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132-707: Most scientists believe that this climatic oscillation caused the major extinction event that took place during this time. In fact, the Hirnantian (also known as the End Ordovician and the Ordovician-Silurian ) mass extinction event represents the second largest such event in geologic history . Approximately 85% of marine (sea-dwelling) species died. Only the End-Permian mass extinction was larger. Unlike many smaller extinction events, however,

264-539: A mass extinction or biotic crisis ) is a widespread and rapid decrease in the biodiversity on Earth . Such an event is identified by a sharp fall in the diversity and abundance of multicellular organisms . It occurs when the rate of extinction increases with respect to the background extinction rate and the rate of speciation . Estimates of the number of major mass extinctions in the last 540 million years range from as few as five to more than twenty. These differences stem from disagreement as to what constitutes

396-531: A paraphyletic group) by therapsids occurred around the Kungurian / Roadian transition, which is often called Olson's extinction (which may be a slow decline over 20 Ma rather than a dramatic, brief event). Another point of view put forward in the Escalation hypothesis predicts that species in ecological niches with more organism-to-organism conflict will be less likely to survive extinctions. This

528-678: A per-capita basis, Norway is the world's largest producer of oil and natural gas outside of the Middle East. The country has the fourth- and eighth-highest per-capita income in the world on the World Bank 's and IMF 's list, respectively. It has the world's largest sovereign wealth fund , with a value of US$ 1.3 trillion. Norway has two official names: Norge in Bokmål and Noreg in Nynorsk . The English name Norway comes from

660-590: A resistance movement which incorporated civil disobedience and armed resistance including the destruction of Norsk Hydro 's heavy water plant and stockpile of heavy water at Vemork , which crippled the German nuclear programme . More important to the Allied war effort, however, was the role of the Norwegian Merchant Marine , the fourth-largest merchant marine fleet in the world. It was led by

792-407: A unitary state with a constitutional monarchy , Norway divides state power between the parliament , the cabinet , and the supreme court , as determined by the 1814 constitution . Norway has both administrative and political subdivisions on two levels: counties and municipalities . The Sámi people have a certain amount of self-determination and influence over traditional territories through

924-401: A "collection" (such as a time interval) to assess the relative diversity of that collection. Every time a new species (or other taxon ) enters the sample, it brings over all other fossils belonging to that species in the collection (its " share " of the collection). For example, a skewed collection with half its fossils from one species will immediately reach a sample share of 50% if that species

1056-472: A "major" extinction event, and the data chosen to measure past diversity. In a landmark paper published in 1982, Jack Sepkoski and David M. Raup identified five particular geological intervals with excessive diversity loss. They were originally identified as outliers on a general trend of decreasing extinction rates during the Phanerozoic , but as more stringent statistical tests have been applied to

1188-425: A Phanerozoic phenomenon, with merely the observable extinction rates appearing low before large complex organisms with hard body parts arose. Extinction occurs at an uneven rate. Based on the fossil record , the background rate of extinctions on Earth is about two to five taxonomic families of marine animals every million years. The Oxygen Catastrophe, which occurred around 2.45 billion years ago in

1320-664: A backdrop of decreasing extinction rates through time. Four of these peaks were statistically significant: the Ashgillian ( end-Ordovician ), Late Permian , Norian ( end-Triassic ), and Maastrichtian (end-Cretaceous). The remaining peak was a broad interval of high extinction smeared over the later half of the Devonian , with its apex in the Frasnian stage. Through the 1980s, Raup and Sepkoski continued to elaborate and build upon their extinction and origination data, defining

1452-618: A carefully specified global beginning and ending. However, it started out in the nineteenth century as a regional stage in the United Kingdom, where it remains as such today. Since various regions of the world have their own local divisions of geologic time below the Period level, the following list provides correlations between those regional stages (or epochs in some cases) and the internationally recognized Hirnantian Stage. Extinction event An extinction event (also known as

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1584-521: A central role in the peaceful separation of Norway from Sweden on 7 June 1905. A national referendum confirmed the people's preference for a monarchy over a republic. However, no Norwegian could legitimately claim the throne, since none of Norway's noble families could claim royal descent . The government then offered the throne of Norway to Prince Carl of Denmark, a prince of the Dano-German royal house of Schleswig-Holstein-Sonderburg-Glücksburg and

1716-458: A conservative society. Life in Norway (especially economic life) was "dominated by the aristocracy of professional men who filled most of the important posts in the central government". There was no strong bourgeois class to demand a breakdown of this aristocratic control. Thus, even while revolution swept over most of the countries of Europe in 1848, Norway was largely unaffected. Marcus Thrane

1848-409: A considerable period of time after a mass extinction, and which were reduced to only a few species, are likely to have experienced a rebound effect called the " push of the past ". Darwin was firmly of the opinion that biotic interactions, such as competition for food and space – the 'struggle for existence' – were of considerably greater importance in promoting evolution and extinction than changes in

1980-665: A distant relative of Norway's medieval kings. Following the plebiscite, he was unanimously elected king by the Norwegian Parliament ; he took the name Haakon VII . Throughout the First World War , Norway remained neutral; however, diplomatic pressure from the British government meant that it heavily favoured the Allies . During the war, Norway exported fish to both Germany and Britain, until an ultimatum from

2112-457: A distinct national character. The movement covered all branches of culture, including literature ( Henrik Wergeland , Bjørnstjerne Bjørnson , Peter Christen Asbjørnsen , Jørgen Moe ), painting ( Hans Gude , Adolph Tidemand ), music ( Edvard Grieg ), and even language policy, where attempts to define a native written language for Norway led to today's two official written forms for Norwegian: Bokmål and Nynorsk . King Charles III John came to

2244-424: A high-resolution biodiversity curve (the "Sepkoski curve") and successive evolutionary faunas with their own patterns of diversification and extinction. Though these interpretations formed a strong basis for subsequent studies of mass extinctions, Raup and Sepkoski also proposed a more controversial idea in 1984: a 26-million-year periodic pattern to mass extinctions. Two teams of astronomers linked this to

