Poaceae or Gramineae is a large and nearly ubiquitous family of monocotyledonous flowering plants known as grasses referred to collectively as grass. Poaceae includes the cereal grasses and the grasses of natural grassland and cultivated lawns and pasture. Grasses have stems that are hollow except at the nodes and narrow alternate leaves borne in two ranks; the lower part of each leaf encloses the stem. With around 780 genera and around 12,000 species, Poaceae are the fifth-largest plant family, following the Asteraceae, Orchidaceae and Rubiaceae. Grasslands such as savannah and prairie where grasses are dominant are estimated to constitute 40.5% of the land area of the Earth, excluding Greenland and Antarctica. Grasses are an important part of the vegetation in many other habitats, including wetlands and tundra; the Poaceae are the most economically important plant family, providing staple foods from domesticated cereal crops such as maize, rice and millet as well as forage, building materials and fuel.
Though they are called "grasses", seagrasses and sedges fall outside this family. The rushes and sedges are related to the Poaceae, being members of the order Poales, but the seagrasses are members of order Alismatales; the name Poaceae was given by John Hendley Barnhart in 1895, based on the tribe Poeae described in 1814 by Robert Brown, the type genus Poa described in 1753 by Carl Linnaeus. The term is derived from the Ancient Greek πόα. Grasses include some of the most versatile plant life-forms, they became widespread toward the end of the Cretaceous period, fossilized dinosaur dung have been found containing phytoliths of a variety that include grasses that are related to modern rice and bamboo. Grasses have adapted to conditions in lush rain forests, dry deserts, cold mountains and intertidal habitats, are the most widespread plant type. A cladogram shows subfamilies and approximate species numbers in brackets: Before 2005, fossil findings indicated that grasses evolved around 55 million years ago.
Recent findings of grass-like phytoliths in Cretaceous dinosaur coprolites have pushed this date back to 66 million years ago. In 2011, revised dating of the origins of the rice tribe Oryzeae suggested a date as early as 107 to 129 Mya. Wu, You & Li described grass microfossils extracted from a specimen of the hadrosauroid dinosaur Equijubus normani from the Early Cretaceous Zhonggou Formation; the authors noted that India became separated from Antarctica, therefore all other continents at the beginning of late Aptian, so the presence of grasses in both India and China during the Cretaceous indicates that the ancestor of Indian grasses must have existed before late Aptian. Wu, You & Li considered the Barremian origin for grasses to be probableThe relationships among the three subfamilies Bambusoideae and Pooideae in the BOP clade have been resolved: Bambusoideae and Pooideae are more related to each other than to Oryzoideae; this separation occurred within the short time span of about 4 million years.
According to Lester Charles King the spread of grasses in the Late Cenozoic would have changed patterns of hillslope evolution favouring slopes that are convex upslope and concave downslope and lacking a free face were common. King argued that this was the result of more acting surface wash caused by carpets of grass which in turn would have resulted in more soil creep. Grasses may be annual or perennial herbs with the following characteristics: The stems of grasses, called culms, are cylindrical and are hollow, plugged at the nodes, where the leaves are attached. Grass leaves are nearly always alternate and distichous, have parallel veins; each leaf is differentiated into a lower sheath hugging a blade with entire margins. The leaf blades of many grasses are hardened with silica phytoliths, which discourage grazing animals. A membranous appendage or fringe of hairs called the ligule lies at the junction between sheath and blade, preventing water or insects from penetrating into the sheath. Flowers of Poaceae are characteristically arranged in each having one or more florets.
