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Conservation status: Least concern (LR/lc)
Fossil range: Pleistocene - Recent
Image of a man and a woman on the Pioneer plaque.
Image of a man and a woman on the Pioneer plaque.
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Hominidae
Genus: Homo
Species: H. sapiens
Subspecies: H. s. sapiens
Trinomial name
Homo sapiens sapiens
Linnaeus, 1758

Humans are the most common anthropoids belonging to the mammalian species Homo sapiens (Latin: "wise man" or "knowing man") under the family Hominidae (the hominids and great apes).[1][2] Humans have a highly developed brain capable of abstract reasoning, language, and introspection. This mental capability, combined with an erect body carriage that frees their upper limbs for manipulating objects, has allowed humans to make far greater use of tools than any other species. Humans originated in Africa, but now inhabit every continent, with a total population of over 6.5 billion as of 2007.

Like most primates, humans are social by nature. However, humans are particularly adept at utilizing systems of communication for self-expression and the exchange of ideas. Humans create complex social structures composed of cooperating and competing groups, ranging in scale from individual families to nations, and social interaction between humans has established a variety of traditions, rituals, ethics, values, social norms, and laws which form the basis of human society. Humans also have a marked appreciation for beauty and aesthetics which, combined with the human desire for self-expression, has led to cultural innovations such as art, literature and music.

Humans are also noted for their desire to understand and influence the world around them, seeking to explain and manipulate natural phenomena through religion, science, philosophy and mythology. This natural curiosity has led to the development of advanced tools and skills; humans are the only known species to build fires, cook their food, clothe themselves, and use numerous other technologies.


Main article: Human biology

Physiology and genetics[]

Main article: Human anatomy
Skeleton diagram

An old diagram of a male human skeleton.

Human body types vary substantially. Although body size is largely determined by genes, it is also significantly influenced by environmental factors such as diet and exercise. The average height of an adult human is about 5 to 6 feet tall, although this varies significantly from place to place.[3][4] Humans are capable of fully bipedal locomotion, thus leaving their arms available for manipulating objects using their hands, aided especially by opposable thumbs. Because human physiology has not fully adapted to bipedalism, the pelvic region and vertebral column tend to become worn, creating locomotion difficulties in old age.

Although humans appear relatively hairless compared to other primates, with notable hair growth occurring chiefly on the top of the head, underarms and pubic area, the average human has more hair on his or her body than the average chimpanzee. The main distinction is that human hairs are shorter, finer, and less heavily pigmented than the average chimpanzee's, thus making them harder to see.[5]

Inuit women 1907

An Inuit woman, circa 1907.

The hue of human hair and skin is determined by the presence of pigments called melanins. Human skin hues can range from very dark brown to very pale pink, while human hair ranges from blond to brown to red to, most commonly, black.[6] Most researchers believe that skin darkening was an adaptation that evolved as a protection against ultraviolet solar radiation, as melanin is an effective sun-block.[7] The skin pigmentation of contemporary humans is geographically stratified, and in general correlates with the level of ultraviolet radiation. Human skin also has a capacity to darken (sun tanning) in response to exposure to ultraviolet radiation.[8][9]

The average sleep requirement is between seven and eight hours a day for an adult and nine to ten hours for a child; elderly people usually sleep for six to seven hours. Experiencing less sleep than this is common in modern societies; this sleep deprivation can lead to negative effects. A sustained restriction of adult sleep to four hours per day has been shown to correlate with changes in physiology and mental state, including fatigue, aggression, and bodily discomfort.

Humans are a eukaryotic species. Each diploid cell has two sets of 23 chromosomes, each set received from one parent. There are 22 pairs of autosomes and one pair of sex chromosomes. By present estimates, humans have approximately 20,000–25,000 genes. Like other mammals, humans have an XY sex-determination system, so that females have the sex chromosomes XX and males have XY. The X chromosome is larger and carries many genes not on the Y chromosome, which means that recessive diseases associated with X-linked genes, such as hemophilia, affect men more often than women.

Life cycle[]

Tubal Pregnancy with embryo

Human embryo at 5 weeks.

The human life cycle is similar to that of other placental mammals. New humans develop viviparously from conception. An egg is usually fertilized inside the female by sperm from the male through sexual intercourse, though the recent technology of in vitro fertilization is occasionally used. The fertilized egg, called a zygote, divides inside the female's uterus to become an embryo, which over a period of thirty-eight weeks (9 months) of gestation becomes a human fetus. After this span of time, the fully-grown fetus is expelled from the female's body and breathes independently as an infant for the first time. At this point, most modern cultures recognize the baby as a person entitled to the full protection of the law, though some jurisdictions extend personhood to human fetuses while they remain in the uterus.

Two young girls at Camp Christmas Seals

Two young human girls.

