The Permian is a geologic period and system which spans 47 million years from the end of the Carboniferous Period 298.9 million years ago, to the beginning of the Triassic period 251.902 Mya. It is the last period of the Paleozoic era; the concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the city of Perm. The Permian witnessed the diversification of the early amniotes into the ancestral groups of the mammals, turtles and archosaurs; the world at the time was dominated by two continents known as Pangaea and Siberia, surrounded by a global ocean called Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, who could better cope with these drier conditions, rose to dominance in place of their amphibian ancestors; the Permian ended with the Permian–Triassic extinction event, the largest mass extinction in Earth's history, in which nearly 96% of marine species and 70% of terrestrial species died out.
It would take well into the Triassic for life to recover from this catastrophe. Recovery from the Permian–Triassic extinction event was protracted; the term "Permian" was introduced into geology in 1841 by Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Édouard de Verneuil; the region now lies in the Perm Krai of Russia. Official ICS 2017 subdivisions of the Permian System from most recent to most ancient rock layers are: Lopingian epoch Changhsingian Wuchiapingian Others: Waiitian Makabewan Ochoan Guadalupian epoch Capitanian stage Wordian stage Roadian stage Others: Kazanian or Maokovian Braxtonian stage Cisuralian epoch Kungurian stage Artinskian stage Sakmarian stage Asselian stage Others: Telfordian Mangapirian Sea levels in the Permian remained low, near-shore environments were reduced as all major landmasses collected into a single continent—Pangaea; this could have in part caused the widespread extinctions of marine species at the end of the period by reducing shallow coastal areas preferred by many marine organisms.
During the Permian, all the Earth's major landmasses were collected into a single supercontinent known as Pangaea. Pangaea straddled the equator and extended toward the poles, with a corresponding effect on ocean currents in the single great ocean, the Paleo-Tethys Ocean, a large ocean that existed between Asia and Gondwana; the Cimmeria continent rifted away from Gondwana and drifted north to Laurasia, causing the Paleo-Tethys Ocean to shrink. A new ocean was growing on its southern end, the Tethys Ocean, an ocean that would dominate much of the Mesozoic era. Large continental landmass interiors experience climates with extreme variations of heat and cold and monsoon conditions with seasonal rainfall patterns. Deserts seem to have been widespread on Pangaea; such dry conditions favored gymnosperms, plants with seeds enclosed in a protective cover, over plants such as ferns that disperse spores in a wetter environment. The first modern trees appeared in the Permian. Three general areas are noted for their extensive Permian deposits—the Ural Mountains and the southwest of North America, including the Texas red beds.
The Permian Basin in the U. S. states of Texas and New Mexico is so named because it has one of the thickest deposits of Permian rocks in the world. The climate in the Permian was quite varied. At the start of the Permian, the Earth was still in an ice age. Glaciers receded around the mid-Permian period as the climate warmed, drying the continent's interiors. In the late Permian period, the drying continued although the temperature cycled between warm and cool cycles. Permian marine deposits are rich in fossil mollusks and brachiopods. Fossilized shells of two kinds of invertebrates are used to identify Permian strata and correlate them between sites: fusulinids, a kind of shelled amoeba-like protist, one of the foraminiferans, ammonoids, shelled cephalopods that are distant relatives of the modern nautilus. By the close of the Permian, trilobites and a host of other marine groups became extinct. Terrestrial life in the Permian included diverse plants, fungi and various types of tetrapods; the period saw a massive desert covering the interior of Pangaea.
