Central Asia stretches from the Caspian Sea in the west to China in the east and from Afghanistan in the south to Russia in the north. The region consists of the former Soviet republics of Kazakhstan, Tajikistan and Uzbekistan, it is colloquially referred to as "the stans" as the countries considered to be within the region all have names ending with the Persian suffix "-stan", meaning "land of". Central Asia has a population of about 72 million, consisting of five republics: Kazakhstan, Tajikistan and Uzbekistan. Afghanistan, a part of South Asia, is sometimes included in Central Asia. Central Asia has been tied to its nomadic peoples and the Silk Road, it has acted as a crossroads for the movement of people and ideas between Europe, Western Asia, South Asia, East Asia. The Silk Road connected Muslim lands with the people of Europe and China; this crossroads position has intensified the conflict between tribalism and traditionalism and modernization. In pre-Islamic and early Islamic times, Central Asia was predominantly Iranian, populated by Eastern Iranian-speaking Bactrians, Sogdians and the semi-nomadic Scythians and Dahae.
After expansion by Turkic peoples, Central Asia became the homeland for the Kazakhs, Tatars, Turkmen and Uyghurs. From the mid-19th century until the end of the 20th century, most of Central Asia was part of the Russian Empire and the Soviet Union, both Slavic-majority countries, the five former Soviet "-stans" are still home to about 7 million ethnic Russians and 500,000 Ukrainians; the idea of Central Asia as a distinct region of the world was introduced in 1843 by the geographer Alexander von Humboldt. The borders of Central Asia are subject to multiple definitions. Built political geography and geoculture are two significant parameters used in the scholarly literature about the definitions of the Central Asia; the most limited definition was the official one of the Soviet Union, which defined Middle Asia as consisting of Uzbekistan, Turkmenistan and Kyrgyzstan, hence omitting Kazakhstan. This definition was often used outside the USSR during this period. However, the Russian culture has two distinct terms: Средняя Азия and Центральная Азия.
Soon after independence, the leaders of the four former Soviet Central Asian Republics met in Tashkent and declared that the definition of Central Asia should include Kazakhstan as well as the original four included by the Soviets. Since this has become the most common definition of Central Asia; the UNESCO History of the Civilizations of Central Asia, published in 1992, defines the region as "Afghanistan, northeastern Iran and central Pakistan, northern India, western China and the former Soviet Central Asian republics."An alternative method is to define the region based on ethnicity, in particular, areas populated by Eastern Turkic, Eastern Iranian, or Mongolian peoples. These areas include Xinjiang Uyghur Autonomous Region, the Turkic regions of southern Siberia, the five republics, Afghan Turkestan. Afghanistan as a whole, the northern and western areas of Pakistan and the Kashmir Valley of India may be included; the Tibetans and Ladakhi are included. Insofar, most of the mentioned peoples are considered the "indigenous" peoples of the vast region.
Central Asia is sometimes referred to as Turkestan. There are several places that claim to be the geographic center of Asia, for example Kyzyl, the capital of Tuva in the Russian Federation, a village 200 miles north of Ürümqi, the capital of the Xinjiang region of China. Central Asia is an large region of varied geography, including high passes and mountains, vast deserts, treeless, grassy steppes; the vast steppe areas of Central Asia are considered together with the steppes of Eastern Europe as a homogeneous geographical zone known as the Eurasian Steppe. Much of the land of Central Asia is too rugged for farming; the Gobi desert extends from the foot of the Pamirs, 77° E, to the Great Khingan Mountains, 116°–118° E. Central Asia has the following geographic extremes: The world's northernmost desert, at Buurug Deliin Els, Mongolia, 50°18' N; the Northern Hemisphere's southernmost permafrost, at Erdenetsogt sum, Mongolia, 46°17' N. The world's shortest distance between non-frozen desert and permafrost: 770 km.
