The Pliocene Epoch is the epoch in the geologic timescale that extends from 5.333 million to 2.58 million years BP. It is the youngest epoch of the Neogene Period in the Cenozoic Era; the Pliocene is followed by the Pleistocene Epoch. Prior to the 2009 revision of the geologic time scale, which placed the four most recent major glaciations within the Pleistocene, the Pliocene included the Gelasian stage, which lasted from 2.588 to 1.806 million years ago, is now included in the Pleistocene. As with other older geologic periods, the geological strata that define the start and end are well identified but the exact dates of the start and end of the epoch are uncertain; the boundaries defining the Pliocene are not set at an identified worldwide event but rather at regional boundaries between the warmer Miocene and the cooler Pliocene. The upper boundary was set at the start of the Pleistocene glaciations. Charles Lyell gave the Pliocene its name in Principles of Geology; the word pliocene comes from the Greek words πλεῖον and καινός and means "continuation of the recent", referring to the modern marine mollusc fauna.
H. W. Fowler called the term Pliocene a "regrettable barbarism" and an indication that "a good classical scholar" such as Lyell should have requested a philologist's help when coining words. To summarize the usage of these "regrettable barbarisms" in the labelling of the Cenozoic era: with the understanding that these are all new relative to the Mesozoic and Paleozoic eras. In the official timescale of the ICS, the Pliocene is subdivided into two stages. From youngest to oldest they are: Piacenzian Zanclean The Piacenzian is sometimes referred to as the Late Pliocene, whereas the Zanclean is referred to as the Early Pliocene. In the system of North American Land Mammal Ages include Hemphillian, Blancan; the Blancan extends forward into the Pleistocene. South American Land Mammal Ages include Montehermosan and Uquian. In the Paratethys area the Pliocene contains the Romanian stages; as usual in stratigraphy, there are many other local subdivisions in use. In Britain the Pliocene is divided into the following stages: Gedgravian, Pre-Ludhamian, Thurnian, Bramertonian or Antian, Pre-Pastonian or Baventian and Beestonian.
In the Netherlands the Pliocene is divided into these stages: Brunssumian C, Reuverian A, Reuverian B, Reuverian C, Tiglian A, Tiglian B, Tiglian C1-4b, Tiglian C4c, Tiglian C5, Tiglian C6 and Eburonian. The exact correlations between these local stages and the ICS stages is still a matter of detail; the global average temperature in the mid-Pliocene was 2–3 °C higher than today, carbon dioxide levels were the same as today, global sea level was 25 m higher. The northern hemisphere ice sheet was ephemeral before the onset of extensive glaciation over Greenland that occurred in the late Pliocene around 3 Ma; the formation of an Arctic ice cap is signaled by an abrupt shift in oxygen isotope ratios and ice-rafted cobbles in the North Atlantic and North Pacific ocean beds. Mid-latitude glaciation was underway before the end of the epoch; the global cooling that occurred during the Pliocene may have spurred on the disappearance of forests and the spread of grasslands and savannas. Continents continued to drift, moving from positions as far as 250 km from their present locations to positions only 70 km from their current locations.
South America became linked to North America through the Isthmus of Panama during the Pliocene, making possible the Great American Interchange and bringing a nearly complete end to South America's distinctive large marsupial predator and native ungulate faunas. The formation of the Isthmus had major consequences on global temperatures, since warm equatorial ocean currents were cut off and an Atlantic cooling cycle began, with cold Arctic and Antarctic waters dropping temperatures in the now-isolated Atlantic Ocean. Africa's collision with Europe formed the Mediterranean Sea, cutting off the remnants of the Tethys Ocean; the border between the Miocene and the Pliocene is the time of the Messinian salinity crisis. Sea level changes exposed the land bridge between Asia. Pliocene marine rocks are well exposed in the Mediterranean and China. Elsewhere, they are exposed near shores. During the Pliocene parts of southern Norway and southern Sweden, near sea level rose. In Norway this rise elevated the Hardangervidda plateau to 1200 m in the Early Pliocene.