The spikelets are further grouped into spikes. The part of the spikelet that bears the florets is called the rachilla. A spikelet consists of two bracts at called glumes, followed by one or more florets. A floret consists of the flower surrounded by two bracts, one external—the lemma—and one internal—the palea; the flowers are hermaphroditic—maize being an important exception—and anemophilous or wind-pollinated, although insects play a role. The perianth is reduced to two scales, called lodicules, that expand and contract to spread the lemma and palea; this complex structure can be seen in the image on the right. The fruit of grasses is a caryopsis. A tiller is a leafy shoot other than the first shoot produced from the seed. Grass blades grow at the base of the blade and not from elongated stem tips; this low growth point evolved in response to grazing animals and allows grasses to be grazed or mown without severe damage to the plant. Three general classifications of growth habit present in g
A mountain is a large landform that rises above the surrounding land in a limited area in the form of a peak. A mountain is steeper than a hill. Mountains are formed through tectonic forces or volcanism; these forces can locally raise the surface of the earth. Mountains erode through the action of rivers, weather conditions, glaciers. A few mountains are isolated summits. High elevations on mountains produce colder climates than at sea level; these colder climates affect the ecosystems of mountains: different elevations have different plants and animals. Because of the less hospitable terrain and climate, mountains tend to be used less for agriculture and more for resource extraction and recreation, such as mountain climbing; the highest mountain on Earth is Mount Everest in the Himalayas of Asia, whose summit is 8,850 m above mean sea level. The highest known mountain on any planet in the Solar System is Olympus Mons on Mars at 21,171 m. There is no universally accepted definition of a mountain.
Elevation, relief, steepness and continuity have been used as criteria for defining a mountain. In the Oxford English Dictionary a mountain is defined as "a natural elevation of the earth surface rising more or less abruptly from the surrounding level and attaining an altitude which to the adjacent elevation, is impressive or notable."Whether a landform is called a mountain may depend on local usage. Mount Scott outside Lawton, Oklahoma, USA, is only 251 m from its base to its highest point. Whittow's Dictionary of Physical Geography states "Some authorities regard eminences above 600 metres as mountains, those below being referred to as hills." In the United Kingdom and the Republic of Ireland, a mountain is defined as any summit at least 2,000 feet high, whilst the official UK government's definition of a mountain, for the purposes of access, is a summit of 600 metres or higher. In addition, some definitions include a topographical prominence requirement 100 or 500 feet. At one time the U.
S. Board on Geographic Names defined a mountain as being 1,000 feet or taller, but has abandoned the definition since the 1970s. Any similar landform lower. However, the United States Geological Survey concludes that these terms do not have technical definitions in the US; the UN Environmental Programme's definition of "mountainous environment" includes any of the following: Elevation of at least 2,500 m. Using these definitions, mountains cover 33% of Eurasia, 19% of South America, 24% of North America, 14% of Africa; as a whole, 24% of the Earth's land mass is mountainous. There are three main types of mountains: volcanic and block. All three types are formed from plate tectonics: when portions of the Earth's crust move and dive. Compressional forces, isostatic uplift and intrusion of igneous matter forces surface rock upward, creating a landform higher than the surrounding features; the height of the feature makes it either a hill or, if steeper, a mountain. Major mountains tend to occur in long linear arcs, indicating tectonic plate boundaries and activity.
Volcanoes are formed when a plate is pushed at a mid-ocean ridge or hotspot. At a depth of around 100 km, melting occurs in rock above the slab, forms magma that reaches the surface; when the magma reaches the surface, it builds a volcanic mountain, such as a shield volcano or a stratovolcano. Examples of volcanoes include Mount Pinatubo in the Philippines; the magma does not have to reach the surface in order to create a mountain: magma that solidifies below ground can still form dome mountains, such as Navajo Mountain in the US. Fold mountains occur when two plates collide: shortening occurs along thrust faults and the crust is overthickened. Since the less dense continental crust "floats" on the denser mantle rocks beneath, the weight of any crustal material forced upward to form hills, plateaus or mountains must be balanced by the buoyancy force of a much greater volume forced downward into the mantle, thus the continental crust is much thicker under mountains, compared to lower lying areas.