The Eurasian pole of inaccessibility. A majority of the people earn a living by herding livestock. Industrial activity centers in the region's cities. Major rivers of the region include the Amu Darya, the Syr Darya, the Hari River and the Murghab River. Major bodies of water include the Aral Sea and Lake Balkhash, both of which are part of the huge west-central Asian endorheic basin that includes the Caspian Sea. Both of these bodies of water have shrunk in recent decades due to diversion of water from rivers that feed them for irrigation and industrial purposes. Water is an valuable resource in arid Central Asia and can lead to rather significant international disputes. Central Asia is bounded on the north by the forests of Siberia; the northern half of Cent
Animals are multicellular eukaryotic organisms that form the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, grow from a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from 8.5 millionths of a metre to 33.6 metres and have complex interactions with each other and their environments, forming intricate food webs. The category includes humans, but in colloquial use the term animal refers only to non-human animals; the study of non-human animals is known as zoology. Most living animal species are in the Bilateria, a clade whose members have a bilaterally symmetric body plan; the Bilateria include the protostomes—in which many groups of invertebrates are found, such as nematodes and molluscs—and the deuterostomes, containing the echinoderms and chordates.
Life forms interpreted. Many modern animal phyla became established in the fossil record as marine species during the Cambrian explosion which began around 542 million years ago. 6,331 groups of genes common to all living animals have been identified. Aristotle divided animals into those with those without. Carl Linnaeus created the first hierarchical biological classification for animals in 1758 with his Systema Naturae, which Jean-Baptiste Lamarck expanded into 14 phyla by 1809. In 1874, Ernst Haeckel divided the animal kingdom into the multicellular Metazoa and the Protozoa, single-celled organisms no longer considered animals. In modern times, the biological classification of animals relies on advanced techniques, such as molecular phylogenetics, which are effective at demonstrating the evolutionary relationships between animal taxa. Humans make use of many other animal species for food, including meat and eggs. Dogs have been used in hunting, while many aquatic animals are hunted for sport.
Non-human animals have appeared in art from the earliest times and are featured in mythology and religion. The word "animal" comes from the Latin animalis, having soul or living being; the biological definition includes all members of the kingdom Animalia. In colloquial usage, as a consequence of anthropocentrism, the term animal is sometimes used nonscientifically to refer only to non-human animals. Animals have several characteristics. Animals are eukaryotic and multicellular, unlike bacteria, which are prokaryotic, unlike protists, which are eukaryotic but unicellular. Unlike plants and algae, which produce their own nutrients animals are heterotrophic, feeding on organic material and digesting it internally. With few exceptions, animals breathe oxygen and respire aerobically. All animals are motile during at least part of their life cycle, but some animals, such as sponges, corals and barnacles become sessile; the blastula is a stage in embryonic development, unique to most animals, allowing cells to be differentiated into specialised tissues and organs.
All animals are composed of cells, surrounded by a characteristic extracellular matrix composed of collagen and elastic glycoproteins. During development, the animal extracellular matrix forms a flexible framework upon which cells can move about and be reorganised, making the formation of complex structures possible; this may be calcified, forming structures such as shells and spicules. In contrast, the cells of other multicellular organisms are held in place by cell walls, so develop by progressive growth. Animal cells uniquely possess the cell junctions called tight junctions, gap junctions, desmosomes. With few exceptions—in particular, the sponges and placozoans—animal bodies are differentiated into tissues; these include muscles, which enable locomotion, nerve tissues, which transmit signals and coordinate the body. There is an internal digestive chamber with either one opening or two openings. Nearly all animals make use of some form of sexual reproduction, they produce haploid gametes by meiosis.
These fuse to form zygotes, which develop via mitosis into a hollow sphere, called a blastula. In sponges, blastula larvae swim to a new location, attach to the seabed, develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement, it first invaginates to form a gastrula with a digestive chamber and two separate germ layers, an external ectoderm and an internal endoderm. In most cases, a third germ layer, the mesoderm develops between them; these germ layers differentiate to form tissues and organs. Repeated instances of mating with a close relative during sexual reproduction leads to inbreeding depression within a population due to the increased prevalence of harmful recessive traits. Animals have evolved numerous mechanisms for avoiding close inbreeding. In some species, such as the splendid fairywren, females benefit by mating with multiple males, thus producing more offspring of higher genetic quality; some animals are capable of asexual reproduction, which results
Norway the Kingdom of Norway, is a Nordic country in Northern Europe whose territory comprises the western and northernmost portion of the Scandinavian Peninsula. The Antarctic Peter I Island and the sub-Antarctic Bouvet Island are dependent territories and thus not considered part of the kingdom. Norway lays claim to a section of Antarctica known as Queen Maud Land. Norway has a total area of 385,207 square kilometres and a population of 5,312,300; the country shares a long eastern border with Sweden. Norway is bordered by Finland and Russia to the north-east, the Skagerrak strait to the south, with Denmark on the other side. Norway has an extensive coastline, facing the Barents Sea. Harald V of the House of Glücksburg is the current King of Norway. Erna Solberg has been prime minister since 2013. A unitary sovereign state with a constitutional monarchy, Norway divides state power between the parliament, the cabinet and the supreme court, as determined by the 1814 constitution; the kingdom was established in 872 as a merger of a large number of petty kingdoms and has existed continuously for 1,147 years.
