title: Femininity

text: In a few parts of Africa and Asia, neck rings are worn in order to elongate the neck. In these cultures, a long neck characterizes feminine beauty. The Padaung of Burma and Tutsi women of Burundi, for instance, practice this form of body modification.


title: Femininity

text: Femininity as a social construct relies on a binary gender system that treats men and masculinity as different from, and opposite to, women and femininity. In patriarchal societies, including Western ones, conventional attitudes to femininity contribute to the subordination of women, as women are seen as more compliant, vulnerable, and less prone to violence.


title: Femininity

text: Gender stereotypes influence traditional feminine occupations, resulting in microaggression toward women who break traditional gender roles. These stereotypes include that women have a caring nature, have skill at household-related work, have greater manual dexterity than men, are more honest than men, and have a more attractive physical appearance. Occupational roles associated with these stereotypes include: midwife, teacher, accountant, data entry clerk, cashier, salesperson, receptionist, housekeeper, cook, maid, social worker, and nurse. Occupational segregation maintains gender inequality and the gender pay gap. Certain medical specializations, such as surgery and emergency medicine, are dominated by a masculine culture and have a higher salary.


title: Femininity

text: Leadership is associated with masculinity in Western culture and women are perceived less favorably as potential leaders. However, some people have argued that feminine-style leadership, which is associated with leadership that focuses on help and cooperation, is advantageous over masculine leadership, which is associated with focusing on tasks and control. Female leaders are more often described by Western media using characteristics associated with femininity, such as emotion.


title: Femininity

text: Psychologist Deborah L. Best argues that primary sex characteristics of men and women, such as the ability to bear children, caused a historical sexual division of labor and that gender stereotypes evolved culturally to perpetuate this division.


title: Femininity

text: The practice of bearing children tends to interrupt the continuity of employment. According to human capital theory, this retracts from the female investment in higher education and employment training. Richard Anker of the International Labour Office argues human capital theory does not explain the sexual division of labor because many occupations tied to feminine roles, such as administrative assistance, require more knowledge, experience, and continuity of employment than low-skilled masculinized occupations, such as truck driving. Anker argues the feminization of certain occupations limits employment options for women.


title: Femininity

text: Role congruity theory proposes that people tend to view deviations from expected gender roles negatively. It supports the empirical evidence that gender discrimination exists in areas traditionally associated with one gender or the other. It is sometimes used to explain why people have a tendency to evaluate behavior that fulfills the prescriptions of a leader role less favorably when it is enacted by a woman.


title: Femininity

text: Shamanism may have originated as early as the Paleolithic period, predating all organized religions. Archeological finds have suggested that the earliest known shamans were female, and contemporary shamanic roles such as the Korean mudang continue to be filled primarily by women.


title: Femininity

text: In Hindu traditions, Devi is the female aspect of the divine. Shakti is the divine feminine creative power, the sacred force that moves through the entire universe and the agent of change. She is the female counterpart without whom the male aspect, which represents consciousness or discrimination, remains impotent and void. As the female manifestation of the supreme lord, she is also called Prakriti, the basic nature of intelligence by which the Universe exists and functions. In Hinduism, the universal creative force Yoni is feminine, with inspiration being the life force of creation.


title: Femininity

text: In Taoism, the concept of "yin" represents the primary force of the female half of yin and yang. The yin is also present, to a smaller proportion, in the male half. The yin can be characterized as slow, soft, yielding, diffuse, cold, wet, and passive.


title: Femininity

text: Although the Abrahamic God is typically described in masculine terms—such as "father" or "king"—many theologians argue that this is not meant to indicate the gender of God. According to the Catechism of the Catholic Church, God "is neither man nor woman: he is God". Several recent writers, such as feminist theologian Sallie McFague, have explored the idea of "God as mother", examining the feminine qualities attributed to God. For example, in the Book of Isaiah, God is compared to a mother comforting her child, while in the Book of Deuteronomy, God is said to have given birth to Israel.


title: Femininity

text: The Book of Genesis describes the divine creation of the world out of nothing or ex nihilo. In Wisdom literature and in the wisdom tradition, "wisdom" is described as feminine. In many books of the Old Testament, including Wisdom and Sirach, wisdom is personified and called "she". According to David Winston, because "wisdom" is God's "creative agent," she must be intimately identified with God.


title: Femininity

text: "The Wisdom of God" is feminine in Hebrew: "Chokhmah", in Arabic: "Hikmah", in Greek: "Sophia", and in Latin: "Sapientia". In Hebrew, both Shekhinah (the Holy Spirit and divine presence of God) and Ruach HaKodesh (divine inspiration) are feminine.


title: Femininity

text: In Christian Kabbalah, Chokhmah (wisdom and intuition) is the force in the creative process that God used to create the heavens and the earth. Binah (understanding and perception) is the great mother, the feminine receiver of energy and giver of form. Binah receives the intuitive insight from Chokhmah and dwells on it in the same way that a mother receives the seed from the father, and keeps it within her until it's time to give birth. The intuition, once received and contemplated with perception, leads to the creation of the Universe.


title: Femininity

text: Communist revolutionaries initially depicted idealized womanhood as muscular, plainly dressed and strong, with good female communists shown as undertaking hard manual labour, using guns, and eschewing self-adornment. Contemporary Western journalists portrayed communist states as the enemy of traditional femininity, describing women in communist countries as "mannish" perversions. In revolutionary China in the 1950s, Western journalists described Chinese women as "drably dressed, usually in sloppy slacks and without makeup, hair waves or nail polish" and wrote that "Glamour was communism's earliest victim in China. You can stroll the cheerless streets of Peking all day, without seeing a skirt or a sign of lipstick; without thrilling to the faintest breath of perfume; without hearing the click of high heels, or catching the glint of legs sheathed in nylon." In communist Poland, changing from high heels to worker's boots symbolized women's shift from the bourgeois to socialism."


title: Femininity

text: Later, the initial state portrayals of idealized femininity as strong and hard-working began to also include more traditional notions such as gentleness, caring and nurturing behaviour, softness, modesty and moral virtue, requiring good communist women to become "superheroes who excelled in all spheres", including working at jobs not traditionally regarded as feminine in nature.


title: Femininity

text: Communist ideology explicitly rejected some aspects of traditional femininity that it viewed as bourgeois and consumerist, such as helplessness, idleness and self-adornment. In Communist countries, some women resented not having access to cosmetics and fashionable clothes. In her 1993 book of essays "How We Survived Communism & Even Laughed", Croatian journalist and novelist Slavenka Drakulic wrote about "a complaint I heard repeatedly from women in Warsaw, Budapest, Prague, Sofia, East Berlin: 'Look at us – we don't even look like women. There are no deodorants, perfumes, sometimes even no soap or toothpaste. There is no fine underwear, no pantyhose, no nice lingerie[']" and "Sometimes I think the real Iron Curtain is made of silky, shiny images of pretty women dressed in wonderful clothes, of pictures from women's magazines ... The images that cross the borders in magazines, movies or videos are therefore more dangerous than any secret weapon, because they make one desire that 'otherness' badly enough to risk one's life trying to escape."


title: Femininity

text: As communist countries such as Romania and the Soviet Union began to liberalize, their official media began representing women in more conventionally feminine ways compared with the "rotund farm workers and plain-Jane factory hand" depictions they had previously been publishing. As perfumes, cosmetics, fashionable clothing, and footwear became available to ordinary women in the Soviet Union, East Germany, Poland, Yugoslavia and Hungary, they began to be presented not as bourgeois frivolities but as signs of socialist modernity. In China, with the economic liberation started by Deng Xiaoping in the 1980s, the state stopped discouraging women from expressing conventional femininity, and gender stereotypes and commercialized sexualization of women which had been suppressed under communist ideology began to rise.


title: Femininity

text: In many cultures, men who display qualities considered feminine are often stigmatized and labeled as weak. Effeminate men are often associated with homosexuality, although femininity is not necessarily related to a man's sexual orientation. Because men are pressured to be masculine and heterosexual, feminine men are assumed to be gay or queer because of how they perform their gender. This assumption limits the way one is allowed to express one's gender and sexuality.


title: Femininity

text: Cross-dressing and drag are two public performances of femininity by men that have been popularly known and understood throughout many western cultures. Men who wear clothing associated with femininity are often called cross-dressers. A drag queen is a man who wears flamboyant women's clothing and behaves in an exaggeratedly feminine manner for entertainment purposes.


title: Femininity

text: Feminist philosophers such as Judith Butler and Simone de Beauvoir contend that femininity and masculinity are created through repeated performances of gender; these performances reproduce and define the traditional categories of sex and/or gender.


title: Femininity

text: Many second-wave feminists reject what they regard as constricting standards of female beauty, created for the subordination and objectifying of women and self-perpetuated by reproductive competition and women's own aesthetics.


title: Femininity

text: Others, such as lipstick feminists and some other third-wave feminists, argue that feminism should not devalue feminine culture and identity, and that symbols of feminine identity such as make-up, suggestive clothing and having a sexual allure can be valid and empowering personal choices for both sexes.


title: Femininity

text: Julia Serano notes that masculine girls and women face much less social disapproval than feminine boys and men, which she attributes to sexism. Serano argues that women wanting to be like men is consistent with the idea that maleness is more valued in contemporary culture than femaleness, whereas men being willing to give up masculinity in favour of femininity directly threatens the notion of male superiority as well as the idea that men and women should be opposites. To support her thesis, Serano cites the far greater public scrutiny and disdain experienced by male-to-female cross-dressers compared with that faced by women who dress in masculine clothes, as well as research showing that parents are likelier to respond negatively to sons who like Barbie dolls and ballet or wear nail polish than they are to daughters exhibiting comparably masculine behaviours.


title: Femininity

text: In her 2007 book "Whipping Girl: A Transsexual Woman on Sexism and the Scapegoating of Femininity", American transsexual writer and biologist Julia Serano offers a transfeminist critique of femininity, notable especially for its call to empower femininity:


title: Femininity

text: Serano notes that some behaviors, such as frequent smiling or avoiding eye contact with strangers, are considered feminine because they are practised disproportionately by women, and likely have resulted from women's attempts to negotiate through a world which is sometimes hostile to them.


