History of Television

The history of television records the work of numerous engineers and inventors in several countries over many decades. The fundamental principles of television were initially explored using electromechanical methods to scan, transmit and reproduce an image. As electronic camera and display tubes were perfected, electromechanical television gave way to all-electronic broadcast television systems in nearly all applications.

Electromechanical television

Main article: Mechanical television

The Nipkow disk. This schematic shows the circular paths traced by the holes, that may also be square for greater precision. The area of the disk outlined in black shows the region scanned.
The beginnings of mechanical television can be traced back to the discovery of the photoconductivity of the element selenium by Willoughby Smith in 1873, the invention of a scanning disk by Paul Gottlieb Nipkow in 1884 and John Logie Baird’s demonstration of televised moving images in 1926.

As a 23-year-old German university student, Paul Nipkow proposed and patented the first electromechanical television system in 1884.[1] Although he never built a working model of the system, variations of Nipkow’s spinning-disk “image rasterizer” for television became exceedingly common, and remained in use until 1939.[2] Constantin Perskyi had coined the word television in a paper read to the International Electricity Congress at the International World Fair in Paris on August 25, 1900. Perskyi’s paper reviewed the existing electromechanical technologies, mentioning the work of Nipkow and others.[3]

However, it was not until 1907 that developments in amplification tube technology, by Lee DeForest and Arthur Korn among others, made the design practical.[4] The first demonstration of the instantaneous transmission of still silhouette images was by Georges Rignoux and A. Fournier in Paris in 1909, using a rotating mirror-drum as the scanner and a matrix of 64 selenium cells as the receiver.[5]

In 1911, Boris Rosing and his student Vladimir Zworykin created a television system that used a mechanical mirror-drum scanner to transmit, in Zworykin’s words, “very crude images” over wires to the “Braun tube” (cathode ray tube or “CRT”) in the receiver. Moving images were not possible because, in the scanner, “the sensitivity was not enough and the selenium cell was very laggy”.[6]

On March 25, 1925, Scottish inventor John Logie Baird gave the first public demonstration of televised silhouette images in motion, at Selfridge’s Department Store in London.[7] AT&T’s Bell Telephone Laboratories transmitted halftone still images of transparencies in May 1925. On June 13 of that year, Charles Francis Jenkins transmitted the silhouette image of a toy windmill in motion, over a distance of five miles from a naval radio station in Maryland to his laboratory in Washington, using a lensed disk scanner with a 48-line resolution.[8][9]

However, if television is defined as the live transmission of moving images with continuous tonal variation, Baird first achieved this privately on October 2, 1925. But strictly speaking, Baird had not yet achieved moving images on October 2. His scanner worked at only five images per second, below the threshold required to give the illusion of motion, usually defined as at least 12 images per second. By January, he had improved the scan rate to 12.5 images per second.

Then on January 26, 1926 at his laboratory in London, Baird gave what is widely recognized as being the world’s first demonstration of a working television system to members of the Royal Institution and a newspaper reporter.

Unlike later electronic systems with several hundred lines of resolution, Baird’s vertically scanned image, using a scanning disk embedded with a double spiral of lenses, had only 30 lines, just enough to reproduce a recognizable human face.[citation needed]

In 1927, Baird transmitted a signal over 438 miles (705 km) of telephone line between London and Glasgow. In 1928, Baird’s company (Baird Television Development Company/Cinema Television) broadcast the first transatlantic television signal, between London and New York, and the first shore-to-ship transmission. He also demonstrated an electromechanical color, infrared (dubbed “Noctovision”), and stereoscopic television, using additional lenses, disks and filters. In parallel, Baird developed a video disk recording system dubbed “Phonovision”; a number of the Phonovision recordings, dating back to 1927, still exist.[10] In 1929, he became involved in the first experimental electromechanical television service in Germany. In November of the same year, Baird and Bernard Natan of Pathé established France’s first television company, Télévision-Baird-Natan. In 1931, he made the first outdoor remote broadcast, of the Epsom Derby.[11] In 1932, he demonstrated ultra-short wave television. Baird’s electromechanical system reached a peak of 240-lines of resolution on BBC television broadcasts in 1936 though the mechanical system did not scan the televised scene directly. Instead a 17.5mm film was shot, rapidly developed and then scanned while the film was still wet. On November 2, 1936 the BBC began transmitting the world’s first public television service from the Victorian Alexandra Palace in north London[12] following alternate daily test broadcasts of the Baird and Marconi systems to the Radio Show at Olympia at the end of August. It therefore claims to be the birthplace of television broadcasting as we know it today. The intermediate film system was discontinued within three months in favour of a 405-line all-electronic system developed by Marconi-EMI.[13]

Herbert E. Ives and Frank Gray of Bell Telephone Laboratories gave a dramatic demonstration of mechanical television on April 7, 1927. The reflected-light television system included both small and large viewing screens. The small receiver had a two-inch-wide by 2.5-inch-high screen. The large receiver had a screen 24 inches wide by 30 inches high. Both sets were capable of reproducing reasonably accurate, monochromatic moving images. Along with the pictures, the sets also received synchronized sound. The system transmitted images over two paths: first, a copper wire link from Washington to New York City, then a radio link from Whippany, New Jersey. Comparing the two transmission methods, viewers noted no difference in quality. Subjects of the telecast included Secretary of Commerce Herbert Hoover. A flying-spot scanner beam illuminated these subjects. The scanner that produced the beam had a 50-aperture disk. The disc revolved at a rate of 18 frames per second, capturing one frame about every 56 milliseconds. (Today’s systems typically transmit 30 or 60 frames per second, or one frame every 33.3 or 16.7 milliseconds respectively.) Television historian Albert Abramson underscored the significance of the Bell Labs demonstration: “It was in fact the best demonstration of a mechanical television system ever made to this time. It would be several years before any other system could even begin to compare with it in picture quality.”[14]

Meanwhile in the Soviet Union, Léon Theremin had been developing a mirror drum-based television, starting with 16 lines resolution in 1925, then 32 lines and eventually 64 using interlacing in 1926, and as part of his thesis on May 7, 1926 he electrically transmitted and then projected near-simultaneous moving images on a five foot square screen.[9] By 1927 he achieved an image of 100 lines, a resolution that was not surpassed until 1931 by RCA, with 120 lines.[citation needed]

On December 25, 1926, Kenjiro Takayanagi demonstrated a television system with a 40-line resolution that employed a Nipkow disk scanner and CRT display at Hamamatsu Industrial High School in Japan. This prototype is still on display at the Takayanagi Memorial Museum in Shizuoka University, Hamamatsu Campus. His research in creating a production model were halted by the US after Japan lost World War II.[15]

Mechanical scanning systems, though obsolete for the more familiar television systems, nevertheless survive in long wave infra red cameras because there is no suitable all-electronic pickup device.[citation needed]

Electronic Television

In 1980 Alan Archibald Campbell-Swinton, fellow of the Royal Society (UK), published a letter in the scientific journal Nature in which he described how “distant electric vision” could be achieved by using a cathode ray tube (or “Braun” tube, after its inventor, Karl Braun) as both a transmitting and receiving device,[16][17] apparently the first iteration of the electronic television method that would dominate the field until recently. He expanded on his vision in a speech given in London in 1911 and reported in The Times[18] and the Journal of the Röntgen Society.[19][20] In a letter to Nature published in October 1926, Campbell-Swinton also announced the results of some “not very successful experiments” he had conducted with G. M. Minchin and J. C. M. Stanton. They had attempted to generate an electrical signal by projecting an image onto a selenium-coated metal plate that was simultaneously scanned by a cathode ray beam.[21][22] These experiments were conducted before March 1914, when Minchin died,[23] but they were later repeated by two different teams in 1937, by H. Miller and J. W. Strange from EMI,[24] and by H. Iams and A. Rose from RCA.[25] Both teams succeeded in transmitting “very faint” images with the original Campbell-Swinton’s selenium-coated plate. Although others had experimented with using a cathode ray tube as a receiver, the concept of using one as a transmitter was novel.[26] By the late 1920s, when electromechanical television was still being introduced, several inventors were already working separately on versions of all-electronic transmitting tubes, including Philo Farnsworth and Vladimir Zworykin in the United States, and Kálmán Tihanyi in Hungary.

On September 7, 1927, Farnsworth’s Image Dissector camera tube transmitted its first image, a simple straight line, at his laboratory at 202 Green Street in San Francisco.[27][28] By September 3, 1928, Farnsworth had developed the system sufficiently to hold a demonstration for the press.[28] In 1929, the system was further improved by elimination of a motor generator, so that his television system now had no mechanical parts.[29] That year, Farnsworth transmitted the first live human images with his system, including a three and a half-inch image of his wife Elma (“Pem”) with her eyes closed (possibly due to the bright lighting required).[30]

Meanwhile, Vladimir Zworykin was also experimenting with the cathode ray tube to create and show images. While working for Westinghouse Electric Corporation in 1923, he began to develop an electronic camera tube. But in a 1925 demonstration, the image was dim, had low contrast and poor definition, and was stationary.[31] Zworykin’s imaging tube never got beyond the laboratory stage. But RCA, which acquired the Westinghouse patent, asserted that the patent for Farnsworth’s 1927 image dissector was written so broadly that it would exclude any other electronic imaging device. Thus RCA, on the basis of Zworykin’s 1923 patent application, filed a patent interference suit against Farnsworth. The U.S. Patent Office examiner disagreed in a 1935 decision, finding priority of invention for Farnsworth against Zworykin. Farnsworth claimed that Zworykin’s 1923 system would be unable to produce an electrical image of the type to challenge his patent. Zworykin received a patent in 1928 for a color transmission version of his 1923 patent application,[32] he also divided his original application in 1931.[33] Zworykin was unable or unwilling to introduce evidence of a working model of his tube that was based on his 1923 patent application. In September 1939, after losing an appeal in the courts and determined to go forward with the commercial manufacturing of television equipment, RCA agreed to pay Farnsworth US$1 million (the equivalent of $13.8 million in 2006) over a ten-year period, in addition to license payments, to use Farnsworth’s patents.[34][35]

The problem of low sensitivity to light resulting in low electrical output from transmitting or “camera” tubes would be solved by Tihanyi beginning in 1924.[36] His solution was a camera tube that accumulated and stored electrical charges (“photoelectrons”) within the tube throughout each scanning cycle. The device was first described in a patent application he filed in Hungary in March 1926 for a television system he dubbed “Radioskop”.[37] After further refinements included in a 1928 patent application,[36] Tihanyi was awarded patents for the camera tube in both France and Great Britain in 1928, and applied for patents in the United States in June of the following year. Although his breakthrough would be incorporated into the design of RCA’s “iconoscope” in 1931, the U.S. patent for Tihanyi’s transmitting tube would not be granted until May 1939. The patent for his receiving tube had been granted the previous October. Both patents had been purchased by RCA prior to their approval.[38][39] The idea of charge & storage (with various and very different technological solutions) is still remained[40] as a basic requirement for all type of modern image sensors until this day.

Development continued around the world. At the Berlin Radio Show in August 1931, Manfred von Ardenne gave a public demonstration of a television system using a CRT for both transmission and reception. However, Ardenne had not developed a camera tube, using the CRT instead as a flying-spot scanner to scan slides and film.[41] Philo Farnsworth gave the world’s first public demonstration of an all-electronic television system, using a live camera, at the Franklin Institute of Philadelphia on August 25, 1934, and for ten days afterwards.[42][43]

In 1933 RCA introduced an improved camera tube that relied on Tihanyi’s charge storage principle.[44] Dubbed the Iconoscope by Zworykin, the new tube had a light sensitivity of about 75,000 lux, and thus was claimed to be much more sensitive than Farnsworth’s image dissector.[citation needed] However, Farnsworth had overcome his power problems with his Image Dissector through the invention of a completely unique “multipactor” device that he began work on in 1930, and demonstrated in 1931.[45][46] This small tube could amplify a signal reportedly to the 60th power or better[47] and showed great promise in all fields of electronics. A problem with the multipactor, unfortunately, was that it wore out at an unsatisfactory rate.[48]

In Britain the EMI engineering team led by Isaac Shoenberg applied in 1932 for a patent for a new device they dubbed “the Emitron”,[49][50] which formed the heart of the cameras they designed for the BBC. On November 2, 1936, a 405-line broadcasting service employing the Emitron began at studios in Alexandra Palace, and transmitted from a specially-built mast atop one of the Victorian building’s towers. It alternated for a short time with Baird’s mechanical system in adjoining studios, but was more reliable and visibly superior. This was the world’s first regular high-definition television service.[51]

The original American iconoscope was noisy, had a high ratio of interference to signal, and ultimately gave disappointing results, especially when compared to the high definition mechanical scanning systems then becoming available.[52][53] The EMI team under the supervision of Isaac Shoenberg analyzed how the iconoscope (or Emitron) produces an electronic signal and concluded that its real efficiency was only about 5% of the theoretical maximum.[54][55] They solved this problem by developing and patenting in 1934 two new camera tubes dubbed super-Emitron and CPS Emitron.[56][57][58] The super-Emitron was between ten and fifteen times more sensitive than the original Emitron and iconoscope tubes and, in some cases, this ratio was considerably greater.[54] It was used for an outside broadcasting by the BBC, for the first time, on Armistice Day 1937, when the general public could watch in a television set how the King lay a wreath at the Cenotaph.[59] This was the first time that anyone could broadcast a live street scene from cameras installed on the roof of neighbor buildings, because neither Farnsworth nor RCA could do the same before the 1939 New York World’s Fair.

Television antenna on a rooftop
On the other hand, in 1934, Zworykin shared some patent rights with the German licensee company Telefunken.[60] The “image iconoscope” (“Superikonoskop” in Germany) was produced as a results of the collaboration. This tube is essentially identical to the super-Emitron.[citation needed] The production and commercialization of the super-Emitron and image iconoscope in Europe were not affected by the patent war between Zworykin and Farnsworth, because Dieckmann and Hell had priority in Germany for the invention of the image dissector, having submitted a patent application for their Lichtelektrische Bildzerlegerröhre für Fernseher (Photoelectric Image Dissector Tube for Television) in Germany in 1925,[61] two years before Farnsworth did the same in the United States.[62] The image iconoscope (Superikonoskop) became the industrial standard for public broadcasting in Europe from 1936 until 1960, when it was replaced by the vidicon and plumbicon tubes. Indeed it was the representative of the European tradition in electronic tubes competing against the American tradition represented by the image orthicon.[63][64] The German company Heimann produced the Superikonoskop for the 1936 Berlin Olympic Games,[65][66] later Heimann also produced and commercialized it from 1940 to 1955,[67] finally the Dutch company Philips produced and commercialized the image iconoscope and multicon from 1952 to 1958.[64][68]

American television broadcasting at the time consisted of a variety of markets in a wide range of sizes, each competing for programming and dominance with separate technology, until deals were made and standards agreed upon in 1941.[69] RCA, for example, used only Iconoscopes in the New York area, but Farnsworth Image Dissectors in Philadelphia and San Francisco.[70] In September 1939, RCA agreed to pay the Farnsworth Television and Radio Corporation royalties over the next ten years for access to Farnsworth’s patents.[71] With this historic agreement in place, RCA integrated much of what was best about the Farnsworth Technology into their systems.[70]

In 1941, the United States implemented 525-line television.[72][73] The world’s first 625-line television standard was designed in the Soviet Union in 1944, and became a national standard in 1946.[74] The first broadcast in 625-line standard occurred in 1948 in Moscow.[75] The concept of 625 lines per frame was subsequently implemented in the European CCIR standard.[76]

[edit] Color television

Main article: Color television

[edit] Broadcast television

Further information: Timeline of the introduction of television in countries

[edit] Overview

Programming is broadcast by television stations, sometimes called “channels”, as stations are licensed by their governments to broadcast only over assigned channels in the television band. At first, terrestrial broadcasting was the only way television could be widely distributed, and because bandwidth was limited, i.e., there were only a small number of channels available, government regulation was the norm.

In the U.S., the Federal Communications Commission (FCC) allowed stations to broadcast advertisements beginning in July 1941, but required public service programming commitments as a requirement for a license. By contrast, the United Kingdom chose a different route, imposing a television license fee on owners of television reception equipment to fund the British Broadcasting Corporation (BBC), which had public service as part of its Royal Charter.

[edit] United Kingdom

The first British television broadcast was made by Baird Television’s electromechanical system over the BBC radio transmitter in September 1929. Baird provided a limited amount of programming five days a week by 1930. During this time, Southampton earned the distinction of broadcasting the first-ever live television interview, which featured Peggy O’Neil, an actress and singer from Buffalo, New York.[77] On August 22, 1932, BBC launched its own regular service using Baird’s 30-line electromechanical system, continuing until September 11, 1935. On November 2, 1936 the BBC began broadcasting a dual-system service, alternating between Marconi-EMI’s 405-line standard and Baird’s improved 240-line standard, from Alexandra Palace in London, making the BBC Television Service (now BBC One) the world’s first regular high-definition television service. The government, on advice from a special advisory committee, decided that Marconi-EMI’s electronic system gave the superior picture, and the Baird system was dropped in February 1937. TV broadcasts in London were on the air an average of four hours daily from 1936 to 1939. There were 12,000 to 15,000 receivers. Some sets in restaurants or bars might have 100 viewers for sport events (Dunlap, p56).The outbreak of the Second World War caused the BBC service to be suspended without warning on September 1, 1939, mid-way through a Mickey Mouse cartoon. It resumed, again from Alexandra Palace, after the end of the war on June 7, 1946 showing the same cartoon.[citation needed] At the end of 1947 there were 54,000 licensed television receivers, compared with 44,000 television sets in the United States at that time.[78]

The first transatlantic television signal was sent in 1928 from London to New York[79] by the Baird Television Development Company/Cinema Television, although this signal was not broadcast to the public. The first live satellite signal to Britain from the United States was broadcast via the Telstar satellite on July 23, 1962.

The first live broadcast from the European continent was made on August 27, 1950.

United States

WNBT (later WNBC) schedule for first week of commercial TV programming in the United States, July 1941
The first regularly scheduled television service in the United States began on July 2, 1928. The Federal Radio Commission authorized C.F. Jenkins to broadcast from experimental station W3XK in Wheaton Maryland, a suburb of Washington, D.C. For at least the first eighteen months, 48-line silhouette images from motion picture film were broadcast, although beginning in the summer of 1929 he occasionally broadcast in halftones.[80][81]

Hugo Gernsback’s New York City radio station began a regular, if limited, schedule of live television broadcasts on August 14, 1928, using 48-line images. Working with only one transmitter, the station alternated radio broadcasts with silent television images of the station’s call sign, faces in motion, and wind-up toys in motion.[82][83] Speaking later that month, Gernsback downplayed the broadcasts, intended for amateur experimenters. “In six months we may have television for the public, but so far we have not got it.”[84] Gernsback also published Television, the world’s first magazine about the medium.

General Electric’s experimental station in Schenectady, New York, on the air sporadically since January 13, 1928, was able to broadcast reflected-light, 48-line images via shortwave as far as Los Angeles, and by September was making four television broadcasts weekly. It is considered to be the direct predecessor of current television station WRGB. The Queen’s Messenger, a one-act play broadcast on September 11, 1928, was the world’s first live drama on television.[85]

Radio giant RCA began daily experimental television broadcasts in New York City in March 1929 over station W2XBS, the predecessor of current television station WNBC. The 60-line transmissions consisted of pictures, signs, and views of persons and objects.[86] Experimental broadcasts continued to 1931.[87]

General Broadcasting System’s WGBS radio and W2XCR television aired their regular broadcasting debut in New York City on April 26, 1931, with a special demonstration set up in Aeolian Hall at Fifth Avenue and Fifty-fourth Street. Thousands waited to catch a glimpse of the Broadway stars who appeared on the six-inch (15 cm) square image, in an evening event to publicize a weekday programming schedule offering films and live entertainers during the four-hour daily broadcasts. Appearing were boxer Primo Carnera, actors Gertrude Lawrence, Louis Calhern, Frances Upton and Lionel Atwill, WHN announcer Nils Granlund, the Forman Sisters, and a host of others.[88]

CBS’s New York City station W2XAB began broadcasting their first regular seven days a week television schedule on July 21, 1931, with a 60-line electromechanical system. The first broadcast included Mayor Jimmy Walker, the Boswell Sisters, Kate Smith, and George Gershwin. The service ended in February 1933.[89] Don Lee Broadcasting’s station W6XAO in Los Angeles went on the air in December 1931. Using the UHF spectrum, it broadcast a regular schedule of filmed images every day except Sundays and holidays for several years.[90]

By 1935, low-definition electromechanical television broadcasting had ceased in the United States except for a handful of stations run by public universities that continued to 1939. The Federal Communications Commission (FCC) saw television in the continual flux of development with no consistent technical standards, hence all such stations in the U.S. were granted only experimental and non-commercial licenses, hampering television’s economic development. Just as importantly, Philo Farnsworth’s August 1934 demonstration of an all-electronic system at the Franklin Institute in Philadelphia pointed out the direction of television’s future.

On June 15, 1936, Don Lee Broadcasting began a one month-long demonstration of high definition (240+ line) television in Los Angeles on W6XAO (later KTSL) with a 300-line image from motion picture film. By October, W6XAO was making daily television broadcasts of films. RCA and its subsidiary NBC demonstrated in New York City a 343-line electronic television broadcast, with live and film segments, to its licensees on July 7, 1936, and made its first public demonstration to the press on November 6. Irregularly scheduled broadcasts continued through 1937 and 1938.[91] Regularly scheduled electronic broadcasts began in April 1938 in New York (to the second week of June, and resuming in August) and Los Angeles.[92][93][94][95] NBC officially began regularly scheduled television broadcasts in New York on April 30, 1939 with a broadcast of the opening of the 1939 New York World’s Fair. By June 1939, regularly scheduled 441-line electronic television broadcasts were available in New York City and Los Angeles, and by November on General Electric’s station in Schenectady. From May through December 1939, the New York City NBC station (W2XBS) of General Electric broadcast twenty to fifty-eight hours of programming per month, Wednesday through Sunday of each week. The programming was 33% news, 29% drama, and 17% educational programming, with an estimated 2,000 receiving sets by the end of the year, and an estimated audience of five to eight thousand. A remote truck could cover outdoor events from up to 10 miles (16 km) away from the transmitter, which was located atop the Empire State Building. Coaxial cable was used to cover events at Madison Square Garden. The coverage area for reliable reception was a radius of 40 to 50 miles (80 km) from the Empire State Building, an area populated by more than 10,000,000 people (Lohr, 1940).