The warm zone spread in the northern hemisphere. The rocks formed at that time were stained red by iron oxides, the result of intense heating by the sun of a surface devoid of vegetation cover. A number of older types of plants and animals became marginal elements; the Permian began with the Carboniferous flora still flourishing. About the middle of the Permian a major transition in vegetation began; the swamp-loving
The Tibetan Plateau known in China as the Qinghai–Tibet Plateau or the Qing–Zang Plateau or Himalayan Plateau, is a vast elevated plateau in Central Asia and East Asia, covering most of the Tibet Autonomous Region and Qinghai in western China, as well as Ladakh and Lahaul & Spiti in India. It stretches 1,000 kilometres north to south and 2,500 kilometres east to west. With an average elevation exceeding 4,500 metres, the Tibetan Plateau is sometimes called "the Roof of the World" because it stands over 3 miles above sea level and is surrounded by imposing mountain ranges that harbor the world's two highest summits, Mount Everest and K2, is the world's highest and largest plateau, with an area of 2,500,000 square kilometres. Sometimes termed the Third Pole, the Tibetan Plateau contains the headwaters of the drainage basins of most of the streams in surrounding regions, its tens of thousands of glaciers and other geographical and ecological features serve as a "water tower" storing water and maintaining flow.
The impact of global warming on the Tibetan Plateau is of intense scientific interest. The Tibetan Plateau is surrounded by the massive mountain ranges of High-mountain Asia; the plateau is bordered to the south by the inner Himalayan range, to the north by the Kunlun Mountains, which separate it from the Tarim Basin, to the northeast by the Qilian Mountains, which separate the plateau from the Hexi Corridor and Gobi Desert. To the east and southeast the plateau gives way to the forested gorge and ridge geography of the mountainous headwaters of the Salween and Yangtze rivers in northwest Yunnan and western Sichuan. In the west the curve of the rugged Karakoram range of northern Kashmir embraces the plateau; the Indus River originates in the western Tibetan Plateau in the vicinity of Lake Manasarovar. The Tibetan Plateau is bounded in the north by a broad escarpment where the altitude drops from around 5,000 metres to 1,500 metres over a horizontal distance of less than 150 kilometres. Along the escarpment is a range of mountains.
In the west the Kunlun Mountains separate the plateau from the Tarim Basin. About halfway across the Tarim the bounding range becomes the Altyn-Tagh and the Kunluns, by convention, continue somewhat to the south. In the'V' formed by this split is the western part of the Qaidam Basin; the Altyn-Tagh ends near the Dangjin pass on the Dunhuang-Golmud road. To the west are short ranges called the Danghe, Yema and Tulai Nanshans; the easternmost range is the Qilian Mountains. The line of mountains continues east of the plateau as the Qinling, which separates the Ordos Plateau from Sichuan. North of the mountains runs the Gansu or Hexi Corridor, the main silk-road route from China proper to the West; the plateau is a high-altitude arid steppe interspersed with mountain ranges and large brackish lakes. Annual precipitation ranges from 100 to 300 millimetres and falls as hail; the southern and eastern edges of the steppe have grasslands which can sustainably support populations of nomadic herdsmen, although frost occurs for six months of the year.
Permafrost occurs over extensive parts of the plateau. Proceeding to the north and northwest, the plateau becomes progressively higher and drier, until reaching the remote Changtang region in the northwestern part of the plateau. Here the average altitude exceeds 5,000 metres and winter temperatures can drop to −40 °C; as a result of this inhospitable environment, the Changthang region is the least populous region in Asia, the third least populous area in the world after Antarctica and northern Greenland. The geological history of the Tibetan Plateau is related to that of the Himalayas; the Himalayas are among the youngest mountain ranges on the planet and consist of uplifted sedimentary and metamorphic rock. Their formation is a result of a continental collision or orogeny along the convergent boundary between the Indo-Australian Plate and the Eurasian Plate; the collision began in the Upper Cretaceous period about 70 million years ago, when the north-moving Indo-Australian Plate, moving at about 15 cm per year, collided with the Eurasian Plate.