Rock can fold either asymmetrically. The upfolds are anticlines and the downfolds are synclines: in asymmetric folding there may be recumbent and overturned folds; the Balkan Mountains and the Jura Mountains are examples of fold mountains. Block mountains are caused by faults in the crust: a plane; when rocks on one side of a fault rise relative to the other, it can form a mountain. The uplifted blocks are block horsts; the intervening dropped blocks are termed graben: these can be small or form extensive rift valley systems. This form of landscape can be seen in East Africa, the Vosges, the Basin and Range Province of Western North America and the Rhine valley; these areas occur when the regional stress is extensional and the crust is thinned. During and following uplift, mountains are subjected to the agents of erosion which wear the uplifted area down. Erosion causes the surface of mountains to be younger than the rocks that form the mountains themselves. Glacial processes produce characteristic landforms, such as pyramidal peaks, knife-edge arêtes, bowl-shaped cirques that can contai
The Bhagavad Gita referred to as the Gita, is a 700-verse Sanskrit scripture, part of the Hindu epic Mahabharata. The Gita is set in a narrative framework of a dialogue between Pandava prince Arjuna and his guide and charioteer Krishna. At the start of the Dharma Yudhha between Pandavas and Kauravas, Arjuna is filled with moral dilemma and despair about the violence and death the war will cause, he wonders if he should renounce and seeks Krishna's counsel, whose answers and discourse constitute the Bhagadvad Gita. Krishna counsels Arjuna to "fulfill his Kshatriya duty to uphold the Dharma" through "selfless action"; the Krishna–Arjuna dialogue cover a broad range of spiritual topics, touching upon ethical dilemmas and philosophical issues that go far beyond the war Arjuna faces. The Bhagavad Gita presents a synthesis of Hindu ideas about dharma, theistic bhakti, the yogic paths to moksha; the synthesis presents four paths to spirituality – jnana, bhakti and raja yogas. These incorporate ideas from the Vedanta philosophies.
Numerous commentaries have been written on the Bhagavad Gita with differing views on the essentials. Vedanta commentators read varying relations between Self and Brahman in the text: Advaita Vedanta sees the non-dualism of Atman and Brahman as its essence, whereas Bhedabheda and Vishishtadvaita see Atman and Brahman as both different and non-different, Dvaita sees them as different; the setting of the Gita in a battlefield has been interpreted as an allegory for the ethical and moral struggles of the human life. The Bhagavad Gita is the best known and most famous of Hindu texts, with a unique pan-Hindu influence; the Gita's call for selfless action inspired many leaders of the Indian independence movement including Bal Gangadhar Tilak and Mahatma Gandhi. The Gita in the title of the text "Bhagavad Gita" means "song". Religious leaders and scholars interpret the word "Bhagavad" in a number of ways. Accordingly, the title has been interpreted as "the Song of God" by the theistic schools, "the Song of the Lord", "the Divine Song", "the Celestial Song" by others.
The Bhagavad Gita is known as the Isvara Gita, the Ananta Gita, the Hari Gita, the Vyasa Gita, or as the Gita. In the Indian tradition, the Bhagavad Gita, as well as the epic Mahabharata of which it is a part, is attributed to sage Vyasa, whose full name was Krishna Dvaipayana called Veda-Vyasa. Another Hindu legend states that Vyasa narrated it while the elephant-headed deity Ganesha broke one of his tusks and wrote down the Mahabharata along with the Bhagavad Gita. Scholars consider Vyasa to be a mythical or symbolic author, in part because Vyasa is the traditional compiler of the Vedas and the Puranas, texts dated to be from different millennia; the word Vyasa means "arranger, compiler", is a surname in India. According to Kashi Nath Upadhyaya, a Gita scholar, it is possible that a number of different individuals with the same name compiled different texts. Swami Vivekananda, the 19th-century Hindu monk and Vedantist, stated that the Bhagavad Gita may be old but it was unknown in the Indian history till early 8th-century when Adi Shankara made it famous by writing his much-followed commentary on it.
