A chordate is an animal constituting the phylum Chordata. During some period of their life cycle, chordates possess a notochord, a dorsal nerve cord, pharyngeal slits, an endostyle, a post-anal tail: these five anatomical features define this phylum. Chordates are bilaterally symmetric; the Chordata and Ambulacraria together form the superphylum Deuterostomia. Chordates are divided into three subphyla: Vertebrata. There are extinct taxa such as the Vetulicolia. Hemichordata has been presented as a fourth chordate subphylum, but now is treated as a separate phylum: hemichordates and Echinodermata form the Ambulacraria, the sister phylum of the Chordates. Of the more than 65,000 living species of chordates, about half are bony fish that are members of the superclass Osteichthyes. Chordate fossils have been found from as early as the Cambrian explosion, 541 million years ago. Cladistically, vertebrates - chordates with the notochord replaced by a vertebral column during development - are considered to be a subgroup of the clade Craniata, which consists of chordates with a skull.
The Craniata and Tunicata compose the clade Olfactores. Chordates form a phylum of animals that are defined by having at some stage in their lives all of the following anatomical features: A notochord, a stiff rod of cartilage that extends along the inside of the body. Among the vertebrate sub-group of chordates the notochord develops into the spine, in wholly aquatic species this helps the animal to swim by flexing its tail. A dorsal neural tube. In fish and other vertebrates, this develops into the spinal cord, the main communications trunk of the nervous system. Pharyngeal slits; the pharynx is the part of the throat behind the mouth. In fish, the slits are modified to form gills, but in some other chordates they are part of a filter-feeding system that extracts particles of food from the water in which the animals live. Post-anal tail. A muscular tail that extends backwards behind the anus. An endostyle; this is a groove in the ventral wall of the pharynx. In filter-feeding species it produces mucus to gather food particles, which helps in transporting food to the esophagus.
It stores iodine, may be a precursor of the vertebrate thyroid gland. There are soft constraints that separate chordates from certain other biological lineages, but are not part of the formal definition: All chordates are deuterostomes; this means. All chordates are based on a bilateral body plan. All chordates are coelomates, have a fluid filled body cavity called a coelom with a complete lining called peritoneum derived from mesoderm; the following schema is from the third edition of Vertebrate Palaeontology. The invertebrate chordate classes are from Fishes of the World. While it is structured so as to reflect evolutionary relationships, it retains the traditional ranks used in Linnaean taxonomy. Phylum Chordata †Vetulicolia? Subphylum Cephalochordata – Class Leptocardii Clade Olfactores Subphylum Tunicata – Class Ascidiacea Class Thaliacea Class Appendicularia Class Sorberacea Subphylum Vertebrata Infraphylum incertae sedis Cyclostomata Superclass'Agnatha' paraphyletic Class Myxini Class Petromyzontida or Hyperoartia Class †Conodonta Class †Myllokunmingiida Class †Pteraspidomorphi Class †Thelodonti Class †Anaspida Class †Cephalaspidomorphi Infraphylum Gnathostomata Class †Placodermi Class Chondrichthyes Class †Acanthodii Superclass Osteichthyes Class Actinopterygii Class Sarcopterygii Superclass Tetrapoda Class Amphibia Class Sauropsida Class Synapsida Craniates, one of the three subdivisions of chordates, all have distinct skulls.