2376-425: A hypothetical brown dwarf in the distant reaches of the solar system, inventing the " Nemesis hypothesis " which has been strongly disputed by other astronomers. Around the same time, Sepkoski began to devise a compendium of marine animal genera , which would allow researchers to explore extinction at a finer taxonomic resolution. He began to publish preliminary results of this in-progress study as early as 1986, in

2508-470: A lack of consensus on Late Triassic chronology For much of the 20th century, the study of mass extinctions was hampered by insufficient data. Mass extinctions, though acknowledged, were considered mysterious exceptions to the prevailing gradualistic view of prehistory, where slow evolutionary trends define faunal changes. The first breakthrough was published in 1980 by a team led by Luis Alvarez , who discovered trace metal evidence for an asteroid impact at

2640-664: A long, narrow sea, was Baltica . Composed of modern Norway , Sweden , Finland , Denmark , northeastern Germany and Russia west of the Ural Mountains , this area ranged from the equator in the north to more than 30 degrees south latitude. Stretching westward from its southwest tip was an island arc known as Avalonia by modern scientists. This consisted of what is now the southern parts of Britain and Ireland , and eastern coastal regions of Newfoundland , Nova Scotia , New Brunswick , and New England . The Hirnantian now represents an internationally accepted stage with

2772-440: A long-term stress is compounded by a short-term shock. Over the course of the Phanerozoic , individual taxa appear to have become less likely to suffer extinction, which may reflect more robust food webs, as well as fewer extinction-prone species, and other factors such as continental distribution. However, even after accounting for sampling bias, there does appear to be a gradual decrease in extinction and origination rates during

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2904-399: A new wave of studies into the dynamics of mass extinctions. These papers utilized the compendium to track origination rates (the rate that new species appear or speciate ) parallel to extinction rates in the context of geological stages or substages. A review and re-analysis of Sepkoski's data by Bambach (2006) identified 18 distinct mass extinction intervals, including 4 large extinctions in

3036-813: A paper which identified 29 extinction intervals of note. By 1992, he also updated his 1982 family compendium, finding minimal changes to the diversity curve despite a decade of new data. In 1996, Sepkoski published another paper which tracked marine genera extinction (in terms of net diversity loss) by stage, similar to his previous work on family extinctions. The paper filtered its sample in three ways: all genera (the entire unfiltered sample size), multiple-interval genera (only those found in more than one stage), and "well-preserved" genera (excluding those from groups with poor or understudied fossil records). Diversity trends in marine animal families were also revised based on his 1992 update. Revived interest in mass extinctions led many other authors to re-evaluate geological events in

3168-592: A result, they are likely to cause the climate to oscillate between cooling and warming, but with an overall trend towards warming as the carbon dioxide they emit can stay in the atmosphere for hundreds of years. Norway in Europe  (green and dark grey) Norway ( Bokmål : Norge , Nynorsk : Noreg ), officially the Kingdom of Norway , is a Nordic country in Northern Europe , situated on

3300-628: A separate event from the P–T extinction; if so, it would be larger than some of the "Big Five" extinction events.   The End Cretaceous extinction, or the K–Pg extinction (formerly K–T extinction) occurred at the Cretaceous ( Maastrichtian ) – Paleogene ( Danian ) transition. The event was formerly called the Cretaceous-Tertiary or K–T extinction or K–T boundary; it is now officially named

3432-634: A small group had left Norway following their king to Britain. This group included 13 ships, five aircraft, and 500 men from the Royal Norwegian Navy. By the end of the war, the force had grown to 58 ships and 7,500 men in service in the Royal Norwegian Navy, 5 squadrons of aircraft in the newly formed Norwegian Air Force, and land forces including the Norwegian Independent Company 1 and 5 Troop as well as No. 10 Commandos . During German occupation , Norwegians built

3564-508: A species' true extinction must occur after its last fossil, and that origination must occur before its first fossil. Thus, species which appear to die out just prior to an abrupt extinction event may instead be a victim of the event, despite an apparent gradual decline looking at the fossil record alone. A model by Foote (2007) found that many geological stages had artificially inflated extinction rates due to Signor-Lipps "backsmearing" from later stages with extinction events. Other biases include

3696-586: A time interval, and sampling time intervals in sequence, can together be combined into equations to predict extinction and origination with less bias. In subsequent papers, Alroy continued to refine his equations to improve lingering issues with precision and unusual samples. McGhee et al. (2013), a paper which primarily focused on ecological effects of mass extinctions, also published new estimates of extinction severity based on Alroy's methods. Many extinctions were significantly more impactful under these new estimates, though some were less prominent. Stanley (2016)

3828-686: A union between the two countries. In 1397, under Margaret I , the Kalmar Union was created between the three Scandinavian countries. She waged war against the Germans, resulting in a trade blockade and higher taxation on Norwegian goods, which led to a rebellion . However, the Norwegian Council of State was too weak to pull out of the union. Margaret pursued a centralising policy which inevitably favoured Denmark because of its greater population. Margaret also granted trade privileges to

3960-634: A united Norway. Harald's realm was mainly a South Norwegian coastal state. Fairhair ruled with a strong hand and according to the sagas, many Norwegians left the country to live in Iceland, the Faroe Islands , Greenland , and parts of Britain and Ireland. Haakon I the Good was Norway's first Christian king, in the mid-10th century, though his attempt to introduce the religion was rejected. Norse traditions were replaced slowly by Christian ones in

4092-677: Is Oslo . Norway has a total area of 385,207 square kilometres (148,729 sq mi). The country shares a long eastern border with Sweden , and is bordered by Finland and Russia to the northeast. Norway has an extensive coastline facing the Skagerrak strait, the North Atlantic Ocean, and the Barents Sea . The unified kingdom of Norway was established in 872 as a merger of petty kingdoms and has existed continuously for 1,151–1,152 years. From 1537 to 1814, Norway

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4224-401: Is also the largest known extinction event for insects . The highly successful marine arthropod, the trilobite , became extinct. The evidence regarding plants is less clear, but new taxa became dominant after the extinction. The "Great Dying" had enormous evolutionary significance: on land, it ended the primacy of early synapsids . The recovery of vertebrates took 30 million years, but