Some infer, states Vivekananda, that "Shankaracharya was the author of Gita, that it was he who foisted it into the body of the Mahabharata." This attribution to Adi Shankara is unlikely in part because Shankara himself refers to the earlier commentaries on the Bhagavad Gita, because other Hindu texts and traditions that compete with the ideas of Shankara refer to much older literature referencing the Bhagavad Gita, though much of this ancient secondary literature has not survived into the modern era. According to J. A. B. van Buitenen, an Indologist known for his translations and scholarship on Mahabharata, the Gita is so contextually and philosophically well knit with the Mahabharata that it was not an independent text that "somehow wandered into the epic". The Gita, states van Buitenen, was conceived and developed by the Mahabharata authors to "bring to a climax and solution the dharmic dilemma of a war". According to Alexus McLeod, a scholar of Philosophy and Asian Studies, it is "impossible to link the Bhagavad Gita to a single author", it may be the work of many authors.
This view is shared by the Indologist Arthur Basham, who states that there were three or more authors or compilers of Bhagavad Gita. This is evidenced by the discontinuous intermixing of philosophical verses with theistic or passionately theistic verses, according to Basham. Theories on the date of the composition of the Gita vary considerably. Scholars accept dates from the fifth century to the second century BCE as the probable range, the latter likely; the Hinduism scholar Jeaneane Fowler, in her commentary on the Gita, considers second century BCE to be the probable date of composition. J. A. B. van Buitenen too states that the Gita was composed about 200 BCE. According to the Indologist Arvind Sharma, the Gita is accepted to be a 2nd-century BCE text. Kashi Nath Upadhyaya, in contrast, dates it a bit earlier, he states that the Gita was always a part of the Mahabharata, dating the latter suffices in dating the Gita. On the basis of the estimated dates of Mahabharata as evidenced by exact quotes of it in the Buddhist literature by Asvaghosa, Upadhyaya states that the Mahabharata, therefore Gita, must have been well known by for a Buddhist to be quoting it.
This suggests a terminus ante quem of the Gita to be sometime prior to the 1st-century CE. He c
Jambudvīpa is the dvīpa of the terrestrial world, as envisioned in the cosmologies of Hinduism and Jainism, the realm where ordinary human beings live. The word Jambudvīpa refers to "the land of Jambu trees" where jambu is the Indian Blackberry ( and dvīpa means "island" or "continent". Surya Siddhanta, an astronomical text, refers to Northern Hemisphere of the earth as Jambudvipa whereas the Southern hemisphere is referred to as Patala. According to Puranic cosmography, the world is divided into seven concentric island continents separated by the seven encircling oceans, each double the size of the preceding one; the seven continents of the Puranas are stated as Jambudvipa, Salmalidvipa, Krouncadvipa and Pushkaradvipa. Seven intermediate oceans consist of salt-water, sugarcane juice, ghee, yogurt and water respectively; the mountain range called Lokaloka, meaning "world-no-world", stretches across this final sea, delineating the known world from the dark void. Continent Jambudvipa known as Sudarshanadvipa, forms the innermost concentric island in the above scheme.
Its name is said to derive from a Jambu tree. The fruits of the Jambu tree are said, in the Viṣṇupurāṇa to be as large as elephants and when they become rotten and fall upon the crest of the mountains, a river of juice is formed from their expressed juice; the river so formed is called Jambunadi and flows through Jambudvipa, whose inhabitants drink its waters. Insular continent Jambudvipa is said to comprise eight significant parvatas. Markandeya Purana portrays Jambudvipa as being depressed on its south and north and elevated and broad in the middle; the elevated region forms the varsha named Meruvarsha. At the center of Ila-vrta lies the golden Mount Meru, the king of mountains. On the summit of Mount Meru, is the vast city of Lord Brahma, known as Brahmapuri. Surrounding Brahmapuri are 8 cities - the one of seven other Devatas. Markandeya Purana and Brahmanda Purana divide Jambudvipa into four vast regions shaped like four petals of a lotus with Mount Meru being located at the center like a pericarp.