Compared with that of other species, human childbirth is dangerous. Painful labors lasting twenty-four hours or more are not uncommon, and may result in injury, or even death, to the child or mother. This is because of both the relatively large fetal head circumference (for housing the brain) and the mother's relatively narrow pelvis (a trait required for successful bipedalism), by way of natural selection.[10][11] The chances of a successful labour increased significantly during the 20th century in wealthier countries with the advent of new medical technologies. In contrast, pregnancy and natural childbirth remains a relatively hazardous ordeal in developing regions of the world, with maternal death rates approximately 100 times as common as in developed countries.[12]

File:Old Hmong Man (Sapa Vietnam).jpg

An elderly man.

In developed countries, infants are typically 3–4 kilograms (6–9 pounds) in weight and 50–60 centimeters (20–24 inches) in height at birth.[13] However, low birth weight is common in developing countries, and contributes to the high levels of infant mortality in these regions.[14] Helpless at birth, humans continue to grow for some years, typically reaching sexual maturity at 12 to 15 years of age. Human girls continue to grow physically until around the age of 18, and human boys until around age 21. The human life span can be split into a number of stages: infancy, childhood, adolescence, young adulthood, adulthood and old age. The lengths of these stages, however—particularly the later ones—are not fixed.

There are striking differences in life expectancy around the world. The developed world is quickly getting older, with the median age around 40 years (highest in Monaco at 45.1 years), while in the developing world, the median age is 15–20 years (lowest in Uganda at 14.8 years). Life expectancy at birth in Hong Kong, China is 84.8 years for a female and 78.9 for a male, while in Swaziland, mostly because of AIDS, it is 31.3 years for both sexes.[15] While one in five Europeans is 60 years of age or older, only one in twenty Africans is 60 years of age or older.[16]

The number of centenarians (humans of age 100 years or older) in the world was estimated by the United Nations at 210,000 in 2002.[17] At least one person, Jeanne Calment, is known to have reached the age of 122 years; higher ages have been claimed but they are not well substantiated. Worldwide, there are 81 men aged 60 or older for every 100 women of that age group, and among the oldest, there are 53 men for every 100 women.

The philosophical questions of when human personhood begins and whether it persists after death are the subject of considerable debate. The prospect of death causes unease or fear for most humans. Burial ceremonies are characteristic of human societies, often inspired by beliefs in an afterlife or immortality.

Habitat and population[]

Main article: Human genetic history

Map of early human migrations according to mitochondrial population genetics (The arctic is at the centre of the map and the numbers are millennia before present).

Early human settlements were dependent on proximity to water and, depending on the lifestyle, other natural resources, such as fertile land for growing crops and grazing livestock, or seasonally by hunting populations of prey. However, humans have a great capacity for altering their habitats by various methods, such as through irrigation, urban planning, construction, transport, and manufacturing goods, and with the advent of large-scale trade and transport infrastructure, proximity to these resources has become unnecessary, and in many places these factors are no longer a driving force behind the growth and decline of a population. Nonetheless, the manner in which a habitat is altered is often a major determinant in population change.

Technology has allowed humans to colonize all of the continents and adapt to all climates. Within the last few decades, humans have explored Antarctica, the ocean depths, and space, although long-term habitation of these environments is not yet possible. With a population of over six billion, humans are among the most numerous of the large mammals. Most humans (61%) live in Asia. The vast majority of the remainder live in the Americas (14%), Africa (13%) and Europe (12%), with 0.5% in Oceania. (See list of countries by population and list of countries by population density.)

Human habitation within closed ecological systems in hostile environments, such as Antarctica and outer space, is expensive, typically limited in duration, and restricted to scientific, military, or industrial expeditions. Life in space has been very sporadic, with no more than thirteen humans in space at any given time. Between 1969 and 1972, two humans at a time spent brief intervals on the Moon. As of 2007, no other celestial body has been visited by human beings, although there has been a continuous human presence in outer space since the launch of the initial crew to inhabit the International Space Station on October 31, 2000.

From AD 1800 to 2000, the human population increased from one to six billion. In 2004, around 2.5 billion out of 6.3 billion people (39.7%) lived in urban areas, and this percentage is expected to rise throughout the 21st century. Problems for humans living in cities include various forms of pollution and crime,[18], especially in inner city and suburban slums. Benefits of urban living include increased literacy, access to the global canon of human knowledge and decreased susceptibility to rural famines.

Humans have had a dramatic effect on the environment. It has been hypothesized that in the past, human predation has contributed to the extinction of a number of species; as humans are not generally preyed on themselves, humans have been described as the ultimate superpredators.[19] Currently, through land development and pollution, humans are causing significant climate change, including global warming.[20] This is believed to be a major contributor to the ongoing Holocene extinction event, a mass extinction which, if it continues at its current rate, is predicted to wipe out half of all species over the next century.[21][22]


The human diet is prominently reflected in human culture, and has led to the development of food science. In general, humans can survive for two to eight weeks without food, depending on stored body fat. Survival without water is usually limited to three or four days. Lack of food remains a serious problem, with about 300,000 people starving to death every year.[23] Childhood malnutrition is also common and contributes to the global burden of disease.[24] However global food distribution is not even, and obesity among some human populations has increased to almost epidemic proportions, leading to health complications and increased mortality in some developed, and a few developing countries. The United States Center for Disease Control states that 32% of American adults over the age of 20 are obese, while 66.5% are obese or overweight. Obesity is caused by consuming more calories than are expended, with many attributing excessive weight gain to a combination of overeating and insufficient exercise.