4356-447: Is because the very traits that keep a species numerous and viable under fairly static conditions become a burden once population levels fall among competing organisms during the dynamics of an extinction event. Furthermore, many groups that survive mass extinctions do not recover in numbers or diversity, and many of these go into long-term decline, and these are often referred to as " Dead Clades Walking ". However, clades that survive for

4488-478: Is defined as the first appearance datum of the graptolite species Normalograptus extraordinarius in that section. Secondary markers are Normalograptus ojsuensi 4 cm below the boundary, and the Hirnantia Fauna 39 cm above the boundary. As mentioned above, there was a major climatic oscillation during the Hirnantian, which is believed to have caused a major mass extinction event . When

4620-425: Is from the early Silurian Birkhill shale formations. Radiometric dating placed zircon samples found in another ash deposit at 438.7 mya, with a margin of error of plus or minus 2.1 million years. With these dates as a base, scientists were able to use biostratigraphic correlation techniques to determine close approximations for the timing of various events during the Hirnantian. There are two Graptolite biozones in

4752-454: Is little archaeological evidence dating to the early Iron Age (the last 500 years BC). The dead were cremated, and their graves contained few goods. During the first four centuries AD, the people of Norway were in contact with Roman-occupied Gaul ; about 70 Roman bronze cauldrons, often used as burial urns, have been found. Contact with countries farther south brought a knowledge of runes ; the oldest known Norwegian runic inscription dates from

4884-464: Is strong evidence supporting periodicity in a variety of records, and additional evidence in the form of coincident periodic variation in nonbiological geochemical variables such as Strontium isotopes, flood basalts, anoxic events, orogenies, and evaporite deposition. One explanation for this proposed cycle is carbon storage and release by oceanic crust, which exchanges carbon between the atmosphere and mantle. Mass extinctions are thought to result when

5016-451: Is the " Pull of the recent ", the fact that the fossil record (and thus known diversity) generally improves closer to the modern day. This means that biodiversity and abundance for older geological periods may be underestimated from raw data alone. Alroy (2010) attempted to circumvent sample size-related biases in diversity estimates using a method he called " shareholder quorum subsampling" (SQS). In this method, fossils are sampled from

5148-423: Is the first to be sampled. This continues, adding up the sample shares until a "coverage" or " quorum " is reached, referring to a pre-set desired sum of share percentages. At that point, the number of species in the sample are counted. A collection with more species is expected to reach a sample quorum with more species, thus accurately comparing the relative diversity change between two collections without relying on

5280-584: The Cambrian . These fit Sepkoski's definition of extinction, as short substages with large diversity loss and overall high extinction rates relative to their surroundings. Bambach et al. (2004) considered each of the "Big Five" extinction intervals to have a different pattern in the relationship between origination and extinction trends. Moreover, background extinction rates were broadly variable and could be separated into more severe and less severe time intervals. Background extinctions were least severe relative to

5412-520: The Cambrian explosion , five further major mass extinctions have significantly exceeded the background extinction rate. The most recent and best-known, the Cretaceous–Paleogene extinction event , which occurred approximately 66 Ma (million years ago), was a large-scale mass extinction of animal and plant species in a geologically short period of time. In addition to the five major Phanerozoic mass extinctions, there are numerous lesser ones, and

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5544-584: The German invasion of France . King Haakon and the Norwegian government escaped to Rotherhithe in London. Throughout the war they sent radio speeches and supported clandestine military actions against the Germans. On the day of the invasion, the leader of the small National-Socialist party Nasjonal Samling , Vidkun Quisling , tried to seize power, but was forced by the German occupiers to step aside. Real power

5676-485: The Labour Party held an absolute majority in the parliament. The government, led by prime minister Einar Gerhardsen , embarked on a programme inspired by Keynesian economics , emphasising state financed industrialisation and co-operation between trade unions and employers' organisations . Many measures of state control of the economy imposed during the war were continued, although the rationing of dairy products

5808-483: The Nordic welfare model with universal health care and a comprehensive social security system, and its values are rooted in egalitarian ideals. The Norwegian state has large ownership positions in key industrial sectors, having extensive reserves of petroleum, natural gas, minerals, lumber, seafood, and fresh water. The petroleum industry accounts for around a quarter of the country's gross domestic product (GDP). On

5940-593: The Old English word Norþweg mentioned in 880, meaning "northern way" or "way leading to the north", which is how the Anglo-Saxons referred to the coastline of Atlantic Norway. The Anglo-Saxons of Britain also referred to the kingdom of Norway in 880 as Norðmanna land . There is some disagreement about whether the native name of Norway originally had the same etymology as the English form. According to

6072-538: The Paleoproterozoic , is plausible as the first-ever major extinction event. It was perhaps also the worst-ever, in some sense, but with the Earth's ecology just before that time so poorly understood, and the concept of prokaryote genera so different from genera of complex life, that it would be difficult to meaningfully compare it to any of the "Big Five" even if Paleoproterozoic life were better known. Since

6204-667: The Scandinavian Peninsula with a population of 5.5 million as of 2024. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of Norway. Bouvet Island , located in the Subantarctic , is a dependency , and not a part of the Kingdom; Norway also claims the Antarctic territories of Peter I Island and Queen Maud Land . The capital and largest city in Norway

6336-532: The Syttende mai (Seventeenth of May) holiday. Norwegian opposition to the decision to link Norway with Sweden caused the Norwegian–Swedish War to break out as Sweden tried to subdue Norway by military means. As Sweden's military was not strong enough to defeat the Norwegian forces outright, and Norway's treasury was not large enough to support a protracted war, and as British and Russian navies blockaded

6468-1322: The Sámi Parliament and the Finnmark Act . Norway maintains close ties with the European Union and the United States . Norway is a founding member of the United Nations , NATO , the European Free Trade Association , the Council of Europe , the Antarctic Treaty , and the Nordic Council ; a member of the European Economic Area , the WTO , and the OECD ; and a part of the Schengen Area . The Norwegian dialects share mutual intelligibility with Danish and Swedish . Norway maintains

6600-649: The biosphere rather than the total diversity and abundance of life. For this reason, well-documented extinction events are confined to the Phanerozoic eon – with the sole exception of the Oxygen Catastrophe in the Proterozoic – since before the Phanerozoic, all living organisms were either microbial, or if multicellular then soft-bodied. Perhaps due to the absence of a robust microbial fossil record, mass extinctions might only seem to be mainly