From 1537 to 1814, Norway was a part of the Kingdom of Denmark-Norway, from 1814 to 1905, it was in a personal union with the Kingdom of Sweden. Norway was neutral during the First World War. Norway remained neutral until April 1940 when the country was invaded and occupied by Germany until the end of Second World War. 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 the Sámi Parliament and the Finnmark Act. Norway maintains close ties with both 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, the Nordic Council. Norway maintains the Nordic welfare model with universal health care and a comprehensive social security system, 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, lumber and fresh water.
The petroleum industry accounts for around a quarter of the country's gross domestic product. On 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-highest per capita income in the world on the World IMF lists. On the CIA's GDP per capita list which includes autonomous territories and regions, Norway ranks as number eleven, it has the world's largest sovereign wealth fund, with a value of US$1 trillion. Norway has had the highest Human Development Index ranking in the world since 2009, a position held between 2001 and 2006, it had the highest inequality-adjusted ranking until 2018 when Iceland moved to the top of the list. Norway ranked first on the World Happiness Report for 2017 and ranks first on the OECD Better Life Index, the Index of Public Integrity, the Democracy Index. Norway has one of the lowest crime rates in the world. Norway has two official names: Norge in Noreg in Nynorsk; the English name Norway comes from the Old English word Norþweg mentioned in 880, meaning "northern way" or "way leading to the north", how the Anglo-Saxons referred to the coastline of Atlantic Norway similar to scientific consensus about the origin of the Norwegian language name.
The Anglo-Saxons of Britain referred to the kingdom of Norway in 880 as Norðmanna land. There is some disagreement about whether the native name of Norway had the same etymology as the English form. According to the traditional dominant view, the first component was 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, contrasting with suðrvegar "southern way" for, austrvegr "eastern way" for the Baltic. In the translation of Orosius for Alfred, the name is Norðweg, while in younger Old English sources the ð is gone. In the 10th century many Norsemen settled in Northern France, according to the sagas, in the area, called Normandy from norðmann, although not a Norwegian possession. In France normanni or northmanni referred to people of Sweden or Denmark; until around 1800 inhabitants of Western Norway where referred to as nordmenn while inhabitants of Eastern Norway where referred to as austmenn. According to another theory, the first component was a word nór, meaning "narrow" or "northern", referring to the inner-archipelago sailing route through the land.
The interpretation as "northern", as reflected in the English and Latin forms of the name, would have been due to folk etymology. This latter view originated with philologist Niels Halvorsen Trønnes in 1847; the form Nore is still used in placenames such as the village of Nore and lake Norefjorden in Buskerud county, still has the same meaning. Among other arguments in favour of the theor
Systema Naturae is one of the major works of the Swedish botanist and physician Carl Linnaeus and introduced the Linnaean taxonomy. Although the system, now known as binomial nomenclature, was developed by the Bauhin brothers and Johann, 200 years earlier, Linnaeus was first to use it throughout his book; the first edition was published in 1735. The full title of the 10th edition, the most important one, was Systema naturæ per regna tria naturæ, secundum classes, genera, cum characteribus, synonymis, locis or translated: "System of nature through the three kingdoms of nature, according to classes, orders and species, with characters, synonyms, places"; the tenth edition of this book is considered the starting point of zoological nomenclature. In 1766 -- 1768 Linnaeus published the last under his authorship. Another again enhanced work in the same style and titled "Systema Naturae" was published by Johann Friedrich Gmelin between 1788 and 1793. Since at least the early 1900s zoologists recognized this as the last edition belonging to this series.