title: Femininity

text: Serano argues that because contemporary culture is sexist, it assigns negative connotations to, or trivializes, behaviours understood to be feminine such as gossiping, behaving emotionally or decorating. It also recasts and reimagines femininity through a male heterosexual lens, for example interpreting women's empathy and altruism as husband-and-child-focused rather than globally focused, and interpreting women's interest in aesthetics as intended solely to entice or attract men.


title: 2021–22 Belgian First Division A

text: The 2021–22 Belgian First Division A (officially known as Jupiler Pro League due to sponsorship reasons) was the 119th season of top-tier football in Belgium.


title: 2021–22 Belgian First Division A

text: On the final matchday of the previous season, Royal Excel Mouscron was overtaken by Waasland-Beveren, pushing them into a direct relegation spot and thus causing the Mouscron team to return to the second level after six seasons. Waasland-Beveren would eventually face the same fate as a few weeks later they lost the Relegation play-off against Seraing, ending a span of nearly a decade at the top level.


title: 2021–22 Belgian First Division A

text: The team from Seraing is a newcomer at the highest level, although a former team with the same name, R.F.C. Seraing (1904), last played at the top level 25 seasons ago and many supporters see the current Seraing as a continuation of the former. The place of Excel Mouscron was taken by 2020–21 Belgian First Division B champions and former Belgian giants Union SG, who return to the top level after 48 years and already gained 11 Belgian Championship titles, mostly in the 1900s and 1930s.


title: 2021–22 Belgian First Division A

text: Originally, as decided in 2020, the clubs agreed to reduce the number of teams again to 16 following the 2021–22 season, as due to the COVID-19 pandemic exceptionally no teams were relegated from the 2019–20 Belgian First Division A, which causing the league to temporarily expand to 18. This would mean that there would be three teams relegating from the 2021–22 Belgian First Division A with only one team promoted from the 2021–22 Belgian First Division B. However, on 14 June 2021, the clubs agreed to keep playing with 18 teams at the highest level up to (and including) the 2022–23 season, meaning that the 2021–22 Belgian First Division would continue the format of the previous season, with only one team relegating and the penultimate team playing a play-off match against the runner-up up the 2021–22 Belgian First Division B to avoid relegation. The title and Europa League playoffs remain shortened, with only the top four teams playing for the title and number 5 through 8 playing the Europa League playoffs. For the teams finishing in positions 9 through 16, the season ends immediately following the regular season. The request to keep playing with 18 teams at the highest level mainly came from the smaller teams which were already struggling following the financial impact of the COVID-19 pandemic. The bigger clubs agreed to continue the current format but demanded that U23 teams be permanently added to the lower leagues. As such, the intention is that from the 2022–23 season on, there will be 4 U23 teams playing added to each of the second, third and fourth level of Belgian football, with the final standings of the 2021–22 U23 league to determine which team will start at which level.


title: 2021–22 Belgian First Division A

text: The table lists the positions of teams after completion of each round. However, several matches were not completed in the intended timeframe, resulting in the table below showing teams with different number of matches played as from matchday 19:


title: 2021–22 Belgian First Division A

text: Points obtained during the regular season are halved (and rounded up) before the start of the playoff. Union SG started with 39 points, Club Brugge 36 points, Anderlecht and Antwerp 32 points each. As the points of Union SG and Antwerp were rounded up, in case of ties they will always be ranked below the team (or teams) they are tied with.


title: 2021–22 Belgian First Division A

text: Points obtained during the regular season were halved (and rounded up) before the start of the playoff. Gent started with 31 points, Charleroi with 27 points, and both Mechelen and Genk with 26 points each. The points of Genk were rounded up, and hence in case of ties they will always be ranked below the team (or teams) they are tied with.


title: 2021–22 Belgian First Division A

text: The winner of Play-Off II was originally scheduled to play the fourth-placed team of Play-Off I to determine which team would qualify for the second qualifying round of the 2022–23 UEFA Europa Conference League. However, since Gent won both the 2021–22 Belgian Cup (thus already qualifying for the 2022–23 UEFA Europa League) and Play-off II, the fourth-placed team of Play-Off I qualified automatically for the Europa Conference League and the European play-off was not contested.


title: 2021–22 Belgian First Division A

text: The team finishing in 17th place competes in a two-legged match with the runner-up of the 2021–22 Belgian First Division B, with the aggregate winner to play in the 2022–23 Belgian First Division A, while the losing team will take part in the 2022–23 Belgian First Division B.


title: 2021–22 Belgian First Division A

text: On 2 April 2021, following a draw away to Oostende, Seraing was certain of finishing 17th and forced to play the relegation play-off against a team from the Belgian First Division B. Seraing had won promotion last season by winning the 2020–21 Promotion-Relegation play-off and will now be looking to avoid going down again the same way. One day later in the 2021–22 Belgian First Division B, RWDM lost their match away to Deinze, meaning they would finish second and thus play Seraing for promotion.


title: 2021–22 Belgian First Division A

text: "Seraing won 1–0 on aggregate""Seraing remains in Belgian First Division A. RWD Molenbeek remains in Belgian First Division B."


title: Camel case

text: Camel case (sometimes stylized as camelCase or CamelCase, also known as camel caps or more formally as medial capitals) is the practice of writing phrases without spaces or punctuation. The format indicates the separation of words with a single capitalized letter, and the first word starting with either case. Common examples include "iPhone" and "eBay". It is also sometimes used in online usernames such as "johnSmith", and to make multi-word domain names more legible, for example in promoting "EasyWidgetCompany.com".


title: Camel case

text: Camel case is often used as a naming convention in computer programming, but is an ambiguous definition due to the optional capitalization of the first letter. Some programming styles prefer camel case with the first letter capitalised, others not. For clarity, this article calls the two alternatives upper camel case (initial uppercase letter, also known as Pascal case or bumpy case) and lower camel case (initial lowercase letter, also known as dromedary case). Some people and organizations, notably Microsoft, use the term "camel case" only for lower camel case, designating Pascal case for the upper camel case.


title: Camel case

text: Camel case is distinct from title case, which capitalises all words but retains the spaces between them, and from Tall Man lettering, which uses capitals to emphasize the differences between similar-looking product names such as "predniSONE" and "predniSOLONE". Camel case is also distinct from snake case, which uses underscores interspersed with lowercase letters (sometimes with the first letter capitalized). A combination of snake and camel case (identifiers "Written_Like_This") is recommended in the Ada 95 style guide.


title: Camel case

text: The earliest known occurrence of the term "InterCaps" on Usenet is in an April 1990 post to the group alt.folklore.computers by Avi Rappoport. The earliest use of the name "Camel Case" occurs in 1995, in a post by Newton Love. Love has since said, "With the advent of programming languages having these sorts of constructs, the humpiness of the style made me call it HumpyCase at first, before I settled on CamelCase. I had been calling it CamelCase for years. ... The citation above was just the first time I had used the name on USENET."


title: Camel case

text: The use of medial capitals as a convention in the regular spelling of everyday texts is rare, but is used in some languages as a solution to particular problems which arise when two words or segments are combined.


title: Camel case

text: In Italian, pronouns can be suffixed to verbs, and because the honorific form of second-person pronouns is capitalized, this can produce a sentence like "non ho trovato il tempo di risponderLe" ("I have not found time to answer you" – where "Le" means "to you").


title: Camel case

text: In German, the medial capital letter I, called "Binnen-I", is sometimes used in a word like "StudentInnen" ("students") to indicate that both "Studenten" ("male students") and "Studentinnen" ("female students") are intended simultaneously. However, mid-word capitalisation does not conform to German orthography apart from proper names like "McDonald"; the previous example could be correctly written using parentheses as "Student(inn)en", analogous to "congress(wo)men" in English.


title: Camel case

text: In Irish, camel case is used when an inflectional prefix is attached to a proper noun, for example ("in Galway"), from ("Galway"); ("the Scottish person"), from ("Scottish person"); and ("to Ireland"), from ("Ireland"). In recent Scottish Gaelic orthography, a hyphen has been inserted: .


title: Camel case

text: This convention is also used by several written Bantu languages (e.g. "isiZulu", "Zulu language") and several indigenous languages of Mexico (e.g. Nahuatl, Totonacan, Mixe–Zoque, and some Oto-Manguean languages).


title: Camel case

text: In Dutch, when capitalizing the digraph "ij", both the letter "I" and the letter "J" are capitalized, for example in the country name "IJsland" ("Iceland").


title: Camel case

text: In Chinese pinyin, camel case is sometimes used for place names so that readers can more easily pick out the different parts of the name. For example, places like Beijing (北京), Qinhuangdao (秦皇岛), and Daxing'anling (大兴安岭) can be written as "BeiJing", "QinHuangDao," and "DaXingAnLing" respectively"," with the number of capital letters equaling the number of Chinese characters. Writing word compounds only by the initial letter of each character is also acceptable in some cases, so Beijing can be written as "BJ", Qinghuangdao as "QHD," and Daxing'anling as DXAL.


title: Camel case

text: In English, medial capitals are usually only found in Scottish or Irish "Mac-" or "Mc-" names, where for example "MacDonald, McDonald," and "Macdonald" are common spelling variants of the same name, and in Anglo-Norman "Fitz-" names, where for example both "FitzGerald" and "Fitzgerald" are found.


title: Camel case

text: In their English style guide "The King's English", first published in 1906, H. W. and F. G. Fowler suggested that medial capitals could be used in triple compound words where hyphens would cause ambiguity—the examples they give are "KingMark-like" (as against "King Mark-like") and "Anglo-SouthAmerican" (as against "Anglo-South American"). However, they described the system as "too hopelessly contrary to use at present".


title: Camel case

text: In the scholarly transliteration of languages written in other scripts, medial capitals are used in similar situations. For example, in transliterated Hebrew, "ha'Ivri" means "the Hebrew person" or "the Jew" and "b'Yerushalayim" means "in Jerusalem". In Tibetan proper names like "rLobsang", the "r" stands for a prefix glyph in the original script that functions as tone marker rather than a normal letter. Another example is "tsIurku", a Latin transcription of the Chechen term for the capping stone of the characteristic Medieval defensive towers of Chechnya and Ingushetia; the letter "I" (palochka) is not actually capital, denoting a phoneme distinct from the one transcribed as "i".