Humans can consume both plant and animal products. Most biologists agree humans are omnivorous.[25]. A minority believes that anatomically, they are primarily frugivorous, many members of which avoid consuming food of animal origin.[26] Early Homo sapiens employed a "hunter-gatherer" methodology as their primary means of food collection, involving combining stationary plant and fungal food sources (such as fruits, grains, tubers, and mushrooms) with wild game which must be hunted and killed in order to be consumed. Some humans choose to be vegans or vegetarians, abstaining from eating meat for religious, ethical, ecological, or health reasons. It is believed that humans have used fire to prepare and cook food prior to eating since the time of their divergence from Homo erectus—possibly even earlier. However, a small number of individuals choose a raw foodist approach, consuming little to no cooked food; the raw diet may be fruitarian, vegetarian, or omnivorous.

At least ten thousand years ago, humans developed agriculture, which has substantially altered the kind of food people eat. This has led to increased populations, the development of cities, and because of increased population density, the wider spread of infectious diseases. The types of food consumed, and the way in which they are prepared, has varied widely by time, location, and culture.

The last century or so has produced enormous improvements in food production, preservation, storage and shipping. Today almost every locale in the world has access to not only its traditional cuisine, but many other world cuisines.

Some scientists have speculated that the reason humans are so successful is due to a dietary change. Somewhere along the historical line humans started cooking their food. While cooking meats has benefits such as killing bacteria, for early man it was a great tenderizer. By cooking meat humans were able to cut down on the time it took to consume said meat. This advantage allowed humans to have free time, or time where they were not focused on survival. With free time early humans had time to think and create. It seems as if cooking meats was the catalyst for humans becoming the dominant species on Earth.


Main article: Human brain
Human brain NIH

The human brain.

The human brain is the center of the central nervous system in humans, as well as the primary control center for the peripheral nervous system. The brain controls "lower", or involuntary, autonomic activities such as heart rate, respiration, and digestion. The brain also controls "higher" order, conscious activities, such as thought, reasoning, and abstraction.[27] These cognitive processes constitute the mind, and, along with their behavioral consequences, are studied in the field of psychology.

The human brain is generally regarded as more capable of these higher order activities, and more "intelligent" in general, than that of any other species. While animals are capable of creating structures and using simple tools—mostly as a result of instinct and learning through mimicry—human technology is vastly more complex, constantly evolving and improving with time. Even the most ancient human tools and structures are far more advanced than any structure or tool created by any animals.[28]

Consciousness and thought[]

Main article: Consciousness

The human ability to think abstractly may be unparalleled in the animal kingdom. Humans are one of only six species to pass the mirror test—which tests whether an animal recognizes its reflection as an image of itself—along with chimpanzees, gorillas and orangutans. In October 2006, three elephants at the Bronx Zoo also passed this test.[29] Humans under the age of 2 typically fail this test.[30] However, this may be a matter of degree rather than a sharp divide. Monkeys have been trained to apply abstract rules in tasks.[31]

The brain perceives the external world through the senses, and each individual human is influenced greatly by his or her experiences, leading to subjective views of existence and the passage of time.

Humans are variously said to possess consciousness, self-awareness, and a mind, which correspond roughly to the mental processes of thought. These are said to possess qualities such as self-awareness, sentience, sapience, and the ability to perceive the relationship between oneself and one's environment. The extent to which the mind constructs or experiences the outer world is a matter of debate, as are the definitions and validity of many of the terms used above. The philosopher of cognitive science Daniel Dennett, for example, argues that there is no such thing as a narrative centre called the "mind", but that instead there is simply a collection of sensory inputs and outputs: different kinds of "software" running in parallel.[32]

Humans study the more physical aspects of the mind and brain, and by extension of the nervous system, in the field of neurology, the more behavioral in the field of psychology, and a sometimes loosely-defined area between in the field of psychiatry, which treats mental illness and behavioral disorders. Psychology does not necessarily refer to the brain or nervous system, and can be framed purely in terms of phenomenological or information processing theories of the mind. Increasingly, however, an understanding of brain functions is being included in psychological theory and practice, particularly in areas such as artificial intelligence, neuropsychology, and cognitive neuroscience.

The nature of thought is central to psychology and related fields. Cognitive psychology studies cognition, the mental processes underlying behavior. It uses information processing as a framework for understanding the mind. Perception, learning, problem solving, memory, attention, language and emotion are all well-researched areas as well. Cognitive psychology is associated with a school of thought known as cognitivism, whose adherents argue for an information processing model of mental function, informed by positivism and experimental psychology. Techniques and models from cognitive psychology are widely applied and form the mainstay of psychological theories in many areas of both research and applied psychology. Largely focusing on the development of the human mind through the life span, developmental psychology seeks to understand how people come to perceive, understand, and act within the world and how these processes change as they age. This may focus on intellectual, cognitive, neural, social, or moral development.