The city of Brahmapuri is said to be enclosed by a river, known as Akash Ganga. Akash Ganga is said to issue forth from the foot of Lord Vishnu and after washing the lunar region falls "through the skies" and after encircling the Brahmapuri "splits up into four mighty streams", which are said to flow in four opposite directions from the landscape of Mount Meru and irrigate the vast lands of Jambudvipa; the common names of the dvīpas, having their varṣas with a mountain and a river in each varṣa, is given in several Purāṇas. There is a distinct set of names; the most detailed geography is. The Buddhist cosmology divides the bhūmaṇḍala into three separate levels: Kāmadhātu, Rūpadhātu, Ārūpyadhātu. In the Kāmadhātu is located Mount Sumeru, said to be surrounded by four island-continents. "The southernmost island is called Jambudvīpa". The other three continents of Buddhist accounts around Sumeru are not accessible to humans from Jambudvīpa. Jambudvīpa is shaped like a triangle with a blunted point facing south, somewhat like the Indian subcontinent.
In its center is a gigantic Jambu tree from which the continent takes its name, meaning "Jambu Island". Jambudipa, one of the four Mahādīpas, or great continents, which are included in the Cakkavāla and are ruled by a Cakkavatti, they are grouped round MountSineru. In Jambudīpa is Himavā with its eighty-four thousand peaks, its lakes, mountain ranges, etc; this continent derives its name from the Jambu-tree which grows there, its trunk fifteen yojanas in girth, its outspreading branches fifty yojanas in length, its shade one hundred yojanas in extent and its height one hundred yojanas On account of this tree, Jambudīpa is known as Jambusanda. The continent is ten thousand yojanas in extent. Jambudvīpa is the region where the humans live and is the only place where a being may become enlightened by being born as a human being, it is in Jambudvīpa that one may receive the gift of Dharma and come to understand the Four Noble Truths, the Noble Eightfold Path and realize the liberation from the cycle of life and death.
Another reference is from the Buddhist text Mahavamsa, where the emperor Ashoka's son Mahinda introduces himself to the Sri Lankan king Devanampiyatissa as from Jambudvipa, referring to what is now the Indian subcontinent. According to Jain cosmology, Jambūdvīpa is at the centre of Madhyaloka, or the middle part of the universe, where the humans reside. Jambūdvīpaprajñapti or the treatise on the island of Roseapple tree contains a description of Jambūdvīpa and life biographies of Ṛṣabha and King Bharata. Trilokasāra, Trilokaprajñapti, Trilokadipikā and Kṣetrasamāsa are the other texts that provide the details of Jambūdvīpa and Jain cosmology. Madhyaloka consists of many continent-islands surrounded by oceans, first eight whose names are: Mount Meru is at the centre of the world surrounded by Jambūdvīpa, in form of a circle fo
The Mahābhārata is one of the two major Sanskrit epics of ancient India, the other being the Rāmāyaṇa. It narrates the struggle between two groups of cousins in the Kurukshetra War and the fates of the Kaurava and the Pāṇḍava princes and their succession. Along with the Rāmāyaṇa, it forms the Hindu Itihasa; the Mahābhārata is an epic legendary narrative of the Kurukṣetra War and the fates of the Kaurava and the Pāṇḍava princes. It contains philosophical and devotional material, such as a discussion of the four "goals of life" or puruṣārtha. Among the principal works and stories in the Mahābhārata are the Bhagavad Gita, the story of Damayanti, an abbreviated version of the Rāmāyaṇa, the story of Ṛṣyasringa considered as works in their own right. Traditionally, the authorship of the Mahābhārata is attributed to Vyāsa. There have been many attempts to unravel compositional layers; the oldest preserved parts of the text are thought to be not much older than around 400 BCE, though the origins of the epic fall between the 8th and 9th centuries BCE.
The text reached its final form by the early Gupta period. According to the Mahābhārata itself, the tale is extended from a shorter version of 24,000 verses called Bhārata; the Mahābhārata is the longest epic poem known and has been described as "the longest poem written". Its longest version consists of over 100,000 śloka or over 200,000 individual verse lines, long prose passages. At about 1.8 million words in total, the Mahābhārata is ten times the length of the Iliad and the Odyssey combined, or about four times the length of the Rāmāyaṇa. W. J. Johnson has compared the importance of the Mahābhārata in the context of world civilization to that of the Bible, the works of William Shakespeare, the works of Homer, Greek drama, or the Quran. Within the Indian tradition it is sometimes called the Fifth Veda; the epic is traditionally ascribed to the sage Vyāsa, a major character in the epic. Vyāsa described it as being itihāsa, he describes the Guru-shishya parampara, which traces all great teachers and their students of the Vedic times.
