title: Pig content: long snout that is strengthened by a special prenasal bone and by a disk of cartilage at the tip. The snout is used to dig into the soil to find food and is a very acute sense organ. There are four hoofed toes on each foot, with the two larger central toes bearing most of the weight, but the outer two also being used in soft ground. The dental formula of adult pigs is , giving a total of 44 teeth. The rear teeth are adapted for crushing. In the male, the canine teeth form tusks, which grow continuously and


title: Pig content: are sharpened by constantly being ground against each other. Occasionally, captive mother pigs may savage their own piglets, often if they become severely stressed. Some attacks on newborn piglets are non-fatal. Others may cause the death of the piglets and sometimes, the mother may eat the piglets. It is estimated that 50% of piglet fatalities are due to the mother attacking, or unintentionally crushing, the newborn pre-weaned animals. With around 1 billion individuals alive at any time, the domestic pig is one of the most numerous large mammals on the planet. The ancestor of the domestic pig is the wild


title: Pig content: boar, which is one of the most numerous and widespread large mammals. Its many subspecies are native to all but the harshest climates of continental Eurasia and its islands and Africa as well, from Ireland and India to Japan and north to Siberia. Long isolated from other pigs on the many islands of Indonesia, Malaysia, and the Philippines, pigs have evolved into many different species, including wild boar, bearded pigs, and warty pigs. Humans have introduced pigs into Australia, North and South America, and numerous islands, either accidentally as escaped domestic pigs which have gone feral, or as wild boar.


title: Pig content: The wild pig ("Sus scrofa") can take advantage of any forage resources. Therefore, it can live in virtually any productive habitat that can provide enough water to sustain large mammals such as pigs. If there is increased foraging of wild pigs in certain areas, it can cause a nutritional shortage which can cause the pig population to decrease. If the nutritional state returns to normal, the pig population will most likely rise due to the pigs' naturally increased reproduction rate. Pigs are omnivores, which means that they consume both plants and animals. In the wild, they are foraging animals, primarily


title: Pig content: eating leaves, roots, fruits, and flowers, in addition to some insects and fish. As livestock, pigs are fed mostly corn and soybean meal with a mixture of vitamins and minerals added to the diet. Traditionally, they were raised on dairy farms and called "mortgage lifters", due to their ability to use the excess milk as well as whey from cheese and butter making combined with pasture. Older pigs will consume three to five gallons of water per day. When kept as pets, the optimal healthy diet consists mainly of a balanced diet of raw vegetables, although some may give their


title: Pig content: pigs conventional mini pig pellet feed. Domesticated pigs, especially miniature breeds, are commonly kept as pets. Domestic pigs are raised commercially as livestock; materials that are garnered include their meat (known as pork), leather, and their bristly hairs which are used to make brushes. Because of their foraging abilities and excellent sense of smell, they are used to find truffles in many European countries. Both wild and feral pigs are commonly hunted. The relatively short, stiff, coarse hairs of the pig are called bristles, and were once so commonly used in paintbrushes that in 1946 the Australian Government launched Operation


title: Pig content: Pig Bristle. In May 1946, in response to a shortage of pig bristles for paintbrushes to paint houses in the post-World War II construction boom, the Royal Australian Air Force (RAAF) flew in 28 short tons of pig bristles from China, their only commercially available source at the time. Human skin is very similar to pig skin, therefore pig skin has been used in many preclinical studies. In addition to providing use in biomedical research and for drug testing, genetic advances in human healthcare have provided a pathway for domestic pigs to become xenotransplantation candidates for humans. The genus "Sus"


title: Pig content: is currently thought to contain eight living species. A number of extinct species (†) are known from fossils. The pygmy hog, formerly "Sus salvanius" is now placed in the monotypic genus "Porcula". Pigs have been domesticated since ancient times in the Old World. Archaeological evidence suggests that pigs were being managed in the wild in a way similar to the way they are managed by some modern New Guineans from wild boar as early as 13,000–12,700 BP in the Near East in the Tigris Basin, Çayönü, Cafer Höyük, Nevalı Çori. Remains of pigs have been dated to earlier than 11,400


title: Pig content: BP in Cyprus that must have been introduced from the mainland which suggests domestication in the adjacent mainland by then. A separate domestication also occurred in China. In India, pigs have been domesticated for a long time mostly in Goa and some rural areas for pig toilets. This was also done in China. Though ecologically logical as well as economical, pig toilets are waning in popularity as use of septic tanks and/or sewerage systems is increasing in rural areas. Pigs were brought to southeastern North America from Europe by Hernando de Soto and other early Spanish explorers. Pigs are particularly


title: Pig content: valued in China and on certain oceanic islands, where their self-sufficiency allows them to be turned loose, although the practice is not without its drawbacks (see environmental impact). The domestic pig ("Sus scrofa domesticus") is usually given the scientific name "Sus scrofa", although some taxonomists call it "S. domesticus", reserving "S. scrofa" for the wild boar. It was domesticated approximately 5,000 to 7,000 years ago. The upper canines form sharp distinctive tusks that curve outward and upward. Compared to other artiodactyles, their head is relatively long, pointed, and free of warts. Their head and body length ranges from and they


title: Pig content: can weigh between . In November 2012, scientists managed to sequence the genome of the domestic pig. The similarities between the pig and human genomes mean that the new data may have wide applications in the study and treatment of human genetic diseases. In August 2015, a study looked at over 100 pig genome sequences to ascertain their process of domestication. The process of domestication was assumed to have been initiated by humans, involved few individuals and relied on reproductive isolation between wild and domestic forms. The study found that the assumption of reproductive isolation with population bottlenecks was not


title: Pig content: supported. The study indicated that pigs were domesticated separately in Western Asia and China, with Western Asian pigs introduced into Europe where they crossed with wild boar. A model that fitted the data included admixture with a now extinct ghost population of wild pigs during the Pleistocene. The study also found that despite back-crossing with wild pigs, the genomes of domestic pigs have strong signatures of selection at DNA loci that affect behavior and morphology. The study concluded that human selection for domestic traits likely counteracted the homogenizing effect of gene flow from wild boars and created domestication islands in


title: Pig content: the genome. The same process may also apply to other domesticated animals. Pigs appear in the traditional and popular arts, media, and cultures of many societies, where they sometimes carry religious symbolism. In Asia the wild boar is one of 12 animal images comprising the Chinese zodiac, while in Europe the boar represents a standard charge in heraldry. In Islam and Judaism pigs and those who handle them are viewed negatively, and the consumption of pork is forbidden. Pigs are frequently alluded to in folk art, idioms, metaphors, and proverbs, and also occasionally in parables (e.g. Parable of the Prodigal


title: Pig content: Son). Domestic pigs that have escaped from urban areas or were allowed to forage in the wild, and in some cases wild boars which were introduced as prey for hunting, have given rise to large populations of feral pigs in North and South America, Australia, New Zealand, Hawaii, and other areas where pigs are not native. Accidental or deliberate releases of pigs into countries or environments where they are an alien species have caused extensive environmental change. Their omnivorous diet, aggressive behaviour, and their feeding method of rooting in the ground all combine to severely alter ecosystems unused to pigs.


title: Pig content: Pigs will even eat small animals and destroy nests of ground nesting birds. The Invasive Species Specialist Group lists feral pigs on the list of the world's 100 worst invasive species and says: Because of the biological similarities between each other, pigs can harbour a range of parasites and diseases that can be transmitted to humans. These include trichinosis, "Taenia solium", cysticercosis, and brucellosis. Pigs are also known to host large concentrations of parasitic ascarid worms in their digestive tract. Some strains of influenza are endemic in pigs. Pigs also can acquire human influenza. Pig A pig is any of


title: "Quad Cities" content: connects Le Claire, Iowa, with Rapids City, Illinois. Continuing downstream, the I-74 Bridge connects Bettendorf, Iowa, with Moline, Illinois, and is the busiest bridge with an average of 70,400 cars a day. The Government Bridge connects Downtown Davenport with the Rock Island Arsenal. Three bridges connect Davenport with Rock Island, Illinois; The Rock Island Centennial Bridge, The Crescent Rail Bridge, and the furthest downstream bridge, the Sergeant John F. Baker, Jr. Bridge which carries I-280. Several state highways also serve the area. Iowa Highway 22 is on Davenport's southwest side and runs west through the county, while Iowa Highway 130


title: QWERTY content: QWERTY QWERTY (, ) is a keyboard design for Latin-script alphabets. The name comes from the order of the first six keys on the top left letter row of the keyboard ( ). The QWERTY design is based on a layout created for the Sholes and Glidden typewriter and sold to E. Remington and Sons in 1873. It became popular with the success of the Remington No. 2 of 1878, and remains in widespread use. The QWERTY layout was devised and created in the early 1870s by Christopher Latham Sholes, a newspaper editor and printer who lived in Kenosha, Wisconsin.