The FCC adopted NTSC television engineering standards on May 2, 1941, calling for 525 lines of vertical resolution, 30 frames per second with interlaced scanning, 60 fields per second, and sound carried by frequency modulation. Sets sold since 1939 which were built for slightly lower resolution could still be adjusted to receive the new standard. (Dunlap, p31). The FCC saw television ready for commercial licensing, and the first such licenses were issued to NBC and CBS owned stations in New York on July 1, 1941, followed by Philco’s station WPTZ in Philadelphia. The first advertising to appear on American television occurred on the afternoon of July 1, 1941 when New York NBC station WNBT, now WNBC, broadcast a test pattern modified to look like a clock, with the words “Bulova Watch Time” in the lower right quadrant. Picture at: http://www.earlytelevision.org/images/rca_bulova_ad-1.jpg link title The image appeared just prior to that afternoon’s telecast of a Brooklyn Dodgers game live from Ebbets Field. After the U.S. entry into World War II, the FCC reduced the required minimum air time for commercial television stations from 15 hours per week to 4 hours. Most TV stations suspended broadcasting. On the few that remained, programs included entertainment such as boxing and plays, events at Madison Square Garden, and illustrated war news as well as training for air raid wardens and first aid providers. In 1942, there were 5,000 sets in operation, but production of new TVs, radios, and other broadcasting equipment for civilian purposes was suspended from April 1942 to August 1945 (Dunlap).

The Philco Predicta, 1958. In the collection of The Children’s Museum of Indianapolis
By 1947, when there were 40 million radios in the U.S., there were about 44,000 television sets (with probably 30,000 in the New York area).[78] Regular network television broadcasts began on NBC on a three-station network linking New York with the Capital District and Philadelphia in 1944; on the DuMont Television Network in 1946, and on CBS and ABC in 1948. By 1949, the networks stretched from New York to the Mississippi River, and by 1951 to the West Coast. Commercial color television broadcasts began on CBS in 1951 with a field-sequential color system that was suspended four months later for technical and economic reasons. The television industry’s National Television System Committee (NTSC) developed a color television system based on RCA technology that was compatible with existing black and white receivers, and commercial color broadcasts reappeared in 1953

Canada

The Canadian Broadcasting Corporation (CBC) adopted the American NTSC 525-line B/W 60 field per second system as its broadcast standard. It began television broadcasting in Canada in September 1952. The first broadcast was on September 6, 1952 from its Montreal, Quebec station CBFT. The premiere broadcast was bilingual, spoken in English and French. Two days later, on September 8, 1952, the Toronto, Ontario station CBLT went on the air. This became the English-speaking flagship station for the country, while CBFT became the French-language flagship after a second English-language station was licensed to CBC in Montreal later in the decade. The CBC’s first privately owned affiliate television station, CKSO in Sudbury, Ontario, launched in October 1953 (at the time, all private stations were expected to affiliate with the CBC, a condition that was relaxed in 1960–61 when CTV, Canada’s second national English-language network, was formed).

[edit] France

The first experiments in television broadcasting began in France in the 1930s, but the French were slow to employ the new technology.

In November 1929, Bernard Natan established France’s first television company, Télévision-Baird-Natan. On April 14, 1931, there took place the first transmission with a thirty-line standard by René Barthélemy. On December 6, 1931, Henri de France created the Compagnie Générale de Télévision (CGT). In December 1932, Bathélemy carried out an experimental program in black and white (definition: 60 lines) one hour per week, “Paris Télévision”, which gradually became daily from early 1933.

The first official channel of French television appeared on February 13, 1935, the date of the official inauguration of television in France, which was broadcast in 60 lines from 8:15 to 8:30 pm. The program showed the actress Béatrice Bretty in the studio of Radio-PTT Vision at 103 rue de Grenelle in Paris. The broadcast had a range of 100 km (62 mi). On November 10, George Mandel, Minister of Posts, inaugurated the first broadcast in 180 lines from the transmitter of the Eiffel tower. On the 18th, Susy Wincker, the first announcer since the previous June, carried out a demonstration for the press from 5:30 to 7:30 pm. Broadcasts became regular from January 4, 1937 from 11:00 to 11:30 am and 8:00 to 8:30 pm during the week, and from 5:30 to 7:30 pm on Sundays. In July 1938, a decree defined for three years a standard of 455 lines VHF (whereas three standards were used for the experiments: 441 lines for Gramont, 450 lines for the Compagnie des Compteurs and 455 for Thomson). In 1939, there were about only 200 to 300 individual television sets, some of which were also available in a few public places.

With the entry of France into World War II the same year, broadcasts ceased and the transmitter of the Eiffel tower was sabotaged. On September 3, 1940, French television was seized by the German occupation forces. A technical agreement was signed by the Compagnie des Compteurs and Telefunken, and a financing agreement for the resuming of the service is signed by German Ministry of Post and Radiodiffusion Nationale (Vichy’s radio). On May 7, 1943 at 3:00 evening broadcasts. The first broadcast of Fernsehsender Paris (Paris Télévision) was transmitted from rue Cognac-Jay. These regular broadcasts (5 1/4 hours a day) lasted until August 16, 1944. One thousand 441-line sets, most of which were installed in soldiers’ hospitals, picked up the broadcasts. These Nazi-controlled television broadcasts from the Eiffel Tower in Paris were able to be received on the south coast of England by R.A.F. and BBC engineers http://www.earlytelevision.org/raf.html link title, who photographed the station identification image direct from the screen http://www.earlytelevision.org/images/parisnazitransmitter.jpg link title

In 1944, René Barthélemy developed an 819-line television standard. During the years of occupation, Barthélemy reached 1015 and even 1042 lines. On October 1, 1944, television service resumed after the liberation of Paris. The broadcasts were transmitted from the Cognacq-Jay studios. In October 1945, after repairs, the transmitter of the Eiffel Tower was back in service. On November 20, 1948, Mitterrand decreed a broadcast standard of 819 lines; broadcasting began at the end of 1949 in this definition. France was the only European country to adopt it (others will choose 625 lines).

[edit] Germany

Electromechanical broadcasts began in Germany in 1929, but were without sound until 1934. Network electronic service started on March 22, 1935, on 180 lines using telecine transmission of film, intermediate film system, or cameras using the Nipkow Disk. Transmissions using cameras based on the iconoscope began on January 15, 1936. The Berlin Summer Olympic Games were televised, using both all-electronic iconoscope-based cameras and intermediate film cameras, to Berlin and Hamburg in August 1936. Twenty-eight public television rooms were opened for anybody who did not own a television set. The Germans had a 441-line system on the air in February 1937, and during World War II brought it to France, where they broadcast from the Eiffel Tower.

The American Armed Forces Radio Network at the end of World War II, wishing to provide US TV programming to the occupation forces in Germany, used US TV receivers made to operate at 525 lines and 60 fields. US broadcast equipment was modified; they changed the vertical frequency to 50 Hz in accordance to the European mains frequency standard to avoid power line wiggles, changed the horizontal frequency from 15,750 Hz to 15,625 Hz a 0.5 microsecond change in the length of a line. With this signal, US TV receivers with only an adjustment to the vertical hold control had a 625 line (= 576 visual lines + 49 lines of non-visual synch and burst data), 50 field scan, which became the German standard. This AFN system, however, was not the later PAL standard native to Germany, as the displays themselves were not capable of displaying any more than the standard NTSC 486 visual lines, which effectively were even only 243 visible lines due to display-internal deinterlacing by means of alternatively discarding one field and applying line doubling on the result. Additionally, it still took until the 1960s for the PAL-specific YUV color system to be invented by Walter Bruch, with PAL operating at 576 visual lines.

[edit] Soviet Union (USSR)

The Soviet Union began offering 30-line electromechanical test broadcasts in Moscow on October 31, 1931, and a commercially manufactured television set in 1932.

The first experimental transmissions of electronic television took place in Moscow on March 9, 1937, using equipment manufactured and installed by RCA. Regular broadcasting began on December 31, 1938. It was quickly realized that 343 lines of resolution offered by this format would have become insufficient in the long run, thus a specification for 441-line format was developed in 1940, superseded by a 625-line standard in 1944. This format was ultimately accepted as a national standard.

The experimental transmissions in 625-line format started in Moscow from November 4, 1948. Regular broadcasting began on June 16, 1949. Details for this standard were formalized in 1955 specification called GOST 7845-55, basic parameters for black-and-white television broadcast. In particular, frame size was set to 625 lines, frame rate to 25 frames/s interlaced, and video bandwidth to 6 MHz. These basic parameters were accepted by most countries having 50 Hz mains frequency and became the foundation of television systems presently known as PAL and SECAM.

Starting from 1951 broadcasting in the 625-line standard was introduced in other major cities of the Soviet Union.

Color television broadcast started in 1974, using SECAM color system.[74]

[edit] Japan

In 1979, the Japanese state broadcaster NHK first developed consumer high-definition television with a 5:3 display aspect ratio.[96] The system, known as Hi-Vision or MUSE after its Multiple sub-Nyquist sampling encoding for encoding the signal, required about twice the bandwidth of the existing NTSC system but provided about four times the resolution (1080i/1125 lines). Satellite test broadcasts started in 1989, with regular testing starting in 1991 and regular broadcasting of BS-9ch commenced on November 25, 1994, which featured commercial and NHK television programming.

Sony first demonstrated a wideband analog high-definition television system HDTV capable video camera, monitor and video tape recorder (VTR) in April 1981 at an international meeting of television engineers in Algiers. The HDVS range was launched in April 1984, with the HDC-100 camera, HDV-100 video recorder and HDS-100 video switcher all working in the 1125-line component video format with interlaced video and a 5:3 aspect ratio.

[edit] Technological innovations

The first national live television broadcast in the U.S. took place on September 4, 1951 when President Harry Truman’s speech at the Japanese Peace Treaty Conference in San Francisco, California was transmitted over AT&T’s transcontinental cable and microwave radio relay system to broadcast stations in local markets.[97][98][99]

The first live coast-to-coast commercial television broadcast in the U.S. took place on November 18, 1951 during the premiere of CBS’s See It Now, which showed a split-screen view of the Brooklyn Bridge in New York City and the Golden Gate Bridge in San Francisco. In 1958, the CBC completed the longest television network in the world, from Sydney, Nova Scotia to Victoria, British Columbia. Reportedly, the first continuous live broadcast of a “breaking” news story in the world was conducted by the CBC during the Springhill Mining Disaster, which began on October 23 of that year.

The development of cable and satellite television in the 1970s allowed for more channels and encouraged businessmen to target programming toward specific audiences. It also enabled the rise of subscription television channels, such as Home Box Office (HBO) and Showtime in the U.S., and Sky Television in the U.K.

[edit] Television sets

Main articles: Television set and analog television

In television’s electromechanical era, commercially made television sets were sold from 1928 to 1934 in the United Kingdom,[100] United States, and the Soviet Union.[101] The earliest commercially made sets sold by Baird in the UK in 1928 were radios with the addition of a television device consisting of a neon tube behind a mechanically spinning disk (the Nipkow disk) with a spiral of apertures that produced a red postage-stamp size image, enlarged to twice that size by a magnifying glass. The Baird “Televisor” was also available without the radio. The Televisor sold in 1930–1933 is considered the first mass-produced set, selling about a thousand units.[102]

The first commercially made electronic television sets with cathode ray tubes were manufactured by Telefunken in Germany in 1934,[103][104] followed by other makers in France (1936),[105] Britain (1936),[106] and America (1938).[107][108] The cheapest of the pre-World War II factory-made American sets, a 1938 image-only model with a 3-inch (8 cm) screen, cost US$125, the equivalent of US$1,863 in 2007. The most expensive model with a 12-inch (30 cm) screen was $445 ($6,633).[109]

An estimated 19,000 electronic television sets were manufactured in Britain, and about 1,600 in Germany, before World War II. About 7,000–8,000 electronic sets were made in the U.S.[110] before the War Production Board halted manufacture in April 1942, production resuming in August 1945.

Television usage in the United States skyrocketed after World War II with the lifting of the manufacturing freeze, war-related technological advances, the gradual expansion of the television networks westward, the drop in set prices caused by mass production, increased leisure time, and additional disposable income. In 1947, Motorola introduced the VT-71 television for $189.95, the first television set to be sold for under $200, finally making television affordable for millions of Americans. While only 0.5% of U.S. households had a television set in 1946, 55.7% had one in 1954, and 90% by 1962.[111] In Britain, there were 15,000 television households in 1947, 1.4 million in 1952, and 15.1 million by 1968.

For many years different countries used different technical standards. France initially adopted the German 441-line standard but later upgraded to 819 lines, which gave the highest picture definition of any analogue TV system, approximately double the resolution of the British 405-line system. However this is not without a cost, in that the cameras need to produce four times the pixel rate (thus quadrupling the bandwidth), from pixels one-quarter the size, reducing the sensitivity by an equal amount. In practice the 819-line cameras never achieved anything like the resolution that could theoretically be transmitted by the 819 line system, and for color, France reverted to the 625-line CCIR system used by most European countries.

With advent of color television most Western European countries adopted PAL standard. France, Soviet Union and most Eastern European countries adopted SECAM. In North America the original NTSC 525-line standard was augmented to include color transmission with slight slowing down of frame rate.

Throughout the 1960s, television sets used exclusively vacuum tube electronics. This resulted in relatively heavy and unreliable TVs. In addition, vacuum tubes were poorly-suited to color television, as it required a large amount of tubes which caused further reliability problems. Because vacuum tubes only allowed for very simple NTSC/PAL filtering, the picture quality of early color sets was rather poor. The tint control that is still found on NTSC televisions originally was meant to correct the color burst phase’s drifting when channels were changed. In addition, the large number of vacuum tubes required for color prevented the use of it in portable TVs.

By the early 1970s, solid-state electronics appeared and quickly displaced vacuum tubes in color TVs (black and white sets generally continued to be tube-based). This allowed for significantly more reliable TVs and better picture quality. 1971 was the first year that sales of color TVs in the US exceeded B&W ones. In other countries, color was slower to arrive and did not become common in Western Europe until the ’80s.

By 1965, the FCC began requiring UHF tuners in all TVs sold in the United States. In 1971, there were 170 UHF stations in the country, mostly low-power ones that carried local programming. Previously, UHF support from TV manufacturers was sporadic. Most sets did not come factory-equipped with them, and often merely included an empty slot in the cabinet where an optional UHF tuner could be installed.

During the 1970s, electronic tuners began appearing in high-end TVs in place of traditional dials, and they would gradually become standard along with remote controls. Remotes had first appeared in the 1950s with Zenith’s Space Command Control, but these were mechanical devices that emitted a high-pitched audio frequency that the TV detected. The first electronic remote controls did not appear until the 1980s.

1980s TV developments mainly centered around the above-mentioned features. Electronic television tuners also went hand-in-hand with the rise of cable television. Analog comb filters, first introduced in the ’70s on high-end sets, gradually became more common. Black-and-white TVs virtually disappeared from the American market except for 5-inch, battery-powered models.

The first LCD TVs were introduced in 1988, small, handheld devices with a B&W screen that could not display the full NTSC resolution of 480 lines.

In the 1990s, three-line digital comb filters appeared on high-end TVs. In addition, composite video and S-video inputs began appearing to support devices like video games and VCRs.

Analog broadcast television in the United States ended on June 12, 2009 in favor of Digital terrestrial television (DTV) or digital-only broadcasting.

[edit] Television inventors/pioneers

Important people in the development of TV technology in the 19th or 20th centuries.

Manfred von Ardenne
John Logie Baird
Guillermo González Camarena
Alan Blumlein
Walter Bruch (PAL television)
Alan Archibald Campbell-Swinton
Allen B. DuMont
Philo Taylor Farnsworth
Boris Grabovsky
Charles Francis Jenkins
Siegmund and David Loewe, founders of Loewe AG in 1923

Lubo Micic[112]
Earl Muntz
Paul Gottlieb Nipkow
Constantin Perskyi
Boris Rosing
Ulises Armand Sanabria
David Sarnoff
Kenjiro Takayanagi
Léon Theremin
Kálmán Tihanyi
Vladimir Zworykin

[edit] Television museums
The Paley Center for Media (formerly The Museum of Television & Radio)
Early Television Museum
Museum of Broadcast Communications
National Media Museum
National Australia Film and Archives Museum
MZTV Museum of Television

[edit] See also
List of years in television
History of radio
How television works
Television Hall of Fame
Golden Age of Television, c1949–1960 in the US
Archive of American Television
Video monitor timeline
Oldest television station
List of experimental television stations
Timeline of the introduction of television in countries
Timeline of the introduction of color television in countries
Geographical usage of television
BBC Archives

