Siberia is an extensive geographical region spanning much of Eurasia and North Asia. Siberia has been a part of modern Russia since the 17th century; the territory of Siberia extends eastwards from the Ural Mountains to the watershed between the Pacific and Arctic drainage basins. The Yenisei River conditionally divides Siberia into two parts and Eastern. Siberia stretches southwards from the Arctic Ocean to the hills of north-central Kazakhstan and to the national borders of Mongolia and China. With an area of 13.1 million square kilometres, Siberia accounts for 77% of Russia's land area, but it is home to 36 million people—27% of the country's population. This is equivalent to an average population density of about 3 inhabitants per square kilometre, making Siberia one of the most sparsely populated regions on Earth. If it were a country by itself, it would still be the largest country in area, but in population it would be the world's 35th-largest and Asia's 14th-largest. Worldwide, Siberia is well known for its long, harsh winters, with a January average of −25 °C, as well as its extensive history of use by Russian and Soviet administrations as a place for prisons, labor camps, exile.
The origin of the name is unknown. Some sources say that "Siberia" originates from the Siberian Tatar word for "sleeping land". Another account sees the name as the ancient tribal ethnonym of the Sirtya, an ethnic group which spoke a Paleosiberian language; the Sirtya people were assimilated into the Siberian Tatars. The modern usage of the name was recorded in the Russian language after the Empire's conquest of the Siberian Khanate. A further variant claims; the Polish historian Chyliczkowski has proposed that the name derives from the proto-Slavic word for "north", but Anatole Baikaloff has dismissed this explanation. He said that the neighbouring Chinese and Mongolians, who have similar names for the region, would not have known Russian, he suggests that the name might be a combination of two words with Turkic origin, "su" and "bir". The region has paleontological significance, as it contains bodies of prehistoric animals from the Pleistocene Epoch, preserved in ice or in permafrost. Specimens of Goldfuss cave lion cubs and another woolly mammoth from Oymyakon, a woolly rhinoceros from the Kolyma River, bison and horses from Yukagir have been found.
The Siberian Traps were formed by one of the largest-known volcanic events of the last 500 million years of Earth's geological history. Their activity continued for a million years and some scientists consider it a possible cause of the "Great Dying" about 250 million years ago, – estimated to have killed 90% of species existing at the time. At least three species of human lived in Southern Siberia around 40,000 years ago: H. sapiens, H. neanderthalensis, the Denisovans. In 2010 DNA evidence identified the last as a separate species. Siberia was inhabited by different groups of nomads such as the Enets, the Nenets, the Huns, the Scythians and the Uyghurs; the Khan of Sibir in the vicinity of modern Tobolsk was known as a prominent figure who endorsed Kubrat as Khagan of Old Great Bulgaria in 630. The Mongols conquered a large part of this area early in the 13th century. With the breakup of the Golden Horde, the autonomous Khanate of Sibir was established in the late 15th century. Turkic-speaking Yakut migrated north from the Lake Baikal region under pressure from the Mongol tribes during the 13th to 15th century.
Siberia remained a sparsely populated area. Historian John F. Richards wrote: "... it is doubtful that the total early modern Siberian population exceeded 300,000 persons."The growing power of Russia in the West began to undermine the Siberian Khanate in the 16th century. First, groups of traders and Cossacks began to enter the area; the Russian Army was directed to establish forts farther and farther east to protect new settlers from European Russia. Towns such as Mangazeya, Tara and Tobolsk were developed, the last being declared the capital of Siberia. At this time, Sibir was the name of a fortress at Qashlik, near Tobolsk. Gerardus Mercator, in a map published in 1595, marks Sibier both as the name of a settlement and of the surrounding territory along a left tributary of the Ob. Other sources contend that the Xibe, an indigenous Tungusic people, offered fierce resistance to Russian expansion beyond the Urals; some suggest. By the mid-17th century, Russia had established areas of control; some 230,000 Russians had settled in Siberia by 1709.