6732-587: The introduction of Protestantism in 1536, the archbishopric in Trondheim was dissolved; Norway lost its independence and effectually became a colony of Denmark. The Church's incomes and possessions were instead redirected to the court in Copenhagen. Norway lost the steady stream of pilgrims to the relics of St. Olav at the Nidaros shrine, and with them, much of the contact with cultural and economic life in

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6864-474: The union with Sweden . Under this arrangement, Norway kept its liberal constitution and its own independent institutions, though it shared a monarch and foreign policy with Sweden. Following the recession caused by the Napoleonic Wars , economic development of Norway remained slow until 1830. This period also saw the rise of Norwegian romantic nationalism , as Norwegians sought to define and express

6996-602: The British government and anti-German sentiments as a result of German submarines targeting Norwegian merchantmen led to a termination of trade with Germany. 436 Norwegian merchantmen were sunk by the Kaiserliche Marine , with 1,150 Norwegian sailors killed. Norway once more proclaimed its neutrality during the Second World War , but was invaded by German forces on 9 April 1940. Although Norway

7128-480: The Cretaceous–Paleogene (or K–Pg) extinction event. About 17% of all families, 50% of all genera and 75% of all species became extinct. In the seas all the ammonites , plesiosaurs and mosasaurs disappeared and the percentage of sessile animals was reduced to about 33%. All non-avian dinosaurs became extinct during that time. The boundary event was severe with a significant amount of variability in

7260-693: The Danish kingdom was on the losing side in 1814, it was forced by the Treaty of Kiel to cede Norway to Sweden, while the old Norwegian provinces of Iceland, Greenland, and the Faroe Islands remained with the Danish crown. Norway took this opportunity to declare independence, adopted a constitution based on American and French models, and elected the Crown Prince of Denmark and Norway, Christian Frederick , as king on 17 May 1814 – celebrated as

7392-569: The Hanseatic merchants of Lübeck in Bergen in return for recognition of her rule, and these hurt the Norwegian economy. The Hanseatic merchants formed a state within a state in Bergen for generations. The " Victual Brothers " launched three devastating pirate raids on the port (the last in 1427). Norway slipped ever more to the background under the Oldenburg dynasty (established 1448). There

7524-469: The Hirnantian Stage began, the Earth's climate was hot and sea-levels were substantially higher than today. The seas were filled with a diverse fauna. However, there is considerable evidence to indicate that many of these species were already in trouble when the Hirnantian began, and that overall biological diversity was already in sharp decline. As the climate cooled and glaciers formed during

7656-496: The Hirnantian and these are of approximately equal length. The base (beginning) of the Hirnantian Stage is defined by the first appearance in the geologic record of the graptolite Normalograptus extraordinarius , and thus, the Normalograptus extraordinarius biozone defines the early (or lower) part of the Hirnantian. The later (or upper) part is defined by the first appearance of the graptolite Normalograptus persulptus , and

7788-530: The Hirnantian is the Wangjiawan section ( 30°59′03″N 111°25′11″E  /  30.9841°N 111.4197°E  / 30.9841; 111.4197 ) near the village Wangjiawan , 42 km north of Yichang ( Hubei , China ). It is an outcrop of the Wufeng and overlying Lungmachi Formation , the former containing the base of the Hirnantian. Both formations consist mainly of shale and chert . The base

7920-762: The Journal of the Geological Society of London, proposed a refinement to the Hirnantian Stage. This expanded the stage to include all of the Foel-y-Ddinas Mudstones, of which the Hirnant Limestone is a part. This expansion brought the Hirnantian Stage to its current scope. The International Commission on Stratigraphy (ICS) originally divided the Upper Ordovician into two stages. After considerable research, however, it

8052-532: The Late Devonian extinction interval ( Givetian , Frasnian, and Famennian stages) to be statistically significant. Regardless, later studies have affirmed the strong ecological impacts of the Kellwasser and Hangenberg Events.   The End Permian extinction or the "Great Dying" occurred at the Permian – Triassic transition. It was the Phanerozoic Eon's largest extinction: 53% of marine families died, 84% of marine genera, about 81% of all marine species and an estimated 70% of terrestrial vertebrate species. This

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8184-408: The Normalograptus persulptus biozone lasts from then until the end of the Hirnantian. This also marks the end of the Ordovician Period. These biozones allow for additional refinement in dating events occurring within the Hirnantian Stage. During the Hirnantian, much of the world's land mass was gathered into a supercontinent called Gondwana , which occupied extreme southern latitudes and covered

8316-416: The Norwegian coast, the belligerents were forced to negotiate the Convention of Moss . Christian Frederik abdicated the Norwegian throne and authorised the Parliament of Norway to make the necessary constitutional amendments to allow for the personal union that Norway was forced to accept. On 4 November 1814, the Parliament (Storting) elected Charles XIII of Sweden as king of Norway, thereby establishing

8448-445: The Norwegian shipping company Nortraship under the Allies throughout the war and took part in every war operation from the evacuation of Dunkirk to the Normandy landings . Every December Norway gives a Christmas tree to the United Kingdom as thanks for the British assistance during the war. Svalbard was not occupied by German troops, but Germany secretly established a meteorological station there in 1944. From 1945 to 1962,

8580-430: The Phanerozoic. This may represent the fact that groups with higher turnover rates are more likely to become extinct by chance; or it may be an artefact of taxonomy: families tend to become more speciose, therefore less prone to extinction, over time; and larger taxonomic groups (by definition) appear earlier in geological time. It has also been suggested that the oceans have gradually become more hospitable to life over

8712-411: The South pole. The rest of North America (called Laurentia by scientists) lay to the north and west of Gondwana, with relatively warmer climates. Rotated almost 45 degrees from their modern orientation, the eastern states of today's U.S. were located along the southeast coast of the continent, while the coastal areas of what are now the southeastern states faced south. To the east of Laurentia, across

8844-463: The Sun, oscillations in the galactic plane, or passage through the Milky Way's spiral arms. However, other authors have concluded that the data on marine mass extinctions do not fit with the idea that mass extinctions are periodic, or that ecosystems gradually build up to a point at which a mass extinction is inevitable. Many of the proposed correlations have been argued to be spurious or lacking statistical significance. Others have argued that there

