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Paleontology In Alaska
Paleontology in Alaska refers to paleontological research occurring within or conducted by people from the U.S. state of Alaska. During the Late Precambrian, Alaska was covered by a shallow sea that was home to stromatolite-forming bacteria. Alaska remained submerged into the Paleozoic era and the sea came to be home to creatures including ammonites, brachiopods, and reef-forming corals. An island chain formed in the eastern part of the state. Alaska remained covered in seawater during the Triassic and Jurassic. Local wildlife included ammonites, belemnites, bony fish and ichthyosaurs. Alaska was a more terrestrial environment during the Cretaceous, with a rich flora and dinosaur fauna. During the early Cenozoic, Alaska had a subtropical environment. The local seas continued to drop until a land bridge connected the state with Asia. Early humans crossed this bridge and remains of contemporary local wildlife such as woolly mammoths often show signs of having been butchered. More r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alaska In United States (US50)
Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the northernmost, westernmost, and easternmost (the Aleutian Islands cross the 180th meridian into the eastern hemisphere) state in the United States. It borders the Canadian territory of Yukon and the province of British Columbia to the east. It shares a western maritime border, in the Bering Strait, with Russia's Chukotka Autonomous Okrug. The Chukchi and Beaufort Seas of the Arctic Ocean lie to the north, and the Pacific Ocean lies to the south. Technically, it is a semi-exclave of the U.S., and is the largest exclave in the world. Alaska is the largest U.S. state by area, comprising more total area than the following three largest states of Texas, California, and Montana combined, and is the seventh-largest subnational division in the world ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ichthyosaur
Ichthyosauria is an order of large extinct marine reptiles sometimes referred to as "ichthyosaurs", although the term is also used for wider clades in which the order resides. Ichthyosaurians thrived during much of the Mesozoic era; based on fossil evidence, they first appeared around 250 million years ago ( Ma) and at least one species survived until about 90 million years ago, into the Late Cretaceous. During the Early Triassic epoch, ichthyosaurs and other ichthyosauromorphs evolved from a group of unidentified land reptiles that returned to the sea, in a development similar to how the mammalian land-dwelling ancestors of modern-day dolphins and whales returned to the sea millions of years later, which they gradually came to resemble in a case of convergent evolution. Ichthyosaurians were particularly abundant in the Late Triassic and Early Jurassic periods, until they were replaced as the top aquatic predators by another marine reptilian group, the Plesiosauria, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bonebed
A bone bed is any geological stratum or deposit that contains bones of whatever kind. Inevitably, such deposits are sedimentary in nature. Not a formal term, it tends to be used more to describe especially dense collections such as Lagerstätte. It is also applied to brecciated and stalagmitic deposits on the floor of caves, which frequently contain osseous remains. In a more restricted sense, the term is used to describe certain thin layers of bony fragments, which occur in well-defined geological strata. One of the best-known of these is the Ludlow Bone Bed, which is found at the base of the Downton Sandstone in the Upper Ludlow series. At Ludlow (England) itself, two such beds are actually known, separated by about . of strata. Although quite thin, the Ludlow Bone Bed can be followed from that town into Gloucestershire, for a distance of . It is almost completely made up of fragments of spines, teeth and scales of ganoid fish. Another well-known bed, formerly known as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pachyrhinosaurus
''Pachyrhinosaurus'' (from Ancient Greek ' (), thick; ' (), nose; and (), lizard) is a genus of centrosaurine ceratopsid dinosaur from the Late Cretaceous period of North America. The first examples were discovered by Charles M. Sternberg in Alberta, Canada, in 1946, and named in 1950. Over a dozen partial skulls and a large assortment of other fossils from various species have been found in Alberta and Alaska. A great number were not available for study until the 1980s, resulting in a relatively recent increase of interest in ''Pachyrhinosaurus''. Three species have been identified. ''P. lakustai'', from the Wapiti Formation, the bonebed horizon of which is roughly equivalent in age to the upper Bearpaw and lower Horseshoe Canyon Formations, is known to have existed from about 73.5–72.5 million years ago. ''P. canadensis'' is younger, known from the lower Horseshoe Canyon Formation, about 71.5–71 Ma ago and the St. Mary River Formation. Fossils of the youngest s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mythological
Myth is a genre of folklore consisting primarily of narratives that play a fundamental role in a society. For scholars, this is very different from the vernacular usage of the term "myth" that refers to a belief that is not true. Instead, the veracity of a myth is not a defining criterion. Myths are often endorsed by religious (when they are closely linked to religion or spirituality) and secular authorities. Many societies group their myths, legends, and history together, considering myths and legends to be factual accounts of their remote past. In particular, creation myths take place in a primordial age when the world had not achieved its later form. Origin myths explain how a society's customs, institutions, and taboos were established and sanctified. National myths are narratives about a nation's past that symbolize the nation's values. There is a complex relationship between recital of myths and the enactment of rituals. Etymology The word "myth" comes from Ancient ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Native Americans In The United States