Siberia was a destination for sending exiles. The first great modern change in Siberia was the Trans-Siberian Railway, constructed during 1891–1916, it linked Siberia more to the industrialising Russia of Nicholas II. Around seven million people moved to Siberia from European Russia between 1801 and 1914. From 1859 to 1917, more than half a million people migrated to the Russian Far East. Siberia has extensive natural resources. During the 20th century, large-scale exploitation of these was developed, industrial towns cropped up throughout the region. At 7:15 a.m. on 30 June 1908, millions of trees were felled near the Podkamennaya Tunguska River in central Siberia in the Tunguska Event. Most scientists believe this resulted from the air burst of a comet. Though no crater has been found, the landscape in the area still bears the scars of this event. In the early decades of the Soviet Union (
The Atlas Mountains are a mountain range in the Maghreb. It stretches around 2,500 km through Morocco and Tunisia; the range's highest peak is Toubkal, with an elevation of 4,167 metres in southwestern Morocco. It separates the Atlantic coastlines from the Sahara Desert; the Atlas mountains are inhabited by Berber populations. The terms for'mountain' in some Berber languages are adrar and adras, which are believed to be cognates of the toponym Atlas; the mountains are home to a number of animal and plants unique in Africa more like those of Europe. The basement rock of most of Africa was formed during the Precambrian supereon and is much older than the Atlas Mountains lying on the continent; the Atlas was formed during three subsequent phases of Earth's geology. The first tectonic deformation phase involves only the Anti-Atlas, formed in the Paleozoic Era as the result of continental collisions. North America and Africa were connected millions of years ago; the Anti-Atlas Mountains are believed to have been formed as part of Alleghenian orogeny.
These mountains were formed when Africa and America collided, were once a chain rivaling today's Himalayas. Today, the remains of this chain can be seen in the Fall Line region in the Eastern United States; some remnants can be found in the formed Appalachians in North America. A second phase took place during the Mesozoic Era, it consisted of a widespread extension of the Earth's crust that rifted and separated the continents mentioned above. This extension was responsible for the formation of many thick intracontinental sedimentary basins including the present Atlas. Most of the rocks forming the surface of the present High Atlas were deposited under the ocean at that time. In the Paleogene and Neogene Periods, the mountain chains that today constitute the Atlas were uplifted, as the land masses of Europe and Africa collided at the southern end of the Iberian Peninsula; such convergent tectonic boundaries occur where two plates slide towards each other forming a subduction zone, and/or a continental collision.
In the case of the Africa-Europe collision, it is clear that tectonic convergence is responsible for the formation of the High Atlas, as well as for the closure of the Strait of Gibraltar and the formation of the Alps and the Pyrenees. However, there is a lack of evidence for the nature of the subduction in the Atlas region, or for the thickening of the Earth's crust associated with continental collisions. In fact, one of the most striking features of the Atlas to geologists is the relative small amount of crustal thickening and tectonic shortening despite the important altitude of the mountain range. Recent studies suggest that deep processes rooted in the Earth's mantle may have contributed to the uplift of the High and Middle Atlas; the Atlas are rich in natural resources. There are deposits of iron ore, lead ore, silver, rock salt, marble, anthracite coal and natural gas among other resources; the range can be divided into four general regions: High Atlas and Middle Atlas. Tell Atlas. Aurès Mountains.
Saharan Atlas. The Anti-Atlas extends from the Atlantic Ocean in the southwest of Morocco toward the northeast to the heights of Ouarzazate and further east to the city of Tafilalt. In the south it borders the Sahara; the easternmost point of the anti-Atlas is the Jbel Saghro range and its northern boundary is flanked by sections of the High Atlas range. It includes the Djebel Siroua, a massif of volcanic origin with the highest summit of the range at 3,304 m; the Jebel Bani is a much lower range running along the southern side of the Anti Atlas. The High Atlas in central Morocco rises in the west at the Atlantic coast and stretches in an eastern direction to the Moroccan-Algerian border, it has several peaks over 4,000 m, including the highest summit in North Africa and further east Ighil m'Goun the second major summit of the range. At the Atlantic and to the southwest, the range drops abruptly and makes a transition to the coast and the Anti-Atlas range. To the north, in the direction of Marrakesh, the range descends less abruptly.
On the heights of Ouarzazate the massif is cut through by the Draa Valley. It is inhabited by Berber people, who live in small villages and cultivate the high plains of the Ourika Valley. Near Barrage Cavagnac there is a hydroelectric dam that has created the artificial lake Lalla Takerkoust; the lake serves as a source for fish for the local fishermen. The largest villages and towns of the area are Ouarzazate, Amizmiz, Tin Mal and Ijoukak; the Middle Atlas is in Morocco and is the northernmost of its main three Atlas ranges. The range lies north of High Atlas, separated by the Moulouya and Oum Er-Rbia rivers, south of the Rif mountains, separated by the Sebou River. To the west are the main coastal plains of Morocco with many of the major cities and, to the east, the high barren plateau that lies between the Saharan and Tell Atlas; the high point of the range is the jbel Bou Naceur. The Middle Atlas experiences more rain than the ranges to the south, making it an important water catchment for the coastal plains and important for biodiversity.