8976-415: The accumulating data, it has been established that in the current, Phanerozoic Eon, multicellular animal life has experienced at least five major and many minor mass extinctions. The "Big Five" cannot be so clearly defined, but rather appear to represent the largest (or some of the largest) of a relatively smooth continuum of extinction events. All of the five in the Phanerozoic Eon were anciently preceded by

9108-400: The biases inherent to sample size. Alroy also elaborated on three-timer algorithms, which are meant to counteract biases in estimates of extinction and origination rates. A given taxon is a "three-timer" if it can be found before, after, and within a given time interval, and a "two-timer" if it overlaps with a time interval on one side. Counting "three-timers" and "two-timers" on either end of

9240-536: The coast, where the huge ice shelf of the last ice age first melted between 11,000 and 8000 BC. The oldest finds are stone tools dating from 9500 to 6000 BC, discovered in Finnmark ( Komsa culture ) in the north and Rogaland ( Fosna culture ) in the southwest. Theories about the two cultures being separate were deemed obsolete in the 1970s. Between 3000 and 2500 BC, new settlers ( Corded Ware culture ) arrived in eastern Norway . They were Indo-European farmers who grew grain and kept livestock, and gradually replaced

9372-413: The context of their effects on life. A 1995 paper by Michael Benton tracked extinction and origination rates among both marine and continental (freshwater & terrestrial) families, identifying 22 extinction intervals and no periodic pattern. Overview books by O.H. Walliser (1996) and A. Hallam and P.B. Wignall (1997) summarized the new extinction research of the previous two decades. One chapter in

9504-486: The control of Queen Margaret when the country entered into the Kalmar Union . After Sweden broke out of the Kalmar Union in 1521, Norway tried to follow suit, but the subsequent rebellion was defeated, and Norway remained in a union with Denmark until 1814. This period was by some referred to as the "400-Year Night", since all of the kingdom's intellectual and administrative power was centred in Copenhagen . With

9636-478: The correlation of extinction and origination rates to diversity. High diversity leads to a persistent increase in extinction rate; low diversity to a persistent increase in origination rate. These presumably ecologically controlled relationships likely amplify smaller perturbations (asteroid impacts, etc.) to produce the global effects observed. A good theory for a particular mass extinction should: It may be necessary to consider combinations of causes. For example,

9768-476: The death of Haakon in 1379, his 10-year-old son Olaf IV acceded to the throne. As Olaf had already been elected to the throne of Denmark in 1376, Denmark and Norway entered a personal union . Olaf's mother and Haakon's widow, Queen Margaret, managed the foreign affairs of Denmark and Norway during Olaf's minority. Margaret was on the verge of achieving a union of Sweden with Denmark and Norway when Olaf IV suddenly died. Denmark made Margaret temporary ruler on

9900-434: The death of Olaf. On 2 February 1388, Norway followed suit and crowned Margaret. Queen Margaret knew that her power would be more secure if she were able to find a king to rule in her place. She settled on Eric of Pomerania , grandson of her sister. Thus at an all-Scandinavian meeting held at Kalmar, Erik of Pomerania was crowned king of all three Scandinavian countries, bringing the thrones of Norway, Denmark, and Sweden under

10032-458: The difficulty in assessing taxa with high turnover rates or restricted occurrences, which cannot be directly assessed due to a lack of fine-scale temporal resolution. Many paleontologists opt to assess diversity trends by randomized sampling and rarefaction of fossil abundances rather than raw temporal range data, in order to account for all of these biases. But that solution is influenced by biases related to sample size. One major bias in particular

10164-603: The early part of the Hirnantian, sea level dropped. Estimates of the depth of this drop range from more than 50 meters (based on studies in Nevada and Utah ) to more than 100 meters (from studies in Norway and the United Kingdom ). More recent research indicates a worldwide reduction in sea level of approximately 80 meters. This drop dried up and exposed the extensive shallow-water continental shelves that existed throughout

10296-490: The economy, because of the loans the Hansa had made to the royals and the large debt the kings were carrying. The League's monopolistic control over the economy of Norway put pressure on all classes, especially the peasantry, to the degree that no real burgher class existed in Norway. From the 1040s to 1130, the country was at peace. In 1130, the civil war era broke out on the basis of unclear succession laws , which allowed

10428-497: The effect of reducing the estimated severity of the six sampled mass extinction events. This effect was stronger for mass extinctions which occurred in periods with high rates of background extinction, like the Devonian. Because most diversity and biomass on Earth is microbial , and thus difficult to measure via fossils, extinction events placed on-record are those that affect the easily observed, biologically complex component of

10560-513: The end of the Cretaceous period. The Alvarez hypothesis for the end-Cretaceous extinction gave mass extinctions, and catastrophic explanations, newfound popular and scientific attention. Another landmark study came in 1982, when a paper written by David M. Raup and Jack Sepkoski was published in the journal Science . This paper, originating from a compendium of extinct marine animal families developed by Sepkoski, identified five peaks of marine family extinctions which stand out among

10692-625: The end of the century. Throughout the High Middle Ages , the king established Norway as a sovereign state with a central administration and local representatives. In 1349, the Black Death spread to Norway and within a year killed a third of the population. Later plagues reduced the population to half the starting point by 1400. Many communities were entirely wiped out, resulting in an abundance of land, allowing farmers to switch to more animal husbandry . The reduction in taxes weakened

10824-752: The end of the period of pressure. Their statistical analysis of marine extinction rates throughout the Phanerozoic suggested that neither long-term pressure alone nor a catastrophe alone was sufficient to cause a significant increase in the extinction rate. MacLeod (2001) summarized the relationship between mass extinctions and events that are most often cited as causes of mass extinctions, using data from Courtillot, Jaeger & Yang et al. (1996), Hallam (1992) and Grieve & Pesonen (1992): The most commonly suggested causes of mass extinctions are listed below. The formation of large igneous provinces by flood basalt events could have: Flood basalt events occur as pulses of activity punctuated by dormant periods. As