About 50 million years ago, this fast moving Indo-Australian plate had closed the Tethys Ocean, the existence of, determined by sedimentary rocks settled on the ocean floor, the volcanoes that fringed its edges. Since these sediments were light, they crumpled into mountain ranges rather than sinking to the floor; the Indo-Australian plate continues to be driven horizontally below the Tibetan Plateau, which forces the plateau to move upwards. Much of the Tibetan Plateau is of low relief; the cause of this is debated among geologists. Some argue that the Tibetan Plateau is an uplifted peneplain formed at low altitude, while others argue that the low relief stems from erosion and infill of topographic depressions that occurred at high elevations; the Tibetan Plateau supports a variety of most of them classified as montane grasslands. While parts of the plateau feature an alpine tundra-like environment, other areas feature monsoon-influenced shrublands and forests. Species diversity is reduced on the plateau due to the elevation and low precipitation.
The Tibetan Plateau hosts the Tibetan wolf, species of snow leopard, wild yak, wild donkey, vultures, hawk
Pleistocene megafauna is the set of large animals that lived on Earth during the Pleistocene epoch and became extinct during the Quaternary extinction event. Megafauna are any animals with an adult body weight of over 44 kg; the last glacial period referred to as the'Ice Age', spanned 125,000 to 14,500 years ago and was the most recent glacial period within the current ice age which occurred during the last years of the Pleistocene epoch. The Ice Age reached its peak during the last glacial maximum, when ice sheets commenced advancing from 33,000 years BP and reached their maximum positions 26,500 years BP. Deglaciation commenced in the Northern Hemisphere 19,000 years BP, in Antarctica 14,500 years BP, consistent with evidence that this was the primary source for an abrupt rise in the sea level 14,500 years ago. A vast mammoth steppe stretched from the Iberian peninsula across Eurasia and over the Bering land bridge into Alaska and the Yukon where it was stopped by the Wisconsin glaciation.
This land bridge existed because more of the planet's water was locked up in glaciation than now and therefore the sea-levels were lower. When the sea levels began to rise this bridge was inundated around 11,000 years BP. During the last glacial maximum, the continent of Europe was much colder and drier than it is today, with polar desert in the north and the remainder steppe or tundra. Forest and woodland was non-existent, except for isolated pockets in the mountain ranges of southern Europe; the fossil evidence from many continents points to the extinction of large animals at or near the end of the last glaciation. These animals have been termed the Pleistocene megafauna; the most common definition of megafauna is the set of animals with an adult body weight of over 44 kg. Across Eurasia, the straight-tusked elephant became extinct between 100,000–50,000 years BP; the cave bear, interglacial rhinoceros, heavy-bodied Asian antelope, the Eurasian hippopotamuses died out between 50,000-16,000 years BP.
The spotted hyena, woolly rhinoceros and mammoths died out between 16,000-11,500 years BP. The giant deer died out after 11,500 BP with the last pocket having survived until about 7,700 years BP in western Siberia. A pocket of mammoths survived on Wrangel Island until 4,500 years BP; as some species became extinct, so too did their predators. Among the top predators, the sabre-toothed cat died out 28,000 years BP, the cave lion 11,900 years BP, the leopard in Europe died out 27,000 years BP; the Late Pleistocene was characterized by a series of severe and rapid climate oscillations with regional temperature changes of up to 16 °C, correlated with megafaunal extinctions. There is no evidence of megafaunal extinctions at the height of the LGM, indicating that increasing cold and glaciation were not factors. Multiple events appear to involve the rapid replacement of one species by one within the same genus, or one population by another within the same species, across a broad area; the ancestors of modern humans first appeared in East Africa 195,000 years ago.
Some migrated out with one group reaching Central Asia 50,000 years ago. From there they reached Europe, with human remains dated to 43,000-45,000 years BP discovered in Italy, in the European Russian Arctic dated to 40,000 years ago. Another group left Central Asia and reached the Yana River, well above the Arctic circle, 27,000 years ago. Remains of mammoth, hunted by humans 45,000 YBP have been found at Yenisei Bay in the central Siberian Arctic. Modern humans made their way across the Bering land bridge and into North America between 20,000-11,000 years ago, after the Wisconsin glaciation had retreated but before the Bering land bridge became inundated by the sea; these people populated the Americas. In the Fertile crescent the first agriculture was developing 11,500 years ago. Four theories have been advanced as causes of these extinctions: hunting by the spreading humans, climatic change, spreading disease, an impact from an asteroid or comet; these factors are not exclusive: two or more may have combined to cause the extinctions.
