Ordovician-Silurian Extinction Essay
extinction is the end of an organism or of a group of organisms (taxon), normally a species.
Ordovician-Silurian extinction, global extinction event occurring during the Hirnantian Age (445.6 million to 443.7 million years ago) of the Ordovician Period and the subsequent Rhuddanian Age (443.7 million to 439 million years ago) of the Silurian Period that eliminated an estimated 85 percent of all Ordovician species. This extinction interval ranks second in severity to the one that occurred at the boundary between the Permian and Triassic periods about 251 million years ago in terms of the percentage of marine families affected. The Ordovician-Silurian extinction was almost twice as severe as the K–T extinction event that occurred at the end …show more content…
of the Cretaceous Period, about 65.5 million years ago, which is famous for bringing an end to the dinosaurs.
The Late Devonian extinction was one of five major extinction events in the history of the Earth's biota. A major extinction, the Kellwasser Event, occurred at the boundary that marks the beginning of the last phase of the Devonian period, the Famennian faunal stage, (the Frasnian-Famennian boundary), about 374 million years ago.[1][2] Overall, 19% of all families and 50% of all genera went extinct.[3] A second, distinct mass extinction, the Hangenberg Event, closed the Devonian period.[4]
The Triassic–Jurassic extinction event marks the boundary between the Triassic and Jurassic periods, 201.3 million years ago,[1] and is one of the major extinction events of the Phanerozoic eon, profoundly affecting life on land and in the oceans.
In the seas a whole class (conodonts)[2] and 34% of marine genera disappeared.[3] On land, all large crurotarsans (non-dinosaurian archosaurs) other than crocodilians, some remaining therapsids, and many of the large amphibians became extinct.
The Cretaceous-Tertiary ExtinctionAlmost all the large vertebrates on Earth, on land, at sea, and in the air (all dinosaurs, plesiosaurs, mosasaurs, and pterosaurs) suddenly became extinct about 65 Ma, at the end of the Cretaceous Period. At the same time, most plankton and many tropical invertebrates, especially reef-dwellers, became extinct, and many land plants were severely affected. This extinction event marks a major boundary in Earth's history, the K-T or Cretaceous-Tertiary boundary, and the end of the Mesozoic Era. The K-T extinctions were worldwide, affecting all the major continents and oceans. There are still arguments about just how short the event was. It was certainly sudden in geological terms and may have been catastrophic by anyone's
standards.
The Permian–Triassic (P–Tr) extinction event, one of several events colloquially known as the great dying,[2][3] occurred about 252 Ma (million years) ago,[4] forming the boundary between the Permian and Triassic geologic periods, as well as the Paleozoic and Mesozoic eras. It is the Earth's most severe known extinction event, with up to 96% of all marine species[5] and 70% of terrestrial vertebrate species becoming extinct.[6] It is the only known mass extinction of insects.[7][8] Some 57% of all families and 83% of all genera became extinct. Because so much biodiversity was lost, the recovery of life on Earth took significantly longer than after any other extinction event,[5] possibly up to 10 million years.[9]
Ordovician-Silurian extinction, global extinction event occurring during the Hirnantian Age (445.6 million to 443.7 million years ago) of the Ordovician Period and the subsequent Rhuddanian Age (443.7 million to 439 million years ago) of the Silurian Period that eliminated an estimated 85 percent of all Ordovician species. This extinction interval ranks second in severity to the one that occurred at the boundary between the Permian and Triassic periods about 251 million years ago in terms of the percentage of marine families affected. The Ordovician-Silurian extinction was almost twice as severe as the K–T extinction event that occurred at the end …show more content…
of the Cretaceous Period, about 65.5 million years ago, which is famous for bringing an end to the dinosaurs.
The Late Devonian extinction was one of five major extinction events in the history of the Earth's biota. A major extinction, the Kellwasser Event, occurred at the boundary that marks the beginning of the last phase of the Devonian period, the Famennian faunal stage, (the Frasnian-Famennian boundary), about 374 million years ago.[1][2] Overall, 19% of all families and 50% of all genera went extinct.[3] A second, distinct mass extinction, the Hangenberg Event, closed the Devonian period.[4]
The Triassic–Jurassic extinction event marks the boundary between the Triassic and Jurassic periods, 201.3 million years ago,[1] and is one of the major extinction events of the Phanerozoic eon, profoundly affecting life on land and in the oceans.
In the seas a whole class (conodonts)[2] and 34% of marine genera disappeared.[3] On land, all large crurotarsans (non-dinosaurian archosaurs) other than crocodilians, some remaining therapsids, and many of the large amphibians became extinct.
The Cretaceous-Tertiary ExtinctionAlmost all the large vertebrates on Earth, on land, at sea, and in the air (all dinosaurs, plesiosaurs, mosasaurs, and pterosaurs) suddenly became extinct about 65 Ma, at the end of the Cretaceous Period. At the same time, most plankton and many tropical invertebrates, especially reef-dwellers, became extinct, and many land plants were severely affected. This extinction event marks a major boundary in Earth's history, the K-T or Cretaceous-Tertiary boundary, and the end of the Mesozoic Era. The K-T extinctions were worldwide, affecting all the major continents and oceans. There are still arguments about just how short the event was. It was certainly sudden in geological terms and may have been catastrophic by anyone's
standards.
The Permian–Triassic (P–Tr) extinction event, one of several events colloquially known as the great dying,[2][3] occurred about 252 Ma (million years) ago,[4] forming the boundary between the Permian and Triassic geologic periods, as well as the Paleozoic and Mesozoic eras. It is the Earth's most severe known extinction event, with up to 96% of all marine species[5] and 70% of terrestrial vertebrate species becoming extinct.[6] It is the only known mass extinction of insects.[7][8] Some 57% of all families and 83% of all genera became extinct. Because so much biodiversity was lost, the recovery of life on Earth took significantly longer than after any other extinction event,[5] possibly up to 10 million years.[9]