They include the hagfish. Michael J. Benton commented that "craniates are characterized by their heads, just as chordates, or all deuterostomes, are by their tails". Most craniates are vertebrates; these consist of a series of bony or cartilaginous cylindrical vertebrae with neural arches that protect the spinal cord, with projections that link the vertebrae. However hagfish have incomplete braincases and no vertebrae, are therefore not regarded as vertebrates, but as members of the craniates, the group from which vertebrates are thought to have evolved; however the cladistic exclusion of hagfish from the vertebrates is controversial, as they ma
Monsoon of South Asia
The monsoon of South Asia is among several geographically distributed global monsoons. It affects the Indian subcontinent, where it is one of the oldest and most anticipated weather phenomena and an economically important pattern every year from June through September, but it is only understood and notoriously difficult to predict. Several theories have been proposed to explain the origin, strength, variability and general vagaries of the monsoon, but understanding and predictability are still evolving; the unique geographical features of the Indian subcontinent, along with associated atmospheric and geophysical factors, influence the behavior of the monsoon. Because of its effect on agriculture, on flora and fauna, on the climates of nations such as Bangladesh, India, Nepal and Sri Lanka — among other economic and environmental effects — the monsoon is one of the most anticipated and studied weather phenomena in the region, it has a significant effect on the overall well-being of residents and has been dubbed the "real finance minister of India".
The word monsoon, although defined as a system of winds characterized by a seasonal reversal of direction, lacks a consistent, detailed definition. Some examples are: The American Meteorological Society calls it a name for seasonal winds, first applied to the winds blowing over the Arabian Sea from the northeast for six months and from the southwest for six months; the term has since been extended to similar winds in other parts of the world. The Intergovernmental Panel on Climate Change describes a monsoon as a tropical and subtropical seasonal reversal in both surface winds and associated precipitation, caused by differential heating between a continental-scale land mass and the adjacent ocean; the Indian Meteorological Department defines it as the seasonal reversal of the direction of winds along the shores of the Indian Ocean in the Arabian Sea, which blow from the southwest for half of the year and from the northeast for the other half. Colin Stokes Ramage, in Monsoon Meteorology, defines the monsoon as a seasonal reversing wind accompanied by corresponding changes in precipitation.
Observed by sailors in the Arabian Sea traveling between Africa and Southeast Asia, the monsoon can be categorized into two branches based on their spread over the subcontinent: Arabian Sea branch Bay of Bengal branch Alternatively, it can be categorized into two segments based on the direction of rain-bearing winds: Southwest monsoon Northeast monsoonBased on the time of year that these winds bring rain to India, the monsoon can be categorized into two periods: Summer monsoon Winter monsoon The complexity of the monsoon of South Asia is not understood, making it difficult to predict the quantity and geographic distribution of the accompanying precipitation. These are the most monitored components of the monsoon, they determine the water availability in India for any given year. Monsoons occur in tropical areas. One area that monsoons impact is India. In India monsoons create an entire season. Various atmospheric conditions influence the monsoon winds; the first condition is the differential cooling of land and water.
This creates low pressure on the landmass, while high pressure is created over the seas during daytime, but is reversed during the night time. The second condition is the shift in the position of Inter-Tropical Convergence Zone. In summer, the equatorial trough positioned about 5°N of the equator moves over the Ganga plain creating a monsoon trough during the monsoon season; the third condition is the presence of the high-pressure area. It is at 20°S over the Indian Ocean; the intensity and position of this high-pressure area affects the Indian Monsoon. The fourth condition develops during the summer; the Tibetan Plateau gets intensely heated resulting in strong vertical air currents and high pressure over the plateau about 9 km above sea level. The fifth condition develops during the summer due to the movement of the westerly jet streams to the north of the Himalayas and the presence of the tropical easterly jet stream over the Indian Peninsula. Changes in pressure over the southern oceans affect the monsoons.
In certain years, there is a reversal in the pressure conditions. This periodic change in pressure conditions is known as the Southern Oscillation, or SO; the Southern Oscillation is connected to la nina, a warm ocean current that flows past the Peruvian Coast. It flows every two to five years in place of the cold Peruvian current; the phenomenon is, referred to as ENSO. In India, the monsoon lasts for 100 to 120 days to mid-September; the monsoon winds encounter various atmospheric conditions on their way and hence are pulsating in nature, not steady. The monsoon arrives with a sudden downpour of rainfall; this is known as the ‘burst’ of the monsoon. The rainfall is a result of the convergence of wind flow from the Bay of Bengal and reverse winds from the South China Sea; the onset of the monsoon occurs over the Bay of Bengal in May, arriving at the Indian Peninsula by June, the winds move towards the South China Sea. By early September, the monsoon is a more gradual process. By mid-October, it withdraws from the northern half of the peninsula.