Most evidence suggests. During the American megafaunal extinction event around 12,700 years ago, 90 genera of mammals weighing over 44 kilograms became extinct; the Late Pleistocene fauna in North America included giant sloths, short-faced bears, several species of tapirs, the American lion, giant tortoises, saber-toothed cats like Smilodon and the scimitar cat, dire wolves, camelids such as two species of now extinct llamas and Camelops, at least two species of bison, the stag-moose, the shrub-ox and Harlan's muskox, 14 species of pronghorn, horses and mastodons, the beautiful armadillo and the giant armadillo-like Glyptotherium, giant beavers, as well as birds like giant condors, other teratorns and terror birds. In contrast, today the largest North American land animal is the American bison. South American wildlife in the Pleistocene varied greatly; the continent had quite a few grazers and mixed feeders such as the camel-like litoptern Macrauchenia, Doedicurus, Glyptodon and Toxodon. There were Stegomastodons, found as far south as Patagonia.
The main predators of the region were Smilodon. As with South America, some elements of the Eurasian megafauna were similar to those of North America. Among the most recognizable
Kraków spelled Cracow or Krakow, is the second largest and one of the oldest cities in Poland. Situated on the Vistula River in the Lesser Poland region, the city dates back to the 7th century. Kraków was the official capital of Poland until 1596 and has traditionally been one of the leading centres of Polish academic, economic and artistic life. Cited as one of Europe's most beautiful cities, its Old Town was declared a UNESCO World Heritage Site; the city has grown from a Stone Age settlement to Poland's second most important city. It began as a hamlet on Wawel Hill and was being reported as a busy trading centre of Central Europe in 965. With the establishment of new universities and cultural venues at the emergence of the Second Polish Republic in 1918 and throughout the 20th century, Kraków reaffirmed its role as a major national academic and artistic centre; the city has a population of about 770,000, with 8 million additional people living within a 100 km radius of its main square. After the invasion of Poland by Nazi Germany at the start of World War II, the newly defined Distrikt Krakau became the capital of Germany's General Government.
The Jewish population of the city was forced into a walled zone known as the Kraków Ghetto, from which they were sent to German extermination camps such as the nearby Auschwitz never to return, the Nazi concentration camps like Płaszów. In 1978, Karol Wojtyła, archbishop of Kraków, was elevated to the papacy as Pope John Paul II—the first Slavic pope and the first non-Italian pope in 455 years; that year, UNESCO approved the first sites for its new World Heritage List, including the entire Old Town in inscribing Kraków's Historic Centre. Kraków is classified as a global city with the ranking of high sufficiency by GaWC, its extensive cultural heritage across the epochs of Gothic and Baroque architecture includes the Wawel Cathedral and the Royal Castle on the banks of the Vistula, the St. Mary's Basilica, Saints Peter and Paul Church and the largest medieval market square in Europe, the Rynek Główny. Kraków is home to Jagiellonian University, one of the oldest universities in the world and traditionally Poland's most reputable institution of higher learning.
In 2000, Kraków was named European Capital of Culture. In 2013 Kraków was approved as a UNESCO City of Literature; the city hosted the World Youth Day in July 2016. The name of Kraków is traditionally derived from Krakus, the legendary founder of Kraków and a ruler of the tribe of Lechitians. In Polish, Kraków is an archaic possessive form of Krak and means "Krak's". Krakus's name may derive from "krakula", a Proto-Slavic word meaning a judge's staff, or a Proto-Slavic word "krak" meaning an oak, once a sacred tree most associated with the concept of genealogy; the first mention of Prince Krakus dates back to 1190, although the town existed as early as the 7th century, inhabited by the tribe of Vistulans. The city's full official name is Stołeczne Królewskie Miasto Kraków, which can be translated as "Royal Capital City of Kraków". In English, a person born or living in Kraków is a Cracovian. While in the 1990s the English version of the name was written Cracow, the most widespread modern English version is Krakow.