[edit] References

1.^ Shiers, George and May (1997), Early Television: A Bibliographic Guide to 1940. Taylor & Francis, pp. 13, 22. ISBN 9780824077822.
2.^ Shiers & Shiers, p. 13, 22.
3.^ “Télévision au moyen de l’électricité”, Congrès Inographs by Telegraph”], The New York Times, Sunday Magazine, September 20, 1907, p. 7.
4.^ “Sending Photographs by Telegraph”, The New York Times, Sunday Magazine, September 20, 1907, p. 7.
5.^ Henry de Varigny, “La vision à distance”, L’Illustration, Paris, December 11, 1909, p. 451.
6.^ R.W. Burns, Television: An International History of the Formative Years, IET, 1998, p. 119. ISBN 0852969147.
7.^ “Current Topics and Events”, Nature, vol. 115, April 4, 1925, p. 505–506, doi:10.1038/115504a0.
8.^ “Radio Shows Far Away Objects in Motion”, The New York Times, June 14, 1925, p. 1.
9.^ a b Glinsky, Albert (2000). Theremin: Ether Music and Espionage. Urbana, Illinois: University of Illinois Press. pp. 41–45. ISBN 0-252-02582-2.
10.^ Restoring Baird’s TV Recordings
11.^ J. L. Baird, “Television in 1932”, BBC Annual Report, 1933.
12.^ http://www.teletronic.co.uk/tvera.htm Teletronic – The Television History Site
13.^ Richard G. Elen, “The fools on the hill”, Baird: The Birth of Television, 2003, 2009.
14.^ Abramson, Albert, The History of Television, 1880 to 1941, McFarland & Co., Inc., 1987, p. 101. ISBN 9780899502847.
15.^ Kenjiro Takayanagi: The Father of Japanese Television, NHK (Japan Broadcasting Corporation), 2002, retrieved 2009-05-23.
16.^ Campbell-Swinton, A. A. (1908-06-18). “Distant Electric Vision (first paragraph)”. Nature 78 (2016): 151. doi:10.1038/078151a0.
17.^ Campbell-Swinton, A. A. (1908-06-18). “Distant Electric Vision (pdf)”. Nature 78 (2016): 151. doi:10.1038/078151a0.
18.^ “Distant Electric Vision”, The Times (London), Nov. 15, 1911, p. 24b.
19.^ Bairdtelevision. “Alan Archivald Campbell-Swinton (1863-1930)”. Biography. Retrieved 2010-05-10.
20.^ Shiers, George and May (1997), Early television: a bibliographic guide to 1940. New York: Garland, p. 56. Retrieved 2010-06-13.
21.^ “Electric Television (abstract)”. Nature 118 (2973): 590. 1926-10-23. doi:10.1038/118590a0.
22.^ Burns, R. W. (1998). Television: An International History of the Formative Years. The Institute of Electrical Engineers (IEE) (History of Technology Series 22) in association with The Science Museum (UK). pp. 123. ISBN 9780852969144.
23.^ News (1914-04-02). “Prof. G. M. Minchin, F.R.S.”. Nature 93 (2318): 115–116. doi:10.1038/093115a0.
24.^ Miller, H. and Strange. J. W. (1938-05-02). “The electrical reproduction of images by the photoconductive effect”. Proceedings of the Physical Society 50 (3): 374–384. doi:10.1088/0959-5309/50/3/307.
25.^ Iams, H. and Rose, A. (1937-08). “Television Pickup Tubes with Cathode-Ray Beam Scanning”. Proceedings of the Institute of Radio Engineers 25 (8): 1048–1070. doi:10.1109/JRPROC.1937.228423.
26.^ Abramson, Albert, Zworykin, Pioneer of Television, p. 16.
27.^ Postman, Neil, “Philo Farnsworth”, The TIME 100: Scientists & Thinkers, TIME.com, 1999-03-29, retrieved 2009-07-28.
28.^ a b “Philo Taylor Farnsworth (1906-1971)”, The Virtual Museum of the City of San Francisco, retrieved 2009-07-15.
29.^ Abramson, Albert, Zworykin, Pioneer of Television, p. 226.
30.^ The Philo T. and Elma G. Farnsworth Papers
31.^ Abramson, Albert, Zworykin, Pioneer of Television, University of Illinois Press, 1995, p. 51. ISBN 0252021045.
32.^ Zworykin, Vladimir K., Television System. Patent No. 1691324, U.S. Patent Office. Filed 1925-07-13, issued 1928-11-13. Retrieved 2009-07-28
33.^ Zworykin, Vladimir K., Television System. Patent No. 2022450, U.S. Patent Office. Filed 1923-12-29, issued 1935-11-26. Retrieved 2010-05-10.
34.^ Stashower, Daniel, The Boy Genius and the Mogul: The Untold Story of Television, Broadway Books, 2002, p. 243–244. ISBN 978-0767907590.
35.^ Everson, George (1949), The Story of Television, The Life of Philo T. Farnsworth New York, NY: W. W. Norton & Co,. ISBN 978-0405060427, 266 pages
36.^ a b “Kálmán Tihanyi (1897–1947)”, IEC Techline, International Electrotechnical Commission (IEC), 2009-07-15.
37.^ “Kálmán Tihanyi’s 1926 Patent Application ‘Radioskop'”, Memory of the World, United Nations Educational, Scientific and Cultural Organization (UNESCO), 2005, retrieved 2009-01-29.
38.^ United States Patent Office, Patent No. 2,133,123, Oct. 11, 1938.
39.^ United States Patent Office, Patent No. 2,158,259, May 16, 1939.
40.^ http://www.unesco.org/new/en/communication-and-information/resources/news-and-in-focus-articles/in-focus-articles/2010/spotlight-on-memory-of-the-world-heritage-inventions-and-discoveries-that-changed-our-world
41.^ Albert Abramson, Zworykin: Pioneer of Television, University of Illinois Press, 1995, p. 111.
42.^ “New Television System Uses ‘Magnetic Lens'”, Popular Mechanics, Dec. 1934, p. 838–839.
43.^ Burns, R. W. Television: An international history of the formative years. (1998). IEE History of Technology Series, 22. London: IEE, p. 370. ISBN 0-85296-914-7.
44.^ Lawrence, Williams L. (June 27, 1933). Human-like eye made by engineers to televise images. ‘Iconoscope’ converts scenes into electrical energy for radio transmission. Fast as a movie camera. Three million tiny photo cells ‘memorize’, then pass out pictures. Step to home television. Developed in ten years’ work by Dr. V.K. Zworykin, who describes it at Chicago.. New York Times.. ISBN 9780824077822. Retrieved 2010-01-10.
45.^ Abramson, Albert (1987), The History of Television, 1880 to 1941. Jefferson, NC: Albert Abramson. p. 148. ISBN 0-89950-284-9.
46.^ Everson, George (1949), The Story of Television, The Life of Philo T. Farnsworth New York, NY: W. W. Norton & Co,. ISBN 978-0405060427, pages 137-141.
47.^ Everson, George (1949), The Story of Television, The Life of Philo T. Farnsworth New York, NY: W. W. Norton & Co,. ISBN 978-0405060427, page 139.
48.^ Everson, George (1949), The Story of Television, The Life of Philo T. Farnsworth New York, NY: W. W. Norton & Co,. ISBN 978-0405060427, page 141.
49.^ EMI LTD; Tedham, William F.; and McGee, James D. (filed May 1932, patented 1934). “Improvements in or relating to cathode ray tubes and the like”. Patent No. GB 406,353. United Kingdom Intellectual Property Office. Retrieved 2010-02-22.
50.^ Tedham, William F. and McGee, James D. (filed in Great Britain 1932, filed in USA 1933, patented 1937). “Cathode Ray Tube”. Patent No. 2,077,422. United States Patent Office. Retrieved 2010-01-10.
51.^ Burns, R. W., Television: An international history of the formative years. (1998). IEE History of Technology Series, 22. London: IEE, p. 576. ISBN 0-85296-914-7.
52.^ Winston, Brian (1986). Misunderstanding media. Harvard University Press. pp. 60–61. ISBN 9780674576636. Retrieved 2010-03-09.
53.^ Winston, Brian (1998). Media technology and society. A history: from the telegraph to the Internet. Routledge. p. 105. ISBN 9780415142304. Retrieved 2010-03-09.
54.^ a b Alexander, Robert Charles (2000). The inventor of stereo: the life and works of Alan Dower Blumlein. Focal Press. pp. 217–219. ISBN 9780240516288. Retrieved 2010-01-10.
55.^ Burns, R. W. (2000). The life and times of A D Blumlein. IET. p. 181. ISBN 9780852967737. Retrieved 2010-03-05.
56.^ Lubszynski, Hans Gerhard and Rodda, Sydney (filed May 1934, patented 1936). “Improvements in or relating to television”. Patent No. GB 442,666. United Kingdom Intellectual Property Office. Retrieved 2010-01-15.
57.^ Blumlein, Alan Dower and McGee, James Dwyer (filed August 1934, patented 1936). “Improvements in or relating to television transmitting systems”. Patent No. GB 446,661. United Kingdom Intellectual Property Office. Retrieved 2010-03-09.
58.^ McGee, James Dwyer (filed September 1934, patented 1936). “Improvements in or relating to television transmitting systems”. Patent No. GB 446,664. United Kingdom Intellectual Property Office. Retrieved 2010-03-09.
59.^ Alexander, Robert Charles (2000). The inventor of stereo: the life and works of Alan Dower Blumlein. Focal Press. pp. 216. ISBN 9780240516288. Retrieved 2010-01-10.
60.^ Inglis, Andrew F. (1990). Behind the tube: a history of broadcasting technology and business. Focal Press. p. 172. ISBN 9780240800431. Retrieved 2010-01-15.
61.^ Dieckmann, Max and Rudolf Hell (filed 1925, patented 1927). “Lichtelektrische Bildzerlegerröehre für Fernseher”. Patent No. DE 450,187. Deutsches Reich Reichspatentamt. Retrieved 2009-07-28.
62.^ Farnsworth, Philo T. (filed 1927, patented 1930). “Television System”. Patent No. 1,773,980,. United States Patent Office. Retrieved 2009-07-28.
63.^ de Vries, M. J.; de Vries, Marc; Cross, Nigel; and Grant, Donald P. (1993). Design methodology and relationships with science, Número 71 de NATO ASI series. Springer. p. 222. ISBN 9780792321910. Retrieved 2010-01-15.
64.^ a b Smith, Harry (July 1953). “Multicon – A new TV camera tube”. newspaper article. Early Television Foundation and Museum. Retrieved 2010-01-15.
65.^ Gittel, Joachim (2008-10-11). “Spezialröhren”. photographic album. Jogis Röhrenbude. Retrieved 2010-01-15.
66.^ Early Television Museum. “TV Camera Tubes, German “Super Iconoscope” (1936)”. photographic album. Early Television Foundation and Museum. Retrieved 2010-01-15.
67.^ Gittel, Joachim (2008-10-11). “FAR-Röhren der Firma Heimann”. photographic album. Jogis Röhrenbude. Retrieved 2010-01-15.
68.^ Philips (1952 to 1958). “5854, Image Iconoscope, Philips”. electronic tube handbook. Philips. Retrieved 2010-01-15.
69.^ Everson, George (1949), The Story of Television, The Life of Philo T. Farnsworth New York, NY: W. W. Norton & Co,. ISBN 978-0405060427, page 248.
70.^ a b Abramson, Albert (1987), The History of Television, 1880 to 1941. Jefferson, NC: Albert Abramson. p. 254. ISBN 0-89950-284-9.
71.^ Schatzkin, Paul (2002), The Boy Who Invented Television. Silver Spring, Maryland: Teamcom Books, pp. 187-8. ISBN 1-928791-30-1.
72.^ “Go-Ahead Signal Due for Television”, The New York Times, April 25, 1941, p. 7.
73.^ “An Auspicious Beginning”, The New York Times, August 3, 1941, p. X10.
74.^ a b “On the beginning of broadcast in 625 lines 60 years ago”, 625 magazine (in Russian).
75.^ “M.I. Krivocheev – an engineer’s engineer”, EBU Technical Review, Spring 1993.
76.^ “In the Vanguard of Television Broadcasting”.
77.^ Hawley, Chris, “Peggy O’Neil sang her way from the Hydraulics to stardom”, The Hydraulics [blog], January 15, 2009.
78.^ a b Shagawat, Robert. “Television recording – The origins and earliest surviving live TV broadcast recordings”. Early Electronic Television. Early Television Museum. Retrieved April 20, 2011.
79.^ Associated Press (February 9, 1928). “Human Faces Sent By Radio 3000 Miles Across The Sea”. Evening Independent: p. 1. Retrieved July 15, 2011.
80.^ “What Television Offers You”, Popular Mechanics, November 1928, p. 823.
81.^ “The Latest in Television”, Popular Mechanics, September 1929, p. 472.
82.^ “WRNY to Start Daily Television Broadcasts; Radio Audience Will See Studio Artist”, The New York Times, August 13, 1928, p. 13.
83.^ “WRNY Has Extended Television Schedule”, The New York Times, September 30, 1928, p. 155.
84.^ “Television Drama Shown With Music”, The New York Times, August 22, 1928, p. 1.
85.^ The Queen’s Messenger, Early Television Museum.
86.^ “Television Placed on Daily Schedule”, The New York Times, March 22, 1929, p. 30.
87.^ “Six Visual Stations on the New York Air”, The New York Times, July 19, 1931, p. XX13.
88.^ “Radio Talkies Put On Program Basis”, The New York Times, April 27, 1931, p. 26.
89.^ CBS considers it to be an ancestor of WCBS-TV, which first went on the air on July 1, 1941 as one of the first two commercially licensed television stations in the country (the other being the National Broadcasting Company’s WNBC).
90.^ W6XAO later moved to VHF Channel 1 before World War 2, and to Channel 2 in the post-war television realignment. It was commercially licensed in 1947 as KTSL and is the direct ancestor of current station KCBS-TV.
91.^ “Where Is Television Now?”, Popular Mechanics, August 1938, p. 178.
92.^ “Telecasts Here and Abroad”, The New York Times, Drama-Screen-Radio section, April 24, 1938, p.10.
93.^ “Early Birds”, Time, June 13, 1938.
94.^ “Telecasts to Be Resumed”, The New York Times, Drama-Screen-Radio section, Aug. 21, 1938, p. 10.
95.^ Robert L. Pickering, “Eight Years of Television in California”, California — Magazine of the Pacific, June 1939.
96.^ “Researchers Craft HDTV’s Successor”.
97.^ “Truman to Be Televised In First National Hook-Up”, The New York Times, September 4, 1951, p. 2.
98.^ “Television Highlights”, The Washington Post, September 4, 1951, p. B13.
99.^ “Coast to Coast Television” (CBS advertisement), The Wall Street Journal, September 4, 1951, p. 9.
100.^ Early British Television: Baird, Television History: The First 75 Years.
101.^ Pre-1935, Television History: The First 75 Years. The French model shown does not appear to have entered production.
102.^ Pre-1935 Baird Sets: UK, Television History: The First 75 Years.
103.^ Telefunken, Early Electronic TV Gallery, Early Television Foundation.
104.^ 1934–35 Telefunken, Television History: The First 75 Years.
105.^ 1936 French Television, Television History: The First 75 Years.
106.^ 1936 Baird T5, Television History: The First 75 Years.
107.^ Communicating Systems, Inc., Early Electronic TV Gallery, Early Television Foundation.
108.^ America’s First Electronic Television Set, Television History: The First 75 Years.
109.^ American TV Prices, Television History: The First 75 Years.
110.^ Annual Television Set Sales in USA, Television History: The First 75 Years.
111.^ Number of TV Households in America, Television History: The First 75 Years.
112.^ Lachenbruch, David (1984), “New digital receivers deliver ultimate TV”. Popular Science, Times Mirror Company, June 1984, p. 56.

[edit] Further reading
Abramson, Albert. The History of Television, 1880 to 1941. (1987). Jefferson, NC: McFarland & Co. ISBN 0-89950-284-9.
Abramson, Albert. The History of Television, 1942 to 2000. (2003). Jefferson, NC: McFarland & Co. ISBN 0-78641-220-8.
Burns, R. W. Television: An international history of the formative years. (1998). IEE History of Technology Series, 22. London: IEE. ISBN 0-85296-914-7.
Dunlap, Orrin E. The Future of Television. New York and London: Harper Brothers, 1942.
Everson, George (1949), The Story of Television, The Life of Philo T. Farnsworth New York, NY: W. W. Norton & Co,. ISBN 978-0405060427, 266 pages.
Fisher, David E. and Marshall Jon Fisher. Tube: the Invention of Television. (1996). Washington: Counterpoint. ISBN 1887178171.
Hart, Jeffrey A., Television, technology, and competition: HDTV and digital TV in the United States, Western Europe, and Japan, New York : Cambridge University Press, 2004. ISBN 0521826241
Lohr, Lenox, Television Broadcasting. New York: McGraw Hill, 1940.
Meyrowitz, Joshua(1985). No Sense of Place, Oxford University Press, New York.
Shiers, George. Early Television: A Bibliographic Guide to 1940. (1997). Garland Reference Library of Social Science. ISBN 0-82407-782-2.

[edit] External links

Links related to the development or history of television
History of television – Includes an anthology of early texts on “seeing at a distance by electricity”
Mechanical TV and Illusion Generators including a description of what mechanical TV viewing was like
Television history — inventors including a timeline
Technology Review – Who Really Invented Television?
Who Invented Television – Reconciling The Historical Origins of Electronic Video
Photos of early TV receivers
Article describing development of the television
Early television museum (extensive online presence)
Ed Reitan’s Color Television History
Erics Vintage Television Sets
Detailed timeline of communications media (including the TV)
The History of Australian Television
Video Active: Creating Access to Television History
A Visit to Our Studios: a television program exploring the studios at Johns Hopkins University in 1951
Archive of American Television (information and links to videotaped oral history interviews with TV legends and pioneers)
Canadian Broadcasting Corporation Archives
History of West Australian Television
MZTV Museum of Television & Archive
Television Early Patents and Inventions

List of house types

Houses can be built in a large variety of configurations. A basic division is between free-standing or detached dwellings and various types of attached or multi-user dwellings. Both sorts may vary greatly in scale and amount of accommodation provided. Although there appear to be many different types, many of the variations listed below are purely matters of style rather than spatial arrangement or scale. Some of the terms listed are only used in some parts of the English speaking world

A-frame: so-called because of the appearance of the structure, namely steep roofline.
The Addison house: a type of low-cost house with metal floors and cavity walls made of concrete blocks, mostly built in the United Kingdom and in Ireland during 1920 through 1921 to provide housing for soldiers, sailors, and airmen who had returned home from the First World War. The Airey house: a type of low-cost house that was developed in the United Kingdom during in the 1940s by Sir Edwin Airey, and then widely-constructed between 1945 and 1960 to provide housing for soldiers, sailors, and airmen who had returned home from World War II. These are recognizable by their precast concrete columns and by their walls made of precast “ship-lap” concrete panels.[1]
American Colonial: a traditional style of house that originated in the eastmost United States of America. Georgian Colonial
German Colonial
Hall and parlor house
New England Colonial
Spanish Colonial

Barraca: a traditional style of house originated in Valencia, Spain. Is a historical farm house since XII Century aC until XIX Century around the city of Valencia.
Barndominium: a type of house that includes living space attached to either a workshop or a barn, typically for horses, or a large vehicle such as a Recreational Vehicle or a good-sized recreational boat.
Bay-and-gable: a type of house typically found in the older areas of Toronto, Ontario.
Bungalow: any simple, single-story house without any basement.
Cape Cod: a popular design that originated in the coastal area of New England, especially in eastern Massachusetts.
Cape Dutch: popular in the Western Cape, South Africa, region.
Castle: primarily a defensive structure/dwelling build during the Dark Ages and the Middle Ages, and also during the 18th century and the 19th century.
Chalet bungalow: popular in the United Kingdom, a combination of a house and a bungalow.
Chattel house: a small wooden house occupied by working-class people on Barbados.
Conch house: a vernacular style in Key West and Miami, derived from the Bahamian clapboard house.
Cottage: is usually a small country dwelling, but weavers’ cottages are three-storied townhouses with the top floor reserved for the working quarters.
American Craftsman House
Creole cottage: a type of house native to the Gulf Coast of the United States, roughly corresponding to the location of the former colonial settlements of the French in Louisiana, Southern Mississippi, and Lower Alabama.
Cracker House: a style of wood-framework house built rather widely in the 19th century in Florida, Southern Georgia, and South Georgia. Note that the former Atlanta Crackers pro baseball team has its home in Atlanta, Georgia, because of the many “Crackers” who lived in Georgia decades ago.
Deck House: a custom-built post-and-beam house using high-quality woods and masonry.
Dogtrot house:: two houses connected by an open breezeway.
Earth sheltered:: houses using dirt (“earth”) piled against it exterior walls for thermal mass, which reduces heat flow into or out of the house, maintaining a more steady indoor temperature.
Eyebrow House: A style of house found in Key West, Florida in which the roof overhangs the windows reducing the view, but providing more shade.
A farmhouse: is the main residence house on a farm, or a house built with the same type of styling – located anywhere
Faux chateau (originating in the 1980s): a notably-inflated in size and price American suburban house with non-contextual French Provençal architectural elements.
Federal
American Foursquare house
Gablefront house (or a Gablefront cottage): a generic house type that has a gable roof that faces its street or avenue.[2] See the novel The House of Seven Gables, by the American author Nathaniel Hawthorne.
Gambrel: also known as the Dutch Gambrel
Geodesic dome:: a rugged domed design, using strong metal components, that was pioneered by the architect Buckminster Fuller in the United States of America in the mid-20th century.
The Georgian House’ is built with the style of Georgian architecture that became popular during the time of King George I through King George IV and King William IV of the United Kingdom.
Hawksley BL8 bungalow: an aluminum siding-clad timber-framed house built in Great Britain mostly during the 1950s as housing for soldiers, sailors, and airmen who had returned home from World War II.[1]
I-house: a traditional British folk house, which became popular in the Middle Atlantic and the Southern American Colonies before the beginning of the American Revolutionary War.[3]
Igloo: an Inuit-Eskimo temporary or emergency that was made of knife-sliced blocks of packed snow and/or ice in the Arctic regions of Alaska, Canada, Greenland, and Siberian Russia.
Indian vernacular
Izba: a traditional Russian wooden country house.
Konak: a type of Turkish house that was widely-built during the time of the Ottoman Empire in Turkey, northern Greece, Romania, Bulgaria, Syria, Lebanon, Palestine, Jordan, northern Iraq, etc.
Laneway house: a type of Canadian house that is constructed behind a normal single family home that ones onto a back lane.
Link-detached: adjacent detached properties that do not have a party wall, but which are linked by their garages – and so presenting a single frontage to their street or avenue.
Linked houses are “row-houses” or a “semi-detached houses” that are linked structurally only in their foundations. Above ground, these houses appear to be detached houses. Linking up their foundations cuts the cost of constructing them.
Log cabin: a house built by American, Canadian, and Russian frontiersmen and their families which was built of solid, unsquared wooden logs.
Lustron house: a type of prefabricated house.
Manor House: a large Medieval country house, or one built later on of a similar design, which formerly was the primary dwelling of the nobleman and his family, and also the administrative hub of a Feudal manor, and which was also the lowest unit of land organization and use in the Feudal system during the Dark Ages and the Middle Ages in Europe: in other words, before the ride of the Renaissance and the Age of Enlightenment both of which caused the fall of the Feudal system and serfdom, except for in Russia, where the serfs and vassals were not set free until the second half of the 19th century (the 1850s through the 1890s).
Mansion: a quite-large and usually-luxurious detached house. See also: Manor house, and Georgian House above
maisonette: is flat or apartment in England, that occupies two floors of a building, and so typically has internal stairs.
McMansion: a formulaic, inflated suburban house with references to historical styles of architecture, such as Georgian Architecture and the Manor House mentioned above.
Manufactured house: a prefabricated house that is assembled on the permanent site on which it will sit.
Mews property: a mews is an urban stable-block that has often been converted into residential properties. The houses may have been converted into ground floor garages with a small flat above which used to house the ostler or just a garage with no living quarters.
Microhouse: a dwelling that fulfills all the requirements of habitation (shelter, sleep, cooking, heating, toilet) in a very compact space. These are quite common in Japan, Hong Kong, Singapore, etc.
Monolithic dome: a structure cast in one piece, generally made out of shotcrete inside an airform.
Microapartment: rather common in Japan, Hong Kong, Singapore, etc. These small single-room dwellings contain a kitchen, a bathroom, a sleeping area, etc., in one place, usually in a multistory building.

