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Tiktaalik NT Small
''Tiktaalik'' (; ) is a monospecific genus of extinct sarcopterygian (lobe-finned fish) from the Late Devonian Period, about 375 Mya (million years ago), having many features akin to those of tetrapods (four-legged animals). ''Tiktaalik'' is estimated to have had a total length of on the basis of various specimens. Unearthed in Arctic Canada, ''Tiktaalik'' is a non-tetrapod member of Osteichthyes (bony fish), complete with scales and gills—but it has a triangular, flattened head and unusual, cleaver-shaped fins. Its fins have thin ray bones for paddling like most fish, but they also have sturdy interior bones that would have allowed ''Tiktaalik'' to prop itself up in shallow water and use its limbs for support as most four-legged animals do. Those fins and other mixed characteristics mark ''Tiktaalik'' as a crucial transition fossil, a link in evolution from swimming fish to four-legged vertebrates. This and similar animals might be the common ancestors of all vertebrate terr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at million years ago ( Ma), to the beginning of the succeeding Carboniferous period at Ma. It is the fourth period of both the Paleozoic and the Phanerozoic. It is named after Devon, South West England, where rocks from this period were first studied. The first significant evolutionary radiation of life on land occurred during the Devonian, as free- sporing land plants (pteridophytes) began to spread across dry land, forming extensive coal forests which covered the continents. By the middle of the Devonian, several groups of vascular plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants ( pteridospermatophytes) appeared. This rapid evolution and colonization process, which had begun during the Silurian, is known as the Silurian-Devonian Terrestrial Rev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transitional Fossil
A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group. This is especially important where the descendant group is sharply differentiated by gross anatomy and mode of living from the ancestral group. These fossils serve as a reminder that taxonomic divisions are human constructs that have been imposed in hindsight on a continuum of variation. Because of the incompleteness of the fossil record, there is usually no way to know exactly how close a transitional fossil is to the point of divergence. Therefore, it cannot be assumed that transitional fossils are direct ancestors of more recent groups, though they are frequently used as models for such ancestors. In 1859, when Charles Darwin's ''On the Origin of Species'' was first published, the fossil record was poorly known. Darwin described the perceived lack of transitional fossils as "the most obvious and gravest objection which can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laurentia
Laurentia or the North American craton is a large continental craton that forms the Geology of North America, ancient geological core of North America. Many times in its past, Laurentia has been a separate continent, as it is now in the form of North America, although originally it also included the cratonic areas of Greenland and the Hebridean terrane in northwest Scotland. During other times in its past, Laurentia has been part of larger continents and supercontinents and consists of many smaller terranes assembled on a network of early Proterozoic Orogenic belt, orogenic belts. Small microcontinents and oceanic islands collided with and Suture (geology), sutured onto the ever-growing Laurentia, and together formed the stable Precambrian craton seen today. Etymology The craton is named after the Laurentian Shield, through the Laurentian Mountains, which received their name from the St. Lawrence River, named after Saint Lawrence of Rome. Interior platform In eastern and centra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chicago Tribune
The ''Chicago Tribune'' is an American daily newspaper based in Chicago, Illinois, United States. Founded in 1847, it was formerly self-styled as the "World's Greatest Newspaper", a slogan from which its once integrated WGN (AM), WGN radio and WGN-TV, WGN television received their call letters. It is the most-read daily newspaper in the Chicago metropolitan area and the Great Lakes region, and the List of newspapers in the United States, sixth-largest newspaper by print circulation in the United States. In the 1850s, under Joseph Medill, the ''Chicago Tribune'' became closely associated with the Illinois politician Abraham Lincoln, and the then new Republican Party (United States), Republican Party's progressive wing. In the 20th century, under Medill's grandson 'Colonel' Robert R. McCormick, its reputation was that of a crusading newspaper with an outlook that promoted Conservatism in the United States, American conservatism and opposed the New Deal. Its reporting and commenta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Canada
Northern Canada (), colloquially the North or the Territories, is the vast northernmost region of Canada, variously defined by geography and politics. Politically, the term refers to the three Provinces_and_territories_of_Canada#Territories, territories of Canada: Yukon, Northwest Territories and Nunavut. This area covers about 48 per cent of Canada's total land area, but has less than 0.5 per cent of demographics of Canada, Canada's population. The terms "northern Canada" or "the North" may be used in contrast with ''the far north'', which may refer to the Canadian Arctic, the portion of Canada that lies north of the Arctic Circle, east of Alaska and west of Greenland. However, in many other uses the two areas are treated as a single unit. Capitals The capital cities of the three northern territories, from west to east, are: * Yukon - Whitehorse * Northwest Territories - Yellowknife * Nunavut - Iqaluit Definitions Subdivisions As a social rather than political region, the C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fram Formation
The Fram Formation is an Upper Devonian (Frasnian) sequence of rock strata on Ellesmere Island that came into prominence in 2006 with the discovery in its rocks of examples of the transitional fossil, ''Tiktaalik'', a sarcopterygian or lobe-finned fish showing many tetrapod characteristics. Fossils of '' Laccognathus embryi'', a porolepiform lobe-finned fish, and '' Qikiqtania'', a close relative of ''Tiktaalik'', were also found in the formation. The Fram Formation is a Middle to Upper Devonian clastic wedge forming an extensive continental facies consisting of sediments derived from deposits laid down in braided stream systems that formed some 375 million years ago, Fossil pollen suggest that these rocks lie within the early and middle Frasnian Stage of the Devonian. at a time when the North American craton ("Laurentia") was straddling the equator. Paleobiota Vertebrates See also * List of fossiliferous stratigraphic units in Nunavut * Escuminac Formation, another Frasnia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ellesmere Island 2025