In Southern Sweden similar movements elevated the South Swedish highlands leading to a deflection of the ancient Eridanos river from its original path across south-central Sweden into a course south of Sweden. The change to a cooler, seasonal climate had considerable impacts on Pliocene vegetation, reducing tropical species worldwide. Deciduous forests proliferated, coniferous forests and tundra covered much of the north, grasslands spread on all continents. Tropical forests were limited to a tight band around the equator, in addition to dry savannahs, deserts appeared in Asia and Africa. Both marine and co
The Yangtze or Yangzi, 6,300 km long, is the longest river in Asia and the third-longest in the world. The river is the longest in the world to flow within one country, it drains one-fifth of the land area of China, its river basin is home to nearly one-third of the country's population. The Yangtze is the sixth-largest river by discharge volume in the world; the English name Yangtze derives from the Chinese name Yángzǐ Jiāng, which refers to the lowest 435 km of the river between Nanjing and Shanghai. The whole river is known in China as Cháng Jiāng. In more recent modern texts, it is spelled as the Yangzi, in align with its modern pinyin; the Yangtze plays a large role in the history and economy of China. The prosperous Yangtze River Delta generates as much as 20% of the PRC's GDP; the Yangtze River flows through a wide array of ecosystems and is habitat to several endemic and endangered species including the Chinese alligator, the narrow-ridged finless porpoise, the Chinese paddlefish, the Yangtze River dolphin or baiji, the Yangtze sturgeon.
For thousands of years, the river has been used for water, sanitation, industry, boundary-marking and war. The Three Gorges Dam on the Yangtze River is the largest hydro-electric power station in the world. In recent years, the river has suffered from industrial pollution, plastic pollution, agricultural run-off and loss of wetland and lakes, which exacerbates seasonal flooding; some sections of the river are now protected as nature reserves. A stretch of the upstream Yangtze flowing through deep gorges in western Yunnan is part of the Three Parallel Rivers of Yunnan Protected Areas, a UNESCO World Heritage Site. In mid-2014, the Chinese government announced it was building a multi-tier transport network, comprising railways and airports, to create a new economic belt alongside the river; because the source of the Yangtze was not ascertained until modern times, the Chinese have given different names to lower and upstream sections of the river."Yangtze" was the name of Chang Jiang for the lower part from Nanjing to the river mouth at Shanghai.
However, due to the fact that Christian missionaries carried out their activities in this area and were familiar with the name of this part of Chang Jiang, "Yangtze river" was used to refer to the whole Chang Jiang in the English language. In modern Chinese, Yangtze is still used to refer to the lower part of Chang Jiang from Nanjing to the river mouth. Yangtze never stands for the whole Chang Jiang. Chang Jiang is the modern Chinese name for the lower 2,884 km of the Yangtze from its confluence with the Min River at Yibin in Sichuan province to the river mouth at Shanghai. Chang Jiang means the "Long River." In Old Chinese, this stretch of the Yangtze was called Jiang/Kiang 江, a character of phono-semantic compound origin, combining the water radical 氵 with the homophone 工. Krong was a word in the Austroasiatic language of local peoples such as the Yue. Similar to *krong in Proto-Vietnamese and krung in Mon, all meaning "river", it is related to modern Vietnamese sông and Khmer kôngkea. By the Han dynasty, Jiang had come to mean any river in Chinese, this river was distinguished as the "Great River" 大江.
The epithet 長, means "long", was first formally applied to the river during the Six Dynasties period. Various sections of Chang Jiang have local names. From Yibin to Yichang, the river through Sichuan and Chongqing Municipality is known as the Chuan Jiang or "Sichuan River." In Hubei Province, the river is called the Jing Jiang or the "Jing River" after Jingzhou. In Anhui Province, the river takes on the local name Wan Jiang after the shorthand name for Anhui, wǎn, and Yangzi Jiang or the "Yangzi River", from which the English name Yangtze is derived, is the local name for the Lower Yangtze in the region of Yangzhou. The name comes from an ancient ferry crossing called Yangzi or Yangzijin. Europeans who arrived in the Yangtze River Delta region applied this local name to the Å river; the dividing site between upstream and midstream is considered to be at Yichang and that between midstream and downstream at Hukou. The Jinsha River is the name for 2,308 km of the Yangtze from Yibin upstream to the confluence with the Batang River near Yushu in Qinghai Province.