title: QWERTY content: In October 1867, Sholes filed a patent application for his early writing machine he developed with the assistance of his friends Carlos Glidden and Samuel W. Soulé. The first model constructed by Sholes used a piano-like keyboard with two rows of characters arranged alphabetically as shown below: The construction of the "Type Writer" had two flaws that made the product susceptible to jams. Firstly, characters were mounted on metal arms or type bars, which would clash and jam if neighbouring arms were pressed at the same time or in rapid succession. Secondly, its printing point was located beneath the paper


title: QWERTY content: carriage, invisible to the operator, a so-called "up-stroke" design. Consequently, jams were especially serious, because the typist could only discover the mishap by raising the carriage to inspect what had been typed. The solution was to place commonly used letter-pairs (like "th" or "st") so that their type bars were not neighbouring, avoiding jams. Sholes struggled for the next five years to perfect his invention, making many trial-and-error rearrangements of the original machine's alphabetical key arrangement. The study of bigram (letter-pair) frequency by educator Amos Densmore, brother of the financial backer James Densmore, is believed to have influenced the array


title: QWERTY content: of letters, but the contribution was later called into question. Others suggest instead that the letter groupings evolved from telegraph operators' feedback. In November 1868 he changed the arrangement of the latter half of the alphabet, O to Z, right-to-left. In April 1870 he arrived at a four-row, upper case keyboard approaching the modern QWERTY standard, moving six vowel letters, A, E, I, O, U, and Y, to the upper row as follows: In 1873 Sholes's backer, James Densmore, successfully sold the manufacturing rights for the Sholes & Glidden Type-Writer to E. Remington and Sons. The keyboard layout was finalized


title: QWERTY content: within a few months by Remington's mechanics and was ultimately presented: After they purchased the device, Remington made several adjustments, creating a keyboard with essentially the modern QWERTY layout. These adjustments included placing the "R" key in the place previously allotted to the period key. Apocryphal claims that this change was made to let salesmen impress customers by pecking out the brand name "TYPE WRITER QUOTE" from one keyboard row are not formally substantiated. Vestiges of the original alphabetical layout remained in the "home row" sequence DFGHJKL. The modern layout is: The QWERTY layout became popular with the success of


title: QWERTY content: the Remington No. 2 of 1878, the first typewriter to include both upper and lower case letters, using a shift key. The QWERTY layout depicted in Sholes's 1878 patent is slightly different from the modern layout, most notably in the absence of the numerals 0 and 1, with each of the remaining numerals shifted one position to the left of their modern counterparts. The letter M is located at the end of the third row to the right of the letter L rather than on the fourth row to the right of the N, the letters X and C are


title: QWERTY content: reversed, and most punctuation marks are in different positions or are missing entirely. 0 and 1 were omitted to simplify the design and reduce the manufacturing and maintenance costs; they were chosen specifically because they were "redundant" and could be recreated using other keys. Typists who learned on these machines learned the habit of using the uppercase letter I (or lowercase letter L) for the digit one, and the uppercase O for the zero. In early designs, some characters were produced by printing two symbols with the carriage in the same position. For instance, the exclamation point, which shares a


title: QWERTY content: key with the numeral 1 on modern keyboards, could be reproduced by using a three-stroke combination of an apostrophe, a backspace, and a period. A semicolon (;) was produced by printing a comma (,) over a colon (:). As the backspace key is slow in simple mechanical typewriters (the carriage was heavy and optimized to move in the opposite direction), a more professional approach was to block the carriage by pressing and holding the space bar while printing all characters that needed to be in a shared position. To make this possible, the carriage was designed to advance forward only


title: QWERTY content: after releasing the space bar. The 0 key was added and standardized in its modern position early in the history of the typewriter, but the 1 and exclamation point were left off some typewriter keyboards into the 1970s. There were no particular technological requirements for the QWERTY layout, since at the time there were ways to make a typewriter without the "up-stroke" typebar mechanism that had required it to be devised. Not only were there rival machines with "down-stroke" and "frontstroke" positions that gave a visible printing point, the problem of typebar clashes could be circumvented completely: examples include Thomas


title: QWERTY content: Edison's 1872 electric print-wheel device which later became the basis for Teletype machines; Lucien Stephen Crandall's typewriter (the second to come onto the American market) whose type was arranged on a cylindrical sleeve; the Hammond typewriter of 1887 which used a semi-circular "type-shuttle" of hardened rubber (later light metal); and the Blickensderfer typewriter of 1893 which used a type wheel. The early Blickensderfer's "Ideal" keyboard was also non-QWERTY, instead having the sequence "DHIATENSOR" in the home row, these 10 letters being capable of composing 70% of the words in the English language. Alternating hands while typing is a desirable trait


title: QWERTY content: in a keyboard design. While one hand types a letter, the other hand can prepare to type the next letter, making the process faster and more efficient. However, when a string of letters is typed with the same hand, the chances of stuttering are increased and a rhythm can be broken, thus decreasing speed and increasing errors and fatigue. In the QWERTY layout many more words can be spelled using only the left hand than the right hand. In fact, thousands of English words can be spelled using only the left hand, while only a couple of hundred words can


title: QWERTY content: be typed using only the right hand (the three most frequent letters in the English language, ETA, are all typed with the left hand). In addition, more typing strokes are done with the left hand in the QWERTY layout. This is helpful for left-handed people but disadvantages right-handed people. Contrary to popular belief, the QWERTY layout was not designed to slow the typist down, but rather to speed up typing by preventing jams. Indeed, there is evidence that, aside from the issue of jamming, placing often-used keys farther apart increases typing speed, because it encourages alternation between the hands. There


title: QWERTY content: is another origin story in the Smithsonian that the QWERTY keyboard was made for telegraph operators and has this layout to make it easy for the telegraph operator to work. (On the other hand, in the German keyboard the Z has been moved between the T and the U to help type the frequent bigraphs TZ and ZU in that language.) Almost every word in the English language contains at least one vowel letter, but on the QWERTY keyboard only the vowel letter "A" is on the home row, which requires the typist's fingers to leave the home row for


title: QWERTY content: most words. A feature much less commented-on than the order of the keys is that the keys do not form a rectangular grid, but rather each column slants diagonally. This is because of the mechanical linkages – each key is attached to a lever, and hence the offset prevents the levers from running into each other – and has been retained in most electronic keyboards. Some keyboards, such as the Kinesis or TypeMatrix, retain the QWERTY layout but arrange the keys in vertical columns, to reduce unnecessary lateral finger motion. The words 'typewriter', 'proprietor', 'perpetuity', and 'repertoire' (from French) are


title: QWERTY content: the longest English words that can be written using only the keys in the top row. The first computer terminals such as the Teletype were typewriters that could produce and be controlled by various computer codes. These used the QWERTY layouts and added keys such as escape (ESC) which had special meanings to computers. Later keyboards added function keys and arrow keys. Since the standardization of PC-compatible computers and Windows after the 1980s, most full-sized computer keyboards have followed this standard (see drawing at right). This layout has a separate numeric keypad for data entry at the right, 12 function


title: QWERTY content: keys across the top, and a cursor section to the right and center with keys for Insert, Delete, Home, End, Page Up, and Page Down with cursor arrows in an inverted-T shape. Different computer operating systems have methods of support for input of different languages such as Chinese, Hebrew or Arabic. QWERTY is designed for English, a language with diacritical marks appearing only in a few words of foreign origin. QWERTY keyboards have no standard way of typing an accent. Until recently, no norm was defined for a standard QWERTY keyboard layout allowing the typing of accented characters. The so


title: QWERTY content: called "US-International layout" is, in fact, OS-dependent. There exist other layouts that try to overcome this shortcoming. One popular is EurKEY which is available for Windows, OS X and Linux. A dead key is not used, like a grave accent (`) on a QWERTY keyboard, although some people use a dead key. Depending on the operating system and sometimes the application program being used, there are many ways to generate Latin characters with accents independently of the layout in use. Minor changes to the arrangement are made for other languages. There are a large number of different keyboard layouts used


title: QWERTY content: for different languages written in Latin script. They can be divided into three main families according to where the , , , , and keys are placed on the keyboard. These are usually named after the first six letters. English-speaking Canadians have traditionally most often used the same keyboard layout as in the United States, unless they are in a position where they have to write French on a regular basis. French-speaking Canadians respectively have favoured the Canadian French keyboard layout (see below). The Canadian Multilingual Standard keyboard layout is used by some Canadians. Though this keyboard lacks the caret


title: QWERTY content: (^) character, this is easily accomplished by typing the circumflex accent followed by a space. Note that while the diagram on the right depicts the Q key as if having upper-case and lower-case Greek Omega, that is not in conformance to the Canadian Multilingual Standard, which calls for a single extra character, an Omega-like Ohm symbol, not Omega. The lower-case Omega symbol does not belong in the diagram. This keyboard layout is commonly used in Canada by French-speaking Canadians. It is the most common layout for laptops and stand-alone keyboards targeting French speakers. Unlike the French layout used in France


title: QWERTY content: and Belgium, the Canadian French layout is a true QWERTY and as such is also relatively commonly used by English speakers in the US and Canada (using standard QWERTY keyboards) for easy access to accented letters found in some of the French words commonly used in English. It can be used to type all accented French characters, as well as some from other languages. It also serves all English functions as well. It is popular mainly because of its close similarity to the basic US keyboard commonly used by English-speaking Canadians and Americans, historical use of US-made typewriters by French-Canadians,


title: QWERTY content: and is the standard for keyboards in Quebec. Use of the European French layout in Quebec is practically unheard of. In some variants of this keyboard is (short for Fix Majuscule = Lock Upper Case) or (short for Verrouiller Majuscule = Lock Upper Case), is , and is . The typewriter came to the Czech-speaking area in the late 19th century, when it was part of Austria-Hungary where German was the dominant language of administration. Therefore, Czech typewriters have the QWERTZ layout. However, with the introduction of imported computers, especially since the 1990s, the QWERTY keyboard layout is frequently used


title: QWERTY content: for computer keyboards, too. Czech QWERTY layout differs from QWERTZ in that the characters (e.g. @$& and others) missing from the Czech keyboard are accessible with AltGr on the same keys where they are located on an American keyboard. In Czech QWERTZ keyboard the position of these characters accessed through AltGr differs. Both the Danish and Norwegian keyboards include dedicated keys for the letters Å/å, Æ/æ and Ø/ø, but the placement is a little different, as the and keys are swapped on the Norwegian layout. (The Finnish–Swedish keyboard is also largely similar to the Norwegian layout, but the and are


title: QWERTY content: replaced with and . On some systems, the Danish keyboard may allow typing Ö/ö and Ä/ä by holding the or key while striking and , respectively.) Though it is seldom used (most Dutch keyboards use US International layout), the Dutch layout uses QWERTY but has additions for the € sign, the diaresis (¨), and the braces ({ }) as well as different locations for other symbols. An older version contained a single-stroke key for the Dutch character IJ/ij, which is usually typed by the combination of and . In the 1990s, there was a version with the now-obsolete florin sign


title: QWERTY content: (Dutch: guldenteken) for IBM PCs. In Flanders (the Dutch-speaking part of Belgium), "AZERTY" keyboards are used instead, due to influence from the French-speaking part of Belgium. The keyboard layout used in Estonia is virtually the same as the Swedish layout. The main difference is that the and keys (to the right of ) are replaced with and respectively (the latter letter being the most distinguishing feature of the Estonian alphabet). Some special symbols and dead keys are also moved around. The same as the Danish layout with added (Eth), since the Faroe Islands are a self-governed part of the Kingdom