title: Camel case

text: Medial capitals are traditionally used in abbreviations to reflect the capitalization that the words would have when written out in full, for example in the academic titles PhD or BSc. A more recent example is NaNoWriMo, a contraction of National Novel Writing Month and the designation for both the annual event and the nonprofit organization that runs it. In German, the names of statutes are abbreviated using embedded capitals, e.g. StGB for Strafgesetzbuch (Criminal Code), PatG for Patentgesetz (Patent Act), BVerfG for Bundesverfassungsgericht (Federal Constitutional Court), or the very common GmbH, for Gesellschaft mit beschränkter Haftung (private limited company). In this context, there can even be three or more camel case capitals, e.g. in TzBfG for Teilzeit- und Befristungsgesetz (Act on Part-Time and Limited Term Occupations). In French, camel case acronyms such as OuLiPo (1960) were favored for a time as alternatives to initialisms.


title: Camel case

text: Camel case is often used to transliterate initialisms into alphabets where two letters may be required to represent a single character of the original alphabet, e.g., DShK from Cyrillic ДШК.


title: Camel case

text: The first systematic and widespread use of medial capitals for technical purposes was the notation for chemical formulae invented by the Swedish chemist Jacob Berzelius in 1813. To replace the multitude of naming and symbol conventions used by chemists until that time, he proposed to indicate each chemical element by a symbol of one or two letters, the first one being capitalized. The capitalization allowed formulae like "NaCl" to be written without spaces and still be parsed without ambiguity.


title: Camel case

text: Berzelius' system continues to be used, augmented with three-letter symbols such as "Uue" for unconfirmed or unknown elements and abbreviations for some common substituents (especially in the field of organic chemistry, for instance "Et" for "ethyl-"). This has been further extended to describe the amino acid sequences of proteins and other similar domains.


title: Camel case

text: Since the early 20th century, medial capitals have occasionally been used for corporate names and product trademarks, such as


title: Camel case

text: In the 1970s and 1980s, medial capitals were adopted as a standard or alternative naming convention for multi-word identifiers in several programming languages. The precise origin of the convention in computer programming has not yet been settled. A 1954 conference proceedings occasionally informally referred to IBM's Speedcoding system as "SpeedCo". Christopher Strachey's paper on GPM (1965), shows a program that includes some medial capital identifiers, including "codice_1" and "codice_2".


title: Camel case

text: Multiple-word descriptive identifiers with embedded spaces such as codice_3 or codice_4 cannot be used in most programming languages because the spaces between the words would be parsed as delimiters between tokens. The alternative of running the words together as in codice_5 or codice_6 is difficult to understand and possibly misleading; for example, codice_6 is an English word (able to be charted), whereas codice_8 means a table of codice_9 .


title: Camel case

text: Some early programming languages, notably Lisp (1958) and COBOL (1959), addressed this problem by allowing a hyphen ("-") to be used between words of compound identifiers, as in "END-OF-FILE": Lisp because it worked well with prefix notation (a Lisp parser would not treat a hyphen in the middle of a symbol as a subtraction operator) and COBOL because its operators were individual English words. This convention remains in use in these languages, and is also common in program names entered on a command line, as in Unix.


title: Camel case

text: However, this solution was not adequate for mathematically-oriented languages such as FORTRAN (1955) and ALGOL (1958), which used the hyphen as an infix subtraction operator. FORTRAN ignored blanks altogether, so programmers could use embedded spaces in variable names. However, this feature was not very useful since the early versions of the language restricted identifiers to no more than six characters.


title: Camel case

text: Exacerbating the problem, common punched card character sets of the time were uppercase only and lacked other special characters. It was only in the late 1960s that the widespread adoption of the ASCII character set made both lowercase and the underscore character codice_10 universally available. Some languages, notably C, promptly adopted underscores as word separators, and identifiers such as codice_11 are still prevalent in C programs and libraries (as well as in later languages influenced by C, such as Perl and Python). However, some languages and programmers chose to avoid underscores—among other reasons to prevent confusing them with whitespace—and adopted camel case instead.


title: Camel case

text: Charles Simonyi, who worked at Xerox PARC in the 1970s and later oversaw the creation of Microsoft's Office suite of applications, invented and taught the use of Hungarian Notation, one version of which uses the lowercase letter(s) at the start of a (capitalized) variable name to denote its type. One account claims that the camel case style first became popular at Xerox PARC around 1978, with the Mesa programming language developed for the Xerox Alto computer. This machine lacked an underscore key (whose place was taken by a left arrow "←"), and the hyphen and space characters were not permitted in identifiers, leaving camel case as the only viable scheme for readable multiword names. The PARC Mesa Language Manual (1979) included a coding standard with specific rules for upper and lower camel case that was strictly followed by the Mesa libraries and the Alto operating system. Niklaus Wirth, the inventor of Pascal, came to appreciate camel case during a sabbatical at PARC and used it in Modula, his next programming language.


title: Camel case

text: The Smalltalk language, which was developed originally on the Alto, also uses camel case instead of underscores. This language became quite popular in the early 1980s, and thus may also have been instrumental in spreading the style outside PARC.


title: Camel case

text: Upper camel case (or "Pascal case") is used in Wolfram Language in computer algebraic system Mathematica for predefined identifiers. User defined identifiers should start with a lower case letter. This avoids the conflict between predefined and user defined identifiers both today and in all future versions.


title: Camel case

text: Whatever its origins in the computing field, the convention was used in the names of computer companies and their commercial brands, since the late 1970s — a trend that continues to this day:


title: Camel case

text: In the 1980s and 1990s, after the advent of the personal computer exposed hacker culture to the world, camel case then became fashionable for corporate trade names in non-computer fields as well. Mainstream usage was well established by 1990:


title: Camel case

text: During the dot-com bubble of the late 1990s, the lowercase prefixes "e" (for "electronic") and "i" (for "Internet", "information", "intelligent", etc.) became quite common, giving rise to names like Apple's iMac and the eBox software platform.


title: Camel case

text: In 1998, Dave Yost suggested that chemists use medial capitals to aid readability of long chemical names, e.g. write AmidoPhosphoRibosylTransferase instead of amidophosphoribosyltransferase. This usage was not widely adopted.


title: Camel case

text: Camel case is sometimes used for abbreviated names of certain neighborhoods, e.g. New York City neighborhoods "SoHo" ("So"uth of "Ho"uston Street) and "TriBeCa" ("Tri"angle "Be"low "Ca"nal Street) and San Francisco's "SoMa" ("So"uth of "Ma"rket). Such usages erode quickly, so the neighborhoods are now typically rendered as "Soho", "Tribeca", and "Soma".


title: Camel case

text: The use of medial caps for compound identifiers is recommended by the coding style guidelines of many organizations or software projects. For some languages (such as Mesa, Pascal, Modula, Java and Microsoft's .NET) this practice is recommended by the language developers or by authoritative manuals and has therefore become part of the language's "culture".


title: Camel case

text: Style guidelines often distinguish between upper and lower camel case, typically specifying which variety should be used for specific kinds of entities: variables, record fields, methods, procedures, functions, subroutines, types, etc. These rules are sometimes supported by static analysis tools that check source code for adherence.


title: Camel case

text: The original Hungarian notation for programming, for example, specifies that a lowercase abbreviation for the "usage type" (not data type) should prefix all variable names, with the remainder of the name in upper camel case; as such it is a form of lower camel case.


title: Camel case

text: Programming identifiers often need to contain acronyms and initialisms that are already in uppercase, such as "old HTML file". By analogy with the title case rules, the natural camel case rendering would have the abbreviation all in uppercase, namely "oldHTMLFile". However, this approach is problematic when two acronyms occur together (e.g., "parse DBM XML" would become "parseDBMXML") or when the standard mandates lower camel case but the name begins with an abbreviation (e.g. "SQL server" would become "sQLServer"). For this reason, some programmers prefer to treat abbreviations as if they were words and write "oldHtmlFile", "parseDbmXml" or "sqlServer". However, this can make it harder to recognise that a given word is intended as an acronym.


title: Camel case

text: Difficulties arise when identifiers have different meaning depending only on the case, as can occur with mathematical functions or trademarks. In this situation changing the case of an identifier might not be an option and an alternative name need be chosen.


title: Camel case

text: Camel case is used in some wiki markup languages for terms that should be automatically linked to other wiki pages. This convention was originally used in Ward Cunningham's original wiki software, WikiWikiWeb, and can be activated in most other wikis. Some wiki engines such as TiddlyWiki, Trac and PmWiki make use of it in the default settings, but usually also provide a configuration mechanism or plugin to disable it. Wikipedia formerly used camel case linking as well, but switched to explicit link markup using square brackets and many other wiki sites have done the same. MediaWiki, for example, camel case for linking. Some wikis that do not use camel case linking may still use the camel case as a naming convention, such as AboutUs.


title: Camel case

text: The NIEM registry requires that XML data elements use upper camel case and XML attributes use lower camel case.


title: Camel case

text: Most popular command-line interfaces and scripting languages cannot easily handle file names that contain embedded spaces (usually requiring the name to be put in quotes). Therefore, users of those systems often resort to camel case (or underscores, hyphens and other "safe" characters) for compound file names like MyJobResume.pdf.


title: Camel case

text: Microblogging and social networking services that limit the number of characters in a message are potential outlets for medial capitals. Using camel case between words reduces the number of spaces, and thus the number of characters, in a given message, allowing more content to fit into the limited space. Hashtags, especially long ones, often use camel case to maintain readability (e.g. #CollegeStudentProblems is easier to read than #collegestudentproblems); this practice improves accessibility as screen readers recognize CamelCase in parsing composite hashtags.


title: Camel case

text: In website URLs, spaces are percent-encoded as "%20", making the address longer and less human readable. By omitting spaces, camel case does not have this problem.


title: Camel case

text: Camel case has been criticised as negatively impacting readability due to the removal of spaces and uppercasing of every word.


title: Camel case

text: A 2009 study comparing snake case to camel case found that camel case identifiers could be recognised with higher accuracy among both programmers and non-programmers, and that programmers already trained in camel case were able to recognise those identifiers faster than underscored snake-case identifiers.