Native Americans (also called American Indians, First Americans, or Indigenous Americans) are the Indigenous peoples of the Americas, Indigenous peoples of the United States, particularly of the Contiguous United States, lower 48 states and Alaska. They may also include any Americans whose origins lie in any of the indigenous peoples of North or South America. The United States Census Bureau publishes data about "American Indians and Alaska Natives", whom it defines as anyone "having origins in any of the original peoples of North and South America ... and who maintains tribal affiliation or community attachment". The census does not, however, enumerate "Native Americans" as such, noting that the latter term can encompass a broader set of groups, e.g. Native Hawaiians, which it tabulates separately. The European colonization of the Americas from 1492 resulted in a Population history of Indigenous peoples of the Americas, precipitous decline in the size of the Native American ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Woolly Mammoth
The woolly mammoth (''Mammuthus primigenius'') is an extinct species of mammoth that lived from the Middle Pleistocene until its extinction in the Holocene epoch. It was one of the last in a line of mammoth species, beginning with the African ''Mammuthus subplanifrons'' in the early Pliocene. The woolly mammoth began to diverge from the steppe mammoth about 800,000 years ago in Siberia. Its closest extant relative is the Asian elephant. The Columbian mammoth (''Mammuthus columbi'') lived alongside the woolly mammoth in North America, and DNA studies show that the two Hybrid (biology), hybridised with each other. Mammoth remains were long known in Asia before they became known to Europeans. The origin of these remains was long debated and often explained as the remains of legendary creatures. The mammoth was identified as an extinct elephant species by Georges Cuvier in 1796. The appearance and behaviour of the woolly mammoth are among the best studied of any Prehistory, prehi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asia
Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which has long been home to the majority of the human population, was the site of many of the first civilisations. Its 4.7 billion people constitute roughly 60% of the world's population. Asia shares the landmass of Eurasia with Europe, and of Afro-Eurasia with both Europe and Africa. In general terms, it is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, and on the north by the Arctic Ocean. The border of Asia with Europe is a social constructionism, historical and cultural construct, as there is no clear physical and geographical separation between them. A commonly accepted division places Asia to the east of the Suez Canal separating it from Africa; and to the east of the Turkish straits, the Ural Mountains an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Land Bridge
In biogeography, a land bridge is an isthmus or wider land connection between otherwise separate areas, over which animals and plants are able to cross and colonize new lands. A land bridge can be created by marine regression, in which sea levels fall, exposing shallow, previously submerged sections of continental shelf; or when new land is created by plate tectonics; or occasionally when the sea floor rises due to post-glacial rebound after an ice age. Prominent examples Former land bridges * The Bassian Plain, which linked Australia to Tasmania * The Antarctic Land Bridge, which connected South America, Antarctica, and Australia during the Late Cretaceous and Early Paleogene * The Bering Land Bridge (aka Beringia), which intermittently connected Alaska (Northern America) with Siberia (North Asia) as sea levels rose and fell under the effect of ice ages * GAARlandia, a hypothesized land bridge which potentially connected the Greater Antilles with South America d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subtropical
The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones immediately to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Geographical zone#Temperate zones, temperate zones of both hemispheres, they cover the middle latitudes from to approximately 35° to 40° north and south. The horse latitudes lie within this range. Subtropical climates are often characterized by hot summers and mild winters with infrequent frost. Most subtropical climates fall into two basic types: humid subtropical climate, humid subtropical (Köppen climate classification: Cfa/Cwa), where rainfall is often concentrated in the warmest months, for example list of regions of China, Southeast China and the Southeastern United States, and Mediterranean climate, dry summer or Mediterranean climate (Köppen climate classification: Csa/Csb), where seasonal rainfall is concentrated in the cooler ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cenozoic
The Cenozoic Era ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, insects, birds and angiosperms (flowering plants). It is the latest of three geological eras of the Phanerozoic Eon, preceded by the Mesozoic and Paleozoic. The Cenozoic started with the Cretaceous–Paleogene extinction event, when many species, including the non-avian dinosaurs, became extinct in an event attributed by most experts to the impact of a large asteroid or other celestial body, the Chicxulub impactor. The Cenozoic is also known as the Age of Mammals because the terrestrial animals that dominated both hemispheres were mammalsthe eutherians ( placentals) in the Northern Hemisphere and the metatherians (marsupials, now mainly restricted to Australia and to some extent South America) in the Southern Hemisphere. The extinction of many groups allowed mammals and birds to greatly diversify so that large m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutionary history, evolution of dinosaurs is a subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya and their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, Evolution of birds, having evolved from earlier Theropoda, theropods during the Late Jurassic epoch, and are the only dinosaur lineage known to have survived the Cretaceous–Paleogene extinction event approximately 66 mya. Dinosaurs can therefore be divided into avian dinosaurs—birds—and the extinct non-avian dinosaurs, which are all dinosaurs other than birds. Dinosaurs are varied from taxonomy (biology), taxonomic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