From antiquity until the Ming Dynasty, this stretch of the river was believed to be a tributary of the Yangtze while the Min River was thought to be the main course of the river above Yibin. In the Yu Gong, written in the fifth century BCE, this section is called the Hei Shui 黑水 or the "Black Water." The name "Jinsha" originates in the Song dynasty when the river attracted large numbers of gold prospectors. Gold prospecting along the Jinsha continued to this day. Prior to the Song dynasty, other names were used including, for example Lújiāng from the Three Kingdoms period; the Tongtian River describes the 813 km section from Yushu up to the confluence with the Dangqu River. The name comes from a fabled river in the Journey to the West. In antiquity, it was called the Yak River. In Mongolian, this section is known as the Murui-ussu. and sometimes confused with the nearby Baishui. The Tuotuo River is the official headstream of the Yangtze, a
The Triassic is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.9 million years ago, to the beginning of the Jurassic Period 201.3 Mya. The Triassic is the shortest period of the Mesozoic Era. Both the start and end of the period are marked by major extinction events. Triassic began in the wake of the Permian–Triassic extinction event, which left the Earth's biosphere impoverished. Therapsids and archosaurs were the chief terrestrial vertebrates during this time. A specialized subgroup of archosaurs, called dinosaurs, first appeared in the Late Triassic but did not become dominant until the succeeding Jurassic Period; the first true mammals, themselves a specialized subgroup of therapsids evolved during this period, as well as the first flying vertebrates, the pterosaurs, like the dinosaurs, were a specialized subgroup of archosaurs. The vast supercontinent of Pangaea existed until the mid-Triassic, after which it began to rift into two separate landmasses, Laurasia to the north and Gondwana to the south.
The global climate during the Triassic was hot and dry, with deserts spanning much of Pangaea's interior. However, the climate became more humid as Pangaea began to drift apart; the end of the period was marked by yet another major mass extinction, the Triassic–Jurassic extinction event, that wiped out many groups and allowed dinosaurs to assume dominance in the Jurassic. The Triassic was named in 1834 by Friedrich von Alberti, after the three distinct rock layers that are found throughout Germany and northwestern Europe—red beds, capped by marine limestone, followed by a series of terrestrial mud- and sandstones—called the "Trias"; the Triassic is separated into Early and Late Triassic Epochs, the corresponding rocks are referred to as Lower, Middle, or Upper Triassic. The faunal stages from the youngest to oldest are: During the Triassic all the Earth's land mass was concentrated into a single supercontinent centered more or less on the equator and spanning from pole to pole, called Pangaea.
From the east, along the equator, the Tethys sea penetrated Pangaea, causing the Paleo-Tethys Ocean to be closed. In the mid-Triassic a similar sea penetrated along the equator from the west; the remaining shores were surrounded by the world-ocean known as Panthalassa. All the deep-ocean sediments laid down during the Triassic have disappeared through subduction of oceanic plates; the supercontinent Pangaea was rifting during the Triassic—especially late in that period—but had not yet separated. The first nonmarine sediments in the rift that marks the initial break-up of Pangaea, which separated New Jersey from Morocco, are of Late Triassic age. S. these thick sediments comprise the Newark Group. Because a super-continental mass has less shoreline compared to one broken up, Triassic marine deposits are globally rare, despite their prominence in Western Europe, where the Triassic was first studied. In North America, for example, marine deposits are limited to a few exposures in the west, thus Triassic stratigraphy is based on organisms that lived in lagoons and hypersaline environments, such as Estheria crustaceans.
At the beginning of the Mesozoic Era, Africa was joined with Earth's other continents in Pangaea. Africa shared the supercontinent's uniform fauna, dominated by theropods and primitive ornithischians by the close of the Triassic period. Late Triassic fossils are more common in the south than north; the time boundary separating the Permian and Triassic marks the advent of an extinction event with global impact, although African strata from this time period have not been studied. During the Triassic peneplains are thought to have formed in what is now southern Sweden. Remnants of this peneplain can be traced as a tilted summit accordance in the Swedish West Coast. In northern Norway Triassic peneplains may have been buried in sediments to be re-exposed as coastal plains called strandflats. Dating of illite clay from a strandflat of Bømlo, southern Norway, have shown that landscape there became weathered in Late Triassic times with the landscape also being shaped during that time. At Paleorrota geopark, located in Rio Grande do Sul, the Santa Maria Formation and Caturrita Formations are exposed.