title: QWERTY content: of Denmark. The visual layout used in Finland is basically the same as the Swedish layout. This is practical, as Finnish and Swedish share the special characters Ä/ä and Ö/ö, and while the Swedish Å/å is unnecessary for writing Finnish, it is needed by Swedish-speaking Finns and to write Swedish family names which are common. As of 2008, there is a new standard for the Finnish multilingual keyboard layout, developed as part of a localization project by CSC. All the engravings of the traditional Finnish–Swedish visual layout have been retained, so there is no need to change the hardware, but


title: QWERTY content: the functionality has been extended considerably, as additional characters (e.g., Æ/æ, Ə/ə, Ʒ/ʒ) are available through the key, as well as dead keys, which allow typing a wide variety of letters with diacritics (e.g., Ç/ç, Ǥ/ǥ, Ǯ/ǯ). Based on the Latin letter repertory included in the Multilingual European Subset No. 2 (MES-2) of the Unicode standard, the layout has three main objectives. First, it provides for easy entering of text in both Finnish and Swedish, the two official languages of Finland, using the familiar keyboard layout but adding some advanced punctuation options, such as dashes, typographical quotation marks, and the


title: QWERTY content: non-breaking space (NBSP). Second, it is designed to offer an indirect but intuitive way to enter the special letters and diacritics needed by the other three Nordic national languages (Danish, Norwegian and Icelandic) as well as the regional and minority languages (Northern Sámi, Southern Sámi, Lule Sámi, Inari Sámi, Skolt Sámi, Romani language as spoken in Finland, Faroese, Kalaallisut also known as Greenlandic, and German). As a third objective, it allows for relatively easy entering of particularly names (of persons, places or products) in a variety of European languages using a more or less extended Latin alphabet, such as the


title: QWERTY content: official languages of the European Union (excluding Bulgarian and Greek). Some letters, like Ł/ł needed for Slavic languages, are accessed by a special "overstrike" key combination acting like a dead key. However, the Romanian letters Ș/ș and Ț/ț (S/s and T/t with comma below) are not supported; the presumption is that Ş/ş and Ţ/ţ (with cedilla) suffice as surrogates. The Icelandic keyboard layout is different from the standard QWERTY keyboard because the Icelandic alphabet has some special letters, most of which it shares with the other Nordic countries: Þ/þ, Ð/ð, Æ/æ, and Ö/ö. (Æ/æ also occurs in Norwegian, Danish and


title: QWERTY content: Faroese, Ð/ð in Faroese, and Ö/ö in Swedish, Finnish and Estonian. In Norwegian Ö/ö could be substituted for Ø/Ø which is the same sound/letter and is widely understood). The letters Á/á, Ý/ý, Ú/ú, Í/í, and É/é are produced by first pressing the dead key and then the corresponding letter. The Nordic letters Å/å and Ä/ä can be produced by first pressing , located below the key, and (for ¨) which also works for the non-Nordic ÿ, Ü/ü, Ï/ï, and Ë/ë. These letters are not used natively in Icelandic, but may have been implemented for ease of communication in other Nordic


title: QWERTY content: languages. Additional diacritics may be found behind the key: for ˋ (grave accent) and for ˆ (circumflex). Microsoft Windows includes an Irish layout which supports acute accents with for the Irish language and grave accents with the dead key for Scottish Gaelic. The other Insular Celtic languages have their own layout. The UK or UK-Extended layout is also frequently used. There is an alternate layout, which differs only in disposition of characters accessible through , and includes the tilde and the curly brackets. It is commonly used in IBM keyboards. Italian typewriters often have the QZERTY layout instead. The Italian-speaking


title: QWERTY content: part of Switzerland uses the QWERTZ keyboard. Although rarely used, a keyboard layout specifically designed for the Latvian language called ŪGJRMV exists. The Latvian QWERTY keyboard layout is most commonly used - its layout is the same as latin ones, but with a dead key, which allows entering special characters (āčēģīķļņšūž, sometimes ō and ŗ). The most common dead key is the apostrophe ('), which is followed by Alt+Gr (Windows default for Latvian layout). Some prefer using tick (`). In Lithuanian QWERTY keyboards the number keys on the top row have the following meanings: Ą, Č, Ę, Ė, Į, Š,


title: QWERTY content: Ų, Ū instead of their counterparts 1, 2, 3, 4, 5, 6, 7, 8. Besides these changes the keyboard is standard QWERTY. Besides QWERTY, the ĄŽERTY layout is used. The Maltese language uses Unicode (UTF-8) to display the Maltese diacritics: ċ Ċ; ġ Ġ; ħ Ħ; ż Ż (together with à À; è È; ì Ì; ò Ò; ù Ù). There are two standard keyboard layouts for Maltese, according to "MSA 100:2002 Maltese Keyboard Standard"; one of 47 keys and one of 48 keys. The 48-key layout is the most popular. The Norwegian languages use the same letters as Danish,


title: QWERTY content: but the Norwegian keyboard differs from the Danish layout regarding the placement of the , and (backslash) keys. On the Danish keyboard, the and are swapped. The Swedish keyboard is also similar to the Norwegian layout, but and are replaced with and . On some systems, the Norwegian keyboard may allow typing Ö/ö and Ä/ä by holding the or key while striking and , respectively. There is also an alternative keyboard layout called "Norwegian with Sámi", which allows for easier input of the characters required to write various Sámi (also known as Lapp) languages. All the Sámi characters are accessed


title: QWERTY content: through the key. On Macintosh computers, the "Norwegian" and "Norwegian extended" keyboard layouts have a slightly different placement for some of the symbols obtained with the help of the or keys. Notably, the "$" sign is accessed with and "¢" with . Furthermore, the frequently used "@" is placed between and . Most typewriters use a QWERTZ keyboard with Polish letters (with diacritical marks) accessed directly (officially approved as "Typist's keyboard", , Polish Standard PN-87), which is mainly ignored in Poland as impractical (except custom-made, e.g., in public sector and some Apple computers); the "Polish programmer's" () layout has become


title: QWERTY content: the "de facto" standard, used on virtually all computers sold on the Polish market. Most computer keyboards in Poland are laid out according to the standard US visual and functional layout. Polish diacritics are accessed by using the "AltGr" key with a corresponding similar letter from the base Latin alphabet. Normal capitalization rules apply with respect to "Shift" and "Caps Lock" keys. For example, to enter "Ź", one can type "Shift+AltGr+X" with "Caps Lock" off, or turn on "Caps Lock" and type "AltGr+X". Both ANSI and ISO mechanical layouts are common sights, and even some non-standard mechanical layouts are in


title: QWERTY content: use. ANSI is often preferred, as the additional key provides no additional function, at least in Microsoft Windows where it duplicates the backslash key, while taking space from the Shift key. Many keyboards do not label "AltGr" as such, leaving the "Alt" marking as in the US layout - the right "Alt" key nevertheless functions as "AltGr" in this layout, causing possible confusion when keyboard shortcuts with the "Alt" key are required (these usually work only with the left "Alt") and causing the key to be commonly referred to as "right Alt" (). However, keyboards with "AltGr" marking are available


title: QWERTY content: and it is also officially used by Microsoft when depicting the layout. Also, on MS Windows, the tilde character "~" ("Shift"+"`") acts as a dead key to type Polish letters (with diacritical marks) thus, to obtain an "Ł", one may press "Shift"+"`" followed by "L". The tilde character is obtained with ("Shift"+"`") then "space". In Linux-based systems, the euro symbol is typically mapped to Alt+5 instead of Alt+U, the tilde acts as a normal key, and several accented letters from other European languages are accessible through combinations with left Alt. Polish letters are also accessible by using the compose key.


title: QWERTY content: Software keyboards on touchscreen devices usually make the Polish diacritics available as one of the alternatives which show up after long-pressing the corresponding Latin letter. However, modern predictive text and autocorrection algorithms largely mitigate the need to type them directly on such devices. The Brazilian computer keyboard layout is specified in the ABNT NBR 10346 variant 2 (alphanumeric portion) and 10347 (numeric portion) standards. Essentially, the Brazilian keyboard contains dead keys for five variants of diacritics in use in the language; the letter Ç, the only application of the cedilla in Portuguese, has its own key. In some keyboard layouts


title: QWERTY content: the + combination produces the ₢ character (Unicode 0x20A2), symbol for the old currency cruzeiro, a symbol that is not used in practice (the common abbreviation in the eighties and nineties used to be Cr$). The cent sign ¢, is accessible via +, but is not commonly used for the centavo, subunit of previous currencies as well as the current real, which itself is represented by R$. The Euro sign € is not standardized in this layout. The masculine and feminine ordinals ª and º are accessible via combinations. The section sign § (Unicode U+00A7), in Portuguese called "parágrafo", is


title: QWERTY content: nowadays practically only used to denote sections of laws. Variant 2 of the Brazilian keyboard, the only which gained general acceptance (MS Windows treats both variants as the same layout), has a unique mechanical layout, combining some features of the ISO 9995-3 and the "JIS" keyboards in order to fit 12 keys between the left and right Shift (compared to the American standard of 10 and the international of 11). Its modern, IBM PS/2-based variations, are thus known as 107-keys keyboards, and the original PS/2 variation was 104-key. Variant 1, never widely adopted, was based on the ISO 9995-2 keyboards.