title: Camel case

text: A 2010 follow-up study, with other subjects containing mainly pre-trained programmers and using an improved measurement method with use of eye-tracking equipment, indicates: "While results indicate no difference in accuracy between the two styles, subjects recognize identifiers in the underscore style more quickly."


title: Anterior cruciate ligament

text: The anterior cruciate ligament (ACL) is one of a pair of cruciate ligaments (the other being the posterior cruciate ligament) in the human knee. The two ligaments are also called "cruciform" ligaments, as they are arranged in a crossed formation. In the quadruped stifle joint (analogous to the knee), based on its anatomical position, it is also referred to as the cranial cruciate ligament. The term cruciate translates to cross. This name is fitting because the ACL crosses the posterior cruciate ligament to form an “X”. It is composed of strong, fibrous material and assists in controlling excessive motion. This is done by limiting mobility of the joint. The anterior cruciate ligament is one of the four main ligaments of the knee, providing 85% of the restraining force to anterior tibial displacement at 30 and 90° of knee flexion. The ACL is the most injured ligament of the four located in the knee.


title: Anterior cruciate ligament

text: The ACL originates from deep within the notch of the distal femur. Its proximal fibers fan out along the medial wall of the lateral femoral condyle. The two bundles of the ACL are the anteromedial and the posterolateral, named according to where the bundles insert into the tibial plateau. The tibial plateau is a critical weight-bearing region on the upper extremity of the tibia. The ACL attaches in front of the intercondyloid eminence of the tibia, where it blends with the anterior horn of the medial meniscus.


title: Anterior cruciate ligament

text: The purpose of the ACL is to resist the motions of anterior tibial translation and internal tibial rotation; this is important to have rotational stability. This function prevents anterior tibial subluxation of the lateral and medial tibiofemoral joints, which is important for the pivot-shift phenomenon. The ACL has mechanoreceptors that detect changes in direction of movement, position of the knee joint, and changes in acceleration, speed, and tension. A key factor in instability after ACL injuries is having altered neuromuscular function secondary to diminished somatosensory information. For athletes who participate in sports involving cutting, jumping, and rapid deceleration, the knee must be stable in terminal extension, which is the screw-home mechanism.


title: Anterior cruciate ligament

text: An ACL tear is one of the most common knee injuries, with over 100,000 tears occurring annually in the US. Most ACL tears are a result of a non-contact mechanism such as a sudden change in a direction causing the knee to rotate inward. As the knee rotates inward, additional strain is placed on the ACL, since the femur and tibia, which are the two bones that articulate together forming the knee joint, move in opposite directions, causing the ACL to tear. Most athletes require reconstructive surgery on the ACL, in which the torn or ruptured ACL is completely removed and replaced with a piece of tendon or ligament tissue from the patient (autograft) or from a donor (allograft). Conservative treatment has poor outcomes in ACL injury, since the ACL is unable to form a fibrous clot, as it receives most of its nutrients from synovial fluid; this washes away the reparative cells, making the formation of fibrous tissue difficult. The two most common sources for tissue are the patellar ligament and the hamstrings tendon. The patellar ligament is often used, since bone plugs on each end of the graft are extracted, which helps integrate the graft into the bone tunnels during reconstruction. The surgery is arthroscopic, meaning that a tiny camera is inserted through a small surgical cut. The camera sends video to a large monitor so the surgeon can see any damage to the ligaments. In the event of an autograft, the surgeon makes a larger cut to get the needed tissue. In the event of an allograft, in which material is donated, this is not necessary, since no tissue is taken directly from the patient's own body. The surgeon drills a hole forming the tibial bone tunnel and femoral bone tunnel, allowing for the patient's new ACL graft to be guided through. Once the graft is pulled through the bone tunnels, two screws are placed into the tibial and femoral bone tunnel. Recovery time usually ranges between one and two years, but is sometimes longer, depending if the patient chose an autograft or allograft. A week or so after the occurrence of the injury, the athlete is usually deceived by the fact that he/she is walking normally and not feeling much pain. This is dangerous, as some athletes start resuming some of their activities such as jogging, which with a wrong move or twist, could damage the bones, as the graft has not completely become integrated into the bone tunnels. Injured athletes must understand the significance of each step of an ACL injury to avoid complications and ensure a proper recovery.


title: Anterior cruciate ligament

text: ACL reconstruction is the most common treatment for an ACL tear, but it is not the only treatment available for individuals. Some may find it more beneficial to complete a nonoperative rehabilitation program. Individuals who are going to continue with physical activity that involves cutting and pivoting, and individuals who are no longer participating in those specific activities both are candidates for the nonoperative route. In comparing operative and nonoperative approaches to ACL tears, few differences were noted between surgical and nonsurgical groups, with no significant differences in regard to knee function or muscle strength reported by the patients.


title: Anterior cruciate ligament

text: The main goals to achieve during rehabilitation (rehab) of an ACL tear is to regain sufficient functional stability, maximize full muscle strength, and decrease risk of reinjury. Typically, three phases are involved in nonoperative treatment - the acute phase, the neuromuscular training phase, and the return to sport phase. During the acute phase, the rehab is focusing on the acute symptoms that occur right after the injury and are causing an impairment. The use of therapeutic exercises and appropriate therapeutic modalities is crucial during this phase to assist in repairing the impairments from the injury. The neuromuscular training phase is used to focus on the patient regaining full strength in both the lower extremity and the core muscles. This phase begins when the patient regains full range of motion, no effusion, and adequate lower extremity strength. During this phase, the patient completes advanced balance, proprioception, cardiovascular conditioning, and neuromuscular interventions. In the final, return to sport phase, the patient focuses on sport-specific activities and agility. A functional performance brace is suggested to be used during the phase to assist with stability during pivoting and cutting activities.


title: Anterior cruciate ligament

text: Anterior cruciate ligament surgery is a complex operation that requires expertise in the field of orthopedic and sports medicine. Many factors should be considered when discussing surgery, including the athlete's level of competition, age, previous knee injury, other injuries sustained, leg alignment, and graft choice. Typically, four graft types are possible, the bone-patella tendon-bone graft, the semitendinosus and gracilis tendons (quadrupled hamstring tendon), quadriceps tendon, and an allograft. Although extensive research has been conducted on which grafts are the best, the surgeon typically chooses the type of graft with which he or she is most comfortable. If rehabilitated correctly, the reconstruction should last. In fact, 92.9% of patients are happy with graft choice.


title: Anterior cruciate ligament

text: Prehabilitation has become an integral part of the ACL reconstruction process. This means that the patient exercises before getting surgery to maintain factors such as range of motion and strength. Based on a single leg hop test and self-reported assessment, prehab improved function; these effects were sustained 12 weeks postoperatively.


title: Anterior cruciate ligament

text: Postsurgical rehabilitation is essential in the recovery from the reconstruction. This typically takes a patient 6 to 12 months to return to life as it was prior to the injury. The rehab can be divided into protection of the graft, improving range of motion, decrease swelling, and regaining muscle control. Each phase has different exercises based on the patients' needs. For example, while the ligament is healing, a patient's joint should not be used for full weight-bearing, but the patient should strengthen the quadriceps and hamstrings by doing quad sets and weight shifting drills. Phase two would require full weight-bearing and correcting gait patterns, so exercises such as core strengthening and balance exercises would be appropriate. In phase three, the patient begins running, and can do aquatic workouts to help with reducing joint stresses and cardiorespiratory endurance. Phase four includes multiplanar movements, thus enhancing a running program and beginning agility and plyometric drills. Lastly, phase five focuses on sport- or life-specific motions, depending on the patient.


title: Anterior cruciate ligament

text: A 2010 "Los Angeles Times" review of two medical studies discussed whether ACL reconstruction was advisable. One study found that children under 14 who had ACL reconstruction fared better after early surgery than those who underwent a delayed surgery. For adults 18 to 35, though, patients who underwent early surgery followed by rehabilitation fared no better than those who had rehabilitative therapy and a later surgery.


title: Anterior cruciate ligament

text: The first report focused on children and the timing of an ACL reconstruction. ACL injuries in children are a challenge because children have open growth plates in the bottom of the femur or thigh bone and on the top of the tibia or shin. An ACL reconstruction typically crosses the growth plates, posing a theoretical risk of injury to the growth plate, stunting leg growth, or causing the leg to grow at an unusual angle.


title: Anterior cruciate ligament

text: The second study noted focused on adults. It found no significant statistical difference in performance and pain outcomes for patients who receive early ACL reconstruction vs. those who receive physical therapy with an option for later surgery. This would suggest that many patients without instability, buckling, or giving way after a course of rehabilitation can be managed nonoperatively, but was limited to outcomes after two years and did not involve patients who were serious athletes. Patients involved in sports requiring significant cutting, pivoting, twisting, or rapid acceleration or deceleration may not be able to participate in these activities without ACL reconstruction.


title: Anterior cruciate ligament

text: Risk differences between outcomes in men and women can be attributed to a combination of multiple factors, including anatomical, hormonal, genetic, positional, neuromuscular, and environmental factors. The size of the anterior cruciate ligament is often the most reported difference. Studies look at the length, cross-sectional area, and volume of ACLs. Researchers use cadavers, and "in vivo" placement to study these factors, and most studies confirm that women have smaller anterior cruciate ligaments. Other factors that could contribute to higher risks of ACL tears in women include patient weight and height, the size and depth of the intercondylar notch, the diameter of the ACL, the magnitude of the tibial slope, the volume of the tibial spines, the convexity of the lateral tibiofemoral articular surfaces, and the concavity of the medial tibial plateau. While anatomical factors are most talked about, extrinsic factors, including dynamic movement patterns, might be the most important risk factor when it comes to ACL injury. Environmental factors also play a big role. Extrinsic factors are controlled by the individual. These could be strength, conditioning, shoes, and motivation.