Kraków's early history begins with evidence of a Stone Age settlement on the present site of the Wawel Hill. A legend attributes Kraków's founding to the mythical ruler Krakus, who built it above a cave occupied by a dragon, Smok Wawelski; the first written record of the city's name dates back to 965, when Kraków was described as a notable commercial centre controlled first by Moravia, but captured by a Bohemian duke Boleslaus I in 955. The first acclaimed ruler of Poland, Mieszko I, took Kraków from the Bohemians and incorporated it into the holdings of the Piast dynasty towards the end of his reign. In 1038, Kraków became the seat of the Polish government. By the end of the 10th century, the city was a leading centre of trade. Brick buildings were constructed, including the Royal Wawel Castle with St. Felix and Adaukt Rotunda, Romanesque churches such as St. Adalbert's, a cathedral, a basilica; the city was sacked and burned during the Mongol invasion of 1241. It was rebuilt identical, based on new location act and incorporated in 1257 by the high duke Bolesław V the Chaste who following the example of Wrocław, introduced city rights modelled on the Magdeburg law allowing for tax benefits and new trade privileges for the citizens.
In 1259, the city was again ravaged by the Mongols. A third attack in 1287 was repelled thanks in part to the new built fortifications. In 1335, King Casimir III of Poland declared the two western suburbs to be a new city named after him, Kazimierz; the defensive walls were erected around the central section of Kazimierz in 1362, a plot was set aside for the Augustinian order next to Skałka. The city rose to prominence in 1364, when Casimir III of Poland founded the University of Kraków, the second oldest university in central Europe after the Charles University in Prague. King Casimir began work on a campus for the Academy in Kazimierz, but he died in 1370 and the campus was never completed; the city continued to grow under the joint Lithuanian-Polish Jagiellon dynasty. As the capital of the Kingdom of Poland and a member of the Hanseatic League, the city attracted many craftsmen and guilds as science and the arts began to flourish; the royal chancery and the University ensured a first flourishing of Polish literary culture in the city.
The 15th and 16th centuries were known as Poland's Złoty Golden Age. Many works of Pol
Odd-toed ungulates, mammals which constitute the taxonomic order Perissodactyla, are hoofed animals—ungulates—which bear most of their weight on one of the five toes: the third toe. The non-weight-bearing toes are either present, vestigial, or positioned posteriorly. By contrast, the even-toed ungulates bear most of their weight on two of the five toes: their third and fourth toes. Another difference between the two is that odd-toed ungulates digest plant cellulose in their intestines rather than in one or more stomach chambers as the even-toed ungulates do; the order includes about 17 species divided into three families: Equidae and Tapiridae. Despite their different appearances, they were recognized as related families in the 19th century by the zoologist Richard Owen, who coined the order name; the largest odd-toed ungulates are rhinoceroses, the extinct Paraceratherium, a hornless rhino from the Oligocene, is considered one of the largest land mammals of all time. At the other extreme, an early member of the order, the prehistoric horse Hyracotherium, had a withers height of only 30 to 60 cm.
Apart from dwarf varieties of the domestic horse and donkey, perissodactyls reach a body length of 180–420 cm and a weight of 150 to 4,500 kg. While rhinos have only sparse hair and exhibit a thick epidermis and horses have dense, short coats. Most species are brown, although zebras and young tapirs are striped; the main axes of both the front and rear feet pass through the third toe, always the largest. The remaining toes have been reduced in size to varying degrees. Tapirs, which are adapted to walking on soft ground, have four toes on their fore feet and three on their hind feet. Living rhinos have three toes on both the hind feet. Modern equines possess only a single toe. Rhinos and tapirs, by contrast, have hooves covering only the leading edge of the toes, with the bottom being soft; the ulnae and fibulae are reduced in horses. A common feature that distinguishes this group from other mammals is the saddle-shaped ankle between the astragalus and the scaphoid, which restricts the mobility of the foot.