Some philosophers divide consciousness into phenomenal consciousness, which is experience itself, and access consciousness, which is the processing of the things in experience [33] Phenomenal consciousness is the state of being conscious, such as when we say "I am conscious." Access consciousness is being conscious of something in relation to abstract concepts, such as when one says "I am conscious of these words." Various forms of access consciousness include awareness, self-awareness, conscience, stream of consciousness, Husserl's phenomenology, and intentionality. The concept of phenomenal consciousness, in modern history, according to some, is closely related to the concept of qualia.

Social psychology links sociology with psychology in their shared study of the nature and causes of human social interaction, with an emphasis on how people think towards each other and how they relate to each other. The behavior and mental processes, both human and non-human, can be described through animal cognition, ethology, evolutionary psychology, and comparative psychology as well. Human ecology is an academic discipline that investigates how humans and human societies interact with both their natural environment and the human social environment.

Motivation and emotion[]

Main article: Motivation
Goya Tio Paquete

Goya's Tio Paquete (1820).

Motivation is the driving force of desire behind all deliberate actions of human beings. Motivation is based on emotion—specifically, on the search for satisfaction (positive emotional experiences), and the avoidance of conflict; positive and negative are defined by the individual brain state, not by social norms: a person may be driven to self-injury or violence because their brain is conditioned to create a positive response to these actions. Motivation is important because it is involved in the performance of all learned responses.

Within psychology, conflict avoidance and the libido are seen to be primary motivators. Within economics motivation is often seen to be based on financial incentives, moral incentives, or coercive incentives. Religions generally posit divine or demonic influences.

Happiness, or being happy, is a human emotional condition. The definition of happiness is a common philosophical topic. Some people might define it as the best condition which a human can have—a condition of mental and physical health. Others may define it as freedom from want and distress; consciousness of the good order of things; assurance of one's place in the universe or society, inner peace, and so forth.

Human emotion has a significant influence on, or can even be said to control, human behavior, though historically many cultures and philosophers have for various reasons discouraged allowing this influence to go unchecked.

Emotional experiences perceived as pleasant, like love, admiration, or joy, contrast with those perceived as unpleasant, like hate, envy, or sorrow. There is often a distinction seen between refined emotions, which are socially learned, and survival oriented emotions, which are thought to be innate.

Human exploration of emotions as separate from other neurological phenomena is worthy of note, particularly in those cultures where emotion is considered separate from physiological state. In some cultural medical theories, to provide an example, emotion is considered so synonymous with certain forms of physical health that no difference is thought to exist. The Stoics believed excessive emotion was harmful, while some Sufi teachers (in particular, the poet and astronomer Omar Khayyám) felt certain extreme emotions could yield a conceptual perfection, what is often translated as ecstasy.

In modern scientific thought, certain refined emotions are considered to be a complex neural trait of many domesticated and a few non-domesticated mammals, developed commonly in reaction to superior survival mechanisms and intelligent interaction with each other and the environment; as such, refined emotion is not in all cases as discrete and separate from natural neural function as was once assumed. Still, when humans function in civilized tandem, it has been noted that uninhibited acting on extreme emotion can lead to social disorder and crime.

Love and sexuality[]

Main article: Love
Bildhuggarkonst, Kyssen, af Rodin, Nordisk familjebok

Rodin's "The Kiss"

Human sexuality, besides ensuring biological reproduction, has important social functions: it creates physical intimacy, bonds and hierarchies among individuals; may be directed to spiritual transcendence; and in a hedonistic sense to the enjoyment of activity involving sexual gratification. Sexual desire, or libido, is experienced as a bodily urge, often accompanied by strong emotions such as love, ecstasy and jealousy.

As with other human self-descriptions, humans propose that it is high intelligence and complex societies of humans that have produced the most complex sexual behaviors of any animal, including a great many behaviors that are not directly connected with reproduction.

Human sexual choices are usually made in reference to cultural norms, which vary widely. Restrictions are sometimes determined by religious beliefs or social customs.

Many sexologists believe that the majority of Homo sapiens have the inherent capacity to be attracted to both males and females (a kind of universal potential bisexuality). In a variation of this, pioneering researcher Sigmund Freud believed that humans are born polymorphously perverse, which means that any number of objects could be a source of pleasure. According to Freud, humans then pass through five stages of psychosexual development (and can fixate on any stage because of various traumas during the process). For Alfred Kinsey, another influential sex researcher, people can fall anywhere along a continuous scale of sexual orientation (with only small minorities fully heterosexual or homosexual). Recent studies of neurology and genetics suggest people may be born with one sexual orientation or another, so there is not currently a clear consensus among sex researchers.[34] [35]



Main article: Human evolution

Reconstructed skull of Peking Man, a representative of the extinct species believed to be the nearest ancestor of Homo sapiens, Homo erectus.