title: The Cat in the Hat

text: The Cat in the Hat is a 1957 children's book written and illustrated by the American author Theodor Geisel, using the pen name Dr. Seuss. The story centers on a tall anthropomorphic cat who wears a red and white-striped top hat and a red bow tie. The Cat shows up at the house of Sally and her brother one rainy day when their mother is away. Despite the repeated objections of the children's fish, the Cat shows the children a few of his tricks in an attempt to entertain them. In the process, he and his companions, Thing One and Thing Two, wreck the house. As the children and the fish become more alarmed, the Cat produces a machine that he uses to clean everything up and disappears just before the children's mother comes home.


title: The Cat in the Hat

text: Geisel created the book in response to a debate in the United States about literacy in early childhood and the ineffectiveness of traditional primers such as those featuring Dick and Jane. Geisel was asked to write a more entertaining primer by William Spaulding, whom he had met during World War II and who was then director of the education division at Houghton Mifflin. However, because Geisel was already under contract with Random House, the two publishers agreed to a deal: Houghton Mifflin published the education edition, which was sold to schools, and Random House published the trade edition, which was sold in bookstores.


title: The Cat in the Hat

text: Geisel gave varying accounts of how he created "The Cat in the Hat", but in the version he told most often, he was so frustrated with the word list from which he could choose words to write his story that he decided to scan the list and create a story based on the first two rhyming words he found. The words he found were "cat" and "hat". The book was met with immediate critical and commercial success. Reviewers praised it as an exciting alternative to traditional primers. Three years after its debut, the book had already sold over a million copies, and in 2001, "Publishers Weekly" listed the book at number nine on its list of best-selling children's books of all time. The book's success led to the creation of Beginner Books, a publishing house centered on producing similar books for young children learning to read. In 1983, Geisel said, "It is the book I'm proudest of because it had something to do with the death of the Dick and Jane primers." Since its publication, "The Cat in the Hat" has become one of Dr. Seuss' most famous books, with the Cat himself becoming his signature creation. The book was adapted into a 1971 animated television special and a 2003 live-action film, and the Cat has been included in many Dr. Seuss media.


title: The Cat in the Hat

text: The story begins as an unnamed boy who is the narrator of the book sits alone with his sister Sally in their house on a cold and rainy day, staring wistfully out the window. Then they hear a loud bump which is quickly followed by the arrival of the Cat in the Hat, a tall anthropomorphic cat in a red and white-striped top hat and a red bow tie, who proposes to entertain the children with some tricks that he knows. The children's pet fish refuses, insisting that the Cat should leave. The Cat then responds by balancing the fish on the tip of his umbrella. The game quickly becomes increasingly trickier, as the Cat balances himself on a ball and tries to balance many household items on his limbs until he falls on his head, dropping everything he was holding. The fish admonishes him again, but the Cat in the Hat just proposes another game.


title: The Cat in the Hat

text: The Cat brings in a big red box from outside, from which he releases two identical characters, or "Things" as he refers them to, with blue hair and red suits called Thing One and Thing Two. The Things cause more trouble, such as flying kites in the house, knocking pictures off the wall and picking up the children's mother's new polka-dotted dress. All this comes to an end when the fish spots the children's mother out the window. In response, the boy catches the Things in a net and the Cat, apparently ashamed, stores them back in the big red box. He takes it out the front door as the fish and the children survey the mess he has made. But the Cat soon returns, riding a machine that picks everything up and cleans the house, delighting the fish and the children. The Cat then leaves just before their mother arrives, and the fish and the children are back where they started at the beginning of the story. As she steps in, the mother asks the children what they did while she was out, but the children are hesitant and do not answer. The story ends with the question, "What would "you" do if your mother asked "you"?"


title: The Cat in the Hat

text: Theodor Geisel, writing as Dr. Seuss, created "The Cat in the Hat" partly in response to the May 24, 1954, "Life" magazine article by John Hersey titled "Why Do Students Bog Down on First R? A Local Committee Sheds Light on a National Problem: Reading". In the article, Hersey was critical of school primers like those featuring Dick and Jane:


title: The Cat in the Hat

text: In the classroom boys and girls are confronted with books that have insipid illustrations depicting the slicked-up lives of other children... All feature abnormally courteous, unnaturally clean boys and girls... In bookstores anyone can buy brighter, livelier books featuring strange and wonderful animals and children who behave naturally, i.e., sometimes misbehave... Given incentive from school boards, publishers could do as well with primers.


title: The Cat in the Hat

text: After detailing many issues contributing to the dilemma connected with student reading levels, Hersey asked toward the end of the article:


title: The Cat in the Hat

text: Why should [school primers] not have pictures that widen rather than narrow the associative richness the children give to the words they illustrate—drawings like those of the wonderfully imaginative geniuses among children's illustrators, Tenniel, Howard Pyle, "Dr. Seuss", Walt Disney?


title: The Cat in the Hat

text: This article caught the attention of William Spaulding, who had met Geisel during the war and who was then the director of Houghton Mifflin's education division. Spaulding had also read the best-selling 1955 book "Why Johnny Can't Read" by Rudolf Flesch. Flesch, like Hersey, criticized primers as boring but also criticized them for teaching reading through word recognition rather than phonics. In 1955, Spaulding invited Geisel to dinner in Boston where he proposed that Geisel create a book "for six- and seven-year-olds who had already mastered the basic mechanics of reading". He reportedly challenged, "Write me a story that first-graders can't put down!"


title: The Cat in the Hat

text: At the back of "Why Johnny Can't Read", Flesch had included 72 lists of words that young children should be able to read, and Spaulding provided Geisel with a similar list. Geisel later told biographers Judith and Neil Morgan that Spaulding had supplied him with a list of 348 words that every six-year-old should know and insisted that the book's vocabulary be limited to 225 words. However, according to Philip Nel, Geisel gave varying numbers in interviews from 1964 to 1969. He variously claimed that he could use between 200 and 250 words from a list of between 300 and 400; the finished book contains 236 different words.


title: The Cat in the Hat

text: Geisel gave varying accounts of how he conceived of "The Cat in the Hat". According to the story Geisel told most often, he was so frustrated with the word list that William Spaulding had given him that he finally decided to scan the list and create a story out of the first two words he found that rhymed. The words he found were "cat" and "hat".


title: The Cat in the Hat

text: Near the end of his life, Geisel told his biographers, Judith and Neil Morgan, that he conceived the beginnings of the story while he was with Spaulding, in an elevator in the Houghton Mifflin offices in Boston. It was an old, shuddering elevator and was operated by a "small, stooped woman wearing 'a leather half-glove and a secret smile'". Anita Silvey, recounting a similar story, described the woman as "a very elegant, very petite African-American woman named Annie Williams". Geisel told Silvey that, when he sketched the Cat in the Hat, he thought of Williams and gave the character Williams' white gloves and "sly, even foxy smile".


title: The Cat in the Hat

text: Geisel gave two conflicting, partly fictionalized accounts of the book's creation in two articles, "How Orlo Got His Book" in "The New York Times Book Review" and "My Hassle with the First Grade Language" in the "Chicago Tribune", both published on November 17, 1957. In "My Hassle with the First Grade Language", he wrote about his proposal to a "distinguished schoolbook publisher" to write a book for young children about "scaling the peaks of Everest at 60 degrees below". The publisher was intrigued but informed him that, because of the word list, "you can't use the word "scaling". You can't use the word "peaks". You can't use "Everest". You can't use "60". You can't use "degrees". You can't..." Geisel gave a similar account to Robert Cahn for an article in the July 6, 1957, edition of "The Saturday Evening Post". In "My Hassle With the First Grade Language", he also told a story of the "three excruciatingly painful weeks" in which he worked on a story about a King Cat and a Queen Cat. However, "queen" was not on the word list, nor did his first grade nephew, Norval, recognize it. So Geisel returned to the work but could then think only of words that started with the letter "q", which did not appear in any word on the list. He then had a similar fascination with the letter "z", which also did not appear in any word on the list. When he did finally finish the book and showed it to his nephew, Norval had already graduated from the first grade and was learning calculus. Philip Nel notes, in his dissection of the article, that Norval was Geisel's invention. Geisel's niece, Peggy Owens, did have a son, but he was only a one-year-old when the article was published.


title: The Cat in the Hat

text: In "How Orlo Got His Book", he described Orlo, a fictional, archetypal young child who was turned off of reading by the poor selection of simple reading material. To save Orlo the frustration, Geisel decided to write a book for children like Orlo but found the task "not dissimilar to... being lost with a witch in a tunnel of love". He tried to write a story called "The Queen Zebra" but found that both words did not appear on the list. In fact, like Geisel wrote in "My Hassle with the First Grade Language", the letters "q" and "z" did not appear on the list at all. He then tried to write a story about a bird, without using the word "bird" as it did not appear on the list. He decided to call it a "wing thing" instead but struggled as he discovered that it "couldn't have "legs" or a "beak" or a "tail". Neither a "left" foot or a "right" foot." On his approach to writing "The Cat in the Hat" he wrote, "The method I used is the same method you use when you sit down to make apple stroodle [sic] without stroodles."


title: The Cat in the Hat

text: Geisel variously stated that the book took between nine and 18 months to create. Donald Pease notes that he worked on it primarily alone, unlike with previous books, which had been more collaborative efforts between Geisel and his wife, Helen. This marked a general trend in his work and life. As Robert L. Bernstein later said of that period, "The more I saw of him, the more he liked being in that room and creating all by himself." Pease points to Helen's recovery from Guillain–Barré syndrome, which she was diagnosed with in 1954, as the marker for this change.


title: The Cat in the Hat

text: Geisel agreed to write "The Cat in the Hat" at the request of William Spaulding of Houghton Mifflin; however, because Geisel was under contract with Random House, the head of Random House, Bennett Cerf, made a deal with Houghton Mifflin. Random House retained the rights to trade sales, which encompassed copies of the book sold at book stores, while Houghton Mifflin retained the education rights, which encompassed copies sold to schools.


title: The Cat in the Hat

text: The Houghton Mifflin edition was released in January or February 1957, and the Random House edition was released on March 1. The two editions featured different covers but were otherwise identical. The first edition can be identified by the "200/200" mark in the top right corner of the front dust jacket flap, signifying the $2.00 selling price. The price was reduced to $1.95 on later editions.