title: QWERTY content: To make this layout usable with keyboards with only 11 keys in the last row, the rightmost key (/?°) has its functions replicated across the +, +, and + combinations. Essentially, the Portuguese keyboard contains dead keys for five variants of diacritics; the letter Ç, the only application of the cedilla in Portuguese, has its own key, but there are also a dedicated key for the ordinal indicators and a dedicated key for quotation marks. The + combination for producing the euro sign € (Unicode 0x20AC) has become standard. On some QWERTY keyboards the key labels are translated, but the


title: QWERTY content: majority are labelled in English. During the 20th century, a different keyboard layout, HCESAR, was in widespread use in Portugal. The current Romanian National Standard SR 13392:2004 establishes two layouts for Romanian keyboards: a "primary" one and a "secondary" one. The "primary" layout is intended for traditional users who have learned how to type with older, Microsoft-style implementations of the Romanian keyboard. The "secondary" layout is mainly used by programmers as it does not contradict the physical arrangement of keys on a US-style keyboard. The "secondary" arrangement is used as the default Romanian layout by Linux distributions, as defined in


title: QWERTY content: the "X Keyboard Configuration Database". There are four Romanian-specific characters that are incorrectly implemented in versions of Microsoft Windows until Vista came out: The cedilla-versions of the characters do not exist in the Romanian language (they came to be used due to a historic bug). The UCS now says that encoding this was a mistake because it messed up Romanian data and the letters with cedilla and the letters with comma are the same letter with a different style. Since Romanian hardware keyboards are not widely available, Cristian Secară has created a driver that allows Romanian characters to be generated


title: QWERTY content: with a US-style keyboard in all versions of Windows prior to Vista through the use of the AltGr key modifier. MS Windows 7 now includes the correct diacritical signs in the default Romanian Keyboard layout. This layout has the Z and Y keys mapped like in English layouts and also includes characters like the 'at' (@) and dollar ($) signs, among others. The older cedilla-version layout is still included albeit as the 'Legacy' layout. In Slovakia, similarly to the Czech Republic, both QWERTZ and QWERTY keyboard layouts are used. QWERTZ is the default keyboard layout for Slovak in Microsoft Windows.


title: QWERTY content: The Spanish keyboard layout is used to write in Spanish and in other languages of Spain such as Catalan, Basque, Galician, Aragonese, Asturian and Occitan. It includes Ñ for Spanish, Asturian and Galician, the acute accent, the diaeresis, the inverted question and exclamation marks (¿, ¡), the superscripted o and a (º, ª) for writing abbreviated ordinal numbers in masculine and feminine in Spanish and Galician, and finally, some characters required only for typing Catalan and Occitan that are Ç, the grave accent and the interpunct (' / ', used in "l·l, n·h, s·h"; located at Shift-3). It can also


title: QWERTY content: be used to write other international characters, such as the circumflex accent (used in French and Portuguese among others) and the tilde (used in both Spanish and Portuguese), which are available as dead keys. However, it lacks two characters used in Asturian: Ḥ and Ḷ (historically, general support for these two has been poor – they aren't present in the ISO 8859-1 character encoding standard, or any other ISO/IEC 8859 standard); several alternative distributions, based on this one or created from scratch, have been created to address this issue (see the Other original layouts and layout design software section for


title: QWERTY content: more information). On most keyboards, € is marked as Alt Gr + E and not Alt Gr + 5 as shown in the image. However, in some keyboards, € is found marked twice. An alternative version exists, supporting all of ISO 8859-1. Spanish keyboards are usually labelled in Spanish instead of English, its abbreviations being: The c-cedilla key (Ç), instead of on the right of the acute accent key (´), is located alternatively on some keyboards one or two lines above. In some cases it's placed on the right of the plus sign key (+). In other keyboards it's situated


title: QWERTY content: on the right of the inverted exclamation mark key (¡). The Latin American Spanish keyboard layout is used throughout Mexico, Central and South America. Before its design, Latin American vendors had been selling the Spanish (Spain) layout as default. Its most obvious difference from the Spanish (Spain) layout is the lack of a Ç key; on Microsoft Windows it lacks a tilde (~) dead key, whereas on Linux systems the dead tilde can be optionally enabled. This is not a problem when typing in Spanish, but it is rather problematic when typing in Portuguese, which can be an issue in


title: QWERTY content: countries with large commercial ties to Brazil (Argentina, Uruguay and Paraguay). Normally "Bloq Mayús" is used instead of "Caps Lock", and "Intro" instead of "Enter". The central characteristics of the Swedish keyboard are the three additional letters Å/å, Ä/ä, and Ö/ö. The same visual layout is also in use in Finland, as the letters Ä/ä and Ö/ö are shared with the Swedish language, and even Å/å is needed by Swedish-speaking Finns. However, the Finnish multilingual keyboard adds new letters and punctuation to the functional layout. The Norwegian keyboard largely resembles the Swedish layout, but the and are replaced with and


title: QWERTY content: . The Danish keyboard is also similar, but it has the and swapped. On some systems, the Swedish or Finnish keyboard may allow typing Ø/ø and Æ/æ by holding the or key while striking and , respectively. The "Swedish with Sámi" keyboard allows typing not only Ø/ø and Æ/æ, but even the letters required to write various Sámi (also known as Lapp) languages. This keyboard has the same function for all the keys engraved on the regular Swedish keyboard, and the additional letters are available through the key. On Macintosh computers, the "Swedish" and "Swedish Pro" keyboards differ somewhat from


title: QWERTY content: the image shown above, especially as regards the characters available using the or keys. (on the upper row) produces the "°" sign, and produces the "€" sign. The digit keys produce "©@£$∞§|[]≈" with and "¡"¥¢‰¶\{}≠" with . On Linux systems, the Swedish keyboard may also give access to additional characters as follows: Several of these characters function as dead keys. Today the majority of Turkish keyboards are based on QWERTY (the so-called Q-keyboard layout), although there is also the older F-keyboard layout specifically designed for the language. The United Kingdom and Ireland use a keyboard layout based on the 48-key


title: QWERTY content: version defined in (the now withdrawn) British Standard BS 4822. It is very similar to that of the United States, but has an extra key and a larger Enter key, includes £ and € signs and some rarely used EBCDIC symbols (¬, ¦), and uses different positions for the characters @, ", #, ~, \, and |. See the article British and American keyboards for details. The BS 4822:1994 standard did not make any use of the AltGr key and lacked support for any non-ASCII characters other than ¬ and £. It also assigned a key for the non-ASCII character


title: QWERTY content: broken bar (¦), but lacks one for the far more commonly used ASCII character vertical bar (|). It also lacked support for various diacritics used in the Welsh alphabet, and the Scottish Gaelic alphabet; and also is missing the letter yogh, ȝ, used very rarely in the Scots language. Therefore, various manufacturers have modified or extended the BS 4822 standard: In many Commonwealth countries and other English-speaking jurisdictions (e.g., Canada, Australia, the Caribbean nations, Hong Kong, Malaysia, India, Pakistan, Bangladesh, Singapore, New Zealand, and South Africa), local spelling conforms more closely to British English usage, while the supplied keyboard is


title: QWERTY content: or based on the English (US) keyboard. In Windows 8 and later versions, the backslash key (left of Z or space) is duplicated onto the hash key (left of Enter), press which with key to type backslash , with and keys to type vertical bar . This aids users who are familiar with UK keyboard layout while the keyboard lacks this key (e.g. US Standard keyboard and Japan JIS keyboard). The British version of the Apple Keyboard does not use the standard UK layout. Instead, some older versions have the US layout (see below) with a few differences: the sign


title: QWERTY content: is reached by and the sign by , the opposite to the US layout. The is also present and is typed with . Umlauts are reached by typing and then the vowel, and ß is reached by typing . Newer Apple "British" keyboards use a layout that is relatively unlike either the US or traditional UK keyboard. It uses an elongated return key, a shortened left with and in the newly created position, and in the upper left of the keyboard are and instead of the traditional EBCDIC codes. The middle-row key that fits inside the key has and .


title: QWERTY content: From Windows XP SP2 onwards, Microsoft has included a variant of the British QWERTY keyboard (the "United Kingdom Extended" keyboard layout) that can additionally generate several diacritical marks. This supports input on a standard physical UK keyboard for many languages without changing positions of frequently used keys, which is useful when working with text in Welsh and Scottish Gaelic — languages native to parts of the UK (Wales and parts of Scotland respectively). Although the rarely used grave accent key becomes, as it also does in the US International layout, a dead key modifying the character generated by the next


title: QWERTY content: key pressed, the apostrophe, double-quote, tilde and caret keys are not changed. Instead, the additional characters are obtained using the key. The extended keyboard is software installed from the Windows control panel, and the extended characters are not normally engraved on keyboards. Apple's Mac OS X does not include UK Extended, as it has key combinations for accents on any keyboard layout. The UK International keyboard uses mostly the AltGr key to add diacritics to the letters a, e, i, n, o, u, w and y (the last two being used in Welsh) as appropriate for each character, as well


title: QWERTY content: as to their capitals. Pressing the key and then a character that does not take the specific diacritic produces the behaviour of a standard keyboard. The key presses followed by spacebar generate a stand-alone mark.: The and letter method used for acutes and cedillas does not work for applications which assign shortcut menu functions to these key combinations. For acute accents the and apostrophe method should be used. These combinations are intended to be mnemonic and designed to be easy to remember: the circumflex accent (e.g. â) is similar to a caret (codice_1), printed above the key; the diaeresis/umlaut (e.g.


title: QWERTY content: ö) is visually similar to the double-quote (codice_2) above on the UK keyboard; the tilde (codice_3) is printed on the same key as the . The UK "extended" layout is almost entirely transparent to users familiar with the UK layout. A machine with the extended layout behaves exactly as with the standard UK, except for the rarely used grave accent key. This makes this layout suitable for a machine for shared or public use by a user population in which some use the extended functions. Despite being created for multilingual users, UK-Extended does have some gaps — there are many


title: QWERTY content: languages that it cannot cope with, including Romanian and Turkish, and all languages with different character sets, such as Greek and Russian. It also does not cater for the ß in German, nor for the å, æ, ø, ð, þ in Nordic languages. The arrangement of the character input keys and the Shift keys contained in this layout is specified in the U.S. American national standard ANSI-INCITS 154-1988 (R1999) (formerly ANSI X3.154-1988 (R1999)), where this layout is called "ASCII keyboard". The complete US keyboard layout, as it is usually found, also contains the usual function keys in accordance with the


title: QWERTY content: international standard ISO/IEC 9995-2, although this is not explicitly required by the US American national standard. US keyboards are used not only in the United States, but also in many other English-speaking places, including India, Australia, English Canada, Hong Kong, New Zealand, South Africa, Malaysia, Singapore and Philippines. However, the United Kingdom and Ireland use a slightly different layout because of the Irish language. The US keyboard layout has a second Alt key instead of the AltGr key and does not use any dead keys; this makes it inefficient for all but a handful of languages. On the other hand,


title: QWERTY content: the US keyboard layout (or the similar UK layout) is occasionally used by programmers in countries where the keys for []{} are located in less convenient positions on the locally customary layout. On some keyboards the enter key is bigger than traditionally and takes up also a part of the line above, more or less the area of the traditional location of the backslash key (\). In these cases the backslash is located in alternative places. It can be situated one line above the default location, on the right of the equals sign key (=). Sometimes it's placed one line


title: QWERTY content: below its traditional situation, on the right of the apostrophe key (') (in these cases the enter key is narrower than usual on the line of its default location). It may also be two lines below its default situation on the right of a narrower than traditionally right shift key. A variant of this layout is used in Arabic-speaking countries. This variant has the | \ key to the left of Z, ~ ` key where the | \ key is in the usual layout, and the > < key where the ~ ` key is in the usual layout.