10956-462: The entire Phanerozoic. As data continued to accumulate, some authors began to re-evaluate Sepkoski's sample using methods meant to account for sampling biases . As early as 1982, a paper by Phillip W. Signor and Jere H. Lipps noted that the true sharpness of extinctions was diluted by the incompleteness of the fossil record. This phenomenon, later called the Signor-Lipps effect , notes that

11088-483: The expense of Sweden and Russia. The famine of 1695–1696 killed roughly 10% of Norway's population. The harvest failed in Scandinavia at least nine times between 1740 and 1800, with great loss of life. After Denmark–Norway was attacked by the United Kingdom at the 1807 Battle of Copenhagen , it entered into an alliance with Napoleon , with the war leading to dire conditions and mass starvation in 1812. As

11220-511: The fauna that had survived the first extinction event. While there are no major radiometric dates for the Hirnantian itself, there are two such dates which bracket the Hirnantian. Both dates are from the Dob's Linn area in the United Kingdom. The older one comes from the local Hartfell shale formations. Zircon found in an ash deposit at the site was dated to 445.7 mya , with a margin of error of plus or minus 2.4 million years. The younger date

11352-619: The following section. The "Big Five" mass extinctions are bolded. Graphed but not discussed by Sepkoski (1996), considered continuous with the Late Devonian mass extinction At the time considered continuous with the end-Permian mass extinction Includes late Norian time slices Diversity loss of both pulses calculated together Pulses extend over adjacent time slices, calculated separately Considered ecologically significant, but not analyzed directly Excluded due to

11484-429: The former source lists over 60 geological events which could conceivably be considered global extinctions of varying sizes. These texts, and other widely circulated publications in the 1990s, helped to establish the popular image of mass extinctions as a "big five" alongside many smaller extinctions through prehistory. Though Sepkoski died in 1999, his marine genera compendium was formally published in 2002. This prompted

11616-521: The geological record.   The largest extinction was the Kellwasser Event ( Frasnian - Famennian , or F-F, 372 Ma), an extinction event at the end of the Frasnian, about midway through the Late Devonian. This extinction annihilated coral reefs and numerous tropical benthic (seabed-living) animals such as jawless fish, brachiopods , and trilobites . The other major extinction

11748-553: The hunting-fishing population of the west coast. From about 1500 BC, bronze was gradually introduced. Burial cairns built close to the sea as far north as Harstad and also inland in the south are characteristic of this period, with rock carving motifs that differ from those of the Stone Age , depicting ships resembling the Hjortspring boat , while large stone burial monuments known as stone ships were also erected. There

11880-485: The king's position, and many aristocrats lost the basis for their surplus. High tithes to church made it increasingly powerful and the archbishop became a member of the Council of State . The Hanseatic League took control over Norwegian trade during the 14th century and established a trading centre in Bergen . In 1380, Olaf Haakonsson inherited both the Norwegian (as Olaf IV) and Danish thrones (as Olaf II), creating

12012-419: The king's sons to rule jointly. The Archdiocese of Nidaros was created in 1152 and attempted to control the appointment of kings. The church inevitably had to take sides in the conflicts. The wars ended in 1217 with the appointment of Håkon IV Håkonsson , who introduced clear laws of succession. From 1000 to 1300, the population increased from 150,000 to 400,000, resulting both in more land being cleared and

12144-437: The kings of Sweden and of Denmark were elected to the throne by their respective nobles. Thus Sweden and Norway were united under King Magnus VII. In 1349, the Black Death killed between 50% and 60% of Norway's population and led to a period of social and economic decline. Although the death rate was comparable with the rest of Europe, economic recovery took much longer because of the small, scattered population. Even before

12276-456: The large terrestrial vertebrate niches. The dinosaurs themselves had been beneficiaries of a previous mass extinction, the end-Triassic , which eliminated most of their chief rivals, the crurotarsans . Similarly, within Synapsida , the replacement of taxa that originated in the earliest, Pennsylvanian and Cisuralian evolutionary radiation (often still called " pelycosaurs ", though this is

12408-422: The last 500 million years, and thus less vulnerable to mass extinctions, but susceptibility to extinction at a taxonomic level does not appear to make mass extinctions more or less probable. There is still debate about the causes of all mass extinctions. In general, large extinctions may result when a biosphere under long-term stress undergoes a short-term shock. An underlying mechanism appears to be present in

12540-516: The late 10th and early 11th centuries. This is largely attributed to the missionary kings Olaf I Tryggvasson and Olaf II Haraldsson (St. Olaf). Olaf Tryggvasson conducted raids in England, including attacking London. Arriving back in Norway in 995, Olaf landed in Moster where he built a church which became the first Christian church in Norway. From Moster, Olaf sailed north to Trondheim where he

12672-574: The long stream" in Welsh . The stage was introduced in 1933 by B.B. Bancroft. As proposed by Bancroft, the Hirnantian included the Hirnant Limestone and related sedimentary formations. These formations were located at the very top of Ordovician deposits, and were dominated by a fauna which included brachiopods, trilobites, and other "shelly" or hard-coated animals. In 1966, D. A. Bassett, Harry Blackmore Whittington , and A. Williams, writing in

12804-412: The long-term consequences of the End Ordovician event were relatively small. Following the climatic oscillation, the climate returned to its previous state, and the species that survived soon (within two or three million years) evolved into species very similar to the ones that existed before. The Hirnantian was named after Cwm Hirnant south of Bala , in northern Wales . Cwm Hirnant means the "valley of

12936-430: The marine aspect of the end-Cretaceous extinction appears to have been caused by several processes that partially overlapped in time and may have had different levels of significance in different parts of the world. Arens and West (2006) proposed a "press / pulse" model in which mass extinctions generally require two types of cause: long-term pressure on the eco-system ("press") and a sudden catastrophe ("pulse") towards

13068-434: The mass extinction were global warming , related to volcanism , and anoxia , and not, as considered earlier, cooling and glaciation . However, this is at odds with numerous previous studies, which have indicated global cooling as the primary driver. Most recently, the deposition of volcanic ash has been suggested to be the trigger for reductions in atmospheric carbon dioxide leading to the glaciation and anoxia observed in