title: The Cat in the Hat

text: According to Judith and Neil Morgan, the book sold well immediately. The trade edition initially sold an average of 12,000 copies a month, a figure which rose rapidly. Bullock's department store in Los Angeles, California, sold out of its first, 100-copy order of the book in a day and quickly reordered 250 more. The Morgans attribute these sales numbers to "playground word-of-mouth", asserting that children heard about the book from their friends and nagged their parents to buy it for them. However, Houghton Mifflin's school edition did not sell as well. As Geisel noted in Jonathan Cott's 1983 profile of him, "Houghton Mifflin... had trouble selling it to the schools; there were a lot of Dick and Jane devotees, and my book was considered too fresh and irreverent. But Bennett Cerf at Random House had asked for trade rights, and it just took off in the bookstores." Geisel told the Morgans, "Parents understood better than school people the necessity for this kind of reader."


title: The Cat in the Hat

text: After three years in print, "The Cat in the Hat" had sold nearly one million copies. By then, the book had been translated into French, Chinese, Swedish, and Braille. In 2001, "Publishers Weekly" placed it at number nine on its list of the best-selling children's books of all time. As of 2007, more than 10 million copies of "The Cat in the Hat" have been printed, and it has been translated into more than 12 different languages, including Latin, under the title "Cattus Petasatus". In 2007, on the occasion of the book's fiftieth anniversary, Random House released "The Annotated Cat: Under the Hats of Seuss and His Cats", which includes both "The Cat in the Hat" and its sequel, with annotations and an introduction by Philip Nel.


title: The Cat in the Hat

text: The book was published to immediate critical acclaim. Some reviewers praised the book as an exciting way to learn to read, particularly compared to the primers that it supplanted. Ellen Lewis Buell, in her review for "The New York Times Book Review", noted the book's heavy use of one-syllable words and lively illustrations. She wrote, "Beginning readers and parents who have been helping them through the dreary activities of Dick and Jane and other primer characters are due for a happy surprise." Helen Adams Masten of the "Saturday Review" called the book Geisel's "tour de force" and wrote, "Parents and teachers will bless Mr. Geisel for this amusing reader with its ridiculous and lively drawings, for their children are going to have the exciting experience of learning that they "can" read after all." Polly Goodwin of the "Chicago Sunday Tribune" predicted that "The Cat in the Hat" would cause seven- and eight-year-olds to "look with distinct distaste on the drab adventures of standard primer characters".


title: The Cat in the Hat

text: Both Helen E. Walker of "Library Journal" and Emily Maxwell of "The New Yorker" felt that the book would appeal to older children as well as to its target audience of first- and second-graders. The reviewer for "The Bookmark" concurred, writing, "Recommended enthusiastically as a picture book as well as a reader". In contrast, Heloise P. Mailloux wrote in "The Horn Book Magazine", "This is a fine book for remedial purposes, but self-conscious children often refuse material if it seems meant for younger children." She felt that the book's limited vocabulary kept it from reaching "the absurd excellence of early Seuss books".


title: The Cat in the Hat

text: Based on a 2007 online poll, the National Education Association listed "The Cat in the Hat" as one of its "Teachers' Top 100 Books for Children". In 2012, it was ranked number 36 among the "Top 100 Picture Books" in a survey published by "School Library Journal" – the third of five Dr. Seuss books on the list. It was awarded the Early Readers BILBY Award in 2004 and 2012.


title: The Cat in the Hat

text: The book's fiftieth anniversary in 2007 prompted a reevaluation of the book from some critics. Yvonne Coppard, reviewing the fiftieth anniversary edition in "Carousel" magazine, wondered if the popularity of the Cat and his "delicious naughty behavior" will endure another fifty years. Coppard wrote, "The innocent ignorance of bygone days has given way to an all-embracing, almost paranoid awareness of child protection issues. And here we have the mysterious stranger who comes in, uninvited, while your mother is out."


title: The Cat in the Hat

text: Philip Nel places the book's title character in the tradition of con artists in American art, including the title characters from Meredith Willson's "The Music Man" and L. Frank Baum's "The Wonderful Wizard of Oz". Nel also contends that Geisel identified with the Cat, pointing to a self portrait of Geisel in which he appears as the Cat, which was published alongside a profile about him in "The Saturday Evening Post" on July 6, 1957. Michael K. Frith, who worked as Geisel's editor, concurs, arguing that "The Cat in the Hat and Ted Geisel were inseparable and the same. I think there's no question about it. This is someone who delighted in the chaos of life, who delighted in the seeming insanity of the world around him." Ruth MacDonald asserts that the Cat's primary goal in the book is to create fun for the children. The Cat calls it "fun that is funny", which MacDonald distinguishes from the ordinary, serious fun that parents subject their children to. In an article titled "Was the Cat in the Hat Black?", Philip Nel draws connections between the Cat and stereotyped depictions of African-Americans, including minstrel shows, Geisel's own minstrel-inspired cartoons from early in his career, and the use of the term "cat" to refer to jazz musicians. According to Nel, "Even as [Geisel] wrote books designed to challenge prejudice, he never fully shed the cultural assumptions he grew up with, and was likely unaware of the ways in which his visual imagination replicated the racial ideologies he consciously sought to reject."


title: The Cat in the Hat

text: Geisel once called the fish "my version of Cotton Mather", the Puritan moralist who advised the prosecutors during the Salem witch trials. Betty Mensch and Alan Freeman support this view, writing, "Drawing on old Christian symbolism (the fish was an ancient sign of Christianity) Dr. Seuss portrays the fish as a kind of ever-nagging superego, the embodiment of utterly conventionalized morality." Philip Nel notes that other critics have also compared the fish to the superego. Anna Quindlen called the Cat "pure id" and marked the children, as mediators between the Cat and the fish, as the ego. Mensch and Freeman, however, argue that the Cat shows elements of both id and ego.


title: The Cat in the Hat

text: In her analysis of the fish, MacDonald asserts that it represents the voice of the children's absent mother. Its conflict with the Cat, not only over the Cat's uninvited presence but also their inherent predator-prey relationship, provides the tension of the story. She points out that on the last page, while the children are hesitant to tell their mother about what happened in her absence, the fish gives a knowing look to the readers to assure them "that something did go on but that silence is the better part of valor in this case". Alison Lurie agrees, writing, "there is a strong suggestion that they might not tell her." She argues that, in the Cat's destruction of the house, "the kids—and not only those in the story, but those who read it—have vicariously given full rein to their destructive impulses without guilt or consequences." For a 1983 article, Geisel told Jonathan Cott, ""The Cat in the Hat" is a revolt against authority, but it's ameliorated by the fact that the Cat cleans up everything at the end. It's revolutionary in that it goes as far as Kerensky and then stops. It doesn't go quite as far as Lenin."


title: The Cat in the Hat

text: Donald Pease notes that "The Cat in the Hat" shares some structural similarities with other Dr. Seuss books. Like earlier books, "The Cat in the Hat" starts with "a child's feeling of discontent with his mundane circumstances" which is soon enhanced by make-believe. The book starts in a factual, realistic world, which crosses over into the world of make-believe with the loud bump that heralds the arrival of the Cat. However, this is the first Dr. Seuss book in which the fantasy characters, i.e. the Cat and his companions, are not products of the children's imagination. It also differs from previous books in that Sally and her brother actively participate in the fantasy world; they also have a new opinion of the Cat and his world by the story's end.


title: The Cat in the Hat

text: Ruth MacDonald asserts, ""The Cat in the Hat" is the book that made Dr. Seuss famous. Without "The Cat", Seuss would have remained a minor light in the history of children's literature." Donald Pease concurs, writing, ""The Cat in the Hat" is the classic in the archive of Dr. Seuss stories for which it serves as a cornerstone and a linchpin. Before writing it Geisel was better known for the 'Quick, Henry, the Flit!' ad campaign than for his nine children's books." The publication and popularity of the book thrust Geisel into the center of the United States literacy debate, what Pease called "the most important academic controversy" of the Cold War era. Academic Louis Menand contends that ""The Cat in the Hat" transformed the nature of primary education and the nature of children's books. It not only stood for the idea that reading ought to be taught by phonics; it also stood for the idea that language skills—and many other subjects—ought to be taught through illustrated storybooks, rather than primers and textbooks." In 1983, Geisel told Jonathan Cott, "It is the book I'm proudest of because it had something to do with the death of the "Dick and Jane" primers."


title: The Cat in the Hat

text: The book led directly to the creation of Beginner Books, a publishing house centered on producing books like "The Cat in the Hat" for beginning readers. According to Judith and Neil Morgan, when the book caught the attention of Phyllis Cerf, the wife of Geisel's publisher, Bennett Cerf, she arranged for a meeting with Geisel, where the two agreed to create Beginner Books. Geisel became the president and editor, and the Cat in the Hat served as their mascot. Geisel's wife, Helen, was made third partner. Random House served as distributor until 1960, when Random House purchased Beginner Books. Geisel wrote multiple books for the series, including "The Cat in the Hat Comes Back" (1958), "Green Eggs and Ham" (1960), "Hop on Pop" (1963), and "Fox in Socks" (1965). He initially used word lists of limited vocabularies to create these books, as he had with "The Cat in the Hat", but moved away from the lists as he came to believe "that a child could learn any amount of words if fed them slowly and if the books were amply illustrated". Other authors also contributed notable books to the series, including "A Fly Went By" (1958), "Sam and the Firefly" (1958), "Go, Dog. Go!" (1961), and "The Big Honey Hunt" (1962).


title: The Cat in the Hat

text: The book, or elements of it, has been mentioned multiple times in United States politics. The image of the Cat balancing many objects on his body while in turn balancing himself on a ball has been included in political cartoons and articles. Political caricaturists have portrayed both Bill Clinton and George W. Bush in this way. In 2004, "MAD" magazine published "The Strange Similarities Between the Bush Administration and the World of Dr. Seuss", an article which matched quotes from White House officials to excerpts taken from Dr. Seuss books, and in which George W. Bush's State of the Union promises were contrasted with the Cat vowing (in part), "I can hold up the cup and the milk and the cake! I can hold up these books! And the fish on a rake!" In 2007, during the 110th Congress, Senate Majority Leader Harry Reid compared the impasse over a bill to reform immigration with the mess created by the Cat. He read lines of the book from the Senate floor. He then carried forward his analogy hoping the impasse would be straightened out for "If you go back and read Dr. Seuss, the cat manages to clean up the mess." In 1999, the United States Postal Service issued a stamp featuring the Cat in the Hat.