It is home
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
Bird feet and legs
The anatomy of bird legs and feet is diverse, encompassing many accommodations to perform a wide variety of functions. Most birds are classified as digitigrade animals, meaning they walk on their toes, rather than the entire foot; some of the lower bones of the foot are fused to form the tarsometatarsus – a third segment of the leg, specific to birds. The upper bones of the foot, in turn, are fused with the tibia to form the tibiotarsus, as over time the centralia disappeared; the fibula reduced. The legs are attached to a strong assembly consisting of the pelvic girdle extensively fused with the uniform spinal bone called the synsacrum, built from some of the fused bones. Birds are digitigrade animals, which affects the structure of their leg skeleton, they use only their hindlimbs to walk. Their forelimbs evolved to become wings. Most bones of the avian foot are fused together or with other bones, having changed their function over time; some lower bones of the foot are fused to form the tarsometatarsus – a third segment of the leg specific to birds.
It consists of merged distals and metatarsals II, III and IV. Metatarsus I remains separated as a base of the first toe; the tarsometatarsus is the extended foot area. The foot's upper bones are fused with the tibia to form the tibiotarsus, while the centralia are absent; the anterior side of the dorsal end of the tibiotarsus contains a protruding enlargement called the cnemial crest. At the knee above the cnemial crest is the patella; some species do not have patellas, sometimes only a small extension of the cnemial crest. In grebes both a normal patella and an extension of the cnemial crest are found; the fibula is reduced and adheres extensively to the tibia reaching two-thirds of its length. Only penguins have full-length fibulae; the bird knee joint between the femur and tibia points is hidden within the feathers. The backward-pointing "heel", visible is a joint between the tibiotarsus and tarsometatarsus; the joint inside the tarsus occurs in some reptiles. It is worth noting here that the name "thick knee" of the members of the Burhinidae family is misnomer because their heels are large.
The chicks in the orders Coraciiformes and Piciformes have ankles covered by a patch of tough skins with tubercles known as the heel-pad. They use the heel-pad to shuffle inside the nest holes. Most birds have four toes three facing forward and one pointing backward. In a typical perching bird, they consist of 3, 4, 5 and 2 phalanges; some birds, like the sanderling, have only the forward-facing toes. Others, like the ostrich, have only two toes; the first digit, called the hallux, is homologous to the human big toe. The claws are located on the extreme phalanx of each toe, they consist of a horny keratinous podotheca, or sheath, are not part of the skeleton. The bird foot contains one or two metatarsals not fused in the tarsometatarsus; the legs are attached to a strong, lightweight assembly consisting of the pelvic girdle extensively fused with the uniform spinal bone called the synsacrum, specific to birds. The synsacrum is built from the lumbar fused with the sacral, some of the first sections of the caudal, sometimes the last one or two sections of the thoracic vertebrae, depending on species.
Except for those of ostriches and rheas, pubic bones do not connect to each other, easing egg-laying. Fusions of individual bones into strong, rigid structures are characteristic. Most major bird bones are extensively pneumatized, they contain many air pockets connected to the pulmonary air sacs of the respiratory system. Their spongy interior makes them strong relative to their mass; the number of pneumatic bones depends on the species. For example, in the long-tailed duck, the leg and wing bones are not pneumatic, in contrast with some of the other bones, while loonsand puffins have more massive skeletons with no aired bones; the flightless ostrich and emu have pneumatic femurs, so far this is the only known pneumatic bone in these birds except for the ostrich's cervical vertebrae. Fusions and pneumatic bones are some of the many adaptations of birds for flight. Most birds, except grebes, are digitigrade, not plantigrade. Chicks in the nest can use the entire foot with the heel on the ground. Loons tend to walk this way because their legs and pelvis are specialized for swimming.