13200-571: The ninth century when heading for the Faroe Islands , and eventually came across Vinland , known today as Newfoundland , in Canada. The Vikings from Norway were most active in the northern and western British Isles and eastern North America isles . According to tradition, Harald Fairhair unified them into one in 872 after the Battle of Hafrsfjord in Stavanger , thus becoming the first king of

13332-426: The old, dominant group and makes way for the new one, a process known as adaptive radiation . For example, mammaliaformes ("almost mammals") and then mammals existed throughout the reign of the dinosaurs , but could not compete in the large terrestrial vertebrate niches that dinosaurs monopolized. The end-Cretaceous mass extinction removed the non-avian dinosaurs and made it possible for mammals to expand into

13464-400: The ongoing mass extinction caused by human activity is sometimes called the sixth mass extinction . Mass extinctions have sometimes accelerated the evolution of life on Earth . When dominance of particular ecological niches passes from one group of organisms to another, it is rarely because the newly dominant group is "superior" to the old but usually because an extinction event eliminates

13596-565: The origination rate in the middle Ordovician-early Silurian, late Carboniferous-Permian, and Jurassic-recent. This argues that the Late Ordovician, end-Permian, and end-Cretaceous extinctions were statistically significant outliers in biodiversity trends, while the Late Devonian and end-Triassic extinctions occurred in time periods which were already stressed by relatively high extinction and low origination. Computer models run by Foote (2005) determined that abrupt pulses of extinction fit

13728-686: The pattern of prehistoric biodiversity much better than a gradual and continuous background extinction rate with smooth peaks and troughs. This strongly supports the utility of rapid, frequent mass extinctions as a major driver of diversity changes. Pulsed origination events are also supported, though to a lesser degree which is largely dependent on pulsed extinctions. Similarly, Stanley (2007) used extinction and origination data to investigate turnover rates and extinction responses among different evolutionary faunas and taxonomic groups. In contrast to previous authors, his diversity simulations show support for an overall exponential rate of biodiversity growth through

13860-480: The physical environment. He expressed this in The Origin of Species : Various authors have suggested that extinction events occurred periodically, every 26 to 30 million years, or that diversity fluctuates episodically about every 62 million years. Various ideas, mostly regarding astronomical influences, attempt to explain the supposed pattern, including the presence of a hypothetical companion star to

13992-440: The plague, the population was only about 500,000. After the plague, many farms lay idle while the population slowly increased. However, the few surviving farms' tenants found their bargaining positions with their landlords greatly strengthened. King Magnus VII ruled Norway until 1350, when his son, Haakon, was placed on the throne as Haakon VI . In 1363, Haakon married Margaret , daughter of King Valdemar IV of Denmark . Upon

14124-596: The presumed far more extensive mass extinction of microbial life during the Great Oxidation Event (a.k.a. Oxygen Catastrophe) early in the Proterozoic Eon . At the end of the Ediacaran and just before the Cambrian explosion , yet another Proterozoic extinction event (of unknown magnitude) is speculated to have ushered in the Phanerozoic. In May 2020, studies suggested that the causes of

14256-566: The rate of extinction between and among different clades . Mammals , descended from the synapsids , and birds , a side-branch of the theropod dinosaurs, emerged as the two predominant clades of terrestrial tetrapods. Despite the common presentation focusing only on these five events, no measure of extinction shows any definite line separating them from the many other Phanerozoic extinction events that appear only slightly lesser catastrophes; further, using different methods of calculating an extinction's impact can lead to other events featuring in

14388-489: The reign of Charles III John brought some significant social and political reforms. In 1854, women won the right to inherit property. In 1863, the last trace of keeping unmarried women in the status of minors was removed. Furthermore, women were eligible for different occupations, particularly the common school teacher. By mid-century, Norway's democracy was limited; voting was limited to officials, property owners, leaseholders and burghers of incorporated towns. Norway remained

14520-418: The rest of Europe. Eventually restored as a kingdom (albeit in legislative union with Denmark) in 1661, Norway saw its land area decrease in the 17th century with the loss of the provinces Båhuslen , Jemtland , and Herjedalen to Sweden, as the result of a number of disastrous wars with Sweden. In the north, its territory was increased by the acquisition of the northern provinces of Troms and Finnmark , at

14652-588: The rock exposure of Western Europe indicates that many of the minor events for which a biological explanation has been sought are most readily explained by sampling bias . Research completed after the seminal 1982 paper (Sepkoski and Raup) has concluded that a sixth mass extinction event due to human activities is currently under way: Extinction events can be tracked by several methods, including geological change, ecological impact, extinction vs. origination ( speciation ) rates, and most commonly diversity loss among taxonomic units. Most early papers used families as

14784-639: The same short time interval. To circumvent this issue, background rates of diversity change (extinction/origination) were estimated for stages or substages without mass extinctions, and then assumed to apply to subsequent stages with mass extinctions. For example, the Santonian and Campanian stages were each used to estimate diversity changes in the Maastrichtian prior to the K-Pg mass extinction. Subtracting background extinctions from extinction tallies had

14916-402: The south pole. This included South America , Africa , most of Australia , the bulk of India , and Antarctica . What is now west Africa was then located at the pole, while South America was close by, joined to Africa along the latter's west coast. Along Africa's east coast were Antarctica and India, while Australia lay just to the north of them, straddling the equator. To the north of Australia

15048-543: The subdivision of farms. While in the Viking Age farmers owned their own land, by 1300, seventy per cent of the land was owned by the king, the church, or the aristocracy, and about twenty per cent of yields went to these landowners. The 14th century is described as Norway's golden age , with peace and increase in trade, especially with the British Islands, although Germany became increasingly important towards

15180-582: The third century. By the time of the first historical records of Scandinavia, about the 8th century, several small political entities existed in Norway. It has been estimated that there were nine petty realms in Western Norway during the early Viking Age . Archaeologist Bergljot Solberg on this basis estimates that there would have been at least 20 in the whole country. In the Viking period, Norwegian Viking explorers discovered Iceland by accident in

15312-452: The throne of Norway and Sweden in 1818 and reigned to 1844. He protected the constitution and liberties of Norway and Sweden during the age of Metternich . As such, he was regarded as a liberal monarch. However, he was ruthless in his use of paid informers, secret police and restrictions on the freedom of the press to put down public movements for reform—especially the Norwegian national independence movement. The Romantic Era that followed