title: The Cat in the Hat

text: "The Cat in the Hat"s popularity also led to increased popularity and exposure for Geisel's previous children's books. For example, 1940's "Horton Hatches the Egg" had sold 5,801 copies in its opening year and 1,645 the following year. In 1958, the year after the publication of "The Cat in the Hat", 27,643 copies of "Horton" were sold, and by 1960 the book had sold a total of over 200,000 copies.


title: The Cat in the Hat

text: In 2020, "The Cat in the Hat" placed second on the New York Public Library's list of "Top 10 Checkouts of All Time".


title: The Cat in the Hat

text: "The Cat in the Hat" is an animated musical TV special which premiered in 1971 and starred Allan Sherman as the Cat. In 1973, Sherman reprised the role for Dr. Seuss on the Loose, where the Cat host three stories, and it was his last project before his death that same year.


title: The Cat in the Hat

text: The Cat is the host of "The Wubbulous World of Dr. Seuss", an American puppet series that premiered on October 13, 1996 and ended on December 28, 1998. His chaotic and messy personae from the original "Cat in the Hat" book has been noticeably toned down, portraying him as more of an omniscient trickster narrating, and helping other characters in, stories from around Seussville. The character was performed by Bruce Lanoil in the show's first season, with Martin P. Robinson taking over in season 2. Instead of Thing One and Thing Two from the original story, the Cat is usually seen in the company of Little Cats A, B and C from "Comes Back".


title: The Cat in the Hat

text: "The Cat in the Hat Knows a Lot About That!" is a British-Canadian-American animated television series that premiered on August 7, 2010, and ended on October 14, 2018. It was based on the book series "The Cat in the Hat's Learning Library" which reveals the name of the boy who narrated the original book to be Dick. It starred Martin Short as the voice of the Cat. The Cat in this series is portrayed as a genuinely wise, but still adventurous, guide to Sally and Nick (who replaced Sally's brother Dick).


title: The Cat in the Hat

text: In 2003, "The Cat in the Hat", a live-action film adaptation, was released, starring Mike Myers as the Cat. The film grossed $133,960,541 worldwide on an estimated $109 million budget. It was poorly received by critics, and a planned sequel was subsequently cancelled. Due to the film's failure, Audrey Geisel, Seuss' widow, decided not to allow any further live-action adaptations of her husband's work.


title: The Cat in the Hat

text: In 2012, following the financial success of "The Lorax", an animated film adaptation of "The Lorax", Universal Pictures and Illumination Entertainment announced plans to produce a CGI adaptation of "The Cat in the Hat". Rob Lieber was set to write the script, with Chris Meledandri as producer, and Audrey Geisel as the executive producer. However, the project never came to fruition. On January 24, 2018, it was announced that Warner Animation Group was in development of a different musical animated "Cat in the Hat" film as part of a creative partnership with Seuss Enterprises.


title: The Cat in the Hat

text: In 1984, the book was adapted in Russian as a nine-minute cartoon called "" (The Cat in the Cap). The short omits Thing One and Thing Two, along with changing the Cat's hat into a cap; initially an umbrella when it comes in from the rainy street, and making a number of additional transformations throughout the story. Sally's name is not mentioned, neither is her brother Conrad.


title: The Cat in the Hat

text: In 2009, the Royal National Theatre created a stage version of the book, adapted and directed by Katie Mitchell. It has since toured the UK and been revived.


title: The Cat in the Hat

text: "Seussical", a musical adaptation that incorporates aspects of many Dr. Seuss works, features the Cat in the Hat as narrator. The musical received weak reviews when it opened in November 2001 but eventually became a staple in regional and school theaters.


title: The Cat in the Hat

text: A ride at Universal Studios' Islands of Adventure park in Orlando, Florida, has a "Cat in the Hat" theme.


title: The Cat in the Hat

text: On July 26, 2016, Random House and Dr. Seuss Enterprises announced that the Cat in the Hat was running for US president.


title: The Cat in the Hat

text: The "Johnny Test" episode "Sleepover at Johnny's" parodies the book itself. References and parodies included the talking, rhyming fish (which Susan and Mary created), Bling 1 and Bling 2 (obvious rhyming parodies of Thing One and Thing Two), a scene where Bling 1 and Bling 2 fly kites in the living room, and the 12-Handed Cleaner-Upper Flupper-Wupper (a parody of the cleaning machine). Johnny and Dukey thought it all seemed familiar, but forgot the title, although Johnny remarked, "Maybe I saw this in a book".


title: Sachi Parker

text: Stephanie Sachiko Parker (born September 1, 1956) is an American actress who has film and television credits.


title: Sachi Parker

text: Parker was born in Los Angeles, California, the only child of actress Shirley MacLaine and businessman Steve Parker (1922–2001). MacLaine and her husband had an open marriage. At age two, Parker was sent to Japan to live with her father and his mistress. During the summer and at holidays, she visited her mother. They posed together on the cover of the February 9, 1959, issue of "Life". Parker said her parents were negligent and her father was verbally abusive, calling her "the idiot" and forbidding her to read. Parker was frequently left home alone while her father went out. As a teen, she was sent to boarding school in Europe. Parker recalled that one Christmas neither of her parents showed up to pick her up from boarding school when she was 14, stranding her in Europe for weeks. Parker intended to go to college but claims she was cut off financially from her parents at 17.


title: Sachi Parker

text: Parker taught skiing in New Zealand, worked as a waitress in Hawaii, joined Qantas 24 Apr 1979 and spent five years working as a flight attendant for Qantas Airways, and worked for a brief time as an au pair in Paris, France. In 1981, she returned to Los Angeles, and decided to become an actress. Parker claimed her mother did little to help and sabotaged her career.


title: Sachi Parker

text: Parker's work includes television appearances on "", "Equal Justice", and "Alien Nation", and small film roles in "Stick", "About Last Night...", "Peggy Sue Got Married" and "Bad Influence". Parker has also done small local theater. Parker starred in the 2009 Japanese film "The Witch of the West Is Dead", which showed at the Palm Springs International Film Festival.


title: Sachi Parker

text: On February 7, 2013, the Penguin Group published Parker's autobiography, "Lucky Me: My Life With – and Without – My Mom, Shirley MacLaine". Parker opened up about her unconventional childhood and her estranged relationship with her mother. Parker was a lonely child and she still struggles with "abandonment issues and loneliness." Parker said writing the book was therapeutic and though she struggled with guilt, she "decided to stop protecting her." She sent her mother a copy of the book with a note saying, "I love you." MacLaine called the book "virtually all fiction," and added "I'm sorry to see such a dishonest, opportunistic effort from my daughter for whom I've only ever wanted the best."


title: Sachi Parker

text: Parker was married to investment banker Frank Murray from 1993 to 2011, and they lived for a time in Houston, Texas, while Murray was the chairman and CEO of Goodman Holdings and Amana Appliances. Parker and Murray have two children, a son, Frank Murray Jr. (born 1996), and a daughter, Arin Murray (born 1998).


title: Brian d'Arcy James

text: Brian d'Arcy James (born June 29, 1968) is an American actor and musician. He is known primarily for his Broadway roles, including Shrek in "Shrek The Musical", Nick Bottom in "Something Rotten!", King George III in "Hamilton", and the Baker in "Into the Woods", and has received three Tony Award nominations for his work. On-screen, he is known for his recurring role as Andy Baker on the Netflix series "13 Reasons Why", Officer Krupke in "West Side Story", and reporter Matt Caroll in "Spotlight".


title: Brian d'Arcy James

text: James was born in Saginaw, Michigan to a wealthy family, the son of Mary (née Kelly), a seller of children's books, and Thomas F. James (deceased), a lawyer. His maternal grandfather was Harry Kelly, a former Governor of Michigan. His uncle, Brian Kelly, was an actor featured in the series "Flipper" and a producer of the movie "Blade Runner". He has three siblings: brother Andrew, a portfolio manager; sister Kate, an actress and writer; and sister Anne (Noonan), an actress and teacher. James is of seventh eighths Irish and one eighth Welsh descent.


title: Brian d'Arcy James

text: He received a nomination for the Tony Award for Best Featured Actor in a Musical in 2002 for his portrayal of Sidney Falco in "Sweet Smell of Success", co-starring John Lithgow. He received an Obie Award for his performance in Conor McPherson's one-man play "The Good Thief".


title: Brian d'Arcy James

text: James's additional Broadway credits include "Titanic" (Frederick Barrett), Lincoln Center's "Carousel", and "Blood Brothers". His Off-Broadway credits include Andrew Lippa's "The Wild Party" in 2000 opposite Julia Murney and Idina Menzel, for which he received a Drama Desk Award nomination, as well as Adam Guettel's "Floyd Collins" and the Gershwins' "Pardon My English". He appeared in Martin McDonagh's "The Lieutenant of Inishmore" on Broadway, replaced Norbert Leo Butz in "Dirty Rotten Scoundrels", and starred in "The Apple Tree" opposite Kristin Chenoweth. In 2004, James released a Christmas album titled "From Christmas Eve to Christmas Morn". On Broadway he played Bob Wallace, a character originated by Bing Crosby, in "White Christmas" in 2004. He played Dan Goodman in the new musical "Next to Normal" Off-Broadway at Second Stage Theater in 2008. He then starred opposite Daniel Breaker, Sutton Foster, and Christopher Sieber as the titular character in "Shrek The Musical". The show began previews on Broadway November 8, 2008, and opened on December 14 at The Broadway Theatre after a tryout in Seattle. For this role he won the Outer Critics Circle Award for Outstanding Actor in a Musical and the Drama Desk Award for Outstanding Actor in a Musical. He was also nominated for the Tony Award for Best Actor in a Musical for his portrayal. He departed the cast after one year in the role and was replaced by Ben Crawford.