The thigh is short, the clavicle is absent. Odd-toed ungulates have a long upper jaw with an extended diastema between the front and cheek teeth, giving them an elongated head; the various forms of snout between families are due to differences in the form of the premaxilla. The lacrimal bone has projecting cusps in a wide contact with the nasal bone; the temporomandibular joint is high and the mandible is enlarged. Rhinos have one or two horns made of agglutinated keratin, unlike the horns of even-toed ungulates, which have a bony core; the number and form of the teeth vary according to diet. The incisors and canines can be small or absent, as in the two African species of rhinoceros. In the horses only the males possess canines; the surface shape and height of the molars is dependent on whether soft leaves or hard grass makes up the main component of their diets. Three or four cheek teeth are present on each jaw half, so the dental formula of odd-toed ungulates is: 0-3. 0-1. 2-4. 31-3. 1. 2-4. 3 × 2 = 30-44 All perissodactyls are hindgut fermenters.
In contrast to ruminants, hindgut fermenters store digested food that has left the stomach in an enlarged cecum, where the food is digested by bacteria. No gallbladder is present; the stomach of perissodactyls is built, while the cecum accommodates up to 90 l in horses. The intestine is long, reaching up to 26 m in horses. Extraction of nutrients from food is inefficient, which explains why no odd-toed ungulates are small; the present distribution of most perissodactyl species is only a small fraction of their original range. Members of this group are now found only in Central and South America and southern Africa, central and southeastern Asia. During the peak of odd-toed ungulate existence, from the Eocene to the Oligocene, perissodactyls were distributed over much of the globe, the only exceptions being Australia and Antarctica. Horses and tapirs arrived in South America after the formation of the Isthmus of Panama in the Pliocene, around 3 million years ago. In North America, they died out around 10,000 years ago, while in Europe, the tarpans disappeared in the 19th century.
Hunting and habitat restriction have reduced the present-day species to fragmented relict populations. In contrast, domesticated horses and donkeys have gained a worldwide distribution, feral animals of both species are now found in regions outside of their original range, such as in Australia. Perissodactyls inhabit a number of different habitats. Tapirs are solitary and inhabit tropical rainforests. Rhinos tend to live alone in rather dry savannas, in Asia, wet marsh or forest areas. Horses inhabit open areas such as grasslands, steppes, or semi-deserts, live together in groups. Odd-toed ungulates are herbivores that feed, to varying degrees, on grasses and other plant parts. A distinction is made between grass feeders and leaf feeders. Odd-toed ungulates are characterized by a long gestation period and a small litter size delivering a single young; the g
Poland the Republic of Poland, is a country located in Central Europe. It is divided into 16 administrative subdivisions, covering an area of 312,696 square kilometres, has a temperate seasonal climate. With a population of 38.5 million people, Poland is the sixth most populous member state of the European Union. Poland's capital and largest metropolis is Warsaw. Other major cities include Kraków, Łódź, Wrocław, Poznań, Gdańsk, Szczecin. Poland is bordered by the Baltic Sea, Russia's Kaliningrad Oblast and Lithuania to the north and Ukraine to the east and Czech Republic, to the south, Germany to the west; the establishment of the Polish state can be traced back to AD 966, when Mieszko I, ruler of the realm coextensive with the territory of present-day Poland, converted to Christianity. The Kingdom of Poland was founded in 1025, in 1569 it cemented its longstanding political association with the Grand Duchy of Lithuania by signing the Union of Lublin; this union formed the Polish–Lithuanian Commonwealth, one of the largest and most populous countries of 16th and 17th century Europe, with a uniquely liberal political system which adopted Europe's first written national constitution, the Constitution of 3 May 1791.