title: QWERTY content: An alternative layout uses the physical US keyboard to type diacritics in some operating systems (including Windows). This is the US-International layout, which uses the right key as an key to support many additional characters directly as an additional shift key. (Since many smaller keyboards don't have a right key, Windows also allows + to be used as a substitute for .) This layout also uses keys , , , and as dead keys to generate characters with diacritics by pressing the appropriate key, then the letter on the keyboard. The international keyboard is a software setting installed from the


title: QWERTY content: Windows control panel or similar; the additional functions (shown in blue) may or may not be engraved on the keyboard, but are always functional. It can be used to type most major languages from Western Europe: Afrikaans, Danish, Dutch, English, Faroese, Finnish, French, German, Icelandic, Irish, Italian, Norwegian, Portuguese, Scottish Gaelic, Spanish, and Swedish. Some less common western European languages, such as Maltese and Welsh, are not fully supported by the US-International keyboard layout. A diacritic key is activated by pressing and releasing it, then pressing the letter that requires a diacritic. After the two strokes, the single character with


title: QWERTY content: diacritics is generated. Note that only certain letters, such as vowels and "n", can have diacritics in this way. To generate the symbols ', `, ", ^ and ~, when the following character is capable of having a diacritic, press the after the key. Characters with diacritics can be typed with the following combinations: The US-International layout is not entirely transparent to users familiar with the US layout; when using a machine with the international layout the commonly used single- and double-quote keys and the less commonly used grave accent, tilde, and caret keys behave unexpectedly. This could be disconcerting


title: QWERTY content: on a machine for shared or public use. There are also alternative US-International formats, whereby modifier keys such as shift and alt are used, and the keys for the characters with diacritics are in different places from their unmodified counterparts, for example, using the AltGr modifier key to activate dead keys, so that the ASCII quotation marks or circumflex symbol are not affected and can be typed normally with a single keystroke. The standard keyboard layout in the Netherlands is US-International, as it provides easy access to diacritics on common UK- or US-like keyboards. The Dutch layout is historical, and


title: QWERTY content: keyboards with this layout are rarely used. Many US keyboards sold do not have the extra US-International characters or engraved on the keys, although € () always is; nevertheless, the keys work as expected even if not marked. Many computer-literate Dutch people have retained the old habit of using + number codes to type accented characters; others routinely type without diacritics, then use a spelling checker to produce the correct forms. There are three kinds of Apple Keyboards for English: the United States, the United Kingdom and International English. The International English version is almost identical to the United States


title: QWERTY content: version, but some features are identical to the United Kingdom version: The Vietnamese keyboard layout is an extended Latin QWERTY layout. The letters Ă, Â, Ê, and Ô are found on what would be the number keys – on the US English keyboard, with – producing the tonal marks (grave accent, hook, tilde, acute accent and dot below, in that order), producing Đ, producing the đồng sign (₫) when not shifted, and brackets () producing Ư and Ơ. EurKEY is a free and open source US-based layout which provides easy access to many diacritics of European languages as well as


title: QWERTY content: to common math symbols and Greek letters. It is available for Windows, OS X, Linux (shipped with xkeyboard-config). Several alternatives to QWERTY have been developed over the years, claimed by their designers and users to be more efficient, intuitive, and ergonomic. Nevertheless, none have seen widespread adoption, partly due to the sheer dominance of available keyboards and training. Although some studies have suggested that some of these may allow for faster typing speeds, many other studies have failed to do so, and many of the studies claiming improved typing speeds were severely methodologically flawed or deliberately biased, such as the


title: QWERTY content: studies administered by Dvorak himself before and after World War II. Economists Stan Liebowitz and Stephen Margolis have noted that rigorous studies are inconclusive as to whether they actually offer any real benefits, and some studies on keyboard layout have suggested that, for a skilled typist, layout is largely irrelevant – even randomized and alphabetical keyboards allow for similar typing speeds to QWERTY and Dvorak keyboards, and that switching costs always outweigh the benefits of further training on whichever keyboard you already use. The most widely used such alternative is the Dvorak Simplified Keyboard; another alternative is Colemak, which is


title: QWERTY content: based partly on QWERTY and is claimed to be easier for an existing QWERTY typist to learn while offering several supposed optimisations. Most modern computer operating systems support these and other alternative mappings with appropriate special mode settings, with some modern operating systems allowing the user to map their keyboard in any way they like, but few keyboards are manufactured with keys labeled according to any other standard. Comparisons have been made, between Dvorak, Colemack, QWERTY, and other keyboard input systems, namely stenotype or its electronic implementations (e.g., Plover an opensource project ). However, stenotype is a fundamentally different system,


title: QWERTY content: which relies on Phonetics and simultaneous key presses or chords. Although stenography has long been known as a faster and more accurate typing system, adoption has been limited, likely due to the historically high cost of equipment, steeper initial learning curve, and low awareness of the benefits within primary education and in the general public. The first typed shorthand machines appeared around 1830, with english versions gaining popularity in the early 1900s. Traditionally, stenotype output required interpretation back to longhand by a trained professional, comparable to reading Gregg shorthand, which was very much in vogue at the time and taught


title: QWERTY content: publicly until the 1980s. Gregg shorthand also did not require much more than training and a pen, however machines gradually gained traction in the courtroom. Modern electronic stenotype machines or programs such as Plover Steno, output to written language, which provides an experience similar to other keyboard setups that immediately produce legible work. A half QWERTY keyboard is a combination of an alpha-numeric keypad and a QWERTY keypad, designed for mobile phones. In a half QWERTY keyboard, two characters share the same key, which reduces the number of keys and increases the surface area of each key, useful for mobile


title: QWERTY content: phones that have little space for keys. It means that 'Q' and 'W' share the same key and the user must press the key once to type 'Q' and twice to type 'W'. Citations Informational notes QWERTY QWERTY (, ) is a keyboard design for Latin-script alphabets. The name comes from the order of the first six keys on the top left letter row of the keyboard ( ). The QWERTY design is based on a layout created for the Sholes and Glidden typewriter and sold to E. Remington and Sons in 1873. It became popular with the success of


title: "Quechuan languages" content: precise and truthful. Precision and information source are of the utmost importance. They are a powerful and resourceful method of human communication. Although the body of literature in Quechua is not as sizable as its historical and current prominence would suggest, it is nevertheless not negligible. As in the case of the pre-Columbian Mesoamerica, there are a number of surviving Andean documents in the local language that were written down in Latin characters after the European conquest, but they express, to a great extent, the culture of pre-Conquest times. That type of Quechua literature is somewhat scantier, but nevertheless significant.


title: "RSA (cryptosystem)" content: using several hundred computers, and these are now factored in a few weeks using common hardware. Exploits using 512-bit code-signing certificates that may have been factored were reported in 2011. A theoretical hardware device named TWIRL, described by Shamir and Tromer in 2003, called into question the security of 1024 bit keys. It is currently recommended that "n" be at least 2048 bits long. In 1994, Peter Shor showed that a quantum computer – if one could ever be practically created for the purpose – would be able to factor in polynomial time, breaking RSA; see Shor's algorithm. Finding the


title: "RSA (cryptosystem)" content: of all the other keys "n"′ they had found (a 729 million digit number), instead of computing each gcd("n","n"′) separately, thereby achieving a very significant speedup since after one large division the GCD problem is of normal size. Heninger says in her blog that the bad keys occurred almost entirely in embedded applications, including "firewalls, routers, VPN devices, remote server administration devices, printers, projectors, and VOIP phones" from over 30 manufacturers. Heninger explains that the one-shared-prime problem uncovered by the two groups results from situations where the pseudorandom number generator is poorly seeded initially and then reseeded between the generation


title: "Rugby football" content: Rugby football Rugby refers to the team sports rugby league and rugby union. Legend claims that Rugby football was started around the time of 1845 in Rugby School, Rugby, Warwickshire, England, although forms of football in which the ball was carried and tossed date to medieval times. Rugby eventually split into two sports in 1895 when twenty two clubs split from the original Rugby Football Union, to form the Northern Union (later to be named rugby league in 1922) in the George Hotel, Huddersfield, Northern England over the issue of payment to players, thus making rugby league the first code


title: "Rugby football" content: to turn professional and pay its players, rugby union turned fully professional in 1995. Both sports are run by their respective world governing bodies World Rugby (rugby union) and the Rugby League International Federation (rugby league). Rugby football was one of many versions of football played at English public schools in the 19th century. Although rugby league initially used rugby union rules, they are now wholly separate sports. In addition to these two codes, both American and Canadian football evolved from rugby football. Following the 1895 split in rugby football, the two forms rugby league and rugby union differed in


title: "Rugby football" content: administration only. Soon the rules of rugby league were modified, resulting in two distinctly different forms of rugby. After 100 years, in 1995 rugby union joined rugby league and most other forms of football as an openly professional sport. The Greeks and Romans are known to have played many ball games, some of which involved the use of the feet. The Roman game "harpastum" is believed to have been adapted from a Greek team game known as "ἐπίσκυρος" ("Episkyros") or "φαινίνδα" ("phaininda"), which is mentioned by a Greek playwright, Antiphanes (388–311 BC) and later referred to by the Christian theologian


title: "Rugby football" content: Clement of Alexandria (c.150-c.215 AD). These games appear to have resembled rugby football. The Roman politician Cicero (106–42 BC) describes the case of a man who was killed whilst having a shave when a ball was kicked into a barber's shop. Roman ball games already knew the air-filled ball, the follis. "Episkyros" is recognised as an early form of football by FIFA. In 1871, English clubs met to form the Rugby Football Union (RFU). In 1892, after charges of professionalism (compensation of team members) were made against some clubs for paying players for missing work, the Northern Rugby Football Union,


title: "Rugby football" content: usually called the Northern Union (NU), was formed. The existing rugby union authorities responded by issuing sanctions against the clubs, players, and officials involved in the new organization. After the schism, the separate clubs were named "rugby league" and "rugby union". Rugby union is both a professional and amateur game, and is dominated by the first tier unions: Argentina, Australia, England, France, Ireland, Italy, New Zealand, Scotland, South Africa and Wales. Second and third tier unions include Belgium, Brazil, Canada, Chile, Fiji, Georgia, Germany, Hong Kong, Japan, Kenya, Namibia, the Netherlands, Portugal, Romania, Russia, Samoa, Spain, Tonga, the United States


title: "Rugby football" content: and Uruguay. Rugby Union is administered by World Rugby (WR), whose headquarters are located in Dublin, Ireland. It is the national sport in New Zealand, Wales, Fiji, Samoa, Tonga, Georgia and Madagascar, and is the most popular form of rugby globally. The Olympic Games have admitted the seven-a-side version of the game, known as Rugby sevens, into the programme from Rio de Janeiro in 2016 onwards. There was a possibility sevens would be a demonstration sport at the 2012 London Olympics but many sports including sevens were dropped. In Canada and the United States, rugby union evolved into gridiron football.