title: Brian d'Arcy James

text: James starred in the Broadway play "Time Stands Still", which began preview performances on January 5, 2010, and officially opened on January 25 at the Samuel J. Friedman Theatre. The show ended its limited run on March 27, 2010. For this role he won the Broadway.com Audience Award for Favorite Featured Actor in a Play. He reprised the role of Dan Goodman in the Broadway company of "Next to Normal" at the Booth Theatre. He replaced J. Robert Spencer on May 17, 2010. James ended his limited engagement on July 18, 2010, and was replaced by Jason Danieley.


title: Brian d'Arcy James

text: On July 19, 2010, James performed in front of President Barack Obama and First Lady Michelle Obama at "A Broadway Celebration: In Performance at the White House", which also aired on PBS October 20, 2010. He returned to "Time Stands Still" when the show returned to Broadway. It closed on January 30, 2011. James was part of the cast of the NBC musical series "Smash". NBC officially picked up "Smash" as a series on May 11, 2011. The program made its series premiere on February 6, 2012. He did not return to the show as a series regular for its second and final season. James starred in Torstein Blixfjord's 2012 short film "Bird In A Box".


title: Brian d'Arcy James

text: He co-hosted the 57th Drama Desk Awards with Brooke Shields on June 3, 2012. He performed at the 29th birthday celebration of The New York Pops, titled "Journey On", celebrating the work of Stephen Flaherty and Lynn Ahrens; he performed "Wheels of a Dream" from "Ragtime".


title: Brian d'Arcy James

text: James starred as Bick in the musical "Giant" which ran at the Public Theater from October 26 to December 16, 2012. For this role James received nominations for the Drama Desk Award for Best Actor in a Musical and for the Drama League Award for Distinguished Performance.


title: Brian d'Arcy James

text: He played Banquo in the Lincoln Center Theater production of "Macbeth", which began previews in October 2013 and officially opened at the Vivian Beaumont Theater in November 2013. He starred as the original King George III in the Off-Broadway production of the musical "Hamilton", with previews starting January 20, 2015, and officially opening on February 17. Actor Jonathan Groff replaced James in the Off-Broadway run on March 3, 2015.


title: Brian d'Arcy James

text: He starred in the Broadway musical "Something Rotten!", which opened in previews at the St. James Theatre on March 23, 2015, and officially on April 22, for which he received his third Tony nomination. James played Matt Carroll in the 2015 film "Spotlight". In March 2016, James was cast in the CBS pilot "Superior Donuts", but his role was recast after the show went through some retooling. He reprised his role as King George III in the Broadway production of "Hamilton" for a limited engagement that began on April 13, 2017, and continued through July 16, 2017.


title: Brian d'Arcy James

text: In 2017, James played Andy Baker in the Netflix drama series "13 Reasons Why", a role he later reprised in the second season of the show in 2018. Also in 2018, James played pilot Joseph A. Walker in Damien Chazelle's film "First Man". In May 2018, it was announced that he would star in the upcoming Fox series "Proven Innocent". The following month, however, it was announced that Kelsey Grammer had been cast to replace James in the role of Gore Bellows (previously Cole Bellows).


title: Brian d'Arcy James

text: James starred in the Broadway play "The Ferryman" at the Bernard B. Jacobs Theatre as Quinn Carney beginning on February 19, 2019, replacing Paddy Considine, who originated the role. In December 2020, it was announced he would appear in the Disney+ miniseries "Hawkeye". In May 2022, it was announced that James would star as the Baker in a Broadway revival of "Into the Woods" at the St. James Theatre. He remained with the show through September 4, 2022. James returned to the production on October 25, 2022. He will play his final performance on January 3, 2023 when Arcelus returns to the show for its final week of performances.


title: Brian d'Arcy James

text: James is married to Jennifer Prescott; the two met when they both performed at Lincoln Center. They have one daughter.


title: Tetrapod

text: Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids (reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct therapsids and all extant mammals).


title: Tetrapod

text: Tetrapods evolved from a clade of primitive semiaquatic animals known as the Tetrapodomorpha which, in turn, evolved from ancient lobe-finned fish (sarcopterygians) around 390 million years ago in the Middle Devonian period; their forms were transitional between lobe-finned fishes and true four-limbed tetrapods. Limbed vertebrates (tetrapods in the broad sense of the word) are first known from Middle Devonian trackways, and body fossils became common near the end of the Late Devonian but these were all aquatic. The first crown-tetrapods (last common ancestors of extant tetrapods capable of terrestrial locomotion) appeared by the very early Carboniferous, 350 million years ago.


title: Tetrapod

text: The specific aquatic ancestors of the tetrapods and the process by which they colonized Earth's land after emerging from water remains unclear. The transition from a body plan for gill-based aquatic respiration and tail-propelled locomotion to one that enables the animal to survive out of water and move around on land is one of the most profound evolutionary changes known. Tetrapods have numerous anatomical and physiological features that are distinct from their aquatic fish ancestors. These include distinct head and neck structures for feeding and movements, appendicular skeletons (shoulder and pelvic girdles in particular) for weight bearing and locomotion, more versatile eyes for seeing, middle ears for hearing, and more efficient heart and lungs for oxygen circulation and exchange outside water.


title: Tetrapod

text: The first tetrapods (stem) or "fishapods" were primarily aquatic. Modern amphibians, which evolved from earlier groups, are generally semiaquatic; the first stages of their lives are as waterborne eggs and fish-like larvae known as tadpoles, and later undergo metamorphosis to grow limbs and become partly terrestrial and partly aquatic. However, most tetrapod species today are amniotes, most of which are terrestrial tetrapods whose branch evolved from earlier tetrapods early in the Late Carboniferous. The key innovation in amniotes over amphibians is the amnion, which enables the eggs to retain their aqueous contents on land, rather than needing to stay in water. (Some amniotes later evolved internal fertilization, although many aquatic species outside the tetrapod tree had evolved such before the tetrapods appeared, e.g. "Materpiscis".)


title: Tetrapod

text: Some tetrapods, such as snakes and caecilians, have lost some or all of their limbs through further speciation and evolution; some have only concealed vestigial bones as a remnant of the limbs of their distant ancestors. Others returned to being amphibious or otherwise living partially or fully aquatic lives, the first during the Carboniferous period, others as recently as the Cenozoic.


title: Tetrapod

text: One group of amniotes diverged into the reptiles, which includes lepidosaurs, dinosaurs (which includes birds), crocodilians, turtles, and extinct relatives; while another group of amniotes diverged into the mammals and their extinct relatives. Amniotes include the tetrapods that further evolved for flight—such as birds from among the dinosaurs, pterosaurs from the archosaurs, and bats from among the mammals.


title: Tetrapod

text: The precise definition of "tetrapod" is a subject of strong debate among paleontologists who work with the earliest members of the group.


title: Tetrapod

text: A majority of paleontologists use the term "tetrapod" to refer to all vertebrates with four limbs and distinct digits (fingers and toes), as well as legless vertebrates with limbed ancestors. Limbs and digits are major apomorphies (newly evolved traits) which define tetrapods, though they are far from the only skeletal or biological innovations inherent to the group. The first vertebrates with limbs and digits evolved in the Devonian, including the Late Devonian-age "Ichthyostega" and "Acanthostega", as well as the trackmakers of the Middle Devonian-age Zachelmie trackways.


title: Tetrapod

text: Defining tetrapods based on one or two apomorphies can present a problem if these apomorphies were acquired by more than one lineage through convergent evolution. To resolve this potential concern, the apomorphy-based definition is often supported by an equivalent cladistic definition. Cladistics is a modern branch of taxonomy which classifies organisms through evolutionary relationships, as reconstructed by phylogenetic analyses. A cladistic definition would define a group based on how closely related its constituents are. Tetrapoda is widely considered a monophyletic clade, a group with all of its component taxa sharing a single common ancestor. In this sense, Tetrapoda can also be defined as the "clade of limbed vertebrates", including all vertebrates descended from the first limbed vertebrates.


title: Tetrapod

text: A portion of tetrapod workers, led by French paleontologist Michel Laurin, prefer to restrict the definition of tetrapod to the crown group. A crown group is a subset of a category of animal defined by the most recent common ancestor of living representatives. This cladistic approach defines "tetrapods" as the nearest common ancestor of all living amphibians (the lissamphibians) and all living amniotes (reptiles, birds, and mammals), along with all of the descendants of that ancestor. In effect, "tetrapod" is a name reserved solely for animals which lie among living tetrapods, so-called crown tetrapods. This is a node-based clade, a group with a common ancestry descended from a single "node" (the node being the nearest common ancestor of living species).


title: Tetrapod

text: Defining tetrapods based on the crown group would exclude many four-limbed vertebrates which would otherwise be defined as tetrapods. Devonian "tetrapods", such as "Ichthyostega" and "Acanthostega", certainly evolved prior to the split between lissamphibians and amniotes, and thus lie outside the crown group. They would instead lie along the stem group, a subset of animals related to, but not within, the crown group. The stem and crown group together are combined into the total group, given the name Tetrapodomorpha, which refers to all animals closer to living tetrapods than to Dipnoi (lungfishes), the next closest group of living animals. Many early tetrapodomorphs are clearly fish in ecology and anatomy, but later tetrapodomorphs are much more similar to tetrapods in many regards, such as the presence of limbs and digits.


title: Tetrapod

text: Laurin's approach to the definition of tetrapods is rooted in the belief that the term has more relevance for neontologists (zoologists specializing in living animals) than paleontologists (who primarily use the apomorphy-based definition). In 1998, he re-established the defunct historical term Stegocephali to replace the apomorphy-based definition of tetrapod used by many authors. Other paleontologists use the term stem-tetrapod to refer to those tetrapod-like vertebrates that are not members of the crown group, including both early limbed "tetrapods" and tetrapodomorph fishes. The term "fishapod" was popularized after the discovery and 2006 publication of "Tiktaalik", an advanced tetrapodomorph fish which was closely related to limbed vertebrates and showed many apparently transitional traits.


title: Tetrapod

text: The two subclades of crown tetrapods are Batrachomorpha and Reptiliomorpha. Batrachomorphs are all animals sharing a more recent common ancestry with living amphibians than with living amniotes (reptiles, birds, and mammals). Reptiliomorphs are all animals sharing a more recent common ancestry with living amniotes than with living amphibians. Gaffney (1979) provided the name Neotetrapoda to the crown group of tetrapods, though few subsequent authors followed this proposal.