The withdrawal takes place progressively from north to south from the first week of December to the first week of January. This is the start of t
Sylhet Division, is the northeastern division of Bangladesh, named after its main city, Sylhet. It is bordered by the Indian states of Meghalaya and Tripura to the north and south, respectively. Along with the Indian districts of the Barak Valley, it forms the Greater Sylhet region. Sylhet is an archaeologically rich region of South Asia, has a number of Islamic Sufi shrines; the modern-day Sylhet Division was known as the Jalalabad district in Pakistan. In 1971, Sylhet became part of the newly formed independent country of Bangladesh but remained in the Chittagong Division until 1995; the Sylhet region has a "friendship link" with the city of St Albans, in the United Kingdom. The link was established in 1988 when the St Albans District Council supported a housing project in Sylhet as part of the International Year of Shelter for the Homeless. Sylhet was chosen because it is the area of origin for the largest ethnic minority group in St Albans. According to the St. Albans District Council: the majority of British Bangladeshis are of Sylheti ethnic origin.
The area around Sylhet is a traditional tea growing area. The Surma Valley is covered with terraces of tropical forests. Srimangal is known as the tea capital of Bangladesh; the area has over 150 tea gardens, including three of the largest tea plantations in the world, both in terms of area and production. Nearly 300,000 workers, of which more than 75% are women, are employed on the tea estates. Employers prefer to engage women for plucking tea leaves since they do a better job than, but are paid less than, men. A recent drought has killed nearly a tenth of the tea shrubs; the plantations, or gardens, were developed during the British Raj. The plantations were started by the British, the managers still live in the white timber houses built during the Raj; the bungalows stand on huge lawns. The service and the lifestyle of managers are still unchanged. Numerous projects and businesses in the city and in large towns have been funded by Sylhetis living and working abroad; as of 1986, an estimated 95 percent of ethnic British Bangladeshis originated from or had ancestors from the Sylhet region.
The Bangladesh government has set up a special Export Processing Zone in Sylhet, in order to attract foreign investors from the UK. Sylhet has benefited from Tourism. There are many natural landmarks people tend to visit, such as the Keane Bridge, Amjad Ali Clock, Jaflong, Lakatura Tea Garden, Madhabkunda Waterfall, Raturgal Swamp Forest, Tilagor Haor and Bishnakandi. Sylhet is considered to be the spiritual capital of Bangladesh, due to the resting place of Shahjalal, a Sufi saint who spread Islam in Bangladesh, located in the Shahjalal Mazar, along with another well-known disciple of Shahjalal, Shah Poran Mazar and Shahi Eidgah, a famous place where Eid Prayers take place and it is some of the largest Eidgahs in Bangladesh, created by Mughals during the reign of Aurangzeb. There are a number of resorts. There is Sreemangal Upazila in Moulvibazar and Bahubal in Habiganj. Many Sylheti try to marry spouses within the same regional, cultural and religious backgrounds. Sylheti people are considered a distinct ethnic group in Bangladesh.
These tendencies have led to some rivalry between non-Sylhetis and Sylhetis, due to differences in customs. Marriages are practiced in a traditional Muslim style, with henna ritual, prayers. Sylheti marriages include contracts of marriage outlining the rights and obligations of both partners. People in Sylhet marry partners living in the United Kingdom and the US, of communities from the district, its unique culture and economy, linguistic differences developed in part because the Greater Sylhet region was a part of Assam and Surma Valley State for about 100 years during the British Raj. There is a considerable flow of foreign currency sent from Sylhetis abroad to family in Bangladesh.. In 1995, Sylhet was declared the 6th division of the country. Prior to that it was part of the Chittagong Division; the Sylhet Division is subdivided into four districts: Habiganj, Moulvibazar and Sylhet. Further, the Sylhet Division contains 35 sub-districts, 323 union parishad, 10,185 villages and 14 municipalities.