title: "Rugby football" content: During the late 1800s (and even the early 1900s), the two forms of the game were very similar (to the point where the United States was able to win the gold medal for rugby union at the 1924 Summer Olympics), but numerous rule changes have differentiated the gridiron-based game from its rugby counterpart, introduced by Walter Camp in the United States and John Thrift Meldrum Burnside in Canada. Among unique features of the North American game are the separation of play into downs instead of releasing the ball immediately upon tackling, the requirement that the team with the ball set


title: "Rugby football" content: into a set formation for at least one second before resuming play after a tackle (and the allowance of up to 40 seconds to do so), the allowance for one forward pass from behind the site of the last tackle on each down, the evolution of hard plastic equipment (particularly the football helmet and shoulder pads), a smaller and pointier ball that is favorable to being passed but makes drop kicks impractical, a generally smaller and narrower field measured in customary units instead of metric (in some variants of the American game a field can be as short as 50


title: "Rugby football" content: yards between end zones), and a distinctive field (shaped like a gridiron, from which the code's nickname is derived) with lines marked in five-yard intervals. Rugby league is also both a professional and amateur game, administered on a global level by the Rugby League International Federation. In addition to amateur and semi-professional competitions in the United States, Russia, Lebanon, Serbia, Europe and Australasia, there are two major professional competitions—the Australasian National Rugby League and the European Super League. International Rugby League is dominated by Australia, England and New Zealand. In Papua New Guinea it is the national sport. Other nations


title: "Rugby football" content: from the South Pacific and Europe also play in the Pacific Cup and European Cup respectively. Distinctive features common to both rugby codes include the oval ball and throwing the ball forward is not allowed so that players can gain ground only by running with the ball or by kicking it. As the sport of rugby league moved further away from its union counterpart, rule changes were implemented with the aim of making a faster-paced and more try-oriented game. The main differences between the two games, besides league having teams of 13 players and union of 15, involve the tackle


title: "Rugby football" content: and its aftermath: Set pieces of the union code include the "scrum", in which packs of opposing players push against each other for possession, and the "line-out", in which parallel lines of players from each team, arranged perpendicular to the touch-line, attempt to catch the ball thrown from touch. A rule has been added to line-outs which allows the jumper to be pulled down once a players' feet are on the ground. In the league code, the scrum still exists, but with greatly reduced importance as it involves fewer players and is rarely contested. Set pieces are generally started from


title: "Rugby football" content: the play-the-ball situation. Many of the rugby league positions have similar names and requirements to rugby union positions, but there are no flankers in rugby league. In England, rugby union is widely regarded as an "establishment" sport, played mostly by members of the upper and middle classes. For example, many pupils at public schools and grammar schools play rugby union, although the game (which had a long history of being played at state schools until the 1980s) is becoming increasingly popular in comprehensive schools. Despite this stereotype, the game, particularly in the West Country is popular amongst all classes. In


title: "Rugby football" content: contrast, rugby league has traditionally been seen as a working-class pursuit. Another exception to rugby union's upper-class stereotype is in Wales, where it has been traditionally associated with small village teams made up of coal miners and other industrial workers who played on their days off. In Ireland, both rugby union and rugby league are unifying forces across the national and sectarian divide, with the Ireland international teams representing both political entities. In Australia, support for both codes is concentrated in New South Wales, Queensland and the Australian Capital Territory. The same perceived class barrier as exists between the two


title: "Rugby football" content: games in England also occurs in these states, fostered by rugby union's prominence and support at private schools. Exceptions to the above include New Zealand (although rugby league is still considered to be a lower class game by many or a game for 'westies' referring to lower class western suburbs of Auckland and more recently, southern Auckland where the game is also popular), Wales, France (except Paris), Cornwall, Gloucestershire, Somerset, Scottish Borders, County Limerick (see Munster) and the Pacific Islands, where rugby union is popular in working class communities. Nevertheless, rugby league is perceived as the game of the working-class


title: "Rugby football" content: people in northern England and in the Australian states of New South Wales and Queensland. In the United Kingdom, rugby union fans sometimes used the term "rugger" as an alternative name for the sport, (see Oxford '-er'), although this archaic expression has not had currency since the 1950s or earlier. New Zealanders refer to rugby union simply as either "rugby" or "union", or even simply "football", and to rugby league as "rugby league" or "league". In the U.S., people who play rugby are sometimes called "ruggers", a term little used elsewhere except facetiously. In France, rugby is widely played and


title: "Rugby football" content: has a strong tradition in the Basque, Occitan and Catalan areas along the border regions between Spain and France. The game is very popular in South Africa, having been introduced by English-speaking settlers in the 19th century. British colonists also brought the game with them to Australia and New Zealand, where the game is widely played. It has spread thence to much of Polynesia, having particularly strong followings in Fiji, Samoa, and Tonga. Rugby union continues to grow in the Americas and parts of Asia as well. A rugby ball, originally called a quanco, is a diamond shape ball used


title: "Rugby football" content: for easier passing. Richard Lindon and Bernardo Solano started making balls for Rugby school out of hand stitched, four-panel, leather casings and pigs’ bladders. The rugby ball's distinctive shape is supposedly due to the pig's bladder, although early balls were more plumb-shape than oval. The balls varied in size in the beginning depending upon how large the pig's bladder was. In rugby union, World Rugby regulates the size and shape of the ball under Law 2 (also known as Law E.R.B); an official rugby union ball is oval and made of four panels, has a length in-line of 280–300 millimetres,


title: "Rugby football" content: a circumference (end to end) of 740–770 millimetres, and a circumference (in width) of 580–620 millimetres. It is made of leather or suitable synthetic material and may be treated to make it water resistant and easier to grip. The rugby ball may not weigh more than 460 grams or less than 410 and has an air pressure of 65.71–68.75 kilopascals, or 0.67–0.70 kilograms per square centimetre, or 9.5–10.0 lbs per square inch. Spare balls are allowed under the condition that players or teams do not seek an advantage by changing the ball. Smaller sized balls may also be used in


title: "Rugby football" content: games between younger players. Much larger versions of traditional balls are also available for purchase, but these are mainly for their novelty attraction. The Rugby World Cup, which was first held in New Zealand and Australia in 1987, occurs every four years. It is an international tournament organized by World Rugby. The event is played in the union format and features the top 20 teams from around the world. The current world champions are New Zealand, who won the 2015 Rugby World Cup, which was played in England. The Rugby League World Cup was the first World Cup of either


title: "Rugby football" content: of the Rugby codes and was first held in France in 1954, and as of 2013 occurs on a 4-year cycle. It is an international tournament that is organized by the Rugby League International Federation. The event is played in the league format and features the top 14 teams from around the world. The current world champions are Australia, who won the World Cup in 2013, played in England, Wales, France, and Ireland. Rugby shirts were formerly made of cotton but are now made of a cotton and polyester mix. This material has the advantage of not absorbing as much


title: "Rugby football" content: water or mud as cotton alone. Owing to the more aggressive nature of the game, rugby clothing, in general, is designed to be much more robust and hardwearing than that worn for association football. The rugby jerseys are slightly different depending on the type of rugby game played. The shirts worn by rugby league footballers commonly have a large "V" around the neck. The players in rugby union wear jerseys with a more traditional design, sometimes completely white (Cahors Rugby in France). The number of the player and his or her surname are placed on the upper back of the


title: "Rugby football" content: jersey (often name above number, with the number being significantly larger and more central), and the logo of the team on the upper left chest. With the popularity of rugby over the years, many betting establishments have made it possible for viewers of the game to place wagers on games. The various types of wagers that can be placed on games vary, however, the main types of bets that can be placed are as follows: Like most team sports, both forms of rugby are vulnerable to match-fixing, particularly bets involving easily manipulated outcomes, such as conceding penalties and first point


title: "Rugby football" content: scorer. A recent example is a deliberate infringement by Ryan Tandy in order for the first points scored to be a penalty goal in a 2010 NRL match; the attempt backfired when instead of taking a shot at goal, a try was scored. Rugby football Rugby refers to the team sports rugby league and rugby union. Legend claims that Rugby football was started around the time of 1845 in Rugby School, Rugby, Warwickshire, England, although forms of football in which the ball was carried and tossed date to medieval times. Rugby eventually split into two sports in 1895 when twenty


title: Reptile content: Reptile Reptiles are tetrapod animals in the class Reptilia, comprising today's turtles, crocodilians, snakes, amphisbaenians, lizards, tuatara, and their extinct relatives. The study of these traditional reptile orders, historically combined with that of modern amphibians, is called herpetology. Because some reptiles are more closely related to birds than they are to other reptiles (e.g., crocodiles are more closely related to birds than they are to lizards), the traditional groups of "reptiles" listed above do not together constitute a monophyletic grouping or clade (consisting of all descendants of a common ancestor). For this reason, many modern scientists prefer to consider the


title: Reptile content: birds part of Reptilia as well, thereby making Reptilia a monophyletic class, including all living Diapsids. The earliest known proto-reptiles originated around 312 million years ago during the Carboniferous period, having evolved from advanced reptiliomorph tetrapods that became increasingly adapted to life on dry land. Some early examples include the lizard-like "Hylonomus" and "Casineria". In addition to the living reptiles, there are many diverse groups that are now extinct, in some cases due to mass extinction events. In particular, the Cretaceous–Paleogene extinction event wiped out the pterosaurs, plesiosaurs, ornithischians, and sauropods, as well as many species of theropods, including troodontids,


title: Reptile content: dromaeosaurids, tyrannosaurids, and abelisaurids, along with many Crocodyliformes, and squamates (e.g. mosasaurids). Modern non-avian reptiles inhabit all the continents except Antarctica, although some birds are found on the periphery of Antarctica. Several living subgroups are recognized: Testudines (turtles and tortoises), 350 species; Rhynchocephalia (tuatara from New Zealand), 1 species; Squamata (lizards, snakes, and worm lizards), over 10,200 species; Crocodilia (crocodiles, gavials, caimans, and alligators), 24 species; and Aves (birds), approximately 10,000 species. Reptiles are tetrapod vertebrates, creatures that either have four limbs or, like snakes, are descended from four-limbed ancestors. Unlike amphibians, reptiles do not have an aquatic larval stage.