It was officially regarded by the ICZN in Opinion 296 as the 13th edition of Systema Naturae. Linnaeus published the first edition of Systema Naturae in the year 1735, during his stay in the Netherlands; as was customary for the scientific literature of its day, the book was published in Latin. In it, he outlined his ideas for the hierarchical classification of the natural world, dividing it into the animal kingdom, the plant kingdom, the "mineral kingdom". Linnaeus's Systema Naturae lists only about 10,000 species of organisms, of which about 6,000 are plants and 4,236 are animals. According to the historian of botany William T. Stearn, "Even in 1753 he believed that the number of species of plants in the whole world would hardly reach 10,000, his sexual system, where species with the same number of stamens were treated in the same group, was convenient but in his view artificial. Linnaeus believed in God's creation, that there were no deeper relationships to be expressed, he is quoted to have said: "God created, Linnaeus organized".
The classification of animals was more natural. For instance, humans were for the first time placed together as Anthropomorpha; as a result of the popularity of the work, the number of new specimens sent to him from around the world, Linnaeus kept publishing new and ever-expanding editions of his work. It grew from eleven large pages in the first edition to 2,400 pages in the 12th edition; as the work progressed, he made changes: in the first edition, whales were classified as fishes, following the work of Linnaeus' friend and "father of ichthyology" Peter Artedi. In this same edition, he introduced two-part names for animal species, something that he had done for plant species in the 1753 publication of Species Plantarum; the system developed into modern Linnaean taxonomy, a hierarchically organized biological classification. After Linnaeus' health declined in the early 1770s, publication of editions of Systema Naturae went in two directions. Another Swedish scientist, Johan Andreas Murray issued the Regnum Vegetabile section separately in 1774 as the Systema Vegetabilium, rather confusingly labelled the 13th edition.
Meanwhile, a 13th edition of the entire Systema appeared in parts between 1788 and 1793. It was as the Systema Vegetabilium that Linnaeus' work became known in England following translation from the Latin by the Lichfield Botanical Society, as A System of Vegetables. In his Imperium Naturæ, Linnaeus established three kingdoms, namely Regnum Animale, Regnum Vegetabile and Regnum Lapideum; this approach, the Animal and Mineral Kingdoms, survives until today in the popular mind, notably in the form of parlour games: "Is it animal, vegetable or mineral?". The classification was based on five levels: kingdom, order and species. While species and genus was seen as God-given, the three higher levels were seen by Linnaeus as constructs; the concept behind the set ranks being applied to all groups was to make a system, easy to remember and navigate, a task which most say he succeeded in. Linnaeus's work had a huge impact on science. Two of his works, the first edition of the Species Plantarum for plants and the 10th edition of the Systema Naturæ, are accepted among the starting points of nomenclature.
Most of his names for species and genera were published at early dates, thus take priority over those of other works. In zoology there is one exception, a monograph on Swedish spiders, Svenska Spindlar, published by Carl Clerck in 1757, so the names established there take priority over the Linnean names. However, his impact on science was not because of the value of his taxonomy, his talent for attracting skillful young students and sending them abroad to collect made his work far more influential than that of his contemporaries. At the close of the 18th century, his syste
Carl Linnaeus known after his ennoblement as Carl von Linné, was a Swedish botanist and zoologist who formalised binomial nomenclature, the modern system of naming organisms. He is known as the "father of modern taxonomy". Many of his writings were in Latin, his name is rendered in Latin as Carolus Linnæus. Linnaeus was born in the countryside of Småland in southern Sweden, he received most of his higher education at Uppsala University and began giving lectures in botany there in 1730. He lived abroad between 1735 and 1738, where he studied and published the first edition of his Systema Naturae in the Netherlands, he returned to Sweden where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on several journeys through Sweden to find and classify plants and animals. In the 1750s and 1760s, he continued to collect and classify animals and minerals, while publishing several volumes, he was one of the most acclaimed scientists in Europe at the time of his death. Philosopher Jean-Jacques Rousseau sent him the message: "Tell him I know no greater man on earth."