The scientific study of human evolution encompasses the development of the genus Homo, but usually involves studying other hominids and hominines as well, such as Australopithecus. "Modern humans" are defined as the Homo sapiens species, of which the only extant subspecies is Homo sapiens sapiens; Homo sapiens idaltu (roughly translated as "elder wise man"), the other known subspecies, is extinct.[36] Anatomically modern humans appear in the fossil record in Africa about 200,000 years ago.[37][38]

The closest living relatives of Homo sapiens are the common chimpanzee and the bonobo. Full genome sequencing resulted in the conclusion that "after 6.5 [million] years of separate evolution, the differences between chimpanzee and human are just 10 times greater than those between two unrelated people and 10 times less than those between rats and mice". In fact, 95% of the DNA sequence is identical between chimpanzee and human.[39][40][41] It has been estimated that the human lineage diverged from that of chimpanzees about five million years ago, and from gorillas about eight million years ago. However, a hominid skull discovered in Chad in 2001, classified as Sahelanthropus tchadensis, is approximately seven million years old, which may indicate an earlier divergence.[42]

There are two prominent scientific theories of the origins of contemporary humans. They concern the relationship between modern humans and other hominids. The single-origin, or "out-of-Africa", hypothesis proposes that modern humans evolved in Africa and later migrated outwards to replace hominids in other parts of the world. The multiregional hypothesis, on the other hand, proposes that modern humans evolved, at least in part, from independent hominid populations.[43]

Geneticists Lynn Jorde and Henry Harpending of the University of Utah proposed that the variation in human DNA is minute compared to that of other species, and that during the Late Pleistocene, the human population was reduced to a small number of breeding pairs—no more than 10,000 and possibly as few as 1,000—resulting in a very small residual gene pool. Various reasons for this hypothetical bottleneck have been postulated, the most popular being the Toba catastrophe theory.

Human evolution is characterized by a number of important physiological trends, including the expansion of the brain cavity and brain itself, which is typically 1,400 cm³ in volume, over twice that of a chimpanzee or gorilla. The pattern of human postnatal brain growth differs from that of other apes (heterochrony), allowing for an extended period of social learning and language acquisition in juvenile humans. Physical anthropologists argue that a reorganization of the structure of the brain is more important than cranial expansion itself. Other significant evolutionary changes included a reduction of the canine tooth, development of bipedal locomotion, and the descent of the larynx and hyoid bone, making speech possible. How these trends are related and what their role is in the evolution of complex social organization and culture are matters of ongoing debate.[44][45]

Rise of civilization[]

Main article: History of the world
Farmer plowing

The rise of agriculture led to the foundation of stable human settlements.

The most widely accepted view among current anthropologists is that Homo sapiens originated in the African savanna around 200,000 years ago, descending from Homo erectus, and colonized Eurasia and Oceania by 40,000 years ago, and finally colonized the Americas by 10,000 years ago.[46] They displaced Homo neanderthalensis and other species descended from Homo erectus (which had colonized Eurasia as early as 2 million years ago) through more successful reproduction and competition for resources.

The earliest humans were hunter-gatherers, a lifestyle well-suited to the savanna. They generally lived in small, nomadic groups. Around 10,000 years ago, the advent of agriculture prompted the Neolithic Revolution. Access to a stable food source led to the formation of permanent human settlements, the domestication of animals, and the use of metal tools. Agriculture also encouraged trade and cooperation, leading to complex societies. Villages developed into thriving civilizations in regions such as the Middle East's Fertile Crescent.

Around 6,000 years ago, the first states developed in Mesopotamia, Egypt and the Indus Valley. Military forces were formed for protection, and government bureaucracies for administration. States cooperated and competed for resources, in some cases waging wars. Around 2,000–3,000 years ago, some states, such as Persia, China, and Rome, developed through conquest into the first expansive empires. Influential religions, such as the Abrahamic and Dharmic religions, also rose to prominence at this time.

The late Middle Ages saw the rise of revolutionary ideas and technologies. In China, an advanced and urbanized economy promoted innovations such as printing and the compass, while the Islamic Golden Age saw major scientific advancements in Muslim empires. In Europe, the rediscovery of classical learning and inventions such as the printing press led to the Renaissance in the 14th century. Over the next 500 years, exploration and imperialistic conquest brought much of the Americas, Asia, and Africa under European control, leading to later struggles for independence. The Scientific Revolution in the 17th century and the Industrial Revolution in the 18th–19th centuries promoted major innovations in transport, such as the railway and automobile, energy development, such as coal and electricity, and government, such as democracy and communism.

As a result of such changes, modern humans live in a world that has become increasingly globalized and interconnected. Although this has encouraged the growth of science, art, and technology, it has also led to culture clashes, the development and use of weapons of mass destruction, and increased environmental destruction and pollution.