title: Reptile content: Most reptiles are oviparous, although several species of squamates are viviparous, as were some extinct aquatic clades — the fetus develops within the mother, contained in a placenta rather than an eggshell. As amniotes, reptile eggs are surrounded by membranes for protection and transport, which adapt them to reproduction on dry land. Many of the viviparous species feed their fetuses through various forms of placenta analogous to those of mammals, with some providing initial care for their hatchlings. Extant reptiles range in size from a tiny gecko, "Sphaerodactylus ariasae", which can grow up to to the saltwater crocodile, "Crocodylus porosus",


title: Reptile content: which can reach in length and weigh over . In the 13th century the category of "reptile" was recognized in Europe as consisting of a miscellany of egg-laying creatures, including "snakes, various fantastic monsters, lizards, assorted amphibians, and worms", as recorded by Vincent of Beauvais in his "Mirror of Nature". In the 18th century, the reptiles were, from the outset of classification, grouped with the amphibians. Linnaeus, working from species-poor Sweden, where the common adder and grass snake are often found hunting in water, included all reptiles and amphibians in class "III – Amphibia" in his "Systema Naturæ". The terms


title: Reptile content: "reptile" and "amphibian" were largely interchangeable, "reptile" (from Latin "repere", "to creep") being preferred by the French. Josephus Nicolaus Laurenti was the first to formally use the term "Reptilia" for an expanded selection of reptiles and amphibians basically similar to that of Linnaeus. Today, the two groups are still commonly treated under the same heading as herptiles. It was not until the beginning of the 19th century that it became clear that reptiles and amphibians are, in fact, quite different animals, and Pierre André Latreille erected the class "Batracia" (1825) for the latter, dividing the tetrapods into the four familiar


title: Reptile content: classes of reptiles, amphibians, birds, and mammals. The British anatomist Thomas Henry Huxley made Latreille's definition popular and, together with Richard Owen, expanded Reptilia to include the various fossil "antediluvian monsters", including dinosaurs and the mammal-like (synapsid) "Dicynodon" he helped describe. This was not the only possible classification scheme: In the Hunterian lectures delivered at the Royal College of Surgeons in 1863, Huxley grouped the vertebrates into mammals, sauroids, and ichthyoids (the latter containing the fishes and amphibians). He subsequently proposed the names of Sauropsida and Ichthyopsida for the latter two groups. In 1866, Haeckel demonstrated that vertebrates could be


title: Reptile content: divided based on their reproductive strategies, and that reptiles, birds, and mammals were united by the amniotic egg. The terms "Sauropsida" ("lizard faces") and "Theropsida" ("beast faces") were used again in 1916 by E.S. Goodrich to distinguish between lizards, birds, and their relatives on the one hand (Sauropsida) and mammals and their extinct relatives (Theropsida) on the other. Goodrich supported this division by the nature of the hearts and blood vessels in each group, and other features, such as the structure of the forebrain. According to Goodrich, both lineages evolved from an earlier stem group, Protosauria ("first lizards") in which


title: Reptile content: he included some animals today considered reptile-like amphibians, as well as early reptiles. In 1956, D.M.S. Watson observed that the first two groups diverged very early in reptilian history, so he divided Goodrich's Protosauria between them. He also reinterpreted Sauropsida and Theropsida to exclude birds and mammals, respectively. Thus his Sauropsida included Procolophonia, Eosuchia, Millerosauria, Chelonia (turtles), Squamata (lizards and snakes), Rhynchocephalia, Crocodilia, "thecodonts" (paraphyletic basal Archosauria), non-avian dinosaurs, pterosaurs, ichthyosaurs, and sauropterygians. In the late 19th century, a number of definitions of Reptilia were offered. The traits listed by Lydekker in 1896, for example, include a single occipital condyle,


title: Reptile content: a jaw joint formed by the quadrate and articular bones, and certain characteristics of the vertebrae. The animals singled out by these formulations, the amniotes other than the mammals and the birds, are still those considered reptiles today. The synapsid/sauropsid division supplemented another approach, one that split the reptiles into four subclasses based on the number and position of temporal fenestrae, openings in the sides of the skull behind the eyes. This classification was initiated by Henry Fairfield Osborn and elaborated and made popular by Romer's classic "Vertebrate Paleontology". Those four subclasses were: The composition of Euryapsida was uncertain. Ichthyosaurs


title: Reptile content: were, at times, considered to have arisen independently of the other euryapsids, and given the older name Parapsida. Parapsida was later discarded as a group for the most part (ichthyosaurs being classified as "incertae sedis" or with Euryapsida). However, four (or three if Euryapsida is merged into Diapsida) subclasses remained more or less universal for non-specialist work throughout the 20th century. It has largely been abandoned by recent researchers: in particular, the anapsid condition has been found to occur so variably among unrelated groups that it is not now considered a useful distinction. By the early 21st century, vertebrate paleontologists


title: Reptile content: were beginning to adopt phylogenetic taxonomy, in which all groups are defined in such a way as to be monophyletic; that is, groups include all descendants of a particular ancestor. The reptiles as historically defined are paraphyletic, since they exclude both birds and mammals. These respectively evolved from dinosaurs and from early therapsids, which were both traditionally called reptiles. Birds are more closely related to crocodilians than the latter are to the rest of extant reptiles. Colin Tudge wrote: Mammals are a clade, and therefore the cladists are happy to acknowledge the traditional taxon Mammalia; and birds, too, are a


title: Reptile content: clade, universally ascribed to the formal taxon Aves. Mammalia and Aves are, in fact, subclades within the grand clade of the Amniota. But the traditional class Reptilia is not a clade. It is just a section of the clade Amniota: the section that is left after the Mammalia and Aves have been hived off. It cannot be defined by synapomorphies, as is the proper way. Instead, it is defined by a combination of the features it has and the features it lacks: reptiles are the amniotes that lack fur or feathers. At best, the cladists suggest, we could say that


title: Reptile content: the traditional Reptilia are 'non-avian, non-mammalian amniotes'. Despite the early proposals for replacing the paraphyletic Reptilia with a monophyletic Sauropsida, which includes birds, that term was never adopted widely or, when it was, was not applied consistently. When Sauropsida was used, it often had the same content or even the same definition as Reptilia. In 1988, Jacques Gauthier proposed a cladistic definition of Reptilia as a monophyletic node-based crown group containing turtles, lizards and snakes, crocodilians, and birds, their common ancestor and all its descendants. Because the actual relationship of turtles to other reptiles was not yet well understood at


title: Reptile content: this time, Gauthier's definition came to be considered inadequate. A variety of other definitions were proposed by other scientists in the years following Gauthier's paper. The first such new definition, which attempted to adhere to the standards of the PhyloCode, was published by Modesto and Anderson in 2004. Modesto and Anderson reviewed the many previous definitions and proposed a modified definition, which they intended to retain most traditional content of the group while keeping it stable and monophyletic. They defined Reptilia as all amniotes closer to "Lacerta agilis" and "Crocodylus niloticus" than to "Homo sapiens". This stem-based definition is equivalent


title: Reptile content: to the more common definition of Sauropsida, which Modesto and Anderson synonymized with Reptilia, since the latter is better known and more frequently used. Unlike most previous definitions of Reptilia, however, Modesto and Anderson's definition includes birds, as they are within the clade that includes both lizards and crocodiles. Classification to order level of the reptiles, after Benton, 2014. The cladogram presented here illustrates the "family tree" of reptiles, and follows a simplified version of the relationships found by M.S. Lee, in 2013. All genetic studies have supported the hypothesis that turtles are diapsids; some have placed turtles within archosauriformes,


title: Reptile content: though a few have recovered turtles as lepidosauriformes instead. The cladogram below used a combination of genetic (molecular) and fossil (morphological) data to obtain its results. The placement of turtles has historically been highly variable. Classically, turtles were considered to be related to the primitive anapsid reptiles. Molecular work has usually placed turtles within the diapsids. So far three turtle genomes have been sequenced. The results place turtles as a sister clade to the archosaurs, the group that includes crocodiles, dinosaurs, and birds. The origin of the reptiles lies about 310–320 million years ago, in the steaming swamps of the


title: Reptile content: late Carboniferous period, when the first reptiles evolved from advanced reptiliomorphs. The oldest known animal that may have been an amniote is "Casineria" (though it may have been a temnospondyl). A series of footprints from the fossil strata of Nova Scotia dated to show typical reptilian toes and imprints of scales. These tracks are attributed to "Hylonomus", the oldest unquestionable reptile known. It was a small, lizard-like animal, about long, with numerous sharp teeth indicating an insectivorous diet. Other examples include "Westlothiana" (for the moment considered a reptiliomorph rather than a true amniote) and "Paleothyris", both of similar build and