They have a narrow pelvis, which moves the attachment point of the femur to the rear, their tibiotarsus is much longer than the femur. This shifts the feet behind the center of mass of the loon body, they walk by pushing themselves on their breasts. This position, however, is suitable for swimming because their feet are located at the rear like the propeller on a motorboat. Grebes and many other waterfowl have shorter femur and a more or less narrow pelvis, which gives the impression that their legs are attached to the rear as in loons; because avian forelimbs are wings, many forelimb functions are performed by hindlimbs. It has been proposed; some leg and foot functions, including conventional ones and those specific to birds, are: Locomotion Walking, running hopping, climbing (woodpecker
Old English, or Anglo-Saxon, is the earliest historical form of the English language, spoken in England and southern and eastern Scotland in the early Middle Ages. It was brought to Great Britain by Anglo-Saxon settlers in the mid-5th century, the first Old English literary works date from the mid-7th century. After the Norman conquest of 1066, English was replaced, for a time, as the language of the upper classes by Anglo-Norman, a relative of French; this is regarded as marking the end of the Old English era, as during this period the English language was influenced by Anglo-Norman, developing into a phase known now as Middle English. Old English developed from a set of Anglo-Frisian or Ingvaeonic dialects spoken by Germanic tribes traditionally known as the Angles and Jutes; as the Anglo-Saxons became dominant in England, their language replaced the languages of Roman Britain: Common Brittonic, a Celtic language, Latin, brought to Britain by Roman invasion. Old English had four main dialects, associated with particular Anglo-Saxon kingdoms: Mercian, Northumbrian and West Saxon.
It was West Saxon that formed the basis for the literary standard of the Old English period, although the dominant forms of Middle and Modern English would develop from Mercian. The speech of eastern and northern parts of England was subject to strong Old Norse influence due to Scandinavian rule and settlement beginning in the 9th century. Old English is one of the West Germanic languages, its closest relatives are Old Frisian and Old Saxon. Like other old Germanic languages, it is different from Modern English and difficult for Modern English speakers to understand without study. Old English grammar is similar to that of modern German: nouns, adjectives and verbs have many inflectional endings and forms, word order is much freer; the oldest Old English inscriptions were written using a runic system, but from about the 9th century this was replaced by a version of the Latin alphabet. Englisc, which the term English is derived from, means'pertaining to the Angles'. In Old English, this word was derived from Angles.
During the 9th century, all invading Germanic tribes were referred to as Englisc. It has been hypothesised that the Angles acquired their name because their land on the coast of Jutland resembled a fishhook. Proto-Germanic *anguz had the meaning of'narrow', referring to the shallow waters near the coast; that word goes back to Proto-Indo-European *h₂enǵʰ- meaning'narrow'. Another theory is that the derivation of'narrow' is the more connection to angling, which itself stems from a Proto-Indo-European root meaning bend, angle; the semantic link is the fishing hook, curved or bent at an angle. In any case, the Angles may have been called such because they were a fishing people or were descended from such, therefore England would mean'land of the fishermen', English would be'the fishermen's language'. Old English was not static, its usage covered a period of 700 years, from the Anglo-Saxon settlement of Britain in the 5th century to the late 11th century, some time after the Norman invasion. While indicating that the establishment of dates is an arbitrary process, Albert Baugh dates Old English from 450 to 1150, a period of full inflections, a synthetic language.
Around 85 per cent of Old English words are no longer in use, but those that survived are basic elements of Modern English vocabulary. Old English is a West Germanic language, it came to be spoken over most of the territory of the Anglo-Saxon kingdoms which became the Kingdom of England. This included most of present-day England, as well as part of what is now southeastern Scotland, which for several centuries belonged to the Anglo-Saxon kingdom of Northumbria. Other parts of the island – Wales and most of Scotland – continued to use Celtic languages, except in the areas of Scandinavian settlements where Old Norse was spoken. Celtic speech remained established in certain parts of England: Medieval Cornish was spoken all over Cornwall and in adjacent parts of Devon, while Cumbric survived to the 12th century in parts of Cumbria, Welsh may have been spoken on the English side of the Anglo-Welsh border. Norse was widely spoken in the parts of England which fell under Danish law. Anglo-Saxon literacy developed after Christianisation in the late 7th century.
The oldest surviving text of Old English literature is Cædmon's Hymn, composed between 658 and 680. There is a limited corpus of runic inscriptions from the 5th to 7th centuries, but the oldest coherent runic texts date to the 8th century; the Old English Latin alphabet was introduced around the 9th century. With the unification of the Anglo-Saxon kingdoms by Alfred the Great in the 9th century, the language of government and literature became standardised around the West Saxon dialect. Alfred advocated education in English alongside Latin, had many works translated into the English language. In Old English, typical of the development of literature, poetry arose before prose, but King Alfred the Great chiefly inspired the growth of prose. A literary standard, dating from the 10th century, arose under the influence of Bishop Æthelwold of Winchester, was followed by such writers as the prolific Ælfric of Eynsham. Th