The first section of the Mahābhārata states that it was Gaṇeśa who wrote down the text to Vyasa's dictation. The epic employs the story within a story structure, otherwise known as frametales, popular in many Indian religious and non-religious works, it is first recited at Takshashila by the sage Vaiśampāyana, a disciple of Vyāsa, to the King Janamejaya, the great-grandson of the Pāṇḍava prince Arjuna. The story is recited again by a professional storyteller named Ugraśrava Sauti, many years to an assemblage of sages performing the 12-year sacrifice for the king Saunaka Kulapati in the Naimiśa Forest; the text was described by some early 20th-century western Indologists as chaotic. Hermann Oldenberg supposed that the original poem must once have carried an immense "tragic force" but dismissed the full text as a "horrible chaos." Moritz Winternitz considered that "only unpoetical theologists and clumsy scribes" could have lumped the parts of disparate origin into an unordered whole. Research on the Mahābhārata has put an enormous effort into recognizing and dating layers within the text.
Some elements of the present Mahābhārata can be traced back to Vedic times. The background to the Mahābhārata suggests the origin of the epic occurs "after the early Vedic period" and before "the first Indian'empire' was to rise in the third century B. C." That this is "a date not too far removed from the 8th or 9th century B. C." is likely. Mahābhārata started as an orally-transmitted tale of the charioteer bards, it is agreed that "Unlike the Vedas, which have to be preserved letter-perfect, the epic was a popular work whose reciters would conform to changes in language and style," so the earliest'surviving' components of this dynamic text are believed to be no older than the earliest'external' references we have to the epic, which may include an allusion in Panini's 4th century BCE grammar Aṣṭādhyāyī 4:2:56. It is estimated that the Sanskrit text reached something of a "final form" by the early Gupta period. Vishnu Sukthankar, editor of the first great critical edition of the Mahābhārata, commented: "It is useless to think of reconstructing a fluid text in a original shape, on the basis of an archetype and a stemma codicum.
What is possible? Our objective can only be to reconstruct the oldest form of the text which it is possible to reach on the basis of the manuscript material available." That manuscript evidence is somewhat late, given its material composition and the climate of India, but it is extensive. The Mahābhārata itself distinguishes a core portion of 24,000 verses: the Bhārata proper, as opposed to additional secondary material, while the Aśvalāyana Gṛhyasūtra makes a similar distinction. At least three redactions of the text are recognized: Jaya with 8,800 verses attributed to Vyāsa, Bhārata with 24,000 verses as recited by Vaiśampāyana, the Mahābhārata as recited by Ugraśrava Sauti with over 100,000 verses. However, some scholars, such as John Brockington, argue that Jaya and Bharata refer to the same text, ascribe the theory of Jaya with 8,800 verses to a misreading of a verse in Ādiparvan; the redaction of this large body of text was carried out after formal principles, emphasizing the numbers 18 and 12.
The addition of the latest parts may be dated by the absence of the Anuśāsana-parva and the Virāta parva from the "Spitzer manuscript". The oldest surviving
A continent is one of several large landmasses of the world. Identified by convention rather than any strict criteria, up to seven regions are regarded as continents. Ordered from largest in area to smallest, they are: Asia, North America, South America, Antarctica and Australia. Geologically, the continents correspond to areas of continental crust that are found on the continental plates. However, some areas of continental crust are regions covered with water not included in the list of continents. Zealandia is one such area. Islands are grouped with a neighbouring continent to divide all the world's land into geopolitical regions. Under this scheme, most of the island countries and territories in the Pacific Ocean are grouped together with the continent of Australia to form a geopolitical region called Oceania. By convention, "continents are understood to be large, discrete masses of land, ideally separated by expanses of water." Several of the seven conventionally recognized continents are not discrete landmasses separated by water.
