodland plant species. The successions and extinctions of

neg: Permian–Triassic extinction event biodiversity was lost, the recovery of land-dwelling life took significantly longer than after any other extinction event, possibly up to 10 million years. Studies in Bear Lake County near Paris, Idaho showed a relatively quick rebound in a localized marine ecosystem, taking around 2 million years to recover, suggesting that the impact of the extinction may have been felt less severely in some areas than others. There is evidence for one to three distinct pulses, or phases, of extinction. Suggested mechanisms for the latter include one or more large meteor impact events, massive volcanism such as that of the Siberian

neg: Marine life more than 99 percent of all species that ever lived on Earth, amounting to over five billion species, are estimated to be extinct. These extinctions occur at an uneven rate. The dramatic rise in diversity has been marked by periodic, massive losses of diversity classified as mass extinction events. Mass extinction events occur when life undergoes precipitous global declines. Most diversity and biomass on earth is found among the microorganisms, which are difficult to measure. Recorded extinction events are therefore based on the more easily observed changes in the diversity and abundance of larger multicellular organisms, rather than the total

neg: Permian–Triassic extinction event of the extinction. Models of the Late Permian and Early Triassic atmospheres show a significant but protracted decline in atmospheric oxygen levels, with no acceleration near the P–Tr boundary. Minimum atmospheric oxygen levels in the Early Triassic are never less than present day levels—the decline in oxygen levels does not match the temporal pattern of the extinction. Marine organisms are more sensitive to changes in (carbon dioxide) levels than are terrestrial organisms for a variety of reasons. is 28 times more soluble in water than is oxygen. Marine animals normally function with lower concentrations of in their bodies than land

neg: Permian since Cambrian times, finally became extinct before the end of the Permian. Nautiluses, a species of cephalopods, surprisingly survived this occurrence. There is evidence that magma, in the form of flood basalt, poured onto the surface in what is now called the Siberian Traps, for thousands of years, contributing to the environmental stress that led to mass extinction. The reduced coastal habitat and highly increased aridity probably also contributed. Based on the amount of lava estimated to have been produced during this period, the worst-case scenario is the release of enough carbon dioxide from the eruptions to raise world temperatures

neg: Eurypterid covers the Late Carboniferous)–survived the extinction event in its entirety. All of these were compromised entirely of freshwater animals, rendering the eurypterids extinct in marine environments. With marine eurypterid predators gone, sarcopterygian fish, such as the rhizodonts, were the new apex predators in marine environments. The sole surviving eurypterine family, Adelophthalmidae, was represented only by a single genus, "Adelophthalmus". Both the hibbertopterids and "Adelophthalmus" would survive into the Permian. "Adelophthalmus" became the most common of all late Paleozoic eurypterids, existing in greater number and diversity than surviving stylonurines, and diversified in the absence of other eurypterines. Out of the 31

neg: Lystrosaurus genus, becoming the most common group of terrestrial vertebrates during the Early Triassic; for a while 95% of land vertebrates were "Lystrosaurus". This is the only time that a single species or genus of land animal dominated the Earth to such a degree. A few other Permian therapsid genera also survived the mass extinction and appear in Triassic rocks—the therocephalians "Tetracynodon", "Moschorhinus" and "Ictidosuchoides"—but do not appear to have been abundant in the Triassic; complete ecological recovery took 30 million years, spanning the Early and Middle Triassic. Several attempts have been made to explain why "Lystrosaurus" survived the Permian–Triassic extinction

neg: Beetle antennae, elytra with more fully developed venation and more irregular longitudinal ribbing, and abdomen and ovipositor extending beyond the apex of the elytra. In the Permian–Triassic extinction event at the end of the Permian, some 30% of all insect species became extinct, so the fossil record of insects only includes beetles from the Lower Triassic . Around this time, during the Late Triassic, fungus-feeding species such as Cupedidae appear in the fossil record. In the stages of the Upper Triassic, alga-feeding insects such as Triaplidae and Hydrophilidae begin to appear, alongside predatory water beetles. The first weevils, including the Obrienidae,

neg: Permian became extinct during the former, doubt is cast on the significance of a meteorite impact in creating the latter. Further doubt has been cast on this theory based on fossils in Greenland that show the extinction to have been gradual, lasting about eighty thousand years, with three distinct phases. Many scientists argue that the Permian–Triassic extinction event was caused by a combination of some or all of the hypotheses above and other factors; the formation of Pangaea decreased the number of coastal habitats and may have contributed to the extinction of many clades. Permian The Permian is a geologic period