15444-602: The top five. Fossil records of older events are more difficult to interpret. This is because: It has been suggested that the apparent variations in marine biodiversity may actually be an artifact, with abundance estimates directly related to quantity of rock available for sampling from different time periods. However, statistical analysis shows that this can only account for 50% of the observed pattern, and other evidence such as fungal spikes (geologically rapid increase in fungal abundance) provides reassurance that most widely accepted extinction events are real. A quantification of

15576-498: The traditional dominant view, the first component was originally norðr , a cognate of English north , so the full name was Norðr vegr , "the way northwards", referring to the sailing route along the Norwegian coast, and contrasting with suðrvegar "southern way" (from Old Norse suðr ) for (Germany), and austrvegr "eastern way" (from austr ) for the Baltic . The earliest traces of human occupation in Norway are found along

15708-453: The unit of taxonomy, based on compendiums of marine animal families by Sepkoski (1982, 1992). Later papers by Sepkoski and other authors switched to genera , which are more precise than families and less prone to taxonomic bias or incomplete sampling relative to species. These are several major papers estimating loss or ecological impact from fifteen commonly-discussed extinction events. Different methods used by these papers are described in

15840-494: The vacant niches created the opportunity for archosaurs to become ascendant . In the seas, the percentage of animals that were sessile (unable to move about) dropped from 67% to 50%. The whole late Permian was a difficult time, at least for marine life, even before the P–T boundary extinction. More recent research has indicated that the End-Capitanian extinction event that preceded the "Great Dying" likely constitutes

15972-425: The warm environment species that had thrived during the previous hot period (hot-house to scientists). Just as the species were adapting, however, the climate changed again. During the latter part of the Hirnantian, temperatures rose, the glaciers melted, and sea level rose to the same or perhaps an even higher level than before the glaciation. The exposed shelves were flooded, resulting in additional extinctions among

16104-446: The world at that time, causing the extinction of large numbers of species who depended on this shallow water environment. Those species that survived were greatly reduced in numbers. The overall result was a major reduction in the biodiversity of the world's oceans. During this ice-house period (as scientists sometimes call periods of global cold climate and glaciation), surviving species began to adapt. Cold environment species replaced

16236-511: Was New Guinea . It may have been the northernmost point of land in the world, located just above 30 degrees north latitude. To the north of it lay a vast, uninterrupted sea, known today as the Panthalassic ocean . Not yet joined with what would become North America were Florida, southern Georgia, and the coastal areas of Mississippi , Alabama , and South Carolina wedged into a gap between Africa and South America, and located very near

16368-631: Was a Utopian socialist who in 1848 organised a labour society in Drammen . In just a few months, this society had a membership of 500 and was publishing its own newspaper. Within two years, 300 societies had been organised all over Norway, with a total membership of 20,000 drawn from the lower classes of both urban and rural areas. In the end, the revolt was easily crushed; Thrane was captured and jailed. In 1898, all men were granted universal suffrage , followed by all women in 1913. Christian Michelsen , Prime Minister of Norway from 1905 to 1907, played

16500-457: Was another paper which attempted to remove two common errors in previous estimates of extinction severity. The first error was the unjustified removal of "singletons", genera unique to only a single time slice. Their removal would mask the influence of groups with high turnover rates or lineages cut short early in their diversification. The second error was the difficulty in distinguishing background extinctions from brief mass extinction events within

16632-554: Was determined that no single faunal zone existed that could accommodate the upper stage of this division. Therefore, in 2003, the ICS voted to add an additional stage to its official international time scale. This was named the Hirnantian after Bancroft's stage. In 2006 the ICS ratified the Wangjiawan section as the official Global Boundary Stratotype Section and Point (GSSP) for the Hirnantian Stage. The reference lower rock boundary ( GSSP ) of

16764-408: Was one revolt under Knut Alvsson in 1502. Norway took no part in the events which led to Swedish independence from Denmark in the 1520s. Upon the death of King Haakon V in 1319, Magnus Eriksson , at just three years old, inherited the throne as King Magnus VII. A simultaneous movement to make Magnus King of Sweden proved successful (he was a grandson of King Magnus Ladulås of Sweden), and both

16896-468: Was part of Denmark–Norway , and, from 1814 to 1905, it was in a personal union with Sweden. Norway was neutral during the First World War , and in the Second World War until April 1940 when it was invaded and occupied by Nazi Germany until the end of the war. Harald V of the House of Glücksburg is the current King of Norway . Jonas Gahr Støre has been Prime Minister of Norway since 2021. As

17028-634: Was proclaimed King of Norway by the Eyrathing in 995. One of the most important sources for the history of the 11th century Vikings is the treaty between the Icelanders and Olaf II Haraldsson, king of Norway circa 1015 to 1028. Feudalism never really developed in Norway or Sweden, as it did in the rest of Europe. However, the administration of government took on a very conservative feudal character. The Hanseatic League forced royalty to cede to them greater and greater concessions over foreign trade and

17160-514: Was the Hangenberg Event (Devonian-Carboniferous, or D-C, 359 Ma), which brought an end to the Devonian as a whole. This extinction wiped out the armored placoderm fish and nearly led to the extinction of the newly evolved ammonoids . These two closely spaced extinction events collectively eliminated about 19% of all families, 50% of all genera and at least 70% of all species. Sepkoski and Raup (1982) did not initially consider

17292-455: Was unprepared for the German surprise attack (see: Battle of Drøbak Sound , Norwegian Campaign , and Invasion of Norway ), military and naval resistance lasted for two months. Norwegian armed forces in the north launched an offensive against the German forces in the Battles of Narvik , but were forced to surrender on 10 June after losing British support which had been diverted to France during

17424-582: Was wielded by the leader of the German occupation authority, Josef Terboven . Quisling, as minister president , later formed a collaborationist government under German control . Up to 15,000 Norwegians volunteered to fight in German units, including the Waffen-SS . Many Norwegians and persons of Norwegian descent joined the Allied forces as well as the Free Norwegian Forces . In June 1940,

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