The criterion "large" leads to arbitrary classification: Greenland, with a surface area of 2,166,086 square kilometres is considered the world's largest island, while Australia, at 7,617,930 square kilometres is deemed the smallest continent. Earth's major landmasses all have coasts on a single, continuous World Ocean, divided into a number of principal oceanic components by the continents and various geographic criteria; the most restricted meaning of continent is that of a continuous area of land or mainland, with the coastline and any land boundaries forming the edge of the continent. In this sense the term continental Europe is used to refer to mainland Europe, excluding islands such as Great Britain, Ireland and Iceland, the term continent of Australia may refer to the mainland of Australia, excluding Tasmania and New Guinea; the continental United States refers to the 48 contiguous states and the District of Columbia in central North America and may include Alaska in the northwest of the continent, while excluding Hawaii, Puerto Rico, Guam in the oceans.
From the perspective of geology or physical geography, continent may be extended beyond the confines of continuous dry land to include the shallow, submerged adjacent area and the islands on the shelf, as they are structurally part of the continent. From this perspective, the edge of the continental shelf is the true edge of the continent, as shorelines vary with changes in sea level. In this sense the islands of Great Britain and Ireland are part of Europe, while Australia and the island of New Guinea together form a continent; as a cultural construct, the concept of a continent may go beyond the continental shelf to include oceanic islands and continental fragments. In this way, Iceland is considered Madagascar part of Africa. Extrapolating the concept to its extreme, some geographers group the Australian continental plate with other islands in the Pacific into one continent called Oceania; this divides the entire land surface of Earth into quasi-continents. The ideal criterion that each continent is a discrete landmass is relaxed due to historical conventions.
Of the seven most globally recognized continents, only Antarctica and Australia are separated from other continents by the ocean. Several continents are defined not as distinct bodies but as "more or less discrete masses of land". Asia and Africa are joined by the Isthmus of Suez, North and South America by the Isthmus of Panama. In both cases, there is no complete separation of these landmasses by water. Both these isthmuses are narrow compared to the bulk of the landmasses they unite. North America and South America are treated as separate continents in the seven-continent model. However, they may be viewed as a single continent known as America or the Americas; this viewpoint was common in the United States until World War II, remains prevalent in some Asian six-continent models. This remains the more common vision in Latin American countries, Portugal, Italy and Hungary where they are taught as a single continent; the criterion of a discrete landmass is disregarded if the continuous landmass of Eurasia is classified as two separate continents: Europe and Asia.
Physiographically and South Asia are peninsulas of the Eurasian landmass. However, Europe is considered a continent with its comparatively large land area of 10,180,000 square kilometres, while South Asia, with less than half that area, is considered a subcontinent; the alternative view—in geology and geography—that Eurasia is a single continent results in a six-continent view of the world. Some view separation of Eurasia into Asia and Europe as a residue of Eurocentrism: "In physical and historical diversity and India are comparable to the entire European landmass, not to a single European country.." However, for historical and cultural reasons, the view of Europe as a separate continent continues in several categorizations. If continents are defined as discrete landmasses, embracing all the contiguous land of a body Africa and Europe form a single continent which may be referred to as Afro-Eurasia; this produces a four-continent model consisting of Afro-Eurasia, America and Australia. When sea levels were lower during the Pleistocene ice ages, gre
Devanagari called Nagari, is a left-to-right abugida, based on the ancient Brāhmī script, used in the Indian subcontinent. It was developed in ancient India from the 1st to the 4th century CE, was in regular use by the 7th century CE; the Devanagari script, composed of 47 primary characters including 14 vowels and 33 consonants, is one of the most adopted writing systems in the world, being used for over 120 languages. The ancient Nagari script for Sanskrit had two additional consonantal characters; the orthography of this script reflects the pronunciation of the language. Unlike the Latin alphabet, the script has no concept of letter case, it is written from left to right, has a strong preference for symmetrical rounded shapes within squared outlines, is recognisable by a horizontal line that runs along the top of full letters. In a cursory look, the Devanagari script appears different from other Indic scripts such as Bengali, Odia, or Gurmukhi, but a closer examination reveals they are similar except for angles and structural emphasis.