Human society statistics
World population 6,637,070,000 (August 2006)
Population density 12.7 per km² (4.9 mi²) by total area
43.6 per km² (16.8 mi²) by land area
Largest agglomerations Tokyo, Mexico City, Sao Paulo, Shanghai, New York City, Seoul, Bombay
Major languages by number of native speakers (2000 est.) Mandarin Chinese 14.37 %
Hindi 6.02 %
English 5.61 %
Spanish 5.59 %
Portuguese 4.9 %
Arabic 4.59 %
Largest religions
(2002 est.)
Christianity 32.71 %
Islam 21.67 %
(No religion 14.84 %)
Hinduism 13.28 %
Buddhism 5.84 %
Most widespread currencies United States dollar, Euro, Japanese yen, Pound sterling.
GDP (nominal) $36,356,240 million USD
($5,797 USD per capita)
GDP (PPP) $51,656,251 million IND
($8,236 per capita)
Main article: Culture

Culture is defined here as a set of distinctive material, intellectual, emotional, and spiritual features of a social group, including art, literature, lifestyles, value systems, traditions, rituals, and beliefs. The link between human biology and human behavior and culture is often very close, making it difficult to clearly divide topics into one area or the other; as such, the placement of some subjects may be based primarily on convention.

Culture consists of values, social norms, and artifacts. A culture's values define what it holds to be important or ethical. Closely linked are norms, expectations of how people ought to behave, bound by tradition. Artifacts, or "material culture", are objects derived from the culture's values, norms, and understanding of the world.


Main article: Language

The capacity humans have to transfer concepts, ideas and notions through speech and writing is unrivaled in known species. The faculty of speech is a defining feature of humanity, possibly predating phylogenetic separation of the modern population (see origin of language). Language is central to the communication between humans, as well as being central to the sense of identity that unites nations, cultures and ethnic groups.

The invention of writing systems around 5000 years ago allowed the preservation of language on material objects, and was a major step in cultural evolution. Language is closely tied to ritual and religion (c.f. mantra, sacred text).

The science of linguistics describes the structure of language and the relationship between languages. There are approximately 6,000 different languages currently in use, including sign languages, and many thousands more that are considered extinct.

Art, music and literature[]

Main article: Art
Lorenzo Lippi 001

Allegory of Music (ca. 1594), a painting of a woman writing sheet music by Lorenzo Lippi.

Artistic works have existed for almost as long as humankind, from early pre-historic art to contemporary art. Art is one of the most unusual aspects of human behavior and a key distinguishing feature of humans from other species.

As a form of cultural expression by humans, art may be defined by the pursuit of diversity and the usage of narratives of liberation and exploration (i.e. art history, art criticism, and art theory) to mediate its boundaries. This distinction may be applied to objects or performances, current or historical, and its prestige extends to those who made, found, exhibit, or own them.

In the modern use of the word, art is commonly understood to be the process or result of making material works which, from concept to creation, adhere to the "creative impulse"—that is, art is distinguished from other works by being in large part unprompted by necessity, by biological drive, or by any undisciplined pursuit of recreation.

Music is a natural intuitive phenomenon based on the three distinct and interrelated organization structures of rhythm, harmony, and melody. Listening to music is perhaps the most common and universal form of entertainment for humans, while learning and understanding it are popular disciplines. There are a wide variety of music genres and ethnic musics.

Literature, the body of written—and possibly oral—works, especially creative ones, includes prose, poetry and drama, both fiction and non-fiction. Literature includes such genres as epic, legend, myth, ballad, and folklore.

Spirituality and religion[]

Main article: Spirituality

Sculpture of a man meditating.


The largest religious gathering of humans in history. Around 70 million people from around the world participated in Kumbh Mela at the Hindu holy city of Prayaga, India.

Spirituality, belief or involvement in matters of the soul or spirit, is one of the many different approaches humans take in trying to answer fundamental questions about mankind's place in the universe, the meaning of life, and the ideal way to live one's life. Though these topics have also been addressed by philosophy, and to some extent by science, spirituality is unique in that it focuses on mystical or supernatural concepts such as karma and God. However, critics would argue that spirituality does not actually answer any questions, and complicates the issues further by raising more questions. [47]

A more organized, but related, concept is religion—sometimes used interchangeably with "faith"—which is commonly defined as a belief system concerning the supernatural, sacred, or divine, and the moral codes, practices, values, institutions and rituals associated with such belief. In the course of its development, religion has taken on many forms that vary by culture and individual perspective.

Some of the chief questions and issues religions are concerned with include life after death (commonly involving belief in an afterlife), the origin of life (the source of a variety of origin beliefs), the nature of the universe (religious cosmology) and its ultimate fate (eschatology), and what is moral or immoral. A common source in religions for answers to these questions are transcendent divine beings such as deities or a singular God, although not all religions are theistic—many are nontheistic or ambiguous on the topic, particularly among the Eastern religions.

Although a majority of humans profess some variety of spiritual or religious belief, some are irreligious, lacking or rejecting belief in the supernatural or spiritual. Additionally, although most religions and spiritual beliefs are clearly distinct from science on both a philosophical and methodological level, the two are not generally considered to be mutually exclusive; a majority of humans hold a mix of both scientific and religious views. The distinction between philosophy and religion, on the other hand, is at times less clear, and the two are linked in such fields as the philosophy of religion and theology.