The interior of an Iraqi mudhif Mudhif: a traditional reed house made by the Madan people of Iraq.
Octagon house: a house of symmetrical octagonal floor plan, popularized briefly during the 19th century by Orson Squire Fowler.
Patio house
Pole house: a timber house in which a set of vertical poles carry the load of all of its suspended floors and roof, allowing all of its walls to be non-load-bearing.
Prefabricated house: a house whose main structural sections were manufactured in a factory, and then transported to their final building site to be assembled upon a concrete foundation, which had to be poured locally.
Ranch: a rambling single-story house, often containing a garage and sometimes constructed over a basement.
Queenslander: a house most commonly built in the tropical areas of Australia, especially in the State of Queensland and in the Northern Territory. These are constructed on top of high concrete piers or else upon the stumps of felled trees in order to allow cooling breezes to flow beneath them, and often they have a wide veranda, or porch, that runs partially or completely the way around the house. See the Cracker House, above, which was quite similar to this one.
A Roundhouse dwelling: is a kind of a house built with a circular plan. This kind was constructed in Western Europe before the Conquest by the Roman legions. After this conquest, houses were usually built in the Roman style that came from Italy.
The Saltbox: was a style of wooden house that was widespread during Colonial Times in New England.
Split-level house: a design of house that was commonly built during the 1950s and 1960s. It has two nearly-equal sections that are located on two different levels, with a short stairway in the corridor connecting them. This kind of house is quite suitable for building on slanted or hilly land.
“Sears Catalog Home”: an owner-built “kit” houses that were sold by the Sears, Roebuck and Co. corporation via catalog orders from 1906 to 1940.
Shack: a small, usually rundown, wooden building.
Shotgun house: a style of house that was initially popular in New Orleans starting around 1830, and spread from there to other urban areas throughout the Southern U.S. Its peak period of popularity ran from the Civil War to the Great Depression. This house typically follows the structure of living room, bedrooms, then the bathroom, and kitchen as the last room of the house. The reason for the name is because it all sits in one straight line from front to back.[4]
The detached single-family house is any free-standing house that is structurally separated from its neighboring houses, usually separated by open land, making it distinctive from such dwellings as duplexes, townhouses, and condominiums.
Souterrain: an earthen dwelling typically deriving from Neolithic Age or Bronze Age times.
Spanish Colonial Revival architecture Based on the Spanish Colonial architecture from the Spanish colonization of the Americas, the Spanish Colonial Revival style updated these forms and detailing for a new century and culture.
Stilt houses or Pile dwellings: houses raised on stilts over the surface of the soil or a body of water.
Snout house: a house with the garage door being the closest part of the dwelling to the street.
Splits

Attached Multi-unit housing

Main article: Multi-family residential

Specific terms under various American federal, state, or local laws dealing with fair housing, truth in advertising, and so forth, have been prescribed and engender specific legal meanings. For example, in American housing codes, all “apartments” must contain a kitchen, bathing facilities, and a sleeping area, or else that term may not be used. This generates various differences within the English-speaking world, and the terms such as “single-family”, “two-family”, or “three-family” building, residence, house, home, or property can be generic and thus convey little or no building plan (style of building) information. Such terminology is most common in advertising and real-estate markets that offer leasing of such units, or sales of such buildings.
Apartment: a relatively self-contained housing unit in a building which is often rented out to one person or a family, or two or more people sharing a lease in a partnership, for their exclusive use. Sometimes called a flat or digs (slang). Some locales have legal definitions of what constitutes an apartment. In some locations, “apartment” denotes a building that was built specifically for such units, whereas “flat” denotes a unit in a building that had been originally built as a single-family house, but later on subdivided into some multi-unit house type.[2]
Apartment building, Block of flats: a multi-unit dwelling made up of several (generally four or more) apartments. Contrast this with the two-family house and the three-family dwelling.
Aul: a type of fortified village found throughout the Caucasus Mountains, especially in Dagestan.
Barracks: a type of military housing, formerly connoting a large “open bay” with rows of bunk beds and attached bathroom facilities, but during the most recent several decades for the American Armed Forces most of the new housing units for unmarried servicemen have been constructed with a dormitory-style layout housing two to four servicement. This dormitory-styling providing additional privacy has been found to promote the retention of trained personnel in the all-volunteer Armed Forces of the United States.
Basement apartment
Brownstone: a Northeastern United States type of housing unit: see rowhouse.
Bedsit: A British expression (short for bed-sitting room) for a single-roomed dwelling in a sub-divided larger house. The standard type contains a kitchenette or basic cooking facilities in a combined bedroom/living area, with a separate bathroom and lavatory shared between a number of rooms. Once common in older Victorian properties in British cities, they are less frequently found since the 1980’s as a result of tenancy reforms, property prices and renovation grants that favour the refurbishment of such properties into self-contained flats for leasehold sale.
Choultry: a South-Indian Hindu-Caravanserai
Cluster house: an older form of the Q-type house (see below)[5]
Condominium: a form of ownership with individual apartments for everyone, and co-ownership (by percentages) of all of the common areas, such as corridors, hallways, stairways, lobbies, recreation rooms, porches, rooftops, and any outdoor areas of the grounds of the buildings.
Deck access: a block of “flats” which are accessed from a walkway that is open to the elements.
Flat: In Great Britain and Ireland, this means exactly the same as an “apartment”. In and around San Francisco, Calif., this term means an apartment that takes up an entire floor of a large house, usually one that has been converted from an older Victorian house.
2-Flat, 3-Flat, and 4-Flat houses: Houses or buildings with 2, 3, or 4 flats, respectively, especially when each of the flats takes up one entire floor of the house. There is a common stairway in the front and often in the back providing access to all the flats. 2-Flats and sometimes 3-flats are common in certain older neighborhoods.
Four Plus One: an apartment building consisting of four stories above a parking lot. The four floors containing the apartment units are of wood-frame and masonry construction. It was particularly popular in Chicago during the 1960s and 1970s, especially on the city’s north side.[6].
Garage-apartment: an apartment over a garage; if the garage is attached, the apartment will have a separate entrance from the main house.
Garalow: a portmanteau word “garage” + “bungalow”; similar to a garage-apartment, but with the apartment and garage at the same level.
Garden apartment: a building style usually characterized by two story, semi-detached buildings, each floor being a separate apartment.
Garden flat: a flat which is at garden (ground) level in a multilevel house or apartment building, especially in the case of Georgian and Victorian terraced housing which has been sub-divided into separate dwellings.
Housing cooperative (or Co-op): a form of ownership in which a non-profit corporation owns the entire apartment building or development and residents own shares in the corporation that correspond to their apartment and a percentage of common areas. In Australia this corresponds with a “company title” apartment.
Housing project: a North American term for government-owned housing for low-income tenants (aka Public housing or Social housing).
Live Work: a townhouse / row house having a retail, office or workshop on the ground floor with living premises of the building proprietor and occupier (the one person) of the ground floor commercial space above e.g. like the traditional high street Victorian grocer. Normally with fire rated separation.
Ksar: a village consisting of generally attached houses, widespread among the oasis populations of the Maghreb (northern Africa)
Loft or warehouse conversion can be an apartment building wherein part of the unit, usually consisting of the bedroom(s) and/or a second bedroom level bath is sub-divided vertically within the structurally tall bay between the structural floors of a former factory or warehouse building. The lofts created in such are locally supported by columns and bearing walls and not part of the overall original load bearing structure.
Maisonette: an apartment / flat on two levels with internal stairs, or which has its own entrance at street level.
Mess: a building or flat with single bedroom per tenant and shared facilities like toilets and kitchens. These are popular with students, bachelors or low wage earners in the Indian subcontinent. It is similar to the bedsit in the UK. Some variants include multiple tenants per bedroom and inclusion of a centralized maid service or cooked meals with tenancy.
Mother-in-law apartment: small apartment either at the back, in the basement, or on an upper level subdivision of the main house, usually with a separate entrance (also known as a “Granny flat” in the UK, Australia and New Zealand). If it is a separate structure from the main house, it is called a ‘granny cottage’ or a ‘doddy house’. Such Secondary suites are often efficiency or two room apartments but always have kitchen facilities (which is usually a legal requirement of any apartment).
Officetel: small apartment providing a combined work and living area in one place, especially in South Korea.
Penthouse: the top floor of multi-story building
Plattenbau (East German) / Panelák (Czech, Slovak): a communist-era tower block that is made of slabs of concrete put together.
Q-type: townhouse built mainly in housing estates in the UK beginning in the late 20th century. The houses are arranged in blocks of four with each house at a corner of the block.[7] Similar to the earlier cluster house (see above).
Railroad apartment (or railroad flat): a type of apartment that is in a building built on a very narrow lot (usually about as wide as a railroad car, or Pullman car sections thereof).
Rooming house: a type of Single Room Occupancy building where most washing, kitchen and laundry facilities are shared between residents, which may also share a common suite of living rooms and dining room, with or without board arrangements. When board is provided (no longer common), a common dining time and schedule is imposed by the landlord who in such cases also serves as an innkeeper of sorts. In Australia and the United States, any housing accommodation with 4 or more bedrooms can be regarded as a rooming house if each bedroom is subject to individual tenancy agreements. In the U.S., rooming house lease agreements typically run for very short periods, usually week to week, or a few days at a time. Transient housing arrangements for longer term tenancies are implemented by a “rider” on a case by case basis, if local laws permit.
Rowhouse (USA); also called “Terraced home” (USA); also called “Townhouse”: 3 or more houses in a row sharing a “party” wall with its adjacent neighbour. In New York and Boston, “Brownstones” are rowhouses. Rowhouses are typically multiple stories. The term townhouse is currently coming into wider use in the UK, but terraced house (not “terraced home”) is more common.
Shophouse: the name given in Southeast Asia to a terraced two to five story urban building featuring a shop or other public activity on the street level, with residential accommodation on upper floors.
Single Room Occupancy or SRO: a studio apartment, usually occurring with a block of many similar apartments, intended for use as public housing. They may or may not have their own washing, laundry, and kitchen facilities. In the United States, lack of kitchen facilities prevents use of the term “apartment”, so such would be classified as a boarding house or hotel.
Six-pack: In New England (USA), this refers to a stick-built block of 6 apartments comprising (duplexed) two three story Triple deckers built side by side sharing one wall, a common roof, lot, yards (lawns and gardens, if any), parking arrangements, and basement, but possessing separately metered electric, and separate hot water and heating or air conditioning. In Australia, it refers to a style of apartments that were constructed during the 1960s, 70s and early 80s, usually comprising a single, masonry-built block containing 4 to 8 walk-up apartments (though sometimes, many more), of between 2 and 3 stories in height, with car parking at the side or rear.

Studio apartment or Studio flat (UK), or Bachelor apartment or Efficiency apartment: a suite with a single room that doubles as living/sitting room and bedroom, with a kitchenette and bath squeezed in off to one side. The unit is designed for a single occupant or possibly a couple. Especially in Canada and South Africa, also called bachelor, or bachelorette if very small.
Tenement: a multi-unit dwelling usually of frame construction, quite often brick veneered, made up of several (generally many more than four to six) apartments (i.e. a large apartment building) that can be up to five stories. Tenements do not generally have elevators. In the United States the connotation sometimes implies a run-down or poorly-cared-for building. It often refers to a very large apartment building usually constructed during the late nineteenth to early twentieth century era sited in cities or company towns.

Example of late Victorian terrace in Moss Side, Manchester, UK. Terraced house: Since the late 18th century is a style of housing where (generally) identical individual houses are conjoined into rows – a line of houses which abut directly on to each other built with shared party walls between dwellings whose uniform fronts and uniform height created an ensemble that was more stylish than a “rowhouse”. However this is also the UK term for a “rowhouse” regardless of whether the houses are identical or not.

Multifamily home features Tenants usually have some portion of the basement and/or common attic.
Fire regulations aggressively require a separate emergency egress for all apartments under U.S. laws and national fire codes.
Utilities are either paid as part of the rent, or (now predominant) the units have separately provided heat, air conditioning, electrical distribution panels and meters, and sometimes (uncommonly) water metering, separating all secondary housing costs by rental unit. Common lighting may or may not be off a separate meter and circuitry in subdivided former single family dwellings.
leasehold documents will specify other common factors such as specific parking rights, rights to common spaces such as lawn and gardens on the premises, storage or garage (usually a detached unit, that cannot economically be converted into an additional housing unit) facilities and details such as who has responsibility for upkeep, snow removal, lawn care, and so forth.
Tong Lau: a type of shophouse found in southern China.
Unit: a type of Medium-density housing found in Australia and New Zealand.
Vatara: a housing complex, mainly found in urban Karnataka, India, similar to an apartment complex, but with mostly two stories and homes in a row on each floor.

[edit] Movable dwellings
Park home, also called Mobile home: it is a prefabricated house that is manufactured off-site.
Tent: usually a lightweight, moveable structure.
Travel trailer or Caravan
Yurt or Ger: used by nomads in the steppes of Central Asia.
Houseboat

[edit] See also
Cohousing
Company town
City block
Home
House
Gated community
Intentional Community
List of house styles
Planned Unit Development
Real estate
List of human habitation forms
Spite house, which may or may not be attached to other structures
Sustainable design
Timeshare, form of vacation property

Mobile phone use

A mobile phone (also known as a cellular phone, cell phone and a hand phone) is a device that can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile phone operator, allowing access to the public telephone network. By contrast, a cordless telephone is used only within the short range of a single, private base station.

In addition to telephony, modern mobile phones also support a wide variety of other services such as text messaging, MMS, email, Internet access, short-range wireless communications (infrared, Bluetooth), business applications, gaming and photography. Mobile phones that offer these and more general computing capabilities are referred to as smartphones.

The first hand-held mobile phone was demonstrated by Dr Martin Cooper of Motorola in 1973, using a handset weighing around 1 kg.[1] In 1983, the DynaTAC 8000x was the first to be commercially available. In the twenty years from 1990 to 2011, worldwide mobile phone subscriptions grew from 12.4 million to over 5.6 billion, penetrating the developing economies and reaching the bottom of the economic pyramid.

History

Main article: History of mobile phones

An evolution of mobile phones
Radiophones have a long and varied history going back to Reginald Fessenden’s invention and shore-to-ship demonstration of radio telephony, through the Second World War with military use of radio telephony links and civil services in the 1950s.

The first mobile telephone call made from a car occurred in St. Louis, Missouri, USA on June 17, 1946, using the Bell System’s Mobile Telephone Service.[6] In 1956, the world’s first partly automatic car phone system, Mobile System A (MTA), was launched in Sweden. MTA phones were composed of vacuum tubes and relays, and had a weight of 40 kg.[7][8]

Martin Cooper, a Motorola researcher and executive is considered to be the inventor of the first practical mobile phone for handheld use in a non-vehicle setting, after a long race against Bell Labs for the first portable mobile phone. Using a modern, if somewhat heavy portable handset, Cooper made the first call on a handheld mobile phone on April 3, 1973 to his rival, Dr. Joel S. Engel of Bell Labs.[9]

The world’s first commercial automated cellular network was launched in Japan by NTT in 1979, initially in the metropolitan area of Tokyo. In 1981, this was followed by the simultaneous launch of the Nordic Mobile Telephone (NMT) system in Denmark, Finland, Norway and Sweden.[10] The first 1G network launched in the USA was Chicago-based Ameritech in 1983 using the Motorola DynaTAC mobile phone. Several countries then followed in the early-to-mid 1980s including the UK, Mexico and Canada.

During the initial marketing of cell phones in the U.S., the Federal Communications Commission capped the number of providers for each city (market area) at two, making it complicated to travel to any extent with your cell service. [1]

In 1991, the second generation (2G) cellular technology was launched in Finland by Radiolinja on the GSM standard, which sparked competition in the sector as the new operators challenged the incumbent 1G network operators.

Ten years later, in 2001, the third generation (3G) was launched in Japan by NTT DoCoMo on the WCDMA standard.[11] This was followed by 3.5G, 3G+ or turbo 3G enhancements based on the high-speed packet access (HSPA) family, allowing UMTS networks to have higher data transfer speeds and capacity

Features

Main article: Mobile phone features

See also: Smartphone

A printed circuit board inside a Nokia 3210
All mobile phones have a number of features in common, but manufacturers also try to differentiate their own products by implementing additional functions to make them more attractive to consumers. This has led to great innovation in mobile phone development over the past 20 years.

The common components found on all phones are:
A battery, providing the power source for the phone functions.
An input mechanism to allow the user to interact with the phone. The most common input mechanism is a keypad, but touch screens are also found in some high-end smartphones.
Basic mobile phone services to allow users to make calls and send text messages.
All GSM phones use a SIM card to allow an account to be swapped among devices. Some CDMA devices also have a similar card called a R-UIM.
Individual GSM, WCDMA, iDEN and some satellite phone devices are uniquely identified by an International Mobile Equipment Identity (IMEI) number.

Low-end mobile phones are often referred to as feature phones, and offer basic telephony. Handsets with more advanced computing ability through the use of native software applications became known as smartphones.

Several phone series have been introduced to address a given market segment, such as the RIM BlackBerry focusing on enterprise/corporate customer email needs; the SonyEricsson Walkman series of musicphones and Cybershot series of cameraphones; the Nokia Nseries of multimedia phones, the Palm Pre the HTC Dream and the Apple iPhone

Text messaging

Main article: SMS

The most commonly used data application on mobile phones is SMS text messaging. The first SMS text message was sent from a computer to a mobile phone in 1992 in the UK, while the first person-to-person SMS from phone to phone was sent in Finland in 1993.

The first mobile news service, delivered via SMS, was launched in Finland in 2000. Mobile news services are expanding with many organizations providing “on-demand” news services by SMS. Some also provide “instant” news pushed out by SMS.

SIM card

Main articles: Subscriber Identity Module and Removable User Identity Module

Typical mobile phone SIM card
GSM mobile phones require a small microchip called a Subscriber Identity Module or SIM Card, to function. The SIM card is approximately the size of a small postage stamp and is usually placed underneath the battery in the rear of the unit. The SIM securely stores the service-subscriber key (IMSI) used to identify a subscriber on mobile telephony devices (such as mobile phones and computers). The SIM card allows users to change phones by simply removing the SIM card from one mobile phone and inserting it into another mobile phone or broadband telephony device.

The first SIM card was made in 1991 by Munich smart card maker Giesecke & Devrient for the Finnish wireless network operator Radiolinja. Giesecke & Devrient sold the first 300 SIM cards to Elisa (ex. Radiolinja).

Multi-card hybrid phones

A hybrid mobile phone can take more than one SIM card, even of different types. The SIM and RUIM cards can be mixed together, and some phones also support three or four SIMs.[12][13]

From 2010 onwards they became popular in India and Indonesia and other emerging markets,[14] attributed to the desire to obtain the lowest on-net calling rate. In Q3 2011, Nokia shipped 18 million of its low cost dual SIM phone range in an attempt to make up lost ground in the higher end smartphone market

Mobile phone operators

Main article: Mobile phone operator

Global mobile phone subscribers per country from 1980-2009. The growth in users has been exponential since they were first made available.
The world’s largest individual mobile operator by subscribers is China Mobile with over 500 million mobile phone subscribers.[16] Over 50 mobile operators have over 10 million subscribers each, and over 150 mobile operators had at least one million subscribers by the end of 2009.[17] In February 2010, there were 5.6 billion mobile phone subscribers, a number that is expected to grow.[2]

Manufacturers

See also: List of best-selling mobile phones

Quantity Market Shares by Gartner
(New Sales)

BRAND

Percent

Nokia 2009

 

36.4%

Nokia 2010

 

28.9%

Samsung 2009

 

19.5%

Samsung 2010

 

17.6%

LG Electronics 2009

 

10.1%

LG Electronics 2010

 

7.1%

Research In Motion 2009

 

2.8%

Research In Motion 2010

 

3.0%

Apple 2009

 

2.1%

Apple 2010

 

2.9%

Others-1 2009

 

12.6%

Others-1 2010

 

9.8%

Others-2 2009

 

16.5%

Others-2 2010

 

30.6%

Note: Others-1 consist of Sony Ericsson, Motorola, ZTE, HTC and Huawei.(2009-2010)

Prior to 2010, Nokia was the market leader. However, during that year competition emerged in the Asia Pacific region with brands such as Micromax, Nexian, and i-Mobile and chipped away at Nokia’s market share. Android powered smartphones also gained momentum across the region at the expense of Nokia. In India, their market share also dropped significantly to around 31 percent from 56 percent in the same period. Their share was displaced by Chinese and Indian vendors of low-end mobile phones.[18]

In 2010 worldwide sales were 1.6 billion units, an increase of 31.8 percent from 2009. The top five manufacturers by market share were Nokia followed by Samsung, LG Electronics, ZTE and Apple. The last three replaced RIM, Sony Ericsson and Motorola who were previously among the top five list.[19][20] Outside the top five a significant market share increase from 16.5 percent to 30.6 percent was achieved by many smaller and new brands.

In Q1 2011, Apple surpassed Nokia as the world’s biggest handset vendor by revenue, as Nokia’s market share dropped to 29 percent in Q1 2011, the lowest level since the late 1990s. In June 2011, Nokia announced lower expectations for sales and margin due to global competition in both low-and-high end markets.[21] By Q2 2011, worldwide sales grew 16.5 percent to 428.7 million units.

Manufacturers

See also: List of best-selling mobile phones

Quantity Market Shares by Gartner
(New Sales)

BRAND

Percent

Nokia 2009

 

36.4%

Nokia 2010

 

28.9%

Samsung 2009

 

19.5%

Samsung 2010

 

17.6%

LG Electronics 2009

 

10.1%

LG Electronics 2010

 

7.1%

Research In Motion 2009

 

2.8%

Research In Motion 2010

 

3.0%

Apple 2009

 

2.1%

Apple 2010

 

2.9%

Others-1 2009

 

12.6%

Others-1 2010

 

9.8%

Others-2 2009

 

16.5%

Others-2 2010

 

30.6%

Note: Others-1 consist of Sony Ericsson, Motorola, ZTE, HTC and Huawei.(2009-2010)

Prior to 2010, Nokia was the market leader. However, during that year competition emerged in the Asia Pacific region with brands such as Micromax, Nexian, and i-Mobile and chipped away at Nokia’s market share. Android powered smartphones also gained momentum across the region at the expense of Nokia. In India, their market share also dropped significantly to around 31 percent from 56 percent in the same period. Their share was displaced by Chinese and Indian vendors of low-end mobile phones.[18]

In 2010 worldwide sales were 1.6 billion units, an increase of 31.8 percent from 2009. The top five manufacturers by market share were Nokia followed by Samsung, LG Electronics, ZTE and Apple. The last three replaced RIM, Sony Ericsson and Motorola who were previously among the top five list.[19][20] Outside the top five a significant market share increase from 16.5 percent to 30.6 percent was achieved by many smaller and new brands.

In Q1 2011, Apple surpassed Nokia as the world’s biggest handset vendor by revenue, as Nokia’s market share dropped to 29 percent in Q1 2011, the lowest level since the late 1990s. In June 2011, Nokia announced lower expectations for sales and margin due to global competition in both low-and-high end markets.[21] By Q2 2011, worldwide sales grew 16.5 percent to 428.7 million units

Use of mobile phones

In general

Mobile phone subscribers per 100 inhabitants 1997–2007
Mobile phones are used for a variety of purposes, including keeping in touch with family members, conducting business, and having access to a telephone in the event of an emergency. Some people carry more than one cell phone for different purposes, such as for business and personal use. Multiple SIM cards may also be used to take advantage of the benefits of different calling plans—a particular plan might provide cheaper local calls, long-distance calls, international calls, or roaming. The mobile phone has also been used in a variety of diverse contexts in society, for example:
A study by Motorola found that one in ten cell phone subscribers have a second phone that often is kept secret from other family members. These phones may be used to engage in activities including extramarital affairs or clandestine business dealings.[24]
Some organizations assist victims of domestic violence by providing mobile phones for use in emergencies. They are often refurbished phones.[25]
The advent of widespread text messaging has resulted in the cell phone novel; the first literary genre to emerge from the cellular age via text messaging to a website that collects the novels as a whole.[26]
Mobile telephony also facilitates activism and public journalism being explored by Reuters and Yahoo![27] and small independent news companies such as Jasmine News in Sri Lanka.