In these formations, one of the earliest dinosaurs, Staurikosaurus, as well as the mammal ancestors Brasilitherium and Brasilodon have been discovered. The Triassic continental interior climate was hot and dry, so that typical deposits are red bed sandstones and evaporites. There is no evidence of glaciation near either pole. Pangaea's large size limited the moderating effect of the global ocean; the strong contrast between the Pangea supercontinent and the global ocean triggered intense cross-equatorial monsoons. The Triassic may have been a dry period, but evidence exists that it was punctuated by several episodes of increased rainfall in tropical and subtropical latitudes of the Tethys Sea and its surrounding land. Sediments and fossils suggestive of a more humid climate are known from the Anisian to Ladinian of the Tethysian domain, from the Carnian and Rhaetian of a larger area that includes the Boreal domain, the North
The Cretaceous is a geologic period and system that spans 79 million years from the end of the Jurassic Period 145 million years ago to the beginning of the Paleogene Period 66 mya. It is the last period of the Mesozoic Era, the longest period of the Phanerozoic Eon; the Cretaceous Period is abbreviated K, for its German translation Kreide. The Cretaceous was a period with a warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas; these oceans and seas were populated with now-extinct marine reptiles and rudists, while dinosaurs continued to dominate on land. During this time, new groups of mammals and birds, as well as flowering plants, appeared; the Cretaceous ended with the Cretaceous–Paleogene extinction event, a large mass extinction in which many groups, including non-avian dinosaurs and large marine reptiles died out. The end of the Cretaceous is defined by the abrupt Cretaceous–Paleogene boundary, a geologic signature associated with the mass extinction which lies between the Mesozoic and Cenozoic eras.
The Cretaceous as a separate period was first defined by Belgian geologist Jean d'Omalius d'Halloy in 1822, using strata in the Paris Basin and named for the extensive beds of chalk, found in the upper Cretaceous of Western Europe. The name Cretaceous was derived from Latin creta; the Cretaceous is divided into Early and Late Cretaceous epochs, or Lower and Upper Cretaceous series. In older literature the Cretaceous is sometimes divided into three series: Neocomian and Senonian. A subdivision in eleven stages, all originating from European stratigraphy, is now used worldwide. In many parts of the world, alternative local subdivisions are still in use; as with other older geologic periods, the rock beds of the Cretaceous are well identified but the exact age of the system's base is uncertain by a few million years. No great extinction or burst of diversity separates the Cretaceous from the Jurassic. However, the top of the system is defined, being placed at an iridium-rich layer found worldwide, believed to be associated with the Chicxulub impact crater, with its boundaries circumscribing parts of the Yucatán Peninsula and into the Gulf of Mexico.
This layer has been dated at 66.043 Ma. A 140 Ma age for the Jurassic-Cretaceous boundary instead of the accepted 145 Ma was proposed in 2014 based on a stratigraphic study of Vaca Muerta Formation in Neuquén Basin, Argentina. Víctor Ramos, one of the authors of the study proposing the 140 Ma boundary age sees the study as a "first step" toward formally changing the age in the International Union of Geological Sciences. From youngest to oldest, the subdivisions of the Cretaceous period are: Late Cretaceous Maastrichtian – Campanian – Santonian – Coniacian – Turonian – Cenomanian – Early Cretaceous Albian – Aptian – Barremian – Hauterivian – Valanginian – Berriasian – The high sea level and warm climate of the Cretaceous meant large areas of the continents were covered by warm, shallow seas, providing habitat for many marine organisms; the Cretaceous was named for the extensive chalk deposits of this age in Europe, but in many parts of the world, the deposits from the Cretaceous are of marine limestone, a rock type, formed under warm, shallow marine circumstances.