Among the languages using it – as either their only script or one of their scripts – are Hindi, Pali, Bhojpuri, Braj Bhasha, Haryanvi, Nagpuri, Bhili, Marathi, Maithili, Konkani, Bodo, Nepalbhasa and Santali. The Devanagari script is related to the Nandinagari script found in numerous ancient manuscripts of South India, it is distantly related to a number of southeast Asian scripts. Devanagari is a compound of "deva" देव and "nāgarī" नागरी. Deva meaning "heavenly or divine", is one of the terms for a deity in Hinduism, Nagri comes from नगर, which means abode or city. Hence, Devanagari denotes from the abode of divinity or deities. Devanagari is part of the Brahmic family of scripts of India, Nepal and South-East Asia; some of the earliest epigraphical evidence attesting to the developing Sanskrit Nagari script in ancient India, in a form similar to Devanagari, is from the 1st to 4th century CE inscriptions discovered in Gujarat. It is a descendant of the 3rd century BCE Brahmi script through the Gupta script, along with Siddham and Sharada.
Variants of script called Nāgarī, recognisably close to Devanagari, are first attested from the 1st century CE Rudradaman inscriptions in Sanskrit, while the modern standardised form of Devanagari was in use by about 1000 CE. Medieval inscriptions suggest widespread diffusion of the Nagari-related scripts, with biscripts presenting local script along with the adoption of Nagari scripts. For example, the mid 8th-century Pattadakal pillar in Karnataka has text in both Siddha Matrika script, an early Telugu-Kannada script; the Nagari script was in regular use by the 7th century CE and it was developed by about the end of first millennium. The use of Sanskrit in Nagari script in medieval India is attested by numerous pillar and cave temple inscriptions, including the 11th-century Udayagiri inscriptions in Madhya Pradesh, an inscribed brick found in Uttar Pradesh, dated to be from 1217 CE, now held at the British Museum; the script's proto- and related versions have been discovered in ancient relics outside of India, such as in Sri Lanka and Indonesia.
Nagari has been the primus inter pares of the Indic scripts. It has long been used traditionally by religiously educated people in South Asia to record and transmit information, existing throughout the land in parallel with a wide variety of local scripts used for administration and other daily uses.. Other related scripts such as Siddham Matrka were in use in Indonesia, Vietnam and other parts of East Asia by between 7th- to 10th-century. Sharada remained in parallel use in Kashmir. An early version of Devanagari is visible in the Kutila inscription of Bareilly dated to Vikram Samvat 1049, which demonstrates the emergence of the horizontal bar to group letters belonging to a word. One of the oldest surviving Sanskrit texts from the early post-Maurya period consists of 1,413 Nagari pages of a commentary by Patanjali, with a composition date of about 150 BCE, the surviving copy transcribed about 14th century CE. Nāgarī is the Sanskrit feminine of Nāgara "relating or belonging to a town or city, urban".
It is a phrasing with lipi as nāgarī lipi "script relating to a city", or "spoken in city". The use of the name devanāgarī emerged from the older term nāgarī. According to Fischer, Nagari emerged in the northwest Indian subcontinent around 633 CE, was developed by the 11th-century, was one of the major scripts used for the Sanskrit literature. Most of the southeast Asian scripts have roots in the Dravidian scripts, except for a few found in south-central regions of Java and isolated parts of southeast Asia that resemble Devanagari or its prototype; the Kawi script in particular is similar to the Devanagari in many respects though the morphology of the script has local changes. The earliest inscriptions in the Devanagari-like scripts are from around the 10th-century, with many more between 11th- and 14th-century; some of the old-Devanagari inscriptions are found in Hindu temples of Java, such as the Prambanan temple. The Ligor and the Kalasan inscriptions of central Java, dated to the 8th-century, are in the Nagari script of North India.
According to the epigraphist and Asian Studies scholar Lawrence Briggs, these may be related to the 9th-century copp