A cellphone repair kiosk in Mumbai, India The United Nations reported that mobile phones have spread faster than any other technology and can improve the livelihood of the poorest people in developing countries by providing access to information in places where landlines or the Internet are not available, especially in the least developed countries. Use of mobile phones also spawns a wealth of micro-enterprises, by providing work, such as selling airtime on the streets and repairing or refurbishing handsets.[28]
In Mali and other African countries, people travel from village to village to let friends and relatives know about weddings, births and other events, which is avoided if the villages are within mobile phone coverage areas. In many African countries, mobile phone coverage is greater than land line penetration, so most people own a mobile phone. In the smaller villages without electricity, phones are recharged using a solar panel or motorcycle battery.[29]
The TV industry has recently started using mobile phones to drive live TV viewing through mobile apps, advertising, social tv, and mobile TV.[30] 86% of Americans use their mobile phone while watching TV.
In parts of the world, mobile phone sharing is common. It is prevalent in urban India, as families and groups of friends often share one or more mobiles among their members. There are obvious economic benefits, but often familial customs and traditional gender roles play a part.[31] For example, in Burkina Faso, it is not uncommon for a village to have access to only one mobile phone. The phone is typically owned by a person who is not natively from the village, such as a teacher or missionary, but it is expected that other members of the village are allowed to use the cell phone to make necessary calls.[32]

For distributing content

In 1998, one of the first examples of distributing and selling media content through the mobile phone was the sale of ringtones by Radiolinja in Finland. Soon afterwards, other media content appeared such as news, video games, jokes, horoscopes, TV content and advertising. Most early content for mobile tended to be copies of legacy media, such as the banner advertisement or the TV news highlight video clip. Recently, unique content for mobile has been emerging, from the ringing tones and ringback tones in music to “mobisodes,” video content that has been produced exclusively for mobile phones.

In 2006, the total value of mobile-phone-paid media content exceeded Internet-paid media content and was worth 31 billion dollars.[33] The value of music on phones was worth 9.3 billion dollars in 2007 and gaming was worth over 5 billion dollars in 2007.[34]

The advent of media on the mobile phone has also produced the opportunity to identify and track alpha users or hubs, the most influential members of any social community. AMF Ventures measured in 2007 the relative accuracy of three mass media, and found that audience measures on mobile were nine times more accurate than on the Internet and 90 times more accurate than on TV.[original

For distributing content

In 1998, one of the first examples of distributing and selling media content through the mobile phone was the sale of ringtones by Radiolinja in Finland. Soon afterwards, other media content appeared such as news, video games, jokes, horoscopes, TV content and advertising. Most early content for mobile tended to be copies of legacy media, such as the banner advertisement or the TV news highlight video clip. Recently, unique content for mobile has been emerging, from the ringing tones and ringback tones in music to “mobisodes,” video content that has been produced exclusively for mobile phones.

In 2006, the total value of mobile-phone-paid media content exceeded Internet-paid media content and was worth 31 billion dollars.[33] The value of music on phones was worth 9.3 billion dollars in 2007 and gaming was worth over 5 billion dollars in 2007.[34]

The advent of media on the mobile phone has also produced the opportunity to identify and track alpha users or hubs, the most influential members of any social community. AMF Ventures measured in 2007 the relative accuracy of three mass media, and found that audience measures on mobile were nine times more accurate than on the Internet and 90 times more accurate than on TV.[original research?]

Whilst driving

Main article: Mobile phones and driving safety

Texting in stop-and-go traffic in New York City
Mobile phone use while driving is common but controversial. Being distracted while operating a motor vehicle has been shown to increase the risk of accident. Because of this, many jurisdictions prohibit the use of mobile phones while driving. Egypt, Israel, Japan, Portugal and Singapore ban both handheld and hands-free use of a mobile phone; others —including the UK, France, and many U.S. states—ban handheld phone use only, allowing hands-free use.

Due to the increasing complexity of mobile phones, they are often more like mobile computers in their available uses. This has introduced additional difficulties for law enforcement officials in distinguishing one usage from another as drivers use their devices. This is more apparent in those countries which ban both handheld and hands-free usage, rather those who have banned handheld use only, as officials cannot easily tell which function of the mobile phone is being used simply by looking at the driver. This can lead to drivers being stopped for using their device illegally on a phone call when, in fact, they were using the device for a legal purpose such as the phone’s incorporated controls for car stereo or satnav.

A recently published study has reviewed the incidence of mobile phone use while cycling and its effects on behaviour and safety

In schools

Some schools limit or restrict the use of mobile phones. Schools set restrictions on the use of mobile phones because of the use of cell phones for cheating on tests, harassment and bullying, causing threats to the schools security, distractions to the students, and facilitating gossip and other social activity in school. Many mobile phones are banned in school locker room facilities, public restrooms and swimming pools due to the built-in cameras that most phones now feature.

Mobile banking and payments

Main articles: Mobile banking and Mobile payment

See also: Branchless banking and Contactless payment

In many countries, mobile phones are used to provide mobile banking services, which may include the ability to transfer cash payments by secure SMS text message. Kenya’s M-PESA mobile banking service, for example, allows customers of the mobile phone operator Safaricom to hold cash balances which are recorded on their SIM cards. Cash may be deposited or withdrawn from M-PESA accounts at Safaricom retail outlets located throughout the country, and may be transferred electronically from person to person as well as used to pay bills to companies.

Branchless banking has also been successful in South Africa and Philippines. A pilot project in Bali was launched in 2011 by the International Finance Corporation and an Indonesian bank Bank Mandiri.[36]

Another application of mobile banking technology is Zidisha, a US-based nonprofit microlending platform that allows residents of developing countries to raise small business loans from web users worldwide. Zidisha uses mobile banking for loan disbursements and repayments, transferring funds from lenders in the United States to the borrowers in rural Africa using the internet and mobile phones.[37]

Mobile payments were first trialled in Finland in 1998 when two Coca-Cola vending machines in Espoo were enabled to work with SMS payments. Eventually, the idea spread and in 1999 the Philippines launched the first commercial mobile payments systems, on the mobile operators Globe and Smart.

Some mobile phone can make mobile payments via direct mobile billing schemes or through contactless payments if the phone and point of sale support near field communication (NFC).[38] This requires the co-operation of manufacturers, network operators and retail merchants to enable contactless payments through NFC-equipped mobile phones.[39][40][41]

Tracking and privacy

See also: Mobile phone tracking

Mobile phones are also commonly used to collect location data. While the phone is turned on, the geographical location of a mobile phone can be determined easily (whether it is being used or not), using a technique known as multilateration to calculate the differences in time for a signal to travel from the cell phone to each of several cell towers near the owner of the phone.[42][43]

The movements of a mobile phone user can be tracked by their service provider and, if desired, by law enforcement agencies and their government. Both the SIM card and the handset can be tracked.[44]

China has proposed using this technology to track commuting patterns of Beijing city residents.[45] In the UK and US, law enforcement and intelligence services use mobiles to perform surveillance. They possess technology to activate the microphones in cell phones remotely in order to listen to conversations that take place near to the person who holds the phone.[46][47]

Health effects

Main article: Mobile phone radiation and health

Further information: Mobile phones on aircraft

The effect mobile phone radiation has on human health is the subject of recent interest and study, as a result of the enormous increase in mobile phone usage throughout the world. Mobile phones use electromagnetic radiation in the microwave range, which some believe may be harmful to human health. A large body of research exists, both epidemiological and experimental, in non-human animals and in humans, of which the majority shows no definite causative relationship between exposure to mobile phones and harmful biological effects in humans. This is often paraphrased simply as the balance of evidence showing no harm to humans from mobile phones, although a significant number of individual studies do suggest such a relationship, or are inconclusive. Other digital wireless systems, such as data communication networks, produce similar radiation.

On 31 May 2011, the World Health Organization confirmed that mobile phone use may represent a long-term health risk,[48][49] classifying mobile phone radiation as a “carcinogenic hazard” and “possibly carcinogenic to humans” after a team of scientists reviewed peer-review studies on cell phone safety.[50] One study of past cell phone use cited in the report showed a “40% increased risk for gliomas (brain cancer) in the highest category of heavy users (reported average: 30 minutes per day over a 10‐year period).”[51] This is a reversal from their prior position that cancer was unlikely to be caused by cellular phones or their base stations and that reviews had found no convincing evidence for other health effects.[49][52] Certain countries, including France, have warned against the use of cell phones especially by minors due to health risk uncertainties.[53]

At least some recent studies have found an association between cell phone use and certain kinds of brain and salivary gland tumors. Lennart Hardell and other authors of a 2009 meta-analysis of 11 studies from peer-reviewed journals concluded that cell phone usage for at least ten years “approximately doubles the risk of being diagnosed with a brain tumor on the same (‘ipsilateral’) side of the head as that preferred for cell phone use.”[54]

In addition, a mobile phone can spread infectious diseases by its frequent contact with hands. One study came to the result that pathogenic bacteria are present on approximately 40% of mobile phones belonging to patients in a hospital, and on approximately 20% of mobile phones belonging to hospital staff.[55]

Future evolution: broadband fourth generation (4G)

Main articles: 4G and 5G

The recently released 4th generation, also known as Beyond 3G, aims to provide broadband wireless access with nominal data rates of 100 Mbit/s to fast moving devices, and 1 Gbit/s to stationary devices defined by the ITU-R[56]

4G systems may be based on the 3GPP LTE (Long Term Evolution) cellular standard, offering peak bit rates of 326.4 Mbit/s. It may perhaps also be based on WiMax or Flash-OFDM wireless metropolitan area network technologies that promise broadband wireless access with speeds that reaches 233 Mbit/s for mobile users. The radio interface in these systems is based on all-IP packet switching, MIMO diversity, multi-carrier modulation schemes, Dynamic Channel Assignment (DCA) and channel-dependent scheduling. A 4G system should be a complete replacement for current network infrastructure and is expected to be able to provide a comprehensive and secure IP solution where voice, data, and streamed multimedia can be given to users on a “Anytime, Anywhere” basis, and at much higher data rates than previous generations.

In March 2011, KT from South Korea announced that they has expanded its high-speed wireless broadband network by 4G WiBro cover 85 percent of the population. It is the largest broadband network covered in the world, followed by Japan and US with 70 percent and 36 percent respectively

Human body anatomy

The human body is the entire structure of a human organism, and consists of a head, neck, torso, two arms and two legs. By the time the human reaches adulthood, the body consists of close to 100 trillion cells,[1] the basic unit of life. These cells are organised biologically to eventually form the whole body.

Size, type and proportion

Main article: Body proportion

1. The human body is made up of a head, neck, torso, two arms and two legs. The average height of an adult human is about 5 to 6 feet tall. The human body is made to stand erect, walk on two feet, use the arms to carry and lift, and has opposable thumbs (able to grasp).

2. The adult body is made up of: 100 trillion cells, 206 bones,
600 muscles, and 22 internal organs.

3. There are many systems in the human body:
Circulatory System (heart, blood, vessels)
Respiratory System (nose, trachea, lungs)
Immune System (many types of protein, cells, organs, tissues)
Skeletal System (bones)
Excretory System (lungs, large intestine, kidneys)
Urinary System (bladder, kidneys)
Muscular System (muscles)
Endocrine System (glands)
Digestive System (mouth, esophogus, stomach, intestines)
Nervous System (brain, spinal cord, nerves)
Reproductive System (male and female reproductive organs)

4. Every square inch of the human body has about 19 million skin cells.

5. Every hour about 1 billion cells in the human body must be replaced.

6. The average human head has about 100,000 hairs.

7. The circulatory system of arteries, veins, and capillaries is about 60,000 miles long.

8. The heart beats more than 2.5 billion times in an average lifetime.

9. There are about 9,000 taste buds on the surface of the tongue, in the throat, and on the roof of the mouth.

10. The strongest muscle in the body is the tongue.

11. The human heart creates enough pressure when it pumps out to the body to squirt blood 30 feet.

12. You blink over 10,000,000 times a year.

13. The human brain weighs about 3 pounds.

14. It takes about 20 seconds for a red blood cell to circle the whole body.

15. Only 10% of the population are left handed.

16. One fourth of the bones in your body are in your feet.

17. Children tend to grow faster in the spring.

18. The most sensitive finger on the human hand is the index finger.

19. More men are color-blind than women.

20. More people have brown eyes than any other color.

>

A Children’s Guide to the Human Body

A Look Inside the Human Body

Anatomy of the Human Body
Atlas of the Human Body

BBC: Human Body

Get Body Smart
How the Body Works

Introduction to Gross Anatomy Crossword Puzzles
KidInfo

KidsHealth

Lymphatic System

Medtropolis: The Virtual Body

National Geographic: Explore the Human Body
Science & Nature: Human Body & Mind

Smithsonian: Artificial Anatomy

Southern California Orthopedic Institute Home Page

Surfing Inside the Human Body

Systems
The Human Body: An Online Tour
Wikipedia: Human Body

Youthealth

Cardiovascular System

Circulatory System

Circulatory System 1

Circulatory System: The Life Pump
Circulatory System Theme Page

How Your Heart Works
IMCPL Kids’ Guide: Circulatory System

Kids Health: Your Heart & Circulatory System

Wikipedia: The Circulatory System

Anatomy of the Immune System
How Your Immune System Works
Immune System

Kids’ Health: The Immune System

Kids Health: Your Immune System
Overview: Immune System

The Immune System: Defending Our Bodies

Understanding The Immune System

Wikipedia: The Immune System

eSkeletons Project

Human Skeleton Printout-Enchanted Learning.com

Kids Health: Your Bones

Skeletal System
Skeletal System 1

Skeletal System: The Bone Zone

Skeletal System (Front View)

Skeletal System (Back View)
Skeletal System – Tutorials & Quizzes

The Skeletal System

The Skeleton
Your Gross and Cool Body

Wikipedia: Skeleton

Biology: Human Excretory System
Excretory System
IMCPL Kids’ Guide: Excretory System
Kids Biology: Excretory System

Kids Health: Your Urinary System

Poison Protection
The Excretory System

Urinary System

Urinary System 1

Wikipedia: The Excretory System

Yucky: Armpits

Yucky: Poop

Back View Of The Muscular System
Biology4Kids – Muscular System

Bundles of Energy: The Muscular System

How Muscles Work
IMCPL Kids’ Guide: Muscular System

Kids Health: Your Muscles
Muscular System

Muscular System Information

Muscular Systems (Front View)

Muscle System Overview
Your Gross and Cool Body

Wikipedia: Muscular System

Control of the Thyroid Gland

Endocrine System

Kids Health: Your Endocrine System

The Endocrine System
Wikipedia: Endocrine System

Yucky: The Endocrine System

Digestive System

Digestive System 1

How the Body Works: The Digestive System
Human Digestive System
IMCPL Kids’ Guide: Digestive System

Kids Health: Your Digestive System

My Body
Pictures of the Digestive System

The Digestive System

The Digestive System 1

Wikipedia: Gastrointestinal Tract

IMCPL Kids’ Guide: Nervous System

Kids Health: Your Brain and Nervous System

Nervous System

Nervous System: The Control Center

Neuroscience for Kids

Neuroscience for Kids-Explore the Nervous System

Seeing, Hearing, Smelling the World
The Human Nervous System

Types of Neurons
Your Gross and Cool Body
Welcome to the Nervous System

Wikipedia: The Nervous System

Air Bags: The Respiratory System

How the Body Works: The Respiratory System

Kids Health: Your Lungs & Respiratory System

Oxygen Delivery System

Respiratory System
Teach Your Child – Respiratory System
The Human Respiratory System

Your Respiratory System

Wikipedia: The Respiratory System

Human Digestive System

Constituents of the human body
In a normal man weighing 60 kg

Constituent

Weight [2]

Percent of atoms[2]

Oxygen

38.8 kg

25.5 %

Carbon

10.9 kg

9.5 %

Hydrogen

6.0 kg

63 %

Nitrogen

1.9 kg

1.4 %

Calcium

1.2 kg

0.2%

Phosphorus

0.6 kg

0.2 %

Potassium

0.2 kg

0.07 %

The average height of an adult male human (in developed countries) is about 1.7–1.8 m (5’7″ to 5’11”) tall and the adult female about 1.6–1.7 m (5’2″ to 5’7″) tall.[3] This size is firstly determined by genes and secondly by diet. Body type and body composition are influenced by postnatal factors such as diet and exercise[citation needed].

[edit] Systems

Main article: Organ systems

The organ systems of the body include the musculoskeletal system, cardiovascular system, digestive system, endocrine system, integumentary system, urinary system, lymphatic system, immune system, respiratory system, nervous system and reproductive system.

Anterior (frontal) view of the opened heart. White arrows indicate normal blood flow.
[edit] Cardiovascular system

Main articles: Cardiovascular system and Human heart

The cardiovascular system comprises the heart, veins, arteries and capillaries. The primary function of the heart is to circulate the blood, and through the blood, oxygen and vital minerals are transferred to the tissues and organs that comprise the body. The left side of the main organ (left ventricle and left atrium) is responsible for pumping blood to all parts of the body, while the right side (right ventricle and right atrium) pumps only to the lungs for re-oxygenation of the blood.[4][5] The heart itself is divided into three layers called the endocardium, myocardium and epicardium,(liquidation) which vary in thickness and function.[

Digestive system

Main articles: Digestive system and Human gastrointestinal tract

The digestive system provides the body’s means of processing food and transforming nutrients into energy. The digestive system consists of the – buccal cavity, esophagus, stomach, small intestine, large intestine ending in the rectum and anus. These parts together are called the alimentary canal (digestive tract).

[edit] Integumentary system

Main article: Integumentary system

The integumentary system is the largest organ system in the human body, and is responsible for protecting the body from most physical and environmental factors. The largest organ in the body, is the skin. The integument also includes appendages, primarily the sweat and sebaceous glands, hair, nails and arrectores pili (tiny muscles at the root of each hair that cause goose bumps).

[edit] Lymphatic system

Main articles: Lymphatic system and Immune system

The main function of the lymphatic system is to extract, transport and metabolise lymph, the fluid found in between cells. The lymphatic system is very similar to the circulatory system in terms of both its structure and its most basic function (to carry a body fluid).

[edit] Musculoskeletal system

Main article: Musculoskeletal system

The human musculoskeletal system consists of the human skeleton, made by bones attached to other bones with joints, and skeletal muscle attached to the skeleton by tendons.

[edit] Bones

Main articles: Human skeleton and List of bones of the human skeleton

An adult human has approximately 206 distinct bones:
Spine and vertebral column (26) Cranium (8) Face (14) Hyoid bone, sternum and ribs (26) Upper extremities (70) Lower extremities (62)
[edit] Nervous system

Main articles: Nervous system and Human brain

The nervous system consists of cells that communicate information about an organism’s surroundings and itself.

[edit] Reproductive system

Main article: Reproductive system

Human reproduction takes place as internal fertilization by sexual intercourse. During this process, the erect penis of the male is inserted into the female’s vagina until the male ejaculates semen, which contains sperm, into the female’s vagina. The sperm then travels through the vagina and cervix into the uterus or fallopian tubes for fertilization of the ovum.

The human male reproductive system is a series of organs located outside the body and around the pelvic region of a male that contribute towards the reproductive process. The primary direct function of the male reproductive system is to provide the male gamete or spermatozoa for fertilization of the ovum.

The major reproductive organs of the male can be grouped into three categories. The first category is sperm production and storage. Production takes place in the testes which are housed in the temperature regulating scrotum, immature sperm then travel to the epididymis for development and storage. The second category are the ejaculatory fluid producing glands which include the seminal vesicles, prostate, and the vas deferens. The final category are those used for copulation, and deposition of the spermatozoa (sperm) within the female, these include the penis, urethra, vas deferens and Cowper’s gland.

The human female reproductive system is a series of organs primarily located inside of the body and around the pelvic region of a female that contribute towards the reproductive process. The human female reproductive system contains three main parts: the vagina, which acts as the receptacle for the male’s sperm, the uterus, which holds the developing fetus, and the ovaries, which produce the female’s ova. The breasts are also an important reproductive organ during the parenting stage of reproduction.

The vagina meets the outside at the vulva, which also includes the labia, clitoris and urethra; during intercourse this area is lubricated by mucus secreted by the Bartholin’s glands. The vagina is attached to the uterus through the cervix, while the uterus is attached to the ovaries via the fallopian tubes. At certain intervals, typically approximately every 28 days, the ovaries release an ovum, which passes through the fallopian tube into the uterus. The lining of the uterus, called the endometrium, and unfertilized ova are shed each cycle through a process known as menstruation.

Kind of fishes

A fish (plural: fish or fishes) is any gill-bearing aquatic vertebrate that lacks limbs with digits. It is a paraphyletic term, a typological, but not a phylogenetic classification.

Fish used to be a class of vertebrates that live in water. Now the term covers several classes of animals:
Jawless fish †Armoured fish Cartilaginous fish Ray-finned fish Lobe-finned fish
Fish are usually covered with scales, and have two sets of paired fins, and several unpaired fins. They are usually cold-blooded. A fish takes in the oxygen from the water using gills. There are many different kinds of fish. They live in fresh water in lakes and rivers, and in salt water in the ocean. Some fish are less than one centimeter long. The largest fish is the whale shark, which can be almost 15 meters long and weigh 15 tons. Most fish live in the water. A group of fish called the Lungfish have developed lungs, because they live in rivers and pools that dry up, certain parts of the year.

Certain animals that have the word fish in their name are not really fish: Crayfish are crustaceans, and jellyfish are Cnidarians. Hagfish and Lampreys do not have a jawbone. Hagfish are craniata, Lampreys are Hyperoartia. Certain animals look like fish, but are not. Whales and dolphins are mammals, for example

Fish or fishes?