Population: 10 million, less than 7% of the total population of Bangladesh. Sylhet is a holy place for both Hindus, it is known as the land of 360 awliyas. Famous religious places include the shrines of Shah Jalal, Shah Farhan, Shah Kamal Quhafa in Shaharpara and Sipahsalar Syed Nasiruddin in Habiganj for Muslims. Sylhet has the largest concentration of Hindus in Bangladesh and is an important centre for believers, it is part of the global Shakti Peethas, holy places of cosmic and enormous power, where Goddess Durga is worshipped. Of the fifty-one body parts of Sati, one form of Durga, that fell on Earth, Her neck fell on the south side of Surma River across the Sylhet town and her left palm fell in Jayanti. In addition, Sri Krishna Chaitnaya Mahaprabhu, the God of all Humanity and who will reappear during the kaliyug or end of time, visited his paternal family home in Thakurbari, Dhakadakshin and his maternal family home in Joypur, Habiganj in Sylhet Division in the 16th century. Hindu temples, such as Shri Chaitanya Dev Mandir in Dhakadakshin, Kali Mandir of Jainpur, Narayan Shiva Mandir of Khasa
Wikispecies is a wiki-based online project supported by the Wikimedia Foundation. Its aim is to create a comprehensive free content catalogue of all species. Jimmy Wales stated that editors are not required to fax in their degrees, but that submissions will have to pass muster with a technical audience. Wikispecies is available under the GNU Free Documentation License and CC BY-SA 3.0. Started in September 2004, with biologists across the world invited to contribute, the project had grown a framework encompassing the Linnaean taxonomy with links to Wikipedia articles on individual species by April 2005. Benedikt Mandl co-ordinated the efforts of several people who are interested in getting involved with the project and contacted potential supporters in early summer 2004. Databases were evaluated and the administrators contacted, some of them have agreed on providing their data for Wikispecies. Mandl defined two major tasks: Figure out how the contents of the data base would need to be presented—by asking experts, potential non-professional users and comparing that with existing databases Figure out how to do the software, which hardware is required and how to cover the costs—by asking experts, looking for fellow volunteers and potential sponsorsAdvantages and disadvantages were discussed by the wikimedia-I mailing list.
The board of directors of the Wikimedia Foundation voted by 4 to 0 in favor of the establishment of a Wikispecies. The project is hosted at species.wikimedia.org. It was merged to a sister project of Wikimedia Foundation on September 14, 2004. On October 10, 2006, the project exceeded 75,000 articles. On May 20, 2007, the project exceeded 100,000 articles with a total of 5,495 registered users. On September 8, 2008, the project exceeded 150,000 articles with a total of 9,224 registered users. On October 23, 2011, the project reached 300,000 articles. On June 16, 2014, the project reached 400,000 articles. On January 7, 2017, the project reached 500,000 articles. On October 30, 2018, the project reached 600,000 articles, a total of 1.12 million pages. Wikispecies comprises taxon pages, additionally pages about synonyms, taxon authorities, taxonomical publications, institutions or repositories holding type specimen. Wikispecies asks users to use images from Wikimedia Commons. Wikispecies does not allow the use of content.
All Species Foundation Catalogue of Life Encyclopedia of Life Tree of Life Web Project List of online encyclopedias The Plant List Wikispecies, The free species directory that anyone can edit Species Community Portal The Wikispecies Charter, written by Wales
Nepal the Federal Democratic Republic of Nepal, is a landlocked country in South Asia. It is located in the Himalayas but includes parts of the Indo-Gangetic Plain. With an estimated population of 26.4 million, it is 48th largest country by population and 93rd largest country by area. It borders China in the north and India in the south and west while Bangladesh is located within only 27 km of its southeastern tip and Bhutan is separated from it by the Indian state of Sikkim. Nepal has a diverse geography, including fertile plains, subalpine forested hills, eight of the world's ten tallest mountains, including Mount Everest, the highest point on Earth. Kathmandu is largest city. Nepal is a multiethnic nation with Nepali as the official language; the name "Nepal" is first recorded in texts from the Vedic period of the Indian subcontinent, the era in ancient India when Hinduism was founded, the predominant religion of the country. In the middle of the first millennium BCE, Gautama Buddha, the founder of Buddhism, was born in Lumbini in southern Nepal.