Due to the high sea level, there was extensive space for such sedimentation. Because of the young age and great thickness of the system, Cretaceous rocks are evident in many areas worldwide. Chalk is a rock type characteristic for the Cretaceous, it consists of coccoliths, microscopically small calcite skeletons of coccolithophores, a type of algae that prospered in the Cretaceous seas. In northwestern Europe, chalk deposits from the Upper Cretaceous are characteristic for the Chalk Group, which forms the white cliffs of Dover on the south coast of England and similar cliffs on the French Normandian coast; the group is found in England, northern France, the low countries, northern Germany, Denmark and in the subsurface of the southern part of the North Sea. Chalk is not consolidated and the Chalk Group still consists of loose sediments in many places; the group has other limestones and arenites. Among the fossils it contains are sea urchins, belemnites and sea reptiles such as Mosasaurus. In southern Europe, the Cretaceous is a marine system consisting of competent limestone beds or incompetent marls.
Because the Alpine mountain chains did not yet exist in the Cretaceous, these deposits formed on the southern edge of the European continental shelf, at the margin of the Tethys Ocean. Stagnation of deep sea currents in middle Cretaceous times caused anoxic conditions in the sea water leaving the deposited organic matter undecomposed. Half the worlds petroleum reserves were laid down at this time in the anoxic conditions of what would become the Persian Gulf and the Gulf of Mexico. In many places around the world, dark anoxic shales were formed during this interval; these shales are an important source rock for oil and gas, for example in the subsurface of the North Sea. During th
A caiman is an crocodilian alligatorid belonging to the subfamily Caimaninae, one of two primary lineages within Alligatoridae, the other being alligators. Caimans inhabit South America from marshes and swamps to mangrove rivers and lakes. Caimans have scaly skin, live a nocturnal existence, they are small-sized crocodilians, with an average maximum weight of 6 to 40 kg depending on species, with the exception of the black caiman, which can grow more than 5 m in length and weigh up to 1,100 kg. The black caiman is the largest caiman species in the world and is found in the slow-moving rivers and lakes that surround the Amazon basin; the smallest species is the Cuvier's dwarf caiman. There are six different species of caiman found throughout the watery, jungle habitats of Central and Southern America; the average length for most of the other caiman species is about 2 to 2.5 m long. Caimans are distinguished from alligators, their closest relatives, by a few defining features: a lack of a bony septum between the nostrils, ventral armour composed of overlapping bony scutes formed from two parts united by a suture, longer, more slender, teeth than those possessed by alligators.
The calcium rivets on its scales make their hides stiffer, thus less valuable, than those of alligators and crocodiles, both of which have a similar appearance but are more pliable. Several extinct forms are known, including Purussaurus, a giant Miocene genus that grew to 12 m and the large Mourasuchus, which had a wide duck-like snout; the caimans are predators and, like the alligators and the crocodiles, their diet consists of a great deal of fish. The caimans hunt insects and small mammals and reptiles. Due to the large size and ferocious nature of the caimans, they have few natural predators within their environments. Humans are the main predators of the caimans as they have been hunted for their skin. Jaguars and anacondas are the only other predators of the caimans but they prey only on the smaller specimens. During summer or droughts, the caiman may dig a burrow and go into a form of summer hibernation called aestivation. Female caimans build a large nest in which to lay their eggs, which can be more than 1.5 metres wide.
Female caimans lay between 50 eggs which hatch within about 6 weeks. Once they have hatched, the mother caiman takes her young to a shallow pool of water where they can learn how to hunt and swim. Subfamily Caimaninae Genus †Acresuchus Genus †Centenariosuchus Genus †Protocaiman Genus †Kuttanacaiman Genus †Gnatusuchus Genus †Culebrasuchus Genus †Eocaiman Genus †Globidentosuchus Genus Paleosuchus P. palpebrosus, Cuvier's dwarf caiman P. trigonatus, smooth-fronted caiman Genus †Purussaurus Genus †Mourasuchus Genus †Necrosuchus Genus †Orthogenysuchus Genus †Tsoabichi Genus Caiman C. yacare, yacare caiman C. crocodilus, spectacled caiman C. c. crocodilus, spectacled caiman C. c. apaporiensis, Rio Apaporis caiman C. c. fuscus, brown caiman †C. lutescens †C. venezuelensis †C. wannlangstoni †C. brevirostris C. latirostris, broad-snouted caiman Genus Melanosuchus †M. fisheri M. niger, black caiman Below is a cladogram modified from Brochu. Below is a cladogram modified from Hastings et al
Mitochondrial DNA is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, adenosine triphosphate. Mitochondrial DNA is only a small portion of the DNA in a eukaryotic cell. In humans, the 16,569 base pairs of mitochondrial DNA encode for only 37 genes. Human mitochondrial DNA was the first significant part of the human genome to be sequenced. In most species, including humans, mtDNA is inherited from the mother. However, in exceptional cases, human babies sometimes inherit mtDNA from both their fathers and their mothers resulting in mtDNA heteroplasmy. Since animal mtDNA evolves faster than nuclear genetic markers, it represents a mainstay of phylogenetics and evolutionary biology, it permits an examination of the relatedness of populations, so has become important in anthropology and biogeography. Nuclear and mitochondrial DNA are thought to be of separate evolutionary origin, with the mtDNA being derived from the circular genomes of the bacteria that were engulfed by the early ancestors of today's eukaryotic cells.