Though often used interchangeably, these words have different meanings. Fish is used either as singular noun or to describe a group of specimens from a single species. Fishes describes a group of different species.[4]

[change] Types of fish

Fish, the oldest vertebrate group, includes a huge range of types, from the Middle Ordovician, about 490 million years ago, to the present day. These are the main groups:[4][5][6]
Agnatha: the jawless fish Pteraspids: the head-shields
Anaspids: gills opened as holes. Silurian to end-Devonian. Cephalaspids: early jawless fish
Lampreys: living ectoparasites

Osteostraci: bony-armoured jawless fish.

Gnathostomata: the jawed fish. Includes all types commonly called fish, except the lamprey. Placoderms: heavily armoured fish
Chondrichthyes: cartilaginous fish: sharks, rays and skates.
Acanthodii: extinct spiny sharks

Osteichthyes: bony fish. Actinopterygii: the ray-finned fish. Chondrostei: sturgeons and some other early types.
Neopterygii: first seen in the later Permian, lighter and faster-moving than previous groups. Holostei: the gars and bowfins
Teleostei: the most successful group, Triassic to present day.

Sarcopterygii: the lobe-finned fish Dipnoi: the lungfish; eight genera survive.
Coelacanths: two species survive. Group was probably ancestral to tetrapods.

[change] Anatomy

Bony and cartilagenous fish

Most kinds of fish have bones. Some kinds of fish, such as sharks and rays, do not have real bones (their skeletons are made of cartilage) they are known as cartilaginous fish.

[change] Fish scales

All fish are covered with overlapping scales, and each major group of fish has its own special type of scale. Teleosts (‘modern’ fish) have what are called leptoid scales. These grow in concentric circles and overlap in a head to tail direction like roof tiles. Sharks and other chondrichthyes have placoid scales made of denticles, like small versions of their teeth. These also overlap in a head to tail direction, producing a tough outer layer. Shark skin is available for purchase as shagreen, a leather which as original is smooth in one direction, and rough in the other direction. It may be polished for use, but is always rough in texture and resistant to slipping.

The scales are usually covered with a layer of slime which improves passage through the water, and makes the fish more slippery to a predator.

[change] Swimming

Fish swim by exerting force against the surrounding water. There are exceptions, but this is usually done by the fish contracting muscles on either side of its body in order to generate waves of flexion that travel the length of the body from nose to tail, generally getting larger as they go along. Most fishes generate thrust using lateral movements of their body & tail fin (caudal fin). However, there are also species which move mainly using their median and paired fins. The latter group profits from the gained manoeuvrability that is needed when living in coral reefs for example. But they can not swim as fast as fish using their bodies & caudal fins.[7]

The shape of the body of a fish is important to its swimming. This is because streamlined body shapes makes the water drag less. Here are some common fish shapes.

[change] Streamlining

The picture on the left shows a shark. This shark’s shape is called fusiform, and it is an ovoid shape where both ends of the fish are pointy. This is the best shape for going through water quickly.[8][9] Fishes with fusiform shapes can chase prey and escape predators quickly. Many live in the open ocean and swim constantly, like marlins, swordfish, and tuna. Ichthyosaurs, porpoises, dolphins, killer whales all have similar shapes. This is an example of convergent evolution.

[change] Eel-like

The long, ribbon-like shape of an eel’s body shows another shape. This enables them to hide in cracks, springing out quickly to capture prey, then returning quickly to their hiding spot.

[change] Flatfish

A flounder has both of its eyes on one side of its body.
Flatfish live on the bottom of the ocean or lake. Most use camouflage: they change colors to match the ocean floor.

[change] Compressed

Fish with compressed shapes have flat, vertical bodies, with one eye on each side. They swim upright and can be very thin. They usually live in reefs where their flat bodies can slip in and out among the corals, sponges, and rocks, keeping hidden from predators. Angelfish, surgeonfish, and butterflyfish are all compressed fish.

Swimming in groups

Many fish swim in groups a lot of the time. Schools of fish can swim together for long distances, and may be chased by predators which also swim in schools. Casual groups are called ‘shoals’. This is discussed in shoaling and schooling.

[change] Fish as food

People eat many kinds of fish. The fish that people eat most include carp, cod, herring, perch, sardines, sturgeon, tilapia, trout, tuna, and many others. A person who buys and sells fish for eating is called a fishmonger.

[change] Fish as pets

Some people keep fish as pets. Goldfish and Siamese Fighting Fish are popular types of pet fish. They are often kept by groups of people in public ponds for their beauty and calming nature.

[change] Fishing

See also: Fishing
The word to fish is also used for the activity of catching fish. People catch fish with small nets from the side of the water or from small boats, or with big nets from big boats. People can also catch fish with fishing poles and fishhooks with bait. This is often called fishing. There is also different types of lures that can be used. One is a crank bait. Others are plastic worms and rat-l-traps. These are lots of different ways of catching fish.

Chicken Raising

Are You New To Raising Chickens?

If you’re a beginner interested in learning how to raise chickens at home in your own backyard, then I’m glad you’ve found this website and I know you’ll want to keep reading…

When it comes to keeping chickens at home most people I know would tell you that I am somewhat of an authority on the subject having raised chickens for the last several years. I guess that it is safe to say that I know more about the topic then the average person…but it wasn’t always that way. Before I completed my guide (CLICK here to take a look) I didn’t have a clue how to raise chickens, I was no different than you!

I got started reading a ton of books and magazines but I found that most of them were not created for someone like me…a guy who only wanted to keep just a half dozen hens tucked away in a corner of his backyard. I moved on to the internet but it was honestly overwhelming. Not that there wasn’t good information on the web…there was. But it was overload… there had to be a better way to learn.

That’s about the time that I discovered the urban farm movement…a group of people like me that had an interest in farming and raising small flocks in urban and suburban environments. They knew how to raise chickens and were willing to share their valuable information with me. I spent a lot of time getting to know some of them, asked tons of questions, studied their methods and learned the skills I needed to get started on my own.

If you would like to learn more about raising chickens at home be sure to sign up for my FREE “Incredible Chickens” Newsletter. This popular e-mail series is loaded with lots of word-of-mouth tips, tricks and secrets about poultry keeping…knowledge that’s not really written anywhere…information that is next to impossible to find all in one place. And best of all…it’s FREE!. (CLICK here to sign up.)

Chicken Raising – Eggs or Chicks?

When it comes to Chicken Raising I always seem to get the same old question; should I start with eggs and incubate or purchase new baby’s? The truth is you can start with either…you just need to weigh the facts and decide what is best for you. Hatcheries provide just about every poultry breed available.

Starting with eggs…Fertilized chicken eggs of all types are readily available at many poultry suppliers. They take only 21 days to incubate and you take an active role in their birth from the very beginning. There are several important facts to consider when making this Choice.
•Fertilized chicken eggs are not vaccinated against Mareks Disease or Coccidiosis, the two diseases most common to chickens.
•Temperature and humidity are the two most important aspects of the incubation process. The incubation of eggs is perhaps the most difficult aspect for the novice.
•Eggs in incubation can’t be sexed so you never know exactly what you’re going to get. Most suppliers advertise a 50/50 split between male and female eggs. (This is the ratio found in nature.)

Starting with live chicks…Chicken Raising really begins at this point. You’ll save a little money starting out with this way since you don’t have to invest in the time and expense of an incubator, not to mention the learning curve. Poultry suppliers are the experts at incubating and hatching eggs, except for a hen of course, and they do it very successfully.
•Hatcheries sell day old chirper’s shipped directly to your door. You can purchase them “sexed” (male or female) or “straight-run unsexed” (a 50/50 mix).
• Most come vaccinated against Marek’s disease and Coccidiosis, and come from a salmonella-tested breeding flock. Vaccinations are very inexpensive and hatcheries usually guarantee the chicks health for a certain period of time.
• If the size of the flock you want to keep is relatively low, you may have to search around for a hatchery that will sell you a small amount. Most hatcheries have minimum purchase requirements up to 25 or more. Splitting an order with another enthusiast is one way to mitigate the problem or if you are close to a hatchery you can just pick them up. Feed stores and pet shops will carry them in the spring with no quantity minimums.

These tidbits are from a guide that I put together for persons interested in chicken raising. CLICK HERE to check it out.

Raise Chickens – First Steps | Comments (0)

14

2010

How To Raise Chickens – First Steps!

Several years ago I decided that I was going to pursue my dream of keeping chickens in the backyard of my suburban home. Honestly, at the time I didn’t have a clue how to raise chickens, I just wanted a source of inexpensive organic and drug free chicken eggs.

Now the closest thing to a chicken I’d ever kept was a parakeet named George who I recall taunted the family cat one too many times. My great aunt had a chicken coop for years and I’m sure she knew everything there was to know about keeping them but she had been gone for many years. Thankfully there was plenty of information available in the form of books, magazines and lots of web sites.

Because I didn’t know where to start I decided to make a road map…sort of a guide of the things I would need to do. CLICK HERE to learn more.

Here are some of the most important items you’ll need to know:
•Find out if you local government will allow you to keep chickens on your property… probably the most important thing that you should do before you spend any money. Most municipalities have regulations concerning domesticated animals…make sure that they will allow you to raise them.
•Put together a budget; include cost of your housing, feed, medicines…anything related to your new hobby …make sure that you can afford it.
•Make sure that you have a good spot on your property to put your hen house. You don’t want to put it too close to your neighbor’s home. Hens don’t make too much noise but Rooster’s are positively noisy!
•Decide which breed would be best for you. If you want eggs you’ll need a breed called a “layer”. They are bred to produce lots of fresh chicken eggs.
•Do you have a little farmer in your veins? Keeping a small flock does take some work and dedication. If you’re not willing to tackle the daily chores like feeding and cleaning then this hobby might not be for you.

Do this first:

Start out at your local library by finding a book that has information on how to raise chickens that you can understand. Take your time and study the material.

If possible, visit a farm or find someone in your area with a backyard flock and ask a lot of questions. I’m sure that you’ll discover that you have what it takes to be successful!

How To Raise Chickens The Right Way

Before a person comes up with a plan How To Raise Chickens he should at least know first what his intentions on growing chickens are. Some of the common reasons why people grow chickens are having a daily supply of fresh eggs, pest control, meat production and a supply of nitrogen-rich manure.

When you have determined your purpose, you should now consider the flock that you want to raise. It really depends on your purpose.

To get started, one should buy baby chicks. Baby chicks should be placed on brooders, where they can grow properly until the sixth week. It should be placed in a place where cats cannot reach it. It should also be dry all the time, but however, too much heat can cause dehydration, especially among young chicks.

Fresh water should also be always available for the chicks. Add a tablespoon of sugar to one quart of water as an energy supplement for the newly hatched baby chicks.

The beddings for young chicks should not be slippery, such as newspapers. Wood shavings are also contraindicated until the chicks already know what their food is. They can accidentally eat the wood shavings and choke on it.

As the chicks mature, you should just be able to meet their needs, such as water, food and shelter. They should be protected from rain, wind and temperature extremes.

Perches should also be built for the chickens for them to sleep on. Chickens should be much happier when they have perches to sleep on, rather than being forced to sleep on nest boxes. Straw or wood shavings are placed underneath the perches for their droppings.

Nesting boxes should be provided for the hens. This should look and feel like a real nest as much as possible. It should take time on some instances to persuade the chicken to stay on their nest boxes to lay eggs.

The feeds that are given to the chicks should be suitable for their needs. Different kinds of feeds can be bought from poultry stores.

With your passion and determination to learn How To Raise Chickens you are on your way to growing healthy and happier chickens.

How to Raise Chickens
Raising chickens can be exciting and interesting, when armed with the required knowledge. This is a simplified view of the steps to raise chickens.

Acquiring Stock

There are two choices when raising chickens; buying full grown birds or buying chicks.

Full Grown: They are easy to raise, but the vaccination records should be checked and the birds should be free from disease. Their egg laying capacity should be confirmed, if they are being bought for layers.

Chicks: Baby chicks are the most economical and a safe choice but care is needed for the first eight weeks of their life. These chicks should originate from eggs laid by a clean stock with no diseases. Chicks are usually sexed or straight run; males or females. Stock for egg production can also be purchased as pullets. The price will vary depending on the breed, age, strain and their life as egg layers.

Choosing The Right Breed of Chicken

The kind of stock to select depends on the objectives of raising chicken. Chicken are raised for eggs, for meat, and for exhibition at shows and fairs.
Raising chickens for Egg Production:
Choose breeds that have high egg production, long productive life and bigger egg size. Layers are smaller in size and will lay between 250–300 eggs per year. Choose between white egg layers and brown. The White Leghorns (pronounced leggerns) are prolific layers of white eggs. For brown eggs, the heavier strain crosses, such as the Production Red, Red Sex Links and Golden Comets are the best. Other breeds, such as Rhode Island Reds, New Hampshire Reds are also good for eggs, but not as good as crosses and require more feed.

Layers usually start laying eggs at five months of age and will continue for around ten years. The first season is usually the best in terms of production and the capacity will reduce thereafter.

Raising chickens for Meat Production:
Stock that can make optimum use of its feed is best suited for meat production. If chickens are raised for their meat as broilers, then fast growth to make it economical and high livability should be looked at. The best are the Cornish cross of White Plymouth Rock and White Cornish, as they gain around 4-5 pounds in six weeks, and are excellent and meaty as roasters and fryers.

Dual Purpose: They are good for both eggs and meat. Several English and American breeds such as Sussex and Plymouth Rocks lay reasonably well and are large enough for meat production. They eat better than the layers and are therefore slightly more expensive to maintain.
Raising chickens for Show:
They are judged by their breed, weight and color. Bantams are good as exhibition birds, and they are easy to raise, take up less space and eat less. Popular bantam breeds for exhibition are Cochins, Old English Game and Plymouth Rocks. The most popular large fowl breeds are Rhode Island Red, Leghorns and Black Australorps. There are several other breeds available.

Housing And Confinement

Before bringing the chickens home, good housing should be ready, with floor plans for accommodating the growth of birds and for possible future expansion with more birds.
Space:
Birds need adequate space to move around and exercise, as well as area to nest and roost. A good rule of the thumb is to provide 3 to 3 ½ feet for egg laying chickens. For example, if 50 chicks are being bought, leave space for 25 for egg production and 25 for meat production.
Protection:
Housing should provide optimum conditions for growth and egg production. The bird pens should be protected from extreme temperatures, wind and rain. Planting trees as a protective barrier is helpful.
Caging, Nests and Pens:
When raising chickens of different ages they should be housed separately, because the floor sizing depends on the size of the birds. Community nests that are properly designed with clean litter can be provided for laying eggs. To keep the nests dark, a cloth flap can be used to cover most of the opening. Chickens may be housed in wire cages as well as huge pens with many birds.

Temperature And Environment

Housing should be at least 70 degrees F and for new chicks, 90 degrees F for the first week is recommended, dropping the temperature by 5 degrees each week until they are five weeks old. Keep track of the temperature by hanging a thermometer.

A source of fresh air can be provided by having open sides that are covered with reinforced plastic curtains on rollers, to be able to raise or lower them. A circulating ceiling fan helps enhance air movement in large houses.

The birds can also be allowed to go outside, within the fencing, which is small enough to keep the chicks in and should be extended all the way to the ground.

Cleanliness

When raising chickens they should be kept clean so that the poultry does not catch any diseases due to poor hygiene.

Detachable partitions are great to keep the area clean, especially in case of brooders. There should be a good distance between the breeding, growing and laying areas to ensure disease prevention. The manure under the housing should be cleaned frequently.

Feeding And Watering

Feeders and watererers should be placed conveniently throughout the pen at an easily accessible height. They should be easy to clean and avoid spillage. To avoid feed wastage, troughs can be built. Enough feeder space should be considered so that many birds can feed at the same time. An automatic water fountain is good to provide fresh water at all times, and they are not very expensive.
Nutrition:
The feed depends on the intended use and the age of the bird. The main cost of raising chicken is the cost of their feed and there are several commercial preparations available depending on the age of the birds. Remember, inadequate nutrition can result in losing the birds themselves.

Birds can also be allowed to feed on greens and fresh grass cuttings within the fence, as long as there are no chemicals used. Fresh table scraps such as stale bread and leafy vegetables can be given which will provide a variety to their feeds as well as keep the costs down. Make sure not to overfeed them on these scraps or feed anything that is spoiled.

Water is most important and a constant supply of fresh clean water is essential for healthy poultry and water consumption will increase a lot in hot weather.

Diseases & Vaccinations

Factors that impair the bird’s ability to fight disease are injury, poor nutrition, overcrowding, lack of fresh air, dirty environment and poisons. This happens due to lack of immunity, which can be gained through good nutrition and vaccination.

Diseases can be prevented, by providing them with a clean environment, clean feeders, nutrition-rich feed and fresh water.

This information can help set you up when raising chickens on a farm or small holding that you will be proud to own and enjoy the fruits of for many years to come.

Diet therapy

Diet therapy

Diet therapy can be regarded as a change in the diet we normally consume in order to treat an illness or disease in our body. Basic nutrition for your specific needs is vital for dietary treatments aimed at getting you back to normal, healthy eating patterns. The modification in your diet may mean change in several dietary factors. For instance, modification in consistency may mean a liquid diet, modification in texture often means a low fiber diet and likewise.

used to avoid or treat obesity, post-surgery treatment and fighting or controlling symptoms of disease

Various types of therapeutic diets

For beginning diet therapy, it is necessary to start with a normal or goal diet and mapping a plan to acieve it. In other words we can say that diet therapy is the modification of your normal diet in which this modified diet is taken in such a way that it is nutritional and acceptable at the same time to the patient.
During times of illness, a person moves from one type of modified diet to the other diet gradually and thus ultimately leading to your normal or goal diet. For instance, if a person has under gone a surgery, a liquid diet is very essential and eventually it becomes a stepping stone that leads to your everyday, base diet. The main intention of providing this kind of diet plan is to help the patient to return to the normal absorption and digestion patterns.

Liquid diet

A liquid diet may include many clear liquids, fruit drinks, fruit waters and possibly specialized sport drinks. For example, water, fruit juices, sugarcane juice, clear gatorade or vitamin water and other clear beverages. These liquids provide clear fluids to relieve thirst and prevent dehydration. They maintain the electrolyte balance in our body and provide minimum bowel residue. The liquid diets are recommended only for shorter periods of time, typically after a surgery. This is because of the fact that a liquid diet contains inadequacies in all types of nutrients and usually causes fast weight loss, however that fact may be a desired result of a liquid diet.

Soft diet

The soft diet is often called a low fiber diet. It contains only materials and foods that are soft in consistency and easily chewable. They are free from most of the fibers of a normal diet and are easily digestible. These soft diets contain adequate nutrition and serves as an intermediate diet between liquid and normal diet. This diet is very helpful when you have gastrointestinal problems. These diets also contain nutrition that is adequate and sufficient for most people.

Fluid diet

The fluid diet contains liquified foods as well as clear liquids, milk and milk products. A fluid diet may include food like milk, fruit and vegetable juices. The fluid diet is the recommended diet therapy for patients who cannot tolerate solid food or are unable to chew and swallow their food.

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TYPES OF DIETS Diets used in the treatment of disease are often spoken of by specific names that show a special composition and often indicate the purpose for which the diet is intended. Regular Diet The regular diet is composed of all types of foods and is well balanced and capable of maintaining a state of good nutrition. It is intended for convalescing patients who do not require a therapeutic diet. Modified or Therapeutic Diets Modified or therapeutic diets are modifications of the regular diet and are designed to meet specific patient needs. These include · method of preparation (e.g., baking, boiling, or broiling), · consistency (e.g., ground or chopped), · total calories (e.g., high or low calorie), · nutrients (e.g., altering carbohydrate, protein, fat, vitamins, and minerals), and · allowing only specific foods (e.g., diabetic diet). SOFT DIET.—The soft diet is soft in texture and consists of liquids and semi-solid foods. It is indicated in certain postoperative cases, for convalescents who cannot tolerate a regular diet, in acute illnesses, and in some gastrointestinal disorders. A soft diet is an intermediate step between a liquid and regular diet and is low in connective tissue and indigestible dietary fiber. Little or no spices are used in its preparation. The soft diet includes all liquids other than alcohol, and foods that may be incorporated into a soft 9-7

The Dish on Corned Beef and Cabbage
Corned beef and cabbage is traditionally served across America on St. Patrick’s Day. In moderation meat may actually have some health benefits, although a significant amount of evidence seems to support a vegetarian diet.

The Truth About Coconut Oil
Most smart nutritionists never thought coconut was unhealthy. After all, people in many parts of the world have been consuming coconuts for many years, sometimes in large amounts, with no apparent adverse effects. Coconuts and coconut oil are healthy additions to one’s diet.

Fats: For Your Health
Many people are confused about fats. They think all fats are bad and unhealthy. However, some fats are necessary for optimum health. In this article, Monique Gilbert describes the different types of fats and their function in optimum health.

Get Fabulously Fit with Fiber
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10 Easy Ways to Kick-Start a New Healthy Eating Lifestyle
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Does Excess Protein Turn to Fat? An Anatomy Lesson
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Easy Snack Ideas for a Healthy Diet
Most experts agree that snacking is a part of a balanced and healthy diet, as long as the snacks don’t pile on empty calories. Like any other part of your diet, it’s important to put some thought into what kind of snacks to have on hand; otherwise it’s all too easy to pick something high-calorie, high-fat, or high-sugar.
Creative Cooking and Shopping Techniques for the Busy Mom
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Eating Well When You Eat Out
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How Your Grill Can Help Your Diet
Summer is a great time to break out the barbecue grill and lighten up your diet! Grilling season doesn’t have to only mean hamburgers, bratwurst, and steaks. There are many great choices for the grill that will keep you in great shape for all those fun summer activities.
Identify Your Weaknesses: 21 Common Weight Loss Barriers
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Will Your Plan Lead To Permanent Weight Loss? How To Tell
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Plan Ahead for Healthy Road Trip Snacks and Meals
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Ten Things You Can Do To Make Any Meal Healthier
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Tips for Including More Delicious Fruits and Vegetables in Your Diet
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Weeknight Meal Help
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Are Weight Loss Supplements Worth It?
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Diet Therapy Helps Relieve Sciatica

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Sciatica usually arises from herniated disc or Piriformis Syndrome. But, one of the potentially strong causes leading to sciatica can also be unhealthy lifestyle and bad eating habits. A balanced diet is vital for healthy living. If you are a sciatica sufferer and want to cure your pain completely, follow the diet therapy and treat your sciatic pain in the most natural way.