Philosophy and self-reflection[]

Main article: Philosophy
Sanzio 01 Plato Aristotle

Plato and Aristotle in a detail from The School of Athens by Raphael.


The Thinker, Artist's rendering of the sculpture by Auguste Rodin.

Philosophy is a discipline or field of study involving the investigation, analysis, and development of ideas at a general, abstract, or fundamental level. It is the discipline searching for a general understanding of values and reality by chiefly speculative means.

The core philosophical disciplines are logic, ontology or metaphysics, epistemology, and axiology, which includes the branches of ethics and aesthetics. Philosophy covers a very wide range of approaches, and is also used to refer to a worldview, to a perspective on an issue, or to the positions argued for by a particular philosopher or school of philosophy.

Metaphysics is a branch of philosophy concerned with the study of first principles, being and existence (ontology). In between the doctrines of religion and science, stands the philosophical perspective of metaphysical cosmology. This ancient field of study seeks to draw logical conclusions about the nature of the universe, humanity, god, and/or their connections based on the extension of some set of presumed facts borrowed from religion and/or observation.

Humans often consider themselves to be the dominant species on Earth, and the most advanced in intelligence and ability to manage their environment. This belief is especially strong in modern Western culture. Alongside such claims of dominance is often found radical pessimism because of the frailty and brevity of human life.

Humanism is a philosophy which defines a socio-political doctrine the bounds of which are not constrained by those of locally developed cultures, but which seeks to include all of humanity and all issues common to human beings. Because spiritual beliefs of a community often manifests as religious doctrine, the history of which is as factious as it is unitive, secular humanism grew as an answer to the need for a common philosophy that transcended the cultural boundaries of local moral codes and religions. Many humanists are religious, however, and see humanism as simply a mature expression of a common truth present in most religions. Humanists affirm the possibility of an objective truth and accept that human perception of that truth is imperfect. The most basic tenets of humanism are that humans matter and can solve human problems, and that science, freedom of speech, rational thought, democracy, and freedom in the arts are worthy pursuits or goals for all peoples. Humanism depends chiefly on reason and logic without consideration for the supernatural.

Science and technology[]

Main article: Science
Apollo Moonwalk2

In the mid- to late 20th century, humans achieved a level of technological mastery sufficient to leave the atmosphere of Earth for the first time and explore space.

Science is the discovery of knowledge about the world by verifiable means. Technology is the objects humans make to serve their purposes.

Human cultures are both characterized and differentiated by the objects that they make and use. Archaeology attempts to tell the story of past or lost cultures in part by close examination of the artifacts they produced. Early humans left stone tools, pottery and jewelry that are particular to various regions and times.

Improvements in technology are passed from one culture to another. For instance, the cultivation of crops arose in several different locations, but quickly spread to be an almost ubiquitous feature of human life. Similarly, advances in weapons, architecture and metallurgy are quickly disseminated.

Such techniques can be passed on by oral tradition. The development of writing, itself a kind of technology, made it possible to pass information from generation to generation and from region to region with greater accuracy.

Together, these developments made possible the commencement of civilization and urbanization, with their inherently complex social arrangements. Eventually this led to the institutionalization of the development of new technology, and the associated understanding of the way the world functions. This science now forms a central part of human culture.

In recent times, physics and astrophysics have come to play a central role in shaping what is now known as physical cosmology, that is, the understanding of the universe through scientific observation and experiment. This discipline, which focuses on the universe as it exists on the largest scales and at the earliest times, begins by arguing for the big bang, a sort of cosmic expansion from which the universe itself is said to have erupted ~13.7 ± 0.2 billion (109) years ago. After its violent beginnings and until its very end, scientists then propose that the entire history of the universe has been an orderly progression governed by physical laws.

Race and ethnicity[]

Main article: Race

Humans often categorize themselves in terms of race or ethnicity, although the validity of human races as true biological categories is questionable.[48] Genetic studies have demonstrated that humans on the African continent are most genetically diverse (Y-chromosome and MtDNA lineages), consistent with the theory that humans originated in Africa.[49] However, compared to animals, human gene sequences are remarkably homogeneous. The majority of genetic variation occurs within "racial groups", with only 5 to 15% of total variation occurring between racial groups.[50] Human racial categories are based on both ancestry and visible traits, especially skin color and facial features.

Ethnic groups, on the other hand, are more often linked by linguistic, cultural, ancestral, and national or regional ties. Self-identification with an ethnic group is based on kinship and descent. Race and ethnicity can lead to variant treatment and impact social identity, giving rise to racism and the theory of identity politics.


Main article: Society

Society is the system of organizations and institutions arising from interaction between humans.

Government and politics[]

Main article: Government
United Nations HQ - New York City

The United Nations building in New York City, which houses one of the largest human political organizations in the world.