More than a century after the Partitions of Poland at the end of the 18th century, Poland regained its independence in 1918 with the Treaty of Versailles. In September 1939, World War II started with the invasion of Poland by Germany, followed by the Soviet Union invading Poland in accordance with the Molotov–Ribbentrop Pact. More than six million Polish citizens, including 90% of the country's Jews, perished in the war. In 1947, the Polish People's Republic was established as a satellite state under Soviet influence. In the aftermath of the Revolutions of 1989, most notably through the emergence of the Solidarity movement, Poland reestablished itself as a presidential democratic republic. Poland is regional power, it has the fifth largest economy by GDP in the European Union and one of the most dynamic economies in the world achieving a high rank on the Human Development Index. Additionally, the Polish Stock Exchange in Warsaw is the largest and most important in Central Europe. Poland is a developed country, which maintains a high-income economy along with high standards of living, life quality, safety and economic freedom.
Having a developed school educational system, the country provides free university education, state-funded social security, a universal health care system for all citizens. Poland has 15 UNESCO World Heritage Sites. Poland is a member state of the European Union, the Schengen Area, the United Nations, NATO, the OECD, the Three Seas Initiative, the Visegrád Group; the origin of the name "Poland" derives from the West Slavic tribe of Polans that inhabited the Warta river basin of the historic Greater Poland region starting in the 6th century. The origin of the name "Polanie" itself derives from the early Slavic word "pole". In some languages, such as Hungarian, Lithuanian and Turkish, the exonym for Poland is Lechites, which derives from the name of a semi-legendary ruler of Polans, Lech I. Early Bronze Age in Poland begun around 2400 BC, while the Iron Age commenced in 750 BC. During this time, the Lusatian culture, spanning both the Bronze and Iron Ages, became prominent; the most famous archaeological find from the prehistory and protohistory of Poland is the Biskupin fortified settlement, dating from the Lusatian culture of the early Iron Age, around 700 BC.
Throughout the Antiquity period, many distinct ancient ethnic groups populated the regions of what is now Poland in an era that dates from about 400 BC to 500 AD. These groups are identified as Celtic, Slavic and Germanic tribes. Recent archeological findings in the Kujawy region, confirmed the presence of the Roman Legions on the territory of Poland; these were most expeditionary missions sent out to protect the amber trade. The exact time and routes of the original migration and settlement of Slavic peoples lacks written records and can only be defined as fragmented; the Slavic tribes who would form Poland migrated to these areas in the second half of the 5th century AD. Up until the creation of Mieszko's state and his subsequent conversion to Christianity in 966 AD, the main religion of Slavic tribes that inhabited the geographical area of present-day Poland was Slavic paganism. With the Baptism of Poland the Polish rulers accepted Christianity and the religious authority of the Roman Church.
However, the transition from paganism was not a smooth and instantaneous process for the rest of the population as evident from the pagan reaction of the 1030s. Poland began to form into a recognizable unitary and territorial entity around the middle of the 10th century under the Piast dynasty. Poland's first documented ruler, Mieszko I, accepted Christianity with the Baptism of Poland in 966, as the new official religion of his subjects; the bulk of the population converted in the course of the next few centuries. In 1000, Boleslaw the Brave, continuing the policy of his father Mieszko, held a Congress of Gniezno and created the metropolis of Gniezno and the dioceses of Kraków, Kołobrzeg, Wrocław. However, the pagan unrest led to the transfer of the capital to Kraków in 1038 by Casimir I the Restorer. In 1109, Prince Bolesław III Wrymouth defeated the King of Germany Henry V at the Battle of Hundsfeld, stopping the Ge
The Devonian is a geologic period and system of the Paleozoic, spanning 60 million years from the end of the Silurian, 419.2 million years ago, to the beginning of the Carboniferous, 358.9 Mya. It is named after Devon, where rocks from this period were first studied; the first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, by the end of the period the first seed-bearing plants appeared. Various terrestrial arthropods became well-established. Fish reached substantial diversity during this time, leading the Devonian to be dubbed the "Age of Fishes." The first ray-finned and lobe-finned bony fish appeared, while the placoderms began dominating every known aquatic environment. The ancestors of all four-limbed vertebrates began adapting to walking on land, as their strong pectoral and pelvic fins evolved into legs.