It is a known fact that the pain of sciatica is always accompanied with constipation. Therefore, the food products that intensify indigestion should be strictly avoided. Here is the perfect diet regime for sciatic patients that can help them get over the pain:

Juices
The combination of potatoes and celery leaves is known to ease sciatica. A minimum of 10 ounces of it should be consumed per day. To further fortify the taste as well as strength of this mixture, add lots of beetroots and carrots to it. As an alternative to juice, you can also drink celery tea.

One of the popular juices i.e. believed to cure sciatica symptoms is Elderberry juice. Elderberry tea is also beneficial. Both of them are muscle relaxants as well as stimulants.

Vegetables and carbohydrates
Diet rich in carbohydrates should be taken as it contains cellulose that offers roughage and stimulates bowel movements. Green leafy fibrous vegetables are quite advantageous as they aid in digestion & eliminate waste products. Heavy meals should be strictly avoided.

Vitamin, minerals and supplements
Garlic supplements are known to be remedial for sciatic pain. To get relieved from pain, vitamin B1 as well as B-complex supplements can be taken. These supplements help in circulation and act as an anti-oxidant that provides warmth and energy to the body.

Thiamine and B1 can be found in Nuts, Green Peas, Beef, Whole-Grain Cereals, Bananas, Pork, Spinach, Pinto Beans, Liver, Navy Beans, Breads, Soybeans, Unpolished Rice, etc. These products as well as salads that consist of parsley and watercress can prove as effective sciatica remedies.

Garlic
It is strongly believed that garlic milk is an excellent medium for sciatic pain relief. Mince garlic’s two cloves in ½ cup of milk. Drink this mixture twice a day to see results in just a week. Also, you need to be cautious while consuming garlic as during its intake, other medications such as anticoagulants should be strictly avoided.

Water
Last but the best way to cure your sciatic pain is with the help of water. Drink as much water as you can to treat sciatica. Water improves circulation, stimulates bowel movement and aids in digestion.

Thus, with the diet therapy you can get relief from sciatic pain quite easily. Just eat what is right and sciatica would no longer be a problem for you.

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Rose flower with designing

Pink Roses, Purple Roses, Yellow Roses, White Roses

No other flower is a recognizable as the rose. No other flower conveys love and passion like the rose either. Most roses have five petals and are native to Asia, with smaller numbers of species native to Europe, North America, and Northwest Africa. Roses are the most popular and commonly sold florist’ flowers and they are also great value to the perfume industry. The aggregate fruit of the rose is a berry-like structure called a rose hip. Rose hips of some species are very rich in vitamin C, among the richest sources of any plant. A bouquet of red roses is often used to show love. It is used as a Valentine’s Day gift in many countries.

Roses are perennial flowering vines and shrubs of the genus rosa and family Rosaceae. Their complete scientific classification include kingdom Plantae, class Magnoliopsida, division Magnoliophyta, family Rosaceae, subfamily Rosoideae, order Rosales and genus Rosa.

The Parts of a Rose Flower

The better a flower smells, it will be smaller in size and lighter the color. The sweet odor of these flowers is due to the chemical 2-phenyl ethanol or also called beta-phenyl ethyl alcohol.

Roses have an edible fruit called rose hips and the fruit is believed to have healing properties.

Petals of rose are naturally modified leaves that are given extra nutrients in order to take on different fragrance and colors. They are designed this way to attract birds and bees for pollination. While no black roses yet exist, there are some of such a deep dark red color as to suggest black.

The rose flower has several stigmas within its bloom (unlike many flowers). The stigma is attached to the tube-like formation called style (rose contains several styles) and it is used to provide the path for pollen to travel to its many ovaries that are located within the rose hips.

Ovules are growths that are small and hair-like, which are found within the ovary of the flower. They are responsible for egg production in rose pollination.

Roses have amazing scents and astonishing beauty. Some varieties have vigorous growth and will sprint up a tree, using it as a frame. There are roses that are very small, called Patio Roses or Tea Cup and those that grow very large.

Origin and History of Rose

Roses originate from China and are cultivate now from America to Africa and from Eastern Europe to Far East. Historically, the oldest fossils of rose have been found in Colorado (more than 35 million years old). In 551 BC – 479 BC, Confucius reported that the Imperial Chinese library had many books on roses. Roses were mentioned in a cuneiform tablet (a system of writing) written in about 2860 BC in ancient Sumerians of Mesopotamia (in the Tigris-Euphrates River Valley). In the 15th Century, the English were already cultivating and hybridizing roses when the English War of Roses took place. Tudor Henry VII, the winner of the war, created the Tudor Rose (the Rose of England) by crossbreeding other roses.

In 1996, Americans bought more than 1.2 billion fresh cut roses and that is equal to 4.67 roses for every woman, man and child nationwide. 70,000 roses went into the making of the largest flower bouquet in the world. The 23.4 metre arrangement was the work of Ashrita Furman.

The Netherlands is the world’s leading exporter of roses, with about 8000 hectares of land under rose cultivation. Zambia, a small nation, had 80% of its cultivated land under roses. About 5000 hectares or 54% of the cultivated land in Ecuador is under rose cultivation.

Today, almost all cut roses sold by florists are the hybrid tea variety, while garden roses come in a staggering array of types.

Types of Roses

Roses are divided broadly into 3 classes:
•Species Roses, or also oftenly called as Wild Species Roses. They often have 5-petaled flowers and colorful hips that last well into the winter, prroviding food for birds and winter color. Wild Species Roses usually bloom once in the summer. Species roses are widely hybridized. Rosa rugosa is the most popular rose species for sale today owing to its superior hardiness, easy maintenance and disease resistance. Wild Species Roses include many different varieties.
•Old Garden Roses have a wonderful perfume and delicate beauty, not often found in modern hybrid tea roses. They are a diverse group from those with wonderful fragrance and great winter hardiness to the lovely and tender tea roses, which are best suited for warm climates. Old Garden Roses comprise a mulltifaceted group that in general are disease resistant, easy to grow and winter-hardy. They grow in several shrub and vine sizes. Normally this class of roses are white or pastel in color (although colors do vary). These “antique roses” are generally preferred for home gardens and lawns. Several groupings of roses classified as Old Garden Roses are tea roses, China roses, moss roses, bourbon roses, damask roses, etc.
•This group of roses are very popular. Old Garden Roses are the predecessors of modern roses. The modern roses is the result of crossbreeding the polyanthus (a variety of primrose) with the hybrid tea. Their colors are varied, rich and vibrant. Some of the most popular roses found in the class of modern roses are the floribunda roses, grandiflora roses and hybrid tea roses. Although they are adored by gardeners and florists, the modern roses do not adapt well to colder environments and do require proper care. Any rose identified after 1867 is considered a modern rose.

Uses

The flowers can be used for decorations, making perfumes, medication, essential oils, and cosmetics. It is also used as toxin as roses contain pectin, vitamin C and citric acids. Roses gives soothing effect for the mind and body, they are also used to treat depression, anxiety and as mild sedative because of its fragrance. The essential oils extracted from these flowers are used in aromatherapy.

The Meanings of Roses

The rose is the national flower of England and the United States. Roses have many flower meanings acording to their color and number of roses in a bouquet, but all roses symbolize love and appreciation though.

A rose that is red represents “i love you”, while red rose buds are a way to express love for the first time. Six red roses means “i adore you”, fifteen red roses means “i’m sorry”, twenty-five red roses means “congratulation”, fifty red roses means “i love you no matter what”, hundred red roses means “im devoted to you”, and finally 108 red roses means “ will you marry me?”

Giving an orange rose can say “Can we be more than friends?”, and a pink rose means “you are so sweet” or to express admiration, it represents grace, gentleness and refinement. To represent modesty and friendship, a light peach rose should be selected.

White rose conveys innocence, purity, youth, while white rose buds are an appropriate gift to a young girl from her father. Yellow roses means “let’s just be friends” it represents dying love or platonic love.

Purple roses symbolize love at first sight and can also symbolize eternal love. Purple roses are appropriate for wedding anniversaries beyond 25 years and as memorial flowers for a lost spouse.

Rose is a rose is a rose is a rose.” – Gertrude Stein

Although there are more than 100 species of roses, what most often comes to mind when we think of this flower is the red English rose. With its gorgeous flower made of alternately shaped, pinnate leaves and its seductive fragrance, it has become an immortal symbol for beauty and love. Ancient Greeks and Romans connected the flower to their gods of love and beauty. Poets, from William Shakespeare to Robert Burns, have used the rose as a device to describe their beloveds. And, originating in ancient Persia, the crushed petals of the flower have been used to create perfume for its sweet, floral scent.

Still, there is a great deal of nuance and etiquette associated with giving cut roses as a gift. The number of roses in a bouquet and the color of the flower can send very different messages. Certainly, if the bouquet is intended to express love and passionate desire, red roses, as are commonly given on Valentine’s Day, is the first choice. But how many should be given? A single, blooming red rose simply means “I love you” or perhaps “love at first sight.” A bouquet of two roses symbolizes the union of the two lovers, expressing mutual feelings and satisfaction with being together. Six roses often stands for the hardship of being apart; when you miss someone and hope to be reunited with your other half, you give your beloved half a dozen roses. A full dozen, then, is an invitation to love, meaning “be mine” as the common Valentine’s Day refrain goes. A bouquet of 50 roses stands for unconditional love.

Giving roses in other colors, however, is usually an expression of platonic love, friendship, and support. For example, a bouquet of yellow roses is a way to communicate loyalty and friendship. (Although, some believe that the gift of yellow roses actually expresses jealousy.) Dark crimson roses, on the other hand, are often used to signify mourning and therefore are appropriate gifts for the families of departed loved ones.

Rose Flower Pictures

Plant in the world

Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as flowering plants, conifers, ferns, mosses, and green algae, but do not include seaweeds like kelp, nor fungi and bacteria. The group is also called green plants or Viridiplantae in Latin. They obtain most of their energy from sunlight via photosynthesis using chlorophyll contained in chloroplasts, which gives them their green color. Some plants are parasitic and may not produce normal amounts of chlorophyll or photosynthesize.

Precise numbers are difficult to determine, but as of 2010, there are thought to be 300–315 thousand species of plants, of which the great majority, some 260–290 thousand, are seed plants (see the table below).[2]

Definition

Plants are one of the two groups into which all living things have been traditionally divided; the other is animals. The division goes back at least as far as Aristotle (384 BC – 322 BC) who distinguished between plants which generally do not move, and animals which often are mobile to catch their food. Much later, when Linnaeus (1707–1778) created the basis of the modern system of scientific classification, these two groups became the kingdoms Vegetabilia (later Metaphyta or Plantae) and Animalia (also called Metazoa). Since then, it has become clear that the plant kingdom as originally defined included several unrelated groups, and the fungi and several groups of algae were removed to new kingdoms. However, these organisms are still often considered plants, particularly in popular contexts.

Outside of formal scientific contexts, the term “plant” implies an association with certain traits, such as being multicellular, possessing cellulose, and having the ability to carry out photosynthesis.[3][4]

Current definitions of Plantae

When the name Plantae or plant is applied to a specific group of organisms or taxon, it usually refers to one of three concepts. From least to most inclusive, these three groupings are:

Algae

Green algae from Ernst Haeckel’s Kunstformen der Natur, 1904.
Main article: Algae

Algae comprise several different groups of organisms which produce energy through photosynthesis and for that reason have been included in the plant kingdom in the past. Most conspicuous among the algae are the seaweeds, multicellular algae that may roughly resemble land plants, but are classified among the brown, red and green algae. Each of these algal groups also includes various microscopic and single-celled organisms. There is good evidence that some of these algal groups arose independently from separate non-photosynthetic ancestors, with the result that many groups of algae are no longer classified within the plant kingdom as it is defined here.[6][7]

The Viridiplantae, the green plants – green algae and land plants – form a clade, a group consisting of all the descendants of a common ancestor. With a few exceptions among the green algae, all green plants have many features in common, including cell walls containing cellulose, chloroplasts containing chlorophylls a and b, and food stores in the form of starch. They undergo closed mitosis without centrioles, and typically have mitochondria with flat cristae. The chloroplasts of green plants are surrounded by two membranes, suggesting they originated directly from endosymbiotic cyanobacteria.

Two additional groups, the Rhodophyta (red algae) and Glaucophyta (glaucophyte algae), also have chloroplasts which appear to be derived directly from endosymbiotic cyanobacteria, although they differ in the pigments which are used in photosynthesis and so are different in colour. All three groups together are generally believed to have a single common origin, and so are classified together in the taxon Archaeplastida, whose name implies that the chloroplasts or plastids of all the members of the taxon were derived from a single ancient endosymbiotic event. This is the broadest modern definition of the plants.

In contrast, most other algae (e.g. heterokonts, haptophytes, dinoflagellates, and euglenids) not only have different pigments but also have chloroplasts with three or four surrounding membranes. They are not close relatives of the Archaeplastida, presumably having acquired chloroplasts separately from ingested or symbiotic green and red algae. They are thus not included in even the broadest modern definition of the plant kingdom, although they were in the past.

The green plants or Viridiplantae were traditionally divided into the green algae (including the stoneworts) and the land plants. However, it is now known that the land plants evolved from within a group of green algae, so that the green algae by themselves are a paraphyletic group, i.e. a group which excludes some of the descendants of a common ancestor. Paraphyletic groups are generally avoided in modern classifications, so that in recent treatments the Viridiplantae have been divided into two clades, the Chlorophyta and the Streptophyta (or Charophyta).[8][9]

The Chlorophyta (a name that has also been used for all green algae) are the sister group to the group from which the land plants evolved. There are about 4,300 species[10] of mainly marine organisms, both unicellular and multicellular. The latter include the sea lettuce, Ulva.

The other group within the Viridiplantae are the mainly freshwater or terrestrial Streptophyta (or Charophyta), which consist of several groups of green algae plus the stoneworts and land plants. (The names have been used differently, e.g. Streptophyta to mean the group which excludes the land plants and Charophyta for the stoneworts alone or the stoneworts plus the land plants.) Streptophyte algae are either unicellular or form multicellular filaments, branched or unbranched.[9] The genus Spirogyra is a filamentous streptophyte alga familiar to many, as it is often used in teaching and is one of the organisms responsible for the algal “scum” which pond-owners so dislike. The freshwater stoneworts strongly resemble land plants and are believed to be their closest relatives. Growing underwater, they consist of a central stalk with whorls of branchlets, giving them a superficial resemblance to horsetails, species of the genus Equisetum, which are true land plants.

Fungi

Main article: Fungi

The classification of fungi has been controversial until quite recently in the history of biology. Linnaeus’ original classification placed the fungi within the Plantae, since they were unquestionably not animals or minerals and these were the only other alternatives. With later developments in microbiology, in the 19th century Ernst Haeckel felt that another kingdom was required to classify newly discovered micro-organisms. The introduction of the new kingdom Protista in addition to Plantae and Animalia, led to uncertainty as to whether fungi truly were best placed in the Plantae or whether they ought to be reclassified as protists. Haeckel himself found it difficult to decide and it was not until 1969 that a solution was found whereby Robert Whittaker proposed the creation of the kingdom Fungi. Molecular evidence has since shown that the last common ancestor (concestor) of the Fungi was probably more similar to that of the Animalia than of any other kingdom, including the Plantae.

Whittaker’s original reclassification was based on the fundamental difference in nutrition between the Fungi and the Plantae. Unlike plants, which generally gain carbon through photosynthesis, and so are called autotrophic phototrophs, fungi generally obtain carbon by breaking down and absorbing surrounding materials, and so are called heterotrophic saprotrophs. In addition, the substructure of multicellular fungi is different from that of plants, taking the form of many chitinous microscopic strands called hyphae, which may be further subdivided into cells or may form a syncytium containing many eukaryotic nuclei. Fruiting bodies, of which mushrooms are most familiar example, are the reproductive structures of fungi, and are unlike any structures produced by plants

Diversity of living green plant (Viridiplantae) divisions

Evolution

Further information: Evolutionary history of plants

The evolution of plants has resulted in increasing levels of complexity, from the earliest algal mats, through bryophytes, lycopods, ferns to the complex gymnosperms and angiosperms of today. The groups which appeared earlier continue to thrive, especially in the environments in which they evolved.

Evidence suggests that an algal scum formed on the land 1,200 million years ago, but it was not until the Ordovician Period, around 450 million years ago, that land plants appeared.[21] However, new evidence from the study of carbon isotope ratios in Precambrian rocks has suggested that complex photosynthetic plants developed on the earth over 1000 m.y.a.[22] These began to diversify in the late Silurian Period, around 420 million years ago, and the fruits of their diversification are displayed in remarkable detail in an early Devonian fossil assemblage from the Rhynie chert. This chert preserved early plants in cellular detail, petrified in volcanic springs. By the middle of the Devonian Period most of the features recognised in plants today are present, including roots, leaves and secondary wood, and by late Devonian times seeds had evolved.[23] Late Devonian plants had thereby reached a degree of sophistication that allowed them to form forests of tall trees. Evolutionary innovation continued after the Devonian period. Most plant groups were relatively unscathed by the Permo-Triassic extinction event, although the structures of communities changed. This may have set the scene for the evolution of flowering plants in the Triassic (~200 million years ago), which exploded in the Cretaceous and Tertiary. The latest major group of plants to evolve were the grasses, which became important in the mid Tertiary, from around 40 million years ago. The grasses, as well as many other groups, evolved new mechanisms of metabolism to survive the low CO2 and warm, dry conditions of the tropics over the last 10 million years.

Embryophytes

Main article: Embryophyte

Dicksonia antarctica, a species of tree fern
The plants that are likely most familiar to us are the multicellular land plants, called embryophytes. They include the vascular plants, plants with full systems of leaves, stems, and roots. They also include a few of their close relatives, often called bryophytes, of which mosses and liverworts are the most common.

All of these plants have eukaryotic cells with cell walls composed of cellulose, and most obtain their energy through photosynthesis, using light and carbon dioxide to synthesize food. About three hundred plant species do not photosynthesize but are parasites on other species of photosynthetic plants. Plants are distinguished from green algae, which represent a mode of photosynthetic life similar to the kind modern plants are believed to have evolved from, by having specialized reproductive organs protected by non-reproductive tissues.

Bryophytes first appeared during the early Paleozoic. They can only survive where moisture is available for significant periods, although some species are desiccation tolerant. Most species of bryophyte remain small throughout their life-cycle. This involves an alternation between two generations: a haploid stage, called the gametophyte, and a diploid stage, called the sporophyte. The sporophyte is short-lived and remains dependent on its parent gametophyte.

Vascular plants first appeared during the Silurian period, and by the Devonian had diversified and spread into many different land environments. They have a number of adaptations that allowed them to overcome the limitations of the bryophytes. These include a cuticle resistant to desiccation, and vascular tissues which transport water throughout the organism. In most the sporophyte acts as a separate individual, while the gametophyte remains small.

The first primitive seed plants, Pteridosperms (seed ferns) and Cordaites, both groups now extinct, appeared in the late Devonian and diversified through the Carboniferous, with further evolution through the Permian and Triassic periods. In these the gametophyte stage is completely reduced, and the sporophyte begins life inside an enclosure called a seed, which develops while on the parent plant, and with fertilisation by means of pollen grains. Whereas other vascular plants, such as ferns, reproduce by means of spores and so need moisture to develop, some seed plants can survive and reproduce in extremely arid conditions.

Early seed plants are referred to as gymnosperms (naked seeds), as the seed embryo is not enclosed in a protective structure at pollination, with the pollen landing directly on the embryo. Four surviving groups remain widespread now, particularly the conifers, which are dominant trees in several biomes. The angiosperms, comprising the flowering plants, were the last major group of plants to appear, emerging from within the gymnosperms during the Jurassic and diversifying rapidly during the Cretaceous. These differ in that the seed embryo (angiosperm) is enclosed, so the pollen has to grow a tube to penetrate the protective seed coat; they are the predominant group of flora in most biomes today.

Fossils

Plant fossils include roots, wood, leaves, seeds, fruit, pollen, spores, phytoliths, and amber (the fossilized resin produced by some plants). Fossil land plants are recorded in terrestrial, lacustrine, fluvial and nearshore marine sediments. Pollen, spores and algae (dinoflagellates and acritarchs) are used for dating sedimentary rock sequences. The remains of fossil plants are not as common as fossil animals, although plant fossils are locally abundant in many regions worldwide.

The earliest fossils clearly assignable to Kingdom Plantae are fossil green algae from the Cambrian. These fossils resemble calcified multicellular members of the Dasycladales. Earlier Precambrian fossils are known which resemble single-cell green algae, but definitive identity with that group of algae is uncertain.

The oldest known fossils of embryophytes date from the Ordovician, though such fossils are fragmentary. By the Silurian, fossils of whole plants are preserved, including the lycophyte Baragwanathia longifolia. From the Devonian, detailed fossils of rhyniophytes have been found. Early fossils of these ancient plants show the individual cells within the plant tissue. The Devonian period also saw the evolution of what many believe to be the first modern tree, Archaeopteris. This fern-like tree combined a woody trunk with the fronds of a fern, but produced no seeds.

The Coal measures are a major source of Paleozoic plant fossils, with many groups of plants in existence at this time. The spoil heaps of coal mines are the best places to collect; coal itself is the remains of fossilised plants, though structural detail of the plant fossils is rarely visible in coal. In the Fossil Forest at Victoria Park in Glasgow, Scotland, the stumps of Lepidodendron trees are found in their original growth positions.