Johann Wolfgang von Goethe wrote: "With the exception of Shakespeare and Spinoza, I know no one among the no longer living who has influenced me more strongly." Swedish author August Strindberg wrote: "Linnaeus was in reality a poet who happened to become a naturalist." Linnaeus has been called Princeps botanicorum and "The Pliny of the North". He is considered as one of the founders of modern ecology. In botany and zoology, the abbreviation L. is used to indicate Linnaeus as the authority for a species' name. In older publications, the abbreviation "Linn." is found. Linnaeus's remains comprise the type specimen for the species Homo sapiens following the International Code of Zoological Nomenclature, since the sole specimen that he is known to have examined was himself. Linnaeus was born in the village of Råshult in Småland, Sweden, on 23 May 1707, he was the first child of Christina Brodersonia. His siblings were Anna Maria Linnæa, Sofia Juliana Linnæa, Samuel Linnæus, Emerentia Linnæa, his father taught him Latin as a small child.
One of a long line of peasants and priests, Nils was an amateur botanist, a Lutheran minister, the curate of the small village of Stenbrohult in Småland. Christina was the daughter of the rector of Samuel Brodersonius. A year after Linnaeus's birth, his grandfather Samuel Brodersonius died, his father Nils became the rector of Stenbrohult; the family moved into the rectory from the curate's house. In his early years, Linnaeus seemed to have a liking for plants, flowers in particular. Whenever he was upset, he was given a flower, which calmed him. Nils spent much time in his garden and showed flowers to Linnaeus and told him their names. Soon Linnaeus was given his own patch of earth. Carl's father was the first in his ancestry to adopt a permanent surname. Before that, ancestors had used the patronymic naming system of Scandinavian countries: his father was named Ingemarsson after his father Ingemar Bengtsson; when Nils was admitted to the University of Lund, he had to take on a family name. He adopted the Latinate name Linnæus after a giant linden tree, lind in Swedish, that grew on the family homestead.
This name was spelled with the æ ligature. When Carl was born, he was named Carl Linnæus, with his father's family name; the son always spelled it with the æ ligature, both in handwritten documents and in publications. Carl's patronymic would have been Nilsson, as in Carl Nilsson Linnæus. Linnaeus's father began teaching him basic Latin and geography at an early age; when Linnaeus was seven, Nils decided to hire a tutor for him. The parents picked a son of a local yeoman. Linnaeus did not like him, writing in his autobiography that Telander "was better calculated to extinguish a child's talents than develop them". Two years after his tutoring had begun, he was sent to the Lower Grammar School at Växjö in 1717. Linnaeus studied going to the countryside to look for plants, he reached the last year of the Lower School when he was fifteen, taught by the headmaster, Daniel Lannerus, interested in botany. Lannerus gave him the run of his garden, he introduced him to Johan Rothman, the state doctor of Småland and a teacher at Katedralskolan in Växjö.
A botanist, Rothman broadened Linnaeus's interest in botany and helped him develop an interest in medicine. By the age of 17, Linnaeus had become well acquainted with the existing botanical literature, he remarks in his journal that he "read day and night, knowing like the back of my hand, Arvidh Månsson's Rydaholm Book of Herbs, Tillandz's Flora Åboensis, Palmberg's Serta Florea Suecana, Bromelii Chloros Gothica and Rudbeckii Hortus Upsaliensis...."Linnaeus entered the Växjö Katedralskola in 1724, where he studied Greek, Hebrew and mathematics, a curriculum designed for boys preparing for the priesthood. In the last year at the gymnasium, Linnaeus's father visited to ask the professors how his son's studies were progressing. Rothman believed otherwise; the doctor offered to have Linnaeus live with his family in Växjö and to teach him physiology and botany. Nils accepted this offer. Rothman showed Linnaeus that botany was a serious sub
Devon known as Devonshire, its common and official name, is a county of England, reaching from the Bristol Channel in the north to the English Channel in the south. It is part of South West England, bounded by Cornwall to the west, Somerset to the north east, Dorset to the east; the city of Exeter is the county town. The county includes the districts of East Devon, Mid Devon, North Devon, South Hams, Teignbridge and West Devon. Plymouth and Torbay are each geographically part of Devon, but are administered as unitary authorities. Combined as a ceremonial county, Devon's area is 6,707 km2 and its population is about 1.1 million. Devon derives its name from Dumnonia. During the British Iron Age, Roman Britain, the early Middle Ages, this was the homeland of the Dumnonii Brittonic Celts; the Anglo-Saxon settlement of Britain resulted in the partial assimilation of Dumnonia into the Kingdom of Wessex during the eighth and ninth centuries. The western boundary with Cornwall was set at the River Tamar by King Æthelstan in 936.