This theory is called the endosymbiotic theory. Each mitochondrion is estimated to contain 2–10 mtDNA copies. In the cells of extant organisms, the vast majority of the proteins present in the mitochondria are coded for by nuclear DNA, but the genes for some, if not most, of them are thought to have been of bacterial origin, having since been transferred to the eukaryotic nucleus during evolution; the reasons why mitochondria have retained some genes are debated. The existence in some species of mitochondrion-derived organelles lacking a genome suggests that complete gene loss is possible, transferring mitochondrial genes to the nucleus has several advantages; the difficulty of targeting remotely-produced hydrophobic protein products to the mitochondrion is one hypothesis for why some genes are retained in mtDNA. Recent analysis of a wide range of mtDNA genomes suggests that both these features may dictate mitochondrial gene retention. In most multicellular organisms, mtDNA is inherited from the mother.
Mechanisms for this include simple dilution, degradation of sperm mtDNA in the male genital tract and in the fertilized egg. Whatever the mechanism, this single parent pattern of mtDNA inheritance is found in most animals, most plants and in fungi. In sexual reproduction, mitochondria are inherited from the mother. Most mitochondria are present at the base of the sperm's tail, used for propelling the sperm cells. In 1999 it was reported that paternal sperm mitochondria are marked with ubiquitin to select them for destruction inside the embryo; some in vitro fertilization techniques injecting a sperm into an oocyte, may interfere with this. The fact that mitochondrial DNA is maternally inherited enables genealogical researchers to trace maternal lineage far back in time; this is accomplished on human mitochondrial DNA by sequencing the hypervariable control regions, sometimes the complete molecule of the mitochondrial DNA, as a genealogical DNA test. HVR1, for example, consists of about 440 base pairs.
These 440 base pairs are compared to the same regions of other individuals to determine maternal lineage. Most the comparison is made with the revised Cambridge Reference Sequence. Vilà et al. have published studies tracing the matrilineal descent of domestic dogs from wolves. The concept of the Mitochondrial Eve is based on the same type of analysis, attempting to discover the origin of humanity by tracking the lineage back in time. MtDNA is conserved, its slow mutation rates make it useful for studying the evolutionary relationships—phylogeny—of organisms. Biologists can determine and compare mtDNA sequences among different species and use the comparisons to build an evolutionary tree for the species examined. However, due to the slow mutation rates, it is hard to distinguish between related species to any large degree, so other methods of analysis must be used. Entities subject to uniparental inheritance and with little to no recombination may be expected to be subject to Muller's ratchet, the accumulation of deleterious mutations until functionality is lost.