neg: Logology (science of science) who explained the challenges of climate modelling. Grotzinger was a specialist in historical climate change—specifically, what had caused the great Permian extinction, during which virtually all species died. To properly assess this cataclysm, one had to understand both the rock record and the ocean's composition, but geologists did not interact much with physical oceanographers. Grotzinger's own best collaboration had resulted from a fortuitous lunch with an oceanographer. Climate modelling was an intrinsically difficult problem made worse by academia's structural divisions. "If you had it all under one umbrella... it could result [much sooner] in a major breakthrough." Simons and his

neg: Marine life improved its ability to swim. The biologist Stephen Jay Gould said the ichthyosaur was his favourite example of convergent evolution. The earliest marine reptiles arose in the Permian. During the Mesozoic many groups of reptiles became adapted to life in the seas, including ichthyosaurs, plesiosaurs, mosasaurs, nothosaurs, placodonts, sea turtles, thalattosaurs and thalattosuchians. Marine reptiles were less numerous after mass extinction at the end of the Cretaceous. Marine birds are adapted to life within the marine environment. They are often called "seabirds". While marine birds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the

neg: Mattole Chinook salmon run fell to 100 and coho salmon fell to approximately 100 as well. The American Fisheries Society classified the species as “high risk for extinction”. 1980: The Mattole Salmon Group (MSG) was formed by local residents. Their aim is to restore the native salmon populations. The MSG created gravel-lined “hatchboxes” to substitute for the lost spawning habitat areas. Adult spawners were held until they had their eggs and these were incubated in the hatchboxes. This process jumped the survival rate of “egg-to-fry” from 15 percent to 80 percent. In 1981, local residents and activists began the Mattole salmon

neg: History of Earth which could have led to the depletion of greenhouse gases (like CO2) or the eutrophication of water. 70% of all species became extinct. The third mass extinction was the Permian-Triassic, or the Great Dying, event was possibly caused by some combination of the Siberian Traps volcanic event, an asteroid impact, methane hydrate gasification, sea level fluctuations, and a major anoxic event. Either the proposed Wilkes Land crater in Antarctica or Bedout structure off the northwest coast of Australia may indicate an impact connection with the Permian-Triassic extinction. But it remains uncertain whether either these or other proposed Permian-Triassic boundary craters

neg: Permian have in part caused the widespread extinctions of marine species at the end of the period by severely reducing shallow coastal areas preferred by many marine organisms. During the Permian, all the Earth's major landmasses were collected into a single supercontinent known as Pangaea. Pangaea straddled the equator and extended toward the poles, with a corresponding effect on ocean currents in the single great ocean ("Panthalassa", the "universal sea"), and the Paleo-Tethys Ocean, a large ocean that existed between Asia and Gondwana. The Cimmeria continent rifted away from Gondwana and drifted north to Laurasia, causing the Paleo-Tethys Ocean to shrink.

neg: Trilobite years the Proetida existed untroubled in their ecological niche. An analogy would be today's crinoids, which mostly exist as deep water species; in the Paleozoic era, vast 'forests' of crinoids lived in shallow near-shore environments. Some of the genera of trilobites during the Carboniferous and Permian periods include: Exactly why the trilobites became extinct is not clear; with repeated extinction events (often followed by apparent recovery) throughout the trilobite fossil record, a combination of causes is likely. After the extinction event at the end of the Devonian period, what trilobite diversity remained was bottlenecked into the order Proetida. Decreasing diversity

neg: Paleocontinent terrestrial land became available with rising land masses. The next event was the Permian extinction where almost all species in the oceans died off along with many terrestrial species. This then gave rise to terrestrial animals, such as reptiles, dinosaurs, and small mammals. At the end of this new era was a mass extinction of Dinosaurs and reptiles, this led mammals to flourish as they could take over many of the niches that became vacant. Laurentia experienced a variety of climates as it has been a land mass for billions of years. The craton experienced an ice age during the

neg: Synapsid appeared during the Middle Permian and included the largest terrestrial animals in the Middle and Late Permian. They included herbivores and carnivores, ranging from small animals the size of a rat (e.g.: "Robertia"), to large, bulky herbivores a ton or more in weight (e.g.: "Moschops"). After flourishing for many millions of years, these successful animals were all but wiped out by the Permian-Triassic mass extinction about 250 mya, the largest known extinction in Earth's history, possibly related to the Siberian Traps volcanic event. Only a few therapsids went on to be successful in the new early Triassic landscape; they include

neg: Claraia of the byssal notch and a trend towards a smoother shell in species of "Claria" over time may have led to increased mobility. This increase in mobility may have been an advantage over more sessile animals during the extinction event. It is thought to have lived in anoxic waters at great depths, and therefore may have been better adapted for the anoxic event that may have occurred during the Permian–Triassic extinction event. Claraia Claraia is an extinct genus of scallop-like bivalve molluscs that lived from the Capitanian stage of the Late Permian to the Anisian stage of the Middle Triassic,