In the oceans, primitive sharks became more numerous than in the Late Ordovician. The first ammonites, species of molluscs, appeared. Trilobites, the mollusc-like brachiopods and the great coral reefs, were still common; the Late Devonian extinction which started about 375 million years ago affected marine life, killing off all placodermi, all trilobites, save for a few species of the order Proetida. The palaeogeography was dominated by the supercontinent of Gondwana to the south, the continent of Siberia to the north, the early formation of the small continent of Euramerica in between; the period is named after Devon, a county in southwestern England, where a controversial argument in the 1830s over the age and structure of the rocks found distributed throughout the county was resolved by the definition of the Devonian period in the geological timescale. The Great Devonian Controversy was a long period of vigorous argument and counter-argument between the main protagonists of Roderick Murchison with Adam Sedgwick against Henry De la Beche supported by George Bellas Greenough.
Murchison and Sedgwick named the period they proposed as the Devonian System. While the rock beds that define the start and end of the Devonian period are well identified, the exact dates are uncertain. According to the International Commission on Stratigraphy, the Devonian extends from the end of the Silurian 419.2 Mya, to the beginning of the Carboniferous 358.9 Mya. In nineteenth-century texts the Devonian has been called the "Old Red Age", after the red and brown terrestrial deposits known in the United Kingdom as the Old Red Sandstone in which early fossil discoveries were found. Another common term is "Age of the Fishes", referring to the evolution of several major groups of fish that took place during the period. Older literature on the Anglo-Welsh basin divides it into the Downtonian, Dittonian and Farlovian stages, the latter three of which are placed in the Devonian; the Devonian has erroneously been characterised as a "greenhouse age", due to sampling bias: most of the early Devonian-age discoveries came from the strata of western Europe and eastern North America, which at the time straddled the Equator as part of the supercontinent of Euramerica where fossil signatures of widespread reefs indicate tropical climates that were warm and moderately humid but in fact the climate in the Devonian differed during its epochs and between geographic regions.
For example, during the Early Devonian, arid conditions were prevalent through much of the world including Siberia, North America, China, but Africa and South America had a warm temperate climate. In the Late Devonian, by contrast, arid conditions were less prevalent across the world and temperate climates were more common; the Devonian Period is formally broken into Early and Late subdivisions. The rocks corresponding to those epochs are referred to as belonging to the Lower and Upper parts of the Devonian System. Early DevonianThe Early Devonian lasted from 419.2 ± 2.8 to 393.3 ± 2.5 and began with the Lochkovian stage, which lasted until the Pragian. It spanned from 410.8 ± 2.8 to 407.6 ± 2.5, was followed by the Emsian, which lasted until the Middle Devonian began, 393.3± 2.7 million years ago. During this time, the first ammonoids appeared. Ammonoids during this time period differed little from their nautiloid counterparts; these ammonoids belong to the order Agoniatitida, which in epochs evolved to new ammonoid orders, for example Goniatitida and Clymeniida.
This class of cephalopod molluscs would dominate the marine fauna until the beginning of the Mesozoic era. Middle DevonianThe Middle Devonian comprised two subdivisions: first the Eifelian, which gave way to the Givetian 387.7± 2.7 million years ago. During this time the jawless agnathan fishes began to decline in diversity in freshwater and marine environments due to drastic environmental changes and due to the increasing competition and diversity of jawed fishes; the shallow, oxygen-depleted waters of Devonian inland lakes, surrounded by primitive plants, provided the environment necessary for certain early fish to develop such essential characteristics as well developed lungs, the ability to crawl out of the water and onto the land for short periods of time. Late DevonianFinally, the Late Devonian started with the Frasnian, 382.7 ± 2.8 to 372.2 ± 2.5, during which the first forests took shape on land. The first tetrapods appeared in the fossil record in the ensuing Famennian subdivisi