Animal populations of mitochondria avoid this through a developmental process known as the mtDNA bottleneck. The bottleneck exploits random processes in the cell to increase the cell-to-cell variability in mutant load as an organism develops: a single egg cell with some proportion of mutant mtDNA thus produces an embryo in which different cells have different mutant loads. Cell-level selection may act to remove those cells with more mutant mtDNA, leading to a stabilisation or reduction in mutant load between generations; the mechanism underlying the bottleneck is debated, with a recent mathematical and experimental
Alberta is a western province of Canada. With an estimated population of 4,067,175 as of 2016 census, it is Canada's fourth most populous province and the most populous of Canada's three prairie provinces, its area is about 660,000 square kilometres. Alberta and its neighbour Saskatchewan were districts of the Northwest Territories until they were established as provinces on September 1, 1905; the premier has been Rachel Notley since May 2015. Alberta is bounded by the provinces of British Columbia to the west and Saskatchewan to the east, the Northwest Territories to the north, the U. S. state of Montana to the south. Alberta is one of three Canadian provinces and territories to border only a single U. S. state and one of only two landlocked provinces. It has a predominantly humid continental climate, with stark contrasts over a year. Alberta's capital, Edmonton, is near the geographic centre of the province and is the primary supply and service hub for Canada's crude oil, the Athabasca oil sands and other northern resource industries.
About 290 km south of the capital is the largest city in Alberta. Calgary and Edmonton centre Alberta's two census metropolitan areas, both of which have populations exceeding one million, while the province has 16 census agglomerations. Tourist destinations in the province include Banff, Drumheller, Sylvan Lake and Lake Louise. Alberta is named after the fourth daughter of Queen Victoria. Princess Louise was the wife of Marquess of Lorne, Governor General of Canada. Lake Louise and Mount Alberta were named in her honour. Alberta, with an area of 661,848 km2, is the fourth-largest province after Quebec and British Columbia. To the south, the province borders on the 49th parallel north, separating it from the U. S. state of Montana, while to the north the 60th parallel north divides it from the Northwest Territories. To the east, the 110th meridian west separates it from the province of Saskatchewan, while on the west its boundary with British Columbia follows the 120th meridian west south from the Northwest Territories at 60°N until it reaches the Continental Divide at the Rocky Mountains, from that point follows the line of peaks marking the Continental Divide in a southeasterly direction until it reaches the Montana border at 49°N.
The province extends 660 km east to west at its maximum width. Its highest point is 3,747 m at the summit of Mount Columbia in the Rocky Mountains along the southwest border while its lowest point is 152 m on the Slave River in Wood Buffalo National Park in the northeast. With the exception of the semi-arid steppe of the south-eastern section, the province has adequate water resources. There are numerous lakes used for swimming, fishing and a range of water sports. There are three large lakes, Lake Claire in Wood Buffalo National Park, Lesser Slave Lake, Lake Athabasca which lies in both Alberta and Saskatchewan; the longest river in the province is the Athabasca River which travels 1,538 km from the Columbia Icefield in the Rocky Mountains to Lake Athabasca. The largest river is the Peace River with an average flow of 2161 m3/s; the Peace River originates in the Rocky Mountains of northern British Columbia and flows through northern Alberta and into the Slave River, a tributary of the Mackenzie River.
Alberta's capital city, Edmonton, is located at about the geographic centre of the province. It is the most northerly major city in Canada, serves as a gateway and hub for resource development in northern Canada; the region, with its proximity to Canada's largest oil fields, has most of western Canada's oil refinery capacity. Calgary is about 280 km south of Edmonton and 240 km north of Montana, surrounded by extensive ranching country. 75% of the province's population lives in the Calgary–Edmonton Corridor. The land grant policy to the railroads served as a means to populate the province in its early years. Most of the northern half of the province is boreal forest, while the Rocky Mountains along the southwestern boundary are forested; the southern quarter of the province is prairie, ranging from shortgrass prairie in the southeastern corner to mixed grass prairie in an arc to the west and north of it. The central aspen parkland region extending in a broad arc between the prairies and the forests, from Calgary, north to Edmonton, east to Lloydminster, contains the most fertile soil in the province and most of the population.
Much of the unforested part of Alberta is given over either to grain or to dairy farming, with mixed farming more common in the north and centre, while ranching and irrigated agriculture predominate in the south. The Alberta badlands are located in southeastern Alberta, where the Red Deer River crosses the flat prairie and farmland, features deep canyons and striking landforms. Dinosaur Provincial Park, near Brooks, showcases the badlands terrain, desert flora, remnants from Alberta's past when dinosaurs roamed the lush landscape. Alberta has a humid continental climate with cold winters; the province is open to cold arctic weather systems from the north, which produce cold conditions in winter. As the fronts between the air masses shift north and south across Alberta, the temperature can change rapidly. Arctic