Ellesmere may refer to: Places Australia * Ellesmere, Queensland, a locality in the South Burnett Region, Queensland * the former name of Scottsdale, Tasmania, Australia Canada * Ellesmere Island, an Arctic island of Canada and named for Francis Egerton, 1st Earl of Ellesmere * Ellesmere Road, an arterial road in Toronto, Ontario, Canada and named after Ellesmere, Shropshire * Ellesmere station, a former Toronto subway station in Scarborough, Ontario, Canada, which was the site of a derailment in 2023 New Zealand * Ellesmere, New Zealand, a locality in the Canterbury region of the South Island of New Zealand ** Lake Ellesmere / Te Waihora, a lake near Ellesmere ** Ellesmere (New Zealand electorate), an historic New Zealand electorate United Kingdom * Ellesmere, Shropshire, a market town in Shropshire, England ** Ellesmere Castle ** Ellesmere Rural, a civil parish to the west * Ellesmere Park, area of Eccles, Greater Manchester, England * Ellesmere Port, an industrial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harvard University
Harvard University is a Private university, private Ivy League research university in Cambridge, Massachusetts, United States. Founded in 1636 and named for its first benefactor, the History of the Puritans in North America, Puritan clergyman John Harvard (clergyman), John Harvard, it is the oldest institution of higher learning in the United States. Its influence, wealth, and rankings have made it one of the most prestigious universities in the world. Harvard was founded and authorized by the Massachusetts General Court, the governing legislature of Colonial history of the United States, colonial-era Massachusetts Bay Colony. While never formally affiliated with any Religious denomination, denomination, Harvard trained Congregationalism in the United States, Congregational clergy until its curriculum and student body were gradually secularized in the 18th century. By the 19th century, Harvard emerged as the most prominent academic and cultural institution among the Boston B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Chicago
The University of Chicago (UChicago, Chicago, or UChi) is a Private university, private research university in Chicago, Illinois, United States. Its main campus is in the Hyde Park, Chicago, Hyde Park neighborhood on Chicago's South Side, Chicago, South Side, near the shore of Lake Michigan about from Chicago Loop, the Loop. The university is composed of an College of the University of Chicago, undergraduate college and four graduate divisions: Biological Science, Arts & Humanities, Physical Science, and Social Science, which include various organized departments and institutes. In addition, the university operates eight professional schools in the fields of University of Chicago Booth School of Business, business, Crown Family School of Social Work, Policy, and Practice, social work, University of Chicago Divinity School, divinity, Graham School of Continuing Liberal and Professional Studies, continuing studies, Harris School of Public Policy, public policy, University of Chi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Academy Of Natural Sciences
The Academy of Natural Sciences of Drexel University, formerly the Academy of Natural Sciences of Philadelphia, is the oldest natural science research institution and museum in the Americas. It was founded in 1812, by many of the leading naturalists of the young American republic with an expressed mission of "the encouragement and cultivation of the sciences". It has sponsored expeditions, conducted original environmental and systematics research, and amassed natural history collections containing more than 17 million specimens. The Academy also organizes public exhibits and educational programs for both schools and the general public. History During the first decades of the United States, Philadelphia was the cultural capital and one of the country's commercial centers. Two of the city's institutions, the Library Company and the American Philosophical Society, were centers of enlightened thought and scientific inquiry. The increasing sophistication of the earth and life sci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nunavut
Nunavut is the largest and northernmost Provinces and territories of Canada#Territories, territory of Canada. It was separated officially from the Northwest Territories on April 1, 1999, via the ''Nunavut Act'' and the Nunavut Land Claims Agreement, ''Nunavut Land Claims Agreement Act'', which provided this territory to the Inuit for self-government. The boundaries had been drawn in 1993. The creation of Nunavut resulted in the territorial evolution of Canada, first major change to Canada's political map in half a century since the province of Newfoundland and Labrador, Newfoundland (now Newfoundland and Labrador) was admitted in 1949. Nunavut comprises a major portion of Northern Canada and most of the Arctic Archipelago. Its vast territory makes it the list of the largest country subdivisions by area, fifth-largest country subdivision in the world, as well as North America's second-largest (after Greenland). The capital Iqaluit (formerly "Frobisher Bay"), on Baffin Island in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ellesmere Island
Ellesmere Island (; ) is Canada's northernmost and List of Canadian islands by area, third largest island, and the List of islands by area, tenth largest in the world. It comprises an area of , slightly smaller than Great Britain, and the total length of the island is . Lying within the Arctic Archipelago, Ellesmere Island is considered part of the Queen Elizabeth Islands. Cape Columbia at is the most northerly point of land in Canada and one of the most northern points of land on the planet (the most northerly point of land on Earth is the nearby Kaffeklubben Island of Greenland). The Arctic Cordillera mountain system covers much of Ellesmere Island, making it the most mountainous in the Arctic Archipelago. More than one-fifth of the island is protected as Quttinirpaaq National Park. In 2021, the population of Ellesmere Island was recorded at 144. There are three settlements: Alert, Nunavut, Alert, Eureka, Nunavut, Eureka, and Grise Fiord. Ellesmere Island is administered as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