Parts of northern Nepal were intertwined with the culture of Tibet. The centrally located Kathmandu Valley is intertwined with the culture of Indo-Aryans, was the seat of the prosperous Newar confederacy known as Nepal Mandala; the Himalayan branch of the ancient Silk Road was dominated by the valley's traders. The cosmopolitan region developed distinct traditional architecture. By the 18th century, the Gorkha Kingdom achieved the unification of Nepal; the Shah dynasty established the Kingdom of Nepal and formed an alliance with the British Empire, under its Rajput Rana dynasty of premiers. The country was never colonized but served as a buffer state between Imperial China and British India. Parliamentary democracy was introduced in 1951, but was twice suspended by Nepalese monarchs, in 1960 and 2005; the Nepalese Civil War in the 1990s and early 2000s resulted in the proclamation of a secular republic in 2008, ending the world's last Hindu monarchy. The Constitution of Nepal, adopted in 2015, establishes Nepal as a federal secular parliamentary republic divided into seven provinces.
Nepal was admitted to the United Nations in 1955, friendship treaties were signed with India in 1950 and the People's Republic of China in 1960. Nepal hosts the permanent secretariat of the South Asian Association for Regional Cooperation, of which it is a founding member. Nepal is a member of the Non Aligned Movement and the Bay of Bengal Initiative; the military of Nepal is the fifth largest in South Asia. Local legends have it that a Hindu sage named "Ne" established himself in the valley of Kathmandu in prehistoric times, that the word "Nepal" came into existence as the place was protected by the sage "Nemi", it is mentioned in Vedic texts. According to the Skanda Purana, a rishi called. In the Pashupati Purana, he is mentioned as a protector, he is said to have taught there. The name of the country is identical in origin to the name of the Newar people; the terms "Nepāl", "Newār", "Newāl" and "Nepār" are phonetically different forms of the same word, instances of the various forms appear in texts in different times in history.
Nepal is the learned Sanskrit form and Newar is the colloquial Prakrit form. A Sanskrit inscription dated 512 CE found in Tistung, a valley to the west of Kathmandu, contains the phrase "greetings to the Nepals" indicating that the term "Nepal" was used to refer to both the country and the people, it has been suggested that "Nepal" may be a Sanskritization of "Newar", or "Newar" may be a form of "Nepal". According to another explanation, the words "Newar" and "Newari" are vulgarisms arising from the mutation of P to V, L to R. Neolithic tools found in the Kathmandu Valley indicate that people have been living in the Himalayan region for at least eleven thousand years. Nepal is first mentioned in the late Vedic Atharvaveda Pariśiṣṭa as a place exporting blankets, in the post-Vedic Atharvashirsha Upanishad. In Samudragupta's Allahabad Pillar it is mentioned as a border country; the Skanda Purana has a separate chapter, known as "Nepal Mahatmya", with more details. Nepal is mentioned in Hindu texts such as the Narayana Puja.
Legends and ancient texts that mention the region now known as Nepal reach back to the 30th century BC. The Gopal Bansa were one of the earliest inhabitants of Kathmandu valley; the earliest rulers of Nepal were the Kiratas, peoples mentioned in Hindu texts, who ruled Nepal for many centuries. Various sources mention up to 32 Kirati kings. Around 500 BCE, small kingdoms and confederations of clans arose in the southern regions of Nepal. From one of these, the Shakya polity, arose a prince who renounced his status to lead an ascetic life, founded Buddhism, came to be known as Gautama Buddha. By 250 BCE, the southern regions had come under the influence of the Maurya Empire of North India and became a vassal state under the Gupta Empire in the 4th century CE. There is a quite detailed description of the kingdom of Nepal in the account of the renowned Chinese Buddhist pilgrim monk Xuanzang, dating from about 645 CE. Stone inscriptions in the Kathmandu Valley are important sources for the history of Nepal.