neg: Permian–Triassic extinction event the extinction with millennial precision. U–Pb zircon dates from five volcanic ash beds from the Global Stratotype Section and Point for the Permian–Triassic boundary at Meishan, China, establish a high-resolution age model for the extinction – allowing exploration of the links between global environmental perturbation, carbon cycle disruption, mass extinction, and recovery at millennial timescales. The extinction occurred between 251.941 ± 0.037 and 251.880 ± 0.031 Ma ago, a duration of 60 ± 48 ka. A large (approximately 0.9%), abrupt global decrease in the ratio of the stable isotope to that of , coincides with this extinction, and is sometimes

neg: Methanosarcina role in the evolution of life on Earth. Species of "Methanosarcina" are also noted for unusually large genomes. "M. acetivorans" has the largest known genome of any archaeon. According to a theory published in 2014, "Methanosarcina" may have been largely responsible for the largest extinction event in the Earth's history, the Permian–Triassic extinction event. The theory suggests that acquisition of a new metabolic pathway via gene transfer followed by exponential reproduction allowed the microbe to rapidly consume vast deposits of organic carbon in marine sediments, leading to a sharp buildup of methane and carbon dioxide in the Earth's oceans and

neg: Racing Extinction the Arctic, the latter drawing parallels to the runaway greenhouse effect that may have caused the Permian mass extinction that wiped out 95% of species. Carbon dioxide and methane emissions from transportation, animals and factories are made visible to the human eye for the first time with a specially designed high definition FLIR (forward looking infra red) camera, with a special color filter. Ocean acidification and the subsequent degradation of corals and other calcium carbonate-based marine organisms are revealed with lab experiments and comparisons of archived photographs to the state of the same reefs in the 2010s. The degradation of

neg: Siberian Traps major questions is whether the Siberian Traps were directly responsible for the Permian–Triassic mass extinction event that occurred 250 million years ago, or if they were themselves caused by some other, larger event, such as an asteroid impact. A recent hypothesis put forward is that the volcanism triggered the growth of Methanosarcina, a microbe that then spewed enormous amounts of methane into Earth's atmosphere, ultimately altering the Earth's carbon cycle based on observations such as a significant increase of inorganic carbon reservoirs in marine environments. This extinction event, also called the Great Dying, affected all life on Earth, and is

neg: Permian–Triassic extinction event is calculated to be up to 0.7 units. It is difficult to analyze extinction and survival rates of land organisms in detail, because few terrestrial fossil beds span the Permian–Triassic boundary. Triassic insects are very different from those of the Permian, but a gap in the insect fossil record spans approximately 15 million years from the late Permian to early Triassic. The best-known record of vertebrate changes across the Permian–Triassic boundary occurs in the Karoo Supergroup of South Africa, but statistical analyses have so far not produced clear conclusions. However, analysis of the fossil river deposits of the floodplains indicate

neg: Seashell These tests are fragile and easily broken into pieces. The brachiopods, or lamp shells, superficially resemble clams, but the phylum is not closely related to mollusks. Most lines of brachiopods ended during the Permian-Triassic extinction event, and their ecological niche was filled by bivalves. A few of the remaining species of brachiopods occur in the low intertidal zone and thus can be found live by beachcombers. Some polychaetes, marine annelid worms in the family Serpulidae, secrete a hard tube made of calcium carbonate, adhering to stones or other shells. This tube resembles, and can be confused with, the shell of

neg: Marine life diversity and abundance of life. Marine fossils are mostly used to measure extinction rates because of their superior fossil record and stratigraphic range compared to land organisms. Based on the fossil record, the background rate of extinctions on Earth is about two to five taxonomic families of marine animals every million years. The Great Oxygenation Event was perhaps the first major extinction event. Since the Cambrian explosion five further major mass extinctions have significantly exceeded the background extinction rate. The worst was the Permian-Triassic extinction event, 251 million years ago. Vertebrates took 30 million years to recover from this event.