title: Reptile content: presumably similar habit. The earliest amniotes, including stem-reptiles (those amniotes closer to modern reptiles than to mammals), were largely overshadowed by larger stem-tetrapods, such as "Cochleosaurus", and remained a small, inconspicuous part of the fauna until the Carboniferous Rainforest Collapse. This sudden collapse affected several large groups. Primitive tetrapods were particularly devastated, while stem-reptiles fared better, being ecologically adapted to the drier conditions that followed. Primitive tetrapods, like modern amphibians, need to return to water to lay eggs; in contrast, amniotes, like modern reptiles – whose eggs possess a shell that allows them to be laid on land – were


title: Reptile content: better adapted to the new conditions. Amniotes acquired new niches at a faster rate than before the collapse and at a much faster rate than primitive tetrapods. They acquired new feeding strategies including herbivory and carnivory, previously only having been insectivores and piscivores. From this point forward, reptiles dominated communities and had a greater diversity than primitive tetrapods, setting the stage for the Mesozoic (known as the Age of Reptiles). One of the best known early stem-reptiles is "Mesosaurus", a genus from the early Permian that had returned to water, feeding on fish. It was traditionally assumed that the first


title: Reptile content: reptiles retained an anapsid skull inherited from their ancestors. This type of skull has a skull roof with only holes for the nostrils, eyes and a pineal eye. The discoveries of synapsid-like openings (see below) in the skull roof of the skulls of several members of Parareptilia (the clade containing most of the amniotes traditionally referred to as "anapsids"), including lanthanosuchoids, millerettids, bolosaurids, some nycteroleterids, some procolophonoids and at least some mesosaurs made it more ambiguous and it's currently uncertain whether the ancestral amniote had an anapsid-like or synapsid-like skull. These animals are traditionally referred to as "anapsids", and form


title: Reptile content: a paraphyletic basic stock from which other groups evolved. Very shortly after the first amniotes appeared, a lineage called Synapsida split off; this group was characterized by a temporal opening in the skull behind each eye to give room for the jaw muscle to move. These are the "mammal-like amniotes", or stem-mammals, that later gave rise to the true mammals. Soon after, another group evolved a similar trait, this time with a double opening behind each eye, earning them the name Diapsida ("two arches"). The function of the holes in these groups was to lighten the skull and give room


title: Reptile content: for the jaw muscles to move, allowing for a more powerful bite. Turtles have been traditionally believed to be surviving parareptiles, on the basis of their anapsid skull structure, which was assumed to be primitive trait. The rationale for this classification has been disputed, with some arguing that turtles are diapsids that evolved anapsid skulls in order to improve their armor. Later morphological phylogenetic studies with this in mind placed turtles firmly within Diapsida. All molecular studies have strongly upheld the placement of turtles within diapsids, most commonly as a sister group to extant archosaurs. With the close of the


title: Reptile content: Carboniferous, the amniotes became the dominant tetrapod fauna. While primitive, terrestrial reptiliomorphs still existed, the synapsid amniotes evolved the first truly terrestrial megafauna (giant animals) in the form of pelycosaurs, such as "Edaphosaurus" and the carnivorous "Dimetrodon". In the mid-Permian period, the climate became drier, resulting in a change of fauna: The pelycosaurs were replaced by the therapsids. The parareptiles, whose massive skull roofs had no postorbital holes, continued and flourished throughout the Permian. The pareiasaurian parareptiles reached giant proportions in the late Permian, eventually disappearing at the close of the period (the turtles being possible survivors). Early in the


title: Reptile content: period, the modern reptiles, or crown-group reptiles, evolved and split into two main lineages: the Archosauromorpha (forebears of turtles, crocodiles, and dinosaurs) and the Lepidosauromorpha (predecessors of modern lizards and tuataras). Both groups remained lizard-like and relatively small and inconspicuous during the Permian. The close of the Permian saw the greatest mass extinction known (see the Permian–Triassic extinction event), an event prolonged by the combination of two or more distinct extinction pulses. Most of the earlier parareptile and synapsid megafauna disappeared, being replaced by the true reptiles, particularly archosauromorphs. These were characterized by elongated hind legs and an erect pose,


title: Reptile content: the early forms looking somewhat like long-legged crocodiles. The archosaurs became the dominant group during the Triassic period, though it took 30 million years before their diversity was as great as the animals that lived in the Permian. Archosaurs developed into the well-known dinosaurs and pterosaurs, as well as the ancestors of crocodiles. Since reptiles, first rauisuchians and then dinosaurs, dominated the Mesozoic era, the interval is popularly known as the "Age of Reptiles". The dinosaurs also developed smaller forms, including the feather-bearing smaller theropods. In the Cretaceous period, these gave rise to the first true birds. The sister group


title: Reptile content: to Archosauromorpha is Lepidosauromorpha, containing lizards and tuataras, as well as their fossil relatives. Lepidosauromorpha contained at least one major group of the Mesozoic sea reptiles: the mosasaurs, which lived during the Cretaceous period. The phylogenetic placement of other main groups of fossil sea reptiles – the ichthyopterygians (including ichthyosaurs) and the sauropterygians, which evolved in the early Triassic – is more controversial. Different authors linked these groups either to lepidosauromorphs or to archosauromorphs, and ichthyopterygians were also argued to be diapsids that did not belong to the least inclusive clade containing lepidosauromorphs and archosauromorphs. The close of the Cretaceous


title: Reptile content: period saw the demise of the Mesozoic era reptilian megafauna (see the Cretaceous–Paleogene extinction event). Of the large marine reptiles, only sea turtles were left; and of the non-marine large reptiles, only the semi-aquatic crocodiles and broadly similar choristoderes survived the extinction, with the latter becoming extinct in the Miocene. Of the great host of dinosaurs dominating the Mesozoic, only the small beaked birds survived. This dramatic extinction pattern at the end of the Mesozoic led into the Cenozoic. Mammals and birds filled the empty niches left behind by the reptilian megafauna and, while reptile diversification slowed, bird and mammal


title: Reptile content: diversification took an exponential turn. However, reptiles were still important components of the megafauna, particularly in the form of giant tortoises. After the extinction of most archosaur and marine reptile lines by the end of the Cretaceous, reptile diversification continued throughout the Cenozoic. Squamates took a massive hit during the KT-event, only recovering ten million years after it, but they underwent a great radiation event once they recovered, and today squamates make up the majority of living reptiles (> 95%). Approximately 10,000 extant species of traditional reptiles are known, with birds adding about 10,000 more, almost twice the number of


title: Reptile content: mammals, represented by about 5,700 living species (excluding domesticated species). All squamates and turtles have a three-chambered heart consisting of two atria, one variably partitioned ventricle, and two aortas that lead to the systemic circulation. The degree of mixing of oxygenated and deoxygenated blood in the three-chambered heart varies depending on the species and physiological state. Under different conditions, deoxygenated blood can be shunted back to the body or oxygenated blood can be shunted back to the lungs. This variation in blood flow has been hypothesized to allow more effective thermoregulation and longer diving times for aquatic species, but has


title: Reptile content: not been shown to be a fitness advantage. For example, Iguana hearts, like the majority of the squamates hearts, are composed of three chambers with two aorta and one ventricle, cardiac involuntary muscles. The main structures of the heart are the sinus venosus, the pacemaker, the left atrium, the right atruim, the atrioventricular valve, the cavum venosum, cavum arteriosum, the cavum pulmonale, the muscular ridge, the ventricular ridge, pulmonary veins, and paired aortic arches. Some squamate species (e.g., pythons and monitor lizards) have three-chambered hearts that become functionally four-chambered hearts during contraction. This is made possible by a muscular ridge


title: Reptile content: that subdivides the ventricle during ventricular diastole and completely divides it during ventricular systole. Because of this ridge, some of these squamates are capable of producing ventricular pressure differentials that are equivalent to those seen in mammalian and avian hearts. Crocodilians have an anatomically four-chambered heart, similar to birds, but also have two systemic aortas and are therefore capable of bypassing their pulmonary circulation. Modern non-avian reptiles exhibit some form of cold-bloodedness (i.e. some mix of poikilothermy, ectothermy, and bradymetabolism) so that they have limited physiological means of keeping the body temperature constant and often rely on external sources of


title: Reptile content: heat. Due to a less stable core temperature than birds and mammals, reptilian biochemistry requires enzymes capable of maintaining efficiency over a greater range of temperatures than in the case for warm-blooded animals. The optimum body temperature range varies with species, but is typically below that of warm-blooded animals; for many lizards, it falls in the 24°–35 °C (75°–95 °F) range, while extreme heat-adapted species, like the American desert iguana "Dipsosaurus dorsalis", can have optimal physiological temperatures in the mammalian range, between 35° and 40 °C (95° and 104 °F). While the optimum temperature is often encountered when the animal


title: Reptile content: is active, the low basal metabolism makes body temperature drop rapidly when the animal is inactive. As in all animals, reptilian muscle action produces heat. In large reptiles, like leatherback turtles, the low surface-to-volume ratio allows this metabolically produced heat to keep the animals warmer than their environment even though they do not have a warm-blooded metabolism. This form of homeothermy is called gigantothermy; it has been suggested as having been common in large dinosaurs and other extinct large-bodied reptiles. The benefit of a low resting metabolism is that it requires far less fuel to sustain bodily functions. By using


title: Reptile content: temperature variations in their surroundings, or by remaining cold when they do not need to move, reptiles can save considerable amounts of energy compared to endothermic animals of the same size. A crocodile needs from a tenth to a fifth of the food necessary for a lion of the same weight and can live half a year without eating. Lower food requirements and adaptive metabolisms allow reptiles to dominate the animal life in regions where net calorie availability is too low to sustain large-bodied mammals and birds. It is generally assumed that reptiles are unable to produce the sustained high


title: Reptile content: energy output necessary for long distance chases or flying. Higher energetic capacity might have been responsible for the evolution of warm-bloodedness in birds and mammals. However, investigation of correlations between active capacity and thermophysiology show a weak relationship. Most extant reptiles are carnivores with a sit-and-wait feeding strategy; whether reptiles are cold blooded due to their ecology is not clear. Energetic studies on some reptiles have shown active capacities equal to or greater than similar sized warm-blooded animals. All reptiles breathe using lungs. Aquatic turtles have developed more permeable skin, and some species have modified their cloaca to increase the