All human groups belong to the same species (Homo sapiens) and are mutually fertile. Races arose as a result of mutation, selection, and adaptational changes in human populations. The nature of genetic variation in human beings indicates there has been a common evolution for all races and that racial differentiation occurred relatively late in the history of Homo sapiens. Theories postulating the very early emergence of racial differentiation have been advanced (e.g., C. S. Coon, The Origin of Races, 1962), but they are now scientifically discredited.
To classify humans on the basis of physical traits is difficult, for the coexistence of races through conquests, invasions, migrations, and mass deportations has produced a heterogeneous world population. Nevertheless, by limiting the criteria to such traits as skin pigmentation, color and form of hair, shape of head, stature, and form of nose, most anthropologists historically agreed on the existence of three relatively distinct groups: the Caucasoid, the Mongoloid, and the Negroid.
The Caucasoid, found in Europe, N Africa, and the Middle East to N India, is characterized as pale reddish white to olive brown in skin color, of medium to tall stature, with a long or broad head form. The hair is light blond to dark brown in color, of a fine texture, and straight or wavy. The color of the eyes is light blue to dark brown and the nose bridge is usually high.
The Mongoloid race, including most peoples of E Asia and the indigenous peoples of the Americas, has been described as saffron to yellow or reddish brown in skin color, of medium stature, with a broad head form. The hair is dark, straight, and coarse; body hair is sparse. The eyes are black to dark brown. The epicanthic fold, imparting an almond shape to the eye, is common, and the nose bridge is usually low or medium.
The Negroid race is characterized by brown to brown-black skin, usually a long head form, varying stature, and thick, everted lips. The hair is dark and coarse, usually kinky. The eyes are dark, the nose bridge low, and the nostrils broad. To the Negroid race belong the peoples of Africa south of the Sahara, the Pygmy groups of Indonesia, and the inhabitants of New Guinea and Melanesia.
Each of these broad groups can be divided into subgroups. General agreement is lacking as to the classification of such people as the aborigines of Australia, the Dravidian people of S India, the Polynesians, and the Ainu of N Japan within the traditional three race system. These exceptions highlight the problems associated with attempting to classify humanity into races and also challenge the validity of the notion of race when applied to human beings.
Attempts have been made to classify humans since the 17th cent., when scholars first began to separate types of flora and fauna. Johann Friedrich Blumenbach was the first to divide humanity according to skin color. In the 19th and early 20th cent., people such as Joseph Arthur Gobineau and Houston Stewart Chamberlain, mainly interested in pressing forward the supposed superiority of their own kind of culture or nationality, began to attribute cultural and psychological values to race. This approach, called racism, culminated in the vicious racial doctrines and anti-Semitism of Nazi Germany and was used to justify slavery and segregation (see integration) in the United States, apartheid in the Republic of South Africa, and European imperialism and colonialism generally.
See R. Benedict, Race: Science and Politics (rev. ed. 1943, repr. 1968); C. Lévi-Strauss, Race and History (1962); M. Mead et al., ed., Science and the Concept of Race (1968); S. M. Garn, ed., Readings on Race (2d ed. 1968) and Human Races (3d ed. 1971); J. C. King, The Biology of Race (1971); L. L. Cavalli-Sforza, The Origin and Differentiation of Human Races (1972); S. J. Gould, The Mismeasure of Man (1981); I. F. Haney Lopez, White by Law: The Legal Construction of Race (1996); A. Montagu, Man's Most Dangerous Myth: The Fallacy of Race (6th ed. 1998); G. M. Frederickson, Racism: A Short History (2002).
Sprints are short running races in athletics. They are roughly classified as events in which top runners will not have to "pace themselves", but can run as fast as possible for the entire distance.
Starting blocks are used for all sprint and relay events. The starting blocks consist of two adjustable footplates attached to a rigid frame. Races commence with the firing of the starter's gun. The starting commands are "On your marks" and "Set" or "Get Set". Once all athletes are in the set position, the starter's gun is fired, officially starting the race. For the 100m, all competitors are lined up side-by-side. For the 200m and 400m, which involve curves, runners are staggered for the start.
If a sprinter commences his or her starting motion from the set position before the starter's gun is fired, it is deemed a false start. The first false start of a race results in a warning to the offending runner, but any athlete in that race who thereafter commits a false start will be disqualified.
For all Olympic sprint events, runners must remain within their pre-assigned lanes, which measure 1.22 meters (4 feet) wide, from start to finish. The lanes are numbered 1 through 8, starting with the inside lane. Any athlete who runs outside the assigned lane is subject to disqualification. If the athlete is forced to run outside of his or her lane by another person, and no material advantage is gained, there will be no disqualification. Also, a runner who strays from his or her lane in the straightaway, or crosses the outer line of his or her lane on the bend, and gains no advantage by it, will not be disqualified as long as no other runner is obstructed.
The first athlete whose torso (as distinguished from the head, neck, arms, legs, hands or feet) reaches the vertical plane of the closest edge of the finish line is the winner.