Devon was constituted as a shire of the Kingdom of England. The north and south coasts of Devon each have both cliffs and sandy shores, the county's bays contain seaside resorts, fishing towns, ports; the inland terrain is rural and hilly, has a lower population density than many other parts of England. Dartmoor is the largest open space in southern England, at 954 km2. To the north of Dartmoor are the Culm Measures and Exmoor. In the valleys and lowlands of south and east Devon the soil is more fertile, drained by rivers including the Exe, the Culm, the Teign, the Dart, the Otter; as well as agriculture, much of the economy of Devon is based on tourism. The comparatively mild climate and landscape make Devon a destination for recreation and leisure in England, with visitors attracted to the Dartmoor and Exmoor national parks; the name Devon derives from the name of the Britons who inhabited the southwestern peninsula of Britain at the time of the Roman conquest of Britain known as the Dumnonii, thought to mean "deep valley dwellers" from proto Celtic *dubnos'deep'.
In the Brittonic, Devon is known as Welsh: Dyfnaint, Breton: Devnent and Cornish: Dewnens, each meaning "deep valleys." Among the most common Devon placenames is -combe which derives from Brittonic cwm meaning'valley' prefixed by the name of the possessor. William Camden, in his 1607 edition of Britannia, described Devon as being one part of an older, wider country that once included Cornwall: THAT region which, according to the Geographers, is the first of all Britaine, growing straiter still and narrower, shooteth out farthest into the West, was in antient time inhabited by those Britans whom Solinus called Dumnonii, Ptolomee Damnonii For their habitation all over this Countrey is somewhat low and in valleys, which manner of dwelling is called in the British tongue Dan-munith, in which sense the Province next adjoyning in like respect is at this day named by the Britans Duffneit, to say, Low valleys, but the Country of this nation is at this day divided into two parts, knowen by names of Cornwall and Denshire, The term "Devon" is used for everyday purposes e.g. "Devon County Council" but "Devonshire" continues to be used in the names of the "Devonshire and Dorset Regiment" and "The Devonshire Association".
One erroneous theory is that the "shire" suffix is due to a mistake in the making of the original letters patent for the Duke of Devonshire, resident in Derbyshire. However, there are references to "Defenascire" in Anglo-Saxon texts from before 1000 AD, which translates to modern English as "Devonshire"; the term Devonshire may have originated around the 8th century, when it changed from Dumnonia to Defenascir. Kents Cavern in Torquay had produced. Dartmoor is thought to have been occupied by Mesolithic hunter-gatherer peoples from about 6000 BC; the Romans held the area under military occupation for around 350 years. The area began to experience Saxon incursions from the east around 600 AD, firstly as small bands of settlers along the coasts of Lyme Bay and southern estuaries and as more organised bands pushing in from the east. Devon became a frontier between Brittonic and Anglo-Saxon Wessex, it was absorbed into Wessex by the mid 9th century. A genetic study carried out by the University of Oxford & University College London discovered separate genetic groups in Cornwall and Devon, not only were there differences on either side of the Tamar, with a division exactly along the modern county boundary dating back to the 6th Century but between Devon and the rest of Southern England, similarities with the modern northern France, including Brittany.