A state is an organized political community occupying a definite territory, having an organized government, and possessing internal and external sovereignty. Recognition of the state's claim to independence by other states, enabling it to enter into international agreements, is often important to the establishment of its statehood. The "state" can also be defined in terms of domestic conditions, specifically, as conceptualized by Max Weber, "a state is a human community that (successfully) claims the monopoly of the 'legitimate' use of physical force within a given territory."[51]

Government can be defined as the political means of creating and enforcing laws; typically via a bureaucratic hierarchy.

Politics is the process by which decisions are made within groups. Although the term is generally applied to behavior within governments, politics is also observed in all human group interactions, including corporate, academic, and religious institutions. Many different political systems exist, as do many different ways of understanding them, and many definitions overlap. The most common form of government worldwide is a republic, however other examples include monarchy, social democracy, military dictatorship and theocracy.

All of these issues have a direct relationship with economics.



The atomic bombings of Hiroshima and Nagasaki effectively ended World War II and immediately killed over 120,000 humans.

Main article: War

War is a state of widespread conflict between states, organizations, or relatively large groups of people, which is characterized by the use of lethal violence between combatants or upon civilians. It is estimated that during the 20th Century between 167 and 188 million humans died as a result of war.[52]

A common perception of war is a series of military campaigns between at least two opposing sides involving a dispute over sovereignty, territory, resources, religion or other issues. A war said to liberate an occupied country is sometimes characterized as a "war of liberation", while a war between internal elements of a state is a civil war.

There have been a wide variety of rapidly advancing tactics throughout the history of war, ranging from conventional war to asymmetric warfare to total war and unconventional warfare. Techniques have nearly always included hand to hand combat, the use of ranged weapons, propaganda, Shock and Awe, and ethnic cleansing. Military intelligence has always played a key role in determining victory and defeat. In modern warfare, soldiers and armoured fighting vehicles are used to control the land, warships the sea, and air power the sky. Outer space has recently become an important factor in warfare as well, although no actual warfare is currently carried out in space. War is a strong catalyst in politics, history and technology. Important inventions such as medicine, navigation, metallurgy, mass production, nuclear power and computers having been completely or partially driven by war.[How to reference and link to summary or text]

Throughout history there has been a constant struggle between defense and offense, armour, and the weapons designed to breach it. Modern examples include the bunker buster bomb, and the bunkers which they are designed to destroy.

Trade and economics[]

Main article: Trade

Buyers bargain for good prices while sellers put forth their best front in Chichicastenango Market, Guatemala.

Trade is the voluntary exchange of goods, services, or both, and a form of economics. A mechanism that allows trade is called a market. The original form of trade was barter, the direct exchange of goods and services. Modern traders instead generally negotiate through a medium of exchange, such as money. As a result, buying can be separated from selling, or earning. The invention of money (and later credit, paper money and non-physical money) greatly simplified and promoted trade.

Trade exists for many reasons. Because of specialization and division of labor, most people concentrate on a small aspect of manufacturing or service, trading their labour for products. Trade exists between regions because different regions have an absolute or comparative advantage in the production of some tradable commodity, or because different regions' size allows for the benefits of mass production. As such, trade between locations benefits both locations.

Economics is a social science that studies the production, distribution, trade and consumption of goods and services.

Economics, which focuses on measurable variables, is broadly divided into two main branches: microeconomics, which deals with individual agents, such as households and businesses, and macroeconomics, which considers the economy as a whole, in which case it considers aggregate supply and demand for money, capital and commodities. Aspects receiving particular attention in economics are resource allocation, production, distribution, trade, and competition. Economic logic is increasingly applied to any problem that involves choice under scarcity or determining economic value. Mainstream economics focuses on how prices reflect supply and demand, and uses equations to predict consequences of decisions.

See also[]

  • List of human time periods


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  1. Goodman M, Tagle D, Fitch D, Bailey W, Czelusniak J, Koop B, Benson P, Slightom J (1990). Primate evolution at the DNA level and a classification of hominoids. J Mol Evol 30 (3): 260–6. PMID 2109087.
  2. Hominidae Classification. Animal Diversity Web @ UMich. URL accessed on 2006-09-25.
  3. de Beer H (2004). Observations on the history of Dutch physical stature from the late-Middle Ages to the present.. Econ Hum Biol 2 (1): 45-55. PMID 15463992.
  4. "Pygmy." Britannica Concise Encyclopedia. Encyclopædia Britannica, Inc., 2006. Accessed 30 Oct. 2006.
  5. Why Humans and Their Fur Parted Way by Nicholas Wade, New York Times, August 19 2003, retrieved March 17, 2006.
  6. Rogers, Alan R., Iltis, David & Wooding, Stephen (2004). Genetic variation at the MC1R locus and the time since loss of human body hair. Current Anthropology 45 (1): 105-108.
  7. Jablonski, N.G. & Chaplin, G. (2000). The evolution of human skin coloration (pdf), 'Journal of Human Evolution 39: 57-106.
  8. Harding, Rosalind M., Eugene Healy, Amanda J. Ray, Nichola S. Ellis, Niamh Flanagan, Carol