The fossilized remains of conifer and angiosperm roots, stems and branches may be locally abundant in lake and inshore sedimentary rocks from the Mesozoic and Cenozoic eras. Sequoia and its allies, magnolia, oak, and palms are often found.

Petrified wood is common in some parts of the world, and is most frequently found in arid or desert areas where it is more readily exposed by erosion. Petrified wood is often heavily silicified (the organic material replaced by silicon dioxide), and the impregnated tissue is often preserved in fine detail. Such specimens may be cut and polished using lapidary equipment. Fossil forests of petrified wood have been found in all continents.

Fossils of seed ferns such as Glossopteris are widely distributed throughout several continents of the Southern Hemisphere, a fact that gave support to Alfred Wegener’s early ideas regarding Continental drift theory.

Structure, growth, and development

Further information: Plant morphology

Most of the solid material in a plant is taken from the atmosphere. Through a process known as photosynthesis, most plants use the energy in sunlight to convert carbon dioxide from the atmosphere, plus water, into simple sugars. Parasitic plants, on the other hand, use the resources of its host to grow. These sugars are then used as building blocks and form the main structural component of the plant. Chlorophyll, a green-colored, magnesium-containing pigment is essential to this process; it is generally present in plant leaves, and often in other plant parts as well.

Plants usually rely on soil primarily for support and water (in quantitative terms), but also obtain compounds of nitrogen, phosphorus, and other crucial elemental nutrients. Epiphytic and lithophytic plants often depend on rainwater or other sources for nutrients and carnivorous plants supplement their nutrient requirements with insect prey that they capture. For the majority of plants to grow successfully they also require oxygen in the atmosphere and around their roots for respiration. However, some plants grow as submerged aquatics, using oxygen dissolved in the surrounding water, and a few specialized vascular plants, such as mangroves, can grow with their roots in anoxic conditions.

The leaf is usually the primary site of photosynthesis in plants.

There is no photosynthesis in deciduous leaves in autumn.
Factors affecting growth

The genotype of a plant affects its growth. For example, selected varieties of wheat grow rapidly, maturing within 110 days, whereas others, in the same environmental conditions, grow more slowly and mature within 155 days.[26]

Growth is also determined by environmental factors, such as temperature, available water, available light, and available nutrients in the soil. Any change in the availability of these external conditions will be reflected in the plants growth.

Biotic factors are also capable of affecting plant growth. Plants compete with other plants for space, water, light and nutrients. Plants can be so crowded that no single individual produces normal growth, causing etiolation and chlorosis. Optimal plant growth can be hampered by grazing animals, suboptimal soil composition, lack of mycorrhizal fungi, and attacks by insects or plant diseases, including those caused by bacteria, fungi, viruses, and nematodes.[26]

Simple plants like algae may have short life spans as individuals, but their populations are commonly seasonal. Other plants may be organized according to their seasonal growth pattern: annual plants live and reproduce within one growing season, biennial plants live for two growing seasons and usually reproduce in second year, and perennial plants live for many growing seasons and continue to reproduce once they are mature. These designations often depend on climate and other environmental factors; plants that are annual in alpine or temperate regions can be biennial or perennial in warmer climates. Among the vascular plants, perennials include both evergreens that keep their leaves the entire year, and deciduous plants which lose their leaves for some part of it. In temperate and boreal climates, they generally lose their leaves during the winter; many tropical plants lose their leaves during the dry season.

The growth rate of plants is extremely variable. Some mosses grow less than 0.001 millimeters per hour (mm/h), while most trees grow 0.025-0.250 mm/h. Some climbing species, such as kudzu, which do not need to produce thick supportive tissue, may grow up to 12.5 mm/h.

Dried dead plants
Plants protect themselves from frost and dehydration stress with antifreeze proteins, heat-shock proteins and sugars (sucrose is common). LEA (Late Embryogenesis Abundant) protein expression is induced by stresses and protects other proteins from aggregation as a result of desiccation and freezing.[27]

Plant cell

Plant cell structure
Main article: Plant cell

Plant cells are typically distinguished by their large water-filled central vacuole, chloroplasts, and rigid cell walls that are made up of cellulose, hemicellulose, and pectin. Cell division is also characterized by the development of a phragmoplast for the construction of a cell plate in the late stages of cytokinesis. Just as in animals, plant cells differentiate and develop into multiple cell types. Totipotent meristematic cells can differentiate into vascular, storage, protective (e.g. epidermal layer), or reproductive tissues, with more primitive plants lacking some tissue types.[28]

Flowers growing

flower

sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Magnoliophyta, also called angiosperms). The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs. Flowers may facilitate outcrossing (fusion of sperm and eggs from different individuals in a population) or allow selfing (fusion of sperm and egg from the same flower). Some flowers produce diaspores without fertilization (parthenocarpy). Flowers contain sporangia and are the site where gametophytes develop. Flowers give rise to fruit and seeds. Many flowers have evolved to be attractive to animals, so as to cause them to be vectors for the transfer of pollen.

In addition to facilitating the reproduction of flowering plants, flowers have long been admired and used by humans to beautify their environment, but also as objects of romance, ritual, religion, medicine and as a source of food.

Morphology

Diagram showing the main parts of a mature flower
A stereotypical flower consists of four kinds of structures attached to the tip of a short stalk. Each of these kinds of parts is arranged in a whorl on the receptacle. The four main whorls (starting from the base of the flower or lowest node and working upwards) are as follows:
Calyx: the outermost whorl consisting of units called sepals; these are typically green and enclose the rest of the flower in the bud stage, however, they can be absent or prominent and petal-like in some species.
Corolla: the next whorl toward the apex, composed of units called petals, which are typically thin, soft and colored to attract animals that help the process of pollination.
Androecium (from Greek andros oikia: man’s house): the next whorl (sometimes multiplied into several whorls), consisting of units called stamens. Stamens consist of two parts: a stalk called a filament, topped by an anther where pollen is produced by meiosis and eventually dispersed.
Gynoecium (from Greek gynaikos oikia: woman’s house): the innermost whorl of a flower, consisting of one or more units called carpels. The carpel or multiple fused carpels form a hollow structure called an ovary, which produces ovules internally. Ovules are megasporangia and they in turn produce megaspores by meiosis which develop into female gametophytes. These give rise to egg cells. The gynoecium of a flower is also described using an alternative terminology wherein the structure one sees in the innermost whorl (consisting of an ovary, style and stigma) is called a pistil. A pistil may consist of a single carpel or a number of carpels fused together. The sticky tip of the pistil, the stigma, is the receptor of pollen. The supportive stalk, the style, becomes the pathway for pollen tubes to grow from pollen grains adhering to the stigma.

Although the arrangement described above is considered “typical”, plant species show a wide variation in floral structure. These modifications have significance in the evolution of flowering plants and are used extensively by botanists to establish relationships among plant species.

Christmas Lily (Lilium longiflorum). 1. Stigma, 2. Style, 3. Stamens, 4. Filament, 5. Petal
The four main parts of a flower are generally defined by their positions on the receptacle and not by their function. Many flowers lack some parts or parts may be modified into other functions and/or look like what is typically another part. In some families, like Ranunculaceae, the petals are greatly reduced and in many species the sepals are colorful and petal-like. Other flowers have modified stamens that are petal-like, the double flowers of Peonies and Roses are mostly petaloid stamens.[1] Flowers show great variation and plant scientists describe this variation in a systematic way to identify and distinguish species.

Specific terminology is used to describe flowers and their parts. Many flower parts are fused together; fused parts originating from the same whorl are connate, while fused parts originating from different whorls are adnate, parts that are not fused are free. When petals are fused into a tube or ring that falls away as a single unit, they are sympetalous (also called gamopetalous.) Connate petals may have distinctive regions: the cylindrical base is the tube, the expanding region is the throat and the flaring outer region is the limb. A sympetalous flower, with bilateral symmetry with an upper and lower lip, is bilabiate. Flowers with connate petals or sepals may have various shaped corolla or calyx including: campanulate, funnelform, tubular, urceolate, salverform or rotate.

Many flowers have a symmetry. When the perianth is bisected through the central axis from any point, symmetrical halves are produced, forming a radial symmetry. These flowers are also known to be actinomorphic or regular, e.g. rose or trillium. When flowers are bisected and produce only one line that produces symmetrical halves the flower is said to be irregular or zygomorphic, e.g. snapdragon or most orchids.

Flowers may be directly attached to the plant at their base (sessile—the supporting stalk or stem is highly reduced or absent). The stem or stalk subtending a flower is called a peduncle. If a peduncle supports more than one flower, the stems connecting each flower to the main axis are called pedicels. The apex of a flowering stem forms a terminal swelling which is called the torus or receptacle.

Floral formula

Floral diagram for the genus Nepenthes
A floral formula is a way to represent the structure of a flower using specific letters, numbers, and symbols. Typically, a general formula will be used to represent the flower structure of a plant family rather than a particular species. The following representations are used:
Ca = calyx (sepal whorl; e. g. Ca5 = 5 sepals) Co = corolla (petal whorl; e. g., Co3(x) = petals some multiple of three ) Z = add if zygomorphic (e. g., CoZ6 = zygomorphic with 6 petals) A = androecium (whorl of stamens; e. g., A∞ = many stamens) G = gynoecium (carpel or carpels; e. g., G1 = monocarpous)
x: to represent a “variable number”
∞: to represent “many”

A floral formula would appear something like this:
Ca5Co5A10 – ∞G1
Several additional symbols are sometimes used (see Key to Floral Formulas).

Inflorescence

The familiar calla lily is not a single flower. It is actually an inflorescence of tiny flowers pressed together on a central stalk that is surrounded by a large petal-like bract.
Main article: Inflorescence

In those species that have more than one flower on an axis, the collective cluster of flowers is termed an inflorescence. Some inflorescences are composed of many small flowers arranged in a formation that resembles a single flower. The common example of this is most members of the very large composite (Asteraceae) group. A single daisy or sunflower, for example, is not a flower but a flower head—an inflorescence composed of numerous flowers (or florets).

An inflorescence may include specialized stems and modified leaves known as bracts

Development

A flower is a modified stem tip with compressed internodes, bearing structures that are highly modified leaves.[2] In essence, a flower develops on a modified shoot or axis from a determinate apical meristem (determinate meaning the axis grows to a set size).

Flowering transition

The transition to flowering is one of the major phase changes that a plant makes during its life cycle. The transition must take place at a time that is favorable for fertilization and the formation of seeds, hence ensuring maximal reproductive success. To meet these needs a plant is able to interpret important endogenous and environmental cues such as changes in levels of plant hormones and seasonable temperature and photoperiod changes.[3] Many perennial and most biennial plants require vernalization to flower. The molecular interpretation of these signals is through the transmission of a complex signal known as florigen, which involves a variety of genes, including CONSTANS, FLOWERING LOCUS C and FLOWERING LOCUS T. Florigen is produced in the leaves in reproductively favorable conditions and acts in buds and growing tips to induce a number of different physiological and morphological changes.[4] The first step is the transformation of the vegetative stem primordia into floral primordia. This occurs as biochemical changes take place to change cellular differentiation of leaf, bud and stem tissues into tissue that will grow into the reproductive organs. Growth of the central part of the stem tip stops or flattens out and the sides develop protuberances in a whorled or spiral fashion around the outside of the stem end. These protuberances develop into the sepals, petals, stamens, and carpels. Once this process begins, in most plants, it cannot be reversed and the stems develop flowers, even if the initial start of the flower formation event was dependent of some environmental cue.[5] Once the process begins, even if that cue is removed the stem will continue to develop a flower.

Organ development

Organ development

The ABC model of flower development
The molecular control of floral organ identity determination is fairly well understood. In a simple model, three gene activities interact in a combinatorial manner to determine the developmental identities of the organ primordia within the floral meristem. These gene functions are called A, B and C-gene functions. In the first floral whorl only A-genes are expressed, leading to the formation of sepals. In the second whorl both A- and B-genes are expressed, leading to the formation of petals. In the third whorl, B and C genes interact to form stamens and in the center of the flower C-genes alone give rise to carpels. The model is based upon studies of homeotic mutants in Arabidopsis thaliana and snapdragon, Antirrhinum majus. For example, when there is a loss of B-gene function, mutant flowers are produced with sepals in the first whorl as usual, but also in the second whorl instead of the normal petal formation. In the third whorl the lack of B function but presence of C-function mimics the fourth whorl, leading to the formation of carpels also in the third whorl. See also The ABC Model of Flower Development.

Most genes central in this model belong to the MADS-box genes and are transcription factors that regulate the expression of the genes specific for each floral organ.

Floral function

An example of a “perfect flower”, this Crateva religiosa flower has both stamens (outer ring) and a pistil (center).
The principal purpose of a flower is the reproduction of the individual and the species. All flowering plants are heterosporous, producing two types of spores. Microspores are produced by meiosis inside anthers while megaspores are produced inside ovules, inside an ovary. In fact, anthers typically consist of four microsporangia and an ovule is an integumented megasporangium. Both types of spores develop into gametophytes inside sporangia. As with all heterosporous plants, the gametophytes also develop inside the spores (are endosporic).

In the majority of species, individual flowers have both functional carpels and stamens. These flowers are described by botanists as being perfect or bisexual. Some flowers lack one or the other reproductive organ and called imperfect or unisexual If unisex flowers are found on the same individual plant but in different locations, the species is said to be monoecious. If each type of unisex flower is found only on separate individuals, the plant is dioecious.

Flower specialization and pollination

Flowering plants usually face selective pressure to optimize the transfer of their pollen, and this is typically reflected in the morphology of the flowers and the behaviour of the plants. Pollen may be transferred between plants via a number of ‘vectors’. Some plants make use of abiotic vectors — namely wind (anemophily) or, much less commonly, water (hydrophily). Others use biotic vectors including insects (entomophily), birds (ornithophily), bats (chiropterophily) or other animals. Some plants make use of multiple vectors, but many are highly specialised.

Cleistogamous flowers are self pollinated, after which they may or may not open. Many Viola and some Salvia species are known to have these types of flowers.

The flowers of plants that make use of biotic pollen vectors commonly have glands called nectaries that act as an incentive for animals to visit the flower. Some flowers have patterns, called nectar guides, that show pollinators where to look for nectar. Flowers also attract pollinators by scent and color. Still other flowers use mimicry to attract pollinators. Some species of orchids, for example, produce flowers resembling female bees in color, shape, and scent. Flowers are also specialized in shape and have an arrangement of the stamens that ensures that pollen grains are transferred to the bodies of the pollinator when it lands in search of its attractant (such as nectar, pollen, or a mate). In pursuing this attractant from many flowers of the same species, the pollinator transfers pollen to the stigmas—arranged with equally pointed precision—of all of the flowers it visits.

Anemophilous flowers use the wind to move pollen from one flower to the next. Examples include grasses, birch trees, ragweed and maples. They have no need to attract pollinators and therefore tend not to be “showy” flowers. Male and female reproductive organs are generally found in separate flowers, the male flowers having a number of long filaments terminating in exposed stamens, and the female flowers having long, feather-like stigmas. Whereas the pollen of animal-pollinated flowers tends to be large-grained, sticky, and rich in protein (another “reward” for pollinators), anemophilous flower pollen is usually small-grained, very light, and of little nutritional value to animals.

Pollination

Main article: Pollination

Grains of pollen sticking to this bee will be transferred to the next flower it visits
The primary purpose of a flower is reproduction. Since the flowers are the reproductive organs of plant, they mediate the joining of the sperm, contained within pollen, to the ovules — contained in the ovary. Pollination is the movement of pollen from the anthers to the stigma. The joining of the sperm to the ovules is called fertilization. Normally pollen is moved from one plant to another, but many plants are able to self pollinate. The fertilized ovules produce seeds that are the next generation. Sexual reproduction produces genetically unique offspring, allowing for adaptation. Flowers have specific designs which encourages the transfer of pollen from one plant to another of the same species. Many plants are dependent upon external factors for pollination, including: wind and animals, and especially insects. Even large animals such as birds, bats, and pygmy possums can be employed. The period of time during which this process can take place (the flower is fully expanded and functional) is called anthesis

Attraction methods

A Bee orchid has evolved over many generations to better mimic a female bee to attract male bees as pollinators.
Plants cannot move from one location to another, thus many flowers have evolved to attract animals to transfer pollen between individuals in dispersed populations. Flowers that are insect-pollinated are called entomophilous; literally “insect-loving” in Greek. They can be highly modified along with the pollinating insects by co-evolution. Flowers commonly have glands called nectaries on various parts that attract animals looking for nutritious nectar. Birds and bees have color vision, enabling them to seek out “colorful” flowers. Some flowers have patterns, called nectar guides, that show pollinators where to look for nectar; they may be visible only under ultraviolet light, which is visible to bees and some other insects. Flowers also attract pollinators by scent and some of those scents are pleasant to our sense of smell. Not all flower scents are appealing to humans; a number of flowers are pollinated by insects that are attracted to rotten flesh and have flowers that smell like dead animals, often called Carrion flowers, including Rafflesia, the titan arum, and the North American pawpaw (Asimina triloba). Flowers pollinated by night visitors, including bats and moths, are likely to concentrate on scent to attract pollinators and most such flowers are white.

Still other flowers use mimicry to attract pollinators. Some species of orchids, for example, produce flowers resembling female bees in color, shape, and scent. Male bees move from one such flower to another in search of a mate.

Pollination mechanism

The pollination mechanism employed by a plant depends on what method of pollination is utilized.

Most flowers can be divided between two broad groups of pollination methods:

Entomophilous: flowers attract and use insects, bats, birds or other animals to transfer pollen from one flower to the next. Often they are specialized in shape and have an arrangement of the stamens that ensures that pollen grains are transferred to the bodies of the pollinator when it lands in search of its attractant (such as nectar, pollen, or a mate). In pursuing this attractant from many flowers of the same species, the pollinator transfers pollen to the stigmas—arranged with equally pointed precision—of all of the flowers it visits. Many flowers rely on simple proximity between flower parts to ensure pollination. Others, such as the Sarracenia or lady-slipper orchids, have elaborate designs to ensure pollination while preventing self-pollination.

A grass flower head (Meadow Foxtail) showing the plain coloured flowers with large anthers.
Anemophilous: flowers use the wind to move pollen from one flower to the next, examples include the grasses, Birch trees, Ragweed and Maples. They have no need to attract pollinators and therefore tend not to be “showy” flowers. Whereas the pollen of entomophilous flowers tends to be large-grained, sticky, and rich in protein (another “reward” for pollinators), anemophilous flower pollen is usually small-grained, very light, and of little nutritional value to insects, though it may still be gathered in times of dearth. Honeybees and bumblebees actively gather anemophilous corn (maize) pollen, though it is of little value to them.

Some flowers are self pollinated and use flowers that never open or are self pollinated before the flowers open, these flowers are called cleistogamous. Many Viola species and some Salvia have these types of flowers.

Flower-pollinator relationships

Many flowers have close relationships with one or a few specific pollinating organisms. Many flowers, for example, attract only one specific species of insect, and therefore rely on that insect for successful reproduction. This close relationship is often given as an example of coevolution, as the flower and pollinator are thought to have developed together over a long period of time to match each other’s needs.

This close relationship compounds the negative effects of extinction. The extinction of either member in such a relationship would mean almost certain extinction of the other member as well. Some endangered plant species are so because of shrinking pollinator populations.

Fertilization and dispersal

Main article: biological dispersal

Some flowers with both stamens and a pistil are capable of self-fertilization, which does increase the chance of producing seeds but limits genetic variation. The extreme case of self-fertilization occurs in flowers that always self-fertilize, such as many dandelions. Conversely, many species of plants have ways of preventing self-fertilization. Unisexual male and female flowers on the same plant may not appear or mature at the same time, or pollen from the same plant may be incapable of fertilizing its ovules. The latter flower types, which have chemical barriers to their own pollen, are referred to as self-sterile or self-incompatible (see also: Plant sexuality).

Symbolism

Lilies are often used to denote life or resurrection

Flowers are common subjects of still life paintings, such as this one by Ambrosius Bosschaert the Elder

Chinese Jade ornament with flower design, Jin Dynasty (1115-1234 AD), Shanghai Museum.

Many flowers have important symbolic meanings in Western culture. The practice of assigning meanings to flowers is known as floriography. Some of the more common examples include:
Red roses are given as a symbol of love, beauty, and passion.
Poppies are a symbol of consolation in time of death. In the United Kingdom, New Zealand, Australia and Canada, red poppies are worn to commemorate soldiers who have died in times of war.
Irises/Lily are used in burials as a symbol referring to “resurrection/life”. It is also associated with stars (sun) and its petals blooming/shining.
Daisies are a symbol of innocence

Flowers provide less food than other major plants parts (seeds, fruits, roots, stems and leaves) but they provide several important foods and spices. Flower vegetables include broccoli, cauliflower and artichoke. The most expensive spice, saffron, consists of dried stigmas of a crocus. Other flower spices are cloves and capers. Hops flowers are used to flavor beer. Marigold flowers are fed to chickens to give their egg yolks a golden yellow color, which consumers find more desirable. Dandelion flowers are often made into wine. Bee Pollen, pollen collected from bees, is considered a health food by some people. Honey consists of bee-processed flower nectar and is often named for the type of flower, e.g. orange blossom honey, clover honey and tupelo honey.

Hundreds of fresh flowers are edible but few are widely marketed as food. They are often used to add color and flavor to salads. Squash flowers are dipped in breadcrumbs and fried. Edible flowers include nasturtium, chrysanthemum, carnation, cattail, honeysuckle, chicory, cornflower, Canna, and sunflower. Some edible flowers are sometimes candied such as daisy and rose (you may also come across a candied pansy).

Flowers can also be made into herbal teas. Dried flowers such as chrysanthemum, rose, jasmine, camomile are infused into tea both for their fragrance and medical properties. Sometimes, they are also mixed with tea leaves for the added fragrance