This suggests the Anglo-Saxon migration into Devon was limited rather than a mass movement of people. The border with Cornwall was set by King Æthelstan on the east bank of the River Tamar in 936 AD. Danish raids occurred sporadically along many coastal parts of Devon between around 800AD and just before the time of the Norman conquest, including the silver mint at Hlidaforda Lydford in 997 and Taintona in 1001. Devon has featured in most of th
Amphibians are ectothermic, tetrapod vertebrates of the class Amphibia. Modern amphibians are all Lissamphibia, they inhabit a wide variety of habitats, with most species living within terrestrial, arboreal or freshwater aquatic ecosystems. Thus amphibians start out as larvae living in water, but some species have developed behavioural adaptations to bypass this; the young undergo metamorphosis from larva with gills to an adult air-breathing form with lungs. Amphibians use their skin as a secondary respiratory surface and some small terrestrial salamanders and frogs lack lungs and rely on their skin, they are superficially similar to lizards but, along with mammals and birds, reptiles are amniotes and do not require water bodies in which to breed. With their complex reproductive needs and permeable skins, amphibians are ecological indicators; the earliest amphibians evolved in the Devonian period from sarcopterygian fish with lungs and bony-limbed fins, features that were helpful in adapting to dry land.
They diversified and became dominant during the Carboniferous and Permian periods, but were displaced by reptiles and other vertebrates. Over time, amphibians shrank in size and decreased in diversity, leaving only the modern subclass Lissamphibia; the three modern orders of amphibians are Anura and Apoda. The number of known amphibian species is 8,000, of which nearly 90% are frogs; the smallest amphibian in the world is a frog from New Guinea with a length of just 7.7 mm. The largest living amphibian is the 1.8 m Chinese giant salamander, but this is dwarfed by the extinct 9 m Prionosuchus from the middle Permian of Brazil. The study of amphibians is called batrachology, while the study of both reptiles and amphibians is called herpetology; the word "amphibian" is derived from the Ancient Greek term ἀμφίβιος, which means "both kinds of life", ἀμφί meaning "of both kinds" and βιος meaning "life". The term was used as a general adjective for animals that could live on land or in water, including seals and otters.
Traditionally, the class Amphibia includes all tetrapod vertebrates. Amphibia in its widest sense was divided into three subclasses, two of which are extinct: Subclass Lepospondyli† Subclass Temnospondyli† Subclass Lissamphibia Salientia: Jurassic to present—6,200 current species in 53 families Caudata: Jurassic to present—652 current species in 9 families Gymnophiona: Jurassic to present—192 current species in 10 families The actual number of species in each group depends on the taxonomic classification followed; the two most common systems are the classification adopted by the website AmphibiaWeb, University of California and the classification by herpetologist Darrel Frost and the American Museum of Natural History, available as the online reference database "Amphibian Species of the World". The numbers of species cited above follows Frost and the total number of known amphibian species as of March 31, 2019 is 8,000, of which nearly 90% are frogs. With the phylogenetic classification, the taxon Labyrinthodontia has been discarded as it is a polyparaphyletic group without unique defining features apart from shared primitive characteristics.
Classification varies according to the preferred phylogeny of the author and whether they use a stem-based or a node-based classification. Traditionally, amphibians as a class are defined as all tetrapods with a larval stage, while the group that includes the common ancestors of all living amphibians and all their descendants is called Lissamphibia; the phylogeny of Paleozoic amphibians is uncertain, Lissamphibia may fall within extinct groups, like the Temnospondyli or the Lepospondyli, in some analyses in the amniotes. This means that advocates of phylogenetic nomenclature have removed a large number of basal Devonian and Carboniferous amphibian-type tetrapod groups that were placed in Amphibia in Linnaean taxonomy, included them elsewhere under cladistic taxonomy. If the common ancestor of amphibians and amniotes is included in Amphibia, it becomes a paraphyletic group. All modern amphibians are included in the subclass Lissamphibia, considered a clade, a group of species that have evolved from a common ancestor.
The three modern orders are Anura and Gymnophiona. It has been suggested that salamanders arose separately from a Temnospondyl-like ancestor, that caecilians are the sister group of the advanced reptiliomorph amphibians, thus of amniotes. Although the fossils of several older proto-frogs with primitive characteristics are known, the oldest "true frog" is Prosalirus bitis, from the Early Jurassic Kayenta Formation of Arizona, it is anatomically similar to modern frogs. The oldest known caecilian is another Early Jurassic species, Eocaecilia micropodia from Arizona; the earliest salamander is Beiyanerpeton jianpingensis from the Late Jurassic of northeastern China. Authorities disagree as to whether Salientia is a superorder that includes the order Anura, or whether