Portal:Jurassic

Topics Culture Geography Health History Mathematics Nature People Philosophy Religion Society Technology The Jurassic Portal Mounted skeletons at the AMNH. The Jurassic (/dʒuːˈræsɪk/; from Jura Mountains of the Alps) is a geologic period and system that extends from 201.3 Ma (million years ago) to 145 Ma; from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic Era, also known as the Age of Reptiles. The start of the period is marked by the major Triassic–Jurassic extinction event. Two other extinction events occurred during the period: the Late Piensbachian/Early Toarcian event in the Early Jurassic, and the Late Tithonian event at the end; however, neither event ranks among the 'Big Five' mass extinctions. The Jurassic is named after the Jura Mountains within the European Alps, where limestone strata from the period was first identified. By the beginning of the Jurassic, the supercontinent Pangaea had begun rifting into two landmasses, Laurasia to the north and Gondwana to the south. This created more coastlines and shifted the continental climate from dry to humid, and many of the arid deserts of the Triassic were replaced by lush rainforests. On land, the fauna transitioned from the Triassic fauna, dominated by both dinosauromorph and crocodylomorph archosaurs, to one dominated by dinosaurs alone. The first birds also appeared during the Jurassic, having evolved from a branch of theropod dinosaurs. Other major events include the appearance of the earliest lizards, and the evolution of therian mammals, including primitive placentals. Crocodylians made the transition from a terrestrial to an aquatic mode of life. The oceans were inhabited by marine reptiles such as ichthyosaurs and plesiosaurs, while pterosaurs were the dominant flying vertebrates. (see more...) Template:/box-footer The geology of the Zion and Kolob canyons area includes nine known exposed formations, all visible in Zion National Park in the U.S. state of Utah. Together, these formations represent about 150 million years of local sedimentation from the Late Permian to Early Cretaceous. Part of a super-sequence of rock units called the Grand Staircase, the formations exposed in the Zion and Kolob area were deposited in several different environments that range from the warm shallow seas of the Kaibab and Moenkopi formations, streams and lakes of the Chinle, Moenave, and Kayenta formations to the large deserts of the Navajo and Temple Cap formations and dry near shore environments of the Carmel Formation. Subsequent uplift of the Colorado Plateau slowly raised these formations much higher than where they were deposited. This steepened the stream gradient of the ancestral rivers and other streams on the plateau. The faster-moving streams took advantage of uplift-created joints in the rocks to remove all Cenozoic-aged formations and cut gorges into the plateaus. Zion Canyon was cut by the North Fork of the Virgin River in this way. Lava flows and cinder cones covered parts of the area during the later part of this process. (see more...) Paleontology or palaeontology (/ˌpeɪlɪɒnˈtɒlədʒi/, /ˌpeɪlɪənˈtɒlədʒi/ or /ˌpælɪɒnˈtɒlədʒi/, /ˌpælɪənˈtɒlədʒi/) is the scientific study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments (their paleoecology). As a "historical science" it attempts to explain causes rather than conduct experiments to observe effects. Paleontological observations have been documented as far back as the 5th century BC. The science became established in the 18th century as a result of Georges Cuvier's work on comparative anatomy, and developed rapidly in the 19th century. The term itself originates from Greek: παλαιός (palaios) meaning "old, ancient," ὄν, ὀντ- (on, ont-), meaning "being, creature" and λόγος (logos), meaning "speech, thought, study". Paleontology lies on the border between biology and geology. It now uses techniques drawn from a wide range of sciences, including biochemistry, mathematics and engineering. Use of all these techniques has enabled paleontologists to discover much of the evolutionary history of life, almost all the way back to when Earth became capable of supporting life, about 3,800 million years ago. As knowledge has increased, paleontology has developed specialized sub-divisions, some of which focus on different types of fossil organisms while others study ecology and environmental history, such as ancient climates. Body fossils and trace fossils are the principal types of evidence about ancient life, and geochemical evidence has helped to decipher the evolution of life before there were organisms large enough to leave fossils. (see more...) A skeleton of Steneosaurus, an extinct genus of teleosaurid crocodyliform from the Toarcian Lower Jurassic of Holzmaden, Germany. Photo credit: Didier Descouens Life restoration of Miragaia. ... that the stegosaurid Miragaia had more neck vertebrae than almost all of the sauropod dinosaurs, known for their long necks? ... that the Jurassic crocodile relative Phyllodontosuchus had two types of teeth; one type resembled those of some herbivorous dinosaurs, indicating it may not have been a strict carnivore? ... that based on its skull anatomy, the small Early Jurassic crocodile relative Dibothrosuchus (reconstruction pictured) probably had a keen sense of hearing and was vocal like modern crocodiles? ... that the discovery of feather-like structures on the primitive dinosaur Tianyulong raises the possibility that ancestral dinosaurs were feathered? ... that although its fossils were first discovered in 1946, the pliosaurid genus Gallardosaurus was not declared a valid taxon until 2009? Template:/box-header Epochs - Early Jurassic - Middle Jurassic - Late Jurassic Stages - Hettangian - Sinemurian - Pliensbachian - Toarcian - Aalenian - Bajocian - Bathonian - Callovian - Oxfordian - Kimmeridgian - Tithonian Events - Cambrian–Ordovician extinction event - Great Ordovician Biodiversification Event - Taconic orogeny - Late Ordovician glaciation - Alice Springs Orogeny - Ordovician–Silurian extinction event Landmasses - Baltica - Gondwana - Laurentia - Siberia Bodies of water - Iapetus Ocean - Khanty Ocean - Proto-Tethys Ocean - Rheic Ocean - Tornquist Sea - Ural Ocean Animals - Articulate brachiopods - Bryozoans - Cornulitids - Crinoids - Cystoids - Gastropods - Graptolites - Jawed fishes - Nautiloids - Ostracoderms - Rugose corals - Star fishes - Tabulate corals - Tentaculitids - Trilobites Trace fossils - Petroxestes - Trypanites Plants - Marchantiophyta Fossil sites - Beecher's Trilobite Bed - Walcott–Rust quarry Stratigraphic units - Chazy Formation - Fezouata formation - Holston Formation - Kope Formation - Potsdam Sandstone - St. Peter Sandstone Researchers - Charles Emerson Beecher - Charles Lapworth - Charles Doolittle Walcott Culture - Animal Armageddon - List of creatures in the Walking with... series - Sea Monsters Template:/box-footer Template:/box-header Featured Mesozoic articles - Bone Sharps, Cowboys, and Thunder Lizards - Bone Wars - Edward Drinker Cope - Geology of the Capitol Reef area - Geology of the Death Valley area -Geology of the Grand Canyon area - Geology of the Zion and Kolob canyons area Good Mesozoic articles - Chitinozoan - Coal ball - Dimetrodon - History of paleontology - Evolutionary history of life - Ornatifilum - Opabinia - Paleontology- Schinderhannes - Small shelly fauna - Temnospondyli - Tiktaalik - Waptia Template:/box-footer ▼ Mesozoic ► Triassic ► Jurassic ► Cretaceous ► Mesozoic life Here are some tasks awaiting attention: Stubs : Mesozoic stubs, Triassic stubs, Jurassic stubs, Cretaceous stubs Current Paleozoic FACs - none currently Template:/box-footer Time Earth sciences Paleontology Extinct and Endangered Species Paleozoic Triassic Jurassic Cretaceous Cenozoic What are portals? 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