The kings of the Lichhavi dynasty have been found to have r
Binomial nomenclature called binominal nomenclature or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. Such a name is called a binomen, binominal name or a scientific name; the first part of the name – the generic name – identifies the genus to which the species belongs, while the second part – the specific name or specific epithet – identifies the species within the genus. For example, humans belong within this genus to the species Homo sapiens. Tyrannosaurus rex is the most known binomial; the formal introduction of this system of naming species is credited to Carl Linnaeus beginning with his work Species Plantarum in 1753. But Gaspard Bauhin, in as early as 1623, had introduced in his book Pinax theatri botanici many names of genera that were adopted by Linnaeus; the application of binomial nomenclature is now governed by various internationally agreed codes of rules, of which the two most important are the International Code of Zoological Nomenclature for animals and the International Code of Nomenclature for algae and plants.
Although the general principles underlying binomial nomenclature are common to these two codes, there are some differences, both in the terminology they use and in their precise rules. In modern usage, the first letter of the first part of the name, the genus, is always capitalized in writing, while that of the second part is not when derived from a proper noun such as the name of a person or place. Both parts are italicized when a binomial name occurs in normal text, thus the binomial name of the annual phlox is now written as Phlox drummondii. In scientific works, the authority for a binomial name is given, at least when it is first mentioned, the date of publication may be specified. In zoology "Patella vulgata Linnaeus, 1758"; the name "Linnaeus" tells the reader who it was that first published a description and name for this species of limpet. "Passer domesticus". The original name given by Linnaeus was Fringilla domestica; the ICZN does not require that the name of the person who changed the genus be given, nor the date on which the change was made, although nomenclatorial catalogs include such information.
In botany "Amaranthus retroflexus L." – "L." is the standard abbreviation used in botany for "Linnaeus". "Hyacinthoides italica Rothm. – Linnaeus first named this bluebell species Scilla italica. The name is composed of two word-forming elements: "bi", a Latin prefix for two, "-nomial", relating to a term or terms; the word "binomium" was used in Medieval Latin to mean a two-term expression in mathematics. Prior to the adoption of the modern binomial system of naming species, a scientific name consisted of a generic name combined with a specific name, from one to several words long. Together they formed a system of polynomial nomenclature; these names had two separate functions. First, to designate or label the species, second, to be a diagnosis or description. In a simple genus, containing only two species, it was easy to tell them apart with a one-word genus and a one-word specific name; such "polynomial names" may sometimes look like binomials, but are different. For example, Gerard's herbal describes various kinds of spiderwort: "The first is called Phalangium ramosum, Branched Spiderwort.
The other... is aptly termed Phalangium Ephemerum Virginianum, Soon-Fading Spiderwort of Virginia". The Latin phrases are short descriptions, rather than identifying labels; the Bauhins, in particular Caspar Bauhin, took some important steps towards the binomial system, by pruning the Latin descriptions, in many cases to two words. The adoption by biologists of a system of binomial nomenclature is due to Swedish botanist and physician Carl von Linné, more known by his Latinized name Carl Linnaeus, it was in his 1753 Species Plantarum that he first began using a one-word "trivial name" together with a generic name in a system of binomial nomenclature. This trivial name is what is now known as specific name; the Bauhins' genus names were retained in many of these, but the descriptive part was reduced to a single word. Linnaeus's trivial names introduced an important new idea, namely that the function of a name could be to give a species a unique label; this meant. Thus Gerard's Phalangium ephemerum virginianum became Tradescantia virgi