neg: Ordovician–Silurian extinction events the most cosmopolitan in the Phanerozoic, biogeographic patterns that persisted throughout most of the Silurian. These end Ordovician–Silurian events had nothing like the long-term impact of the Permian–Triassic and Cretaceous-Paleogene extinction events. Nevertheless, a large number of taxa disappeared from the Earth over a short time interval, eliminating and changing diversity. Ordovician–Silurian extinction events The Ordovician–Silurian extinction events, when combined, are the second-largest of the five major extinction events in Earth's history in terms of percentage of genera that became extinct. This event greatly affected marine communities, which caused the disappearance of one third of all brachiopod and bryozoan families,

neg: Late Devonian extinction record for marine invertebrates suggests that some of the losses attributed to the Kellwasser event likely actually occurred during the Hangenberg extinction. The late Devonian crash in biodiversity was more drastic than the familiar extinction event that closed the Cretaceous. A recent survey (McGhee 1996) estimates that 22% of all the 'families' of marine animals (largely invertebrates) were eliminated. The family is a great unit, and to lose so many signifies a deep loss of ecosystem diversity. On a smaller scale, 57% of genera and at least 75% of species did not survive into the Carboniferous. These latter estimates need

neg: Kombuisia Kombuisia Kombuisia is a genus of dicynodont from Early to Middle Triassic (Induan to Anisian) of South Africa and Antarctica. Two species were described for the genus: "Kombuisia frerensis" (type) and "Kombuisia antarctica". Dicynodonts were a diverse clade that inhabited the earth from the Middle Permian to the Late Triassic. "Kombuisia" is one of few species to survive the mass extinction event in the late Permian. "Kombuisia" are non-mammalian synapsid herbivores. Specimens of this genus were discovered in the 1960s and 1970s and years later were determined to be two different species of the genus. The two species were found

neg: Guizhouichthyosaurus vertebrae and 110 caudal vertebrae brings its total length to . Following the Permian-Triassic extinction event (also colloquially known as The Great Dying), the decline and disappearance of eugeneodonts and giant nautiloids left an environmental niche empty that many marine reptiles began to fill. "Guizhouichthyosaurus" was one of the largest marine vertebrates of the time, whose only predators composed of large macro-predatory Ichthyosaurs (that of which preferred to hunt smaller ichthyosaurs). The rise of the shelled cephalopods (ammonites that survived the Permian-Triassic extinction event, along with the appearance of belemnites) gave ichthyosaurs an abundant food supply with little competition."Guizhouichthyosaurus" and

neg: Extinction event event, during which 20% of all marine families became extinct. Furthermore, the Permian–Triassic extinction event has been suggested to have been caused by warming. Clathrates are composites in which a lattice of one substance forms a cage around another. Methane clathrates (in which water molecules are the cage) form on continental shelves. These clathrates are likely to break up rapidly and release the methane if the temperature rises quickly or the pressure on them drops quickly—for example in response to sudden global warming or a sudden drop in sea level or even earthquakes. Methane is a much more powerful greenhouse

neg: Permian–Triassic extinction event P–Tr extinction; the Ceratitida order of ammonites; and crinoids ("sea lilies"), which very nearly became extinct but later became abundant and diverse. The groups with the highest survival rates generally had active control of circulation, elaborate gas exchange mechanisms, and light calcification; more heavily calcified organisms with simpler breathing apparatuses suffered the greatest loss of species diversity. In the case of the brachiopods, at least, surviving taxa were generally small, rare members of a formerly diverse community. The ammonoids, which had been in a long-term decline for the 30 million years since the Roadian (middle Permian), suffered a selective extinction

neg: Brachiopod era, the brachiopods were among the most abundant filter-feeders and reef-builders, and occupied other ecological niches, including swimming in the jet-propulsion style of scallops. Brachiopod fossils have been useful indicators of climate changes during the Paleozoic. However, after the Permian–Triassic extinction event, brachiopods recovered only a third of their former diversity. A study in 2007 concluded the brachiopods were especially vulnerable to the Permian–Triassic extinction, as they built calcareous hard parts (made of calcium carbonate) and had low metabolic rates and weak respiratory systems. It was often thought that brachiopods went into decline after the Permian–Triassic extinction, and were out-competed

neg: Permian–Triassic extinction event out before the end of the Permian. Too few Permian diapsid fossils have been found to support any conclusion about the effect of the Permian extinction on diapsids (the "reptile" group from which lizards, snakes, crocodilians, and dinosaurs (including birds) evolved). The groups that survived suffered extremely heavy losses of species, and some terrestrial vertebrate groups very nearly became extinct at the end-Permian. Some of the surviving groups did not persist for long past this period, while others that barely survived went on to produce diverse and long-lasting lineages. Yet it took 30million years for the terrestrial vertebrate fauna to

neg: Coelacanthus Coelacanthus Coelacanthus ("Hollow Spine") is a genus of extinct coelacanths that first appeared during the Permian period. In fact, this was the first genus of coelacanths ever described, as the order Coelacanthiformes is named after it. They bear a superficial similarity to the living "Latimeria", though they were smaller, and had more elongated heads. Individuals grew up to 3 feet in length, and had small lobed fins, suggesting that "Coelacanthus" were open-water predators. "Coelacanthus" was a long-lived genus with a worldwide distribution. The various species survived the Permian–Triassic extinction event, and the last eventually died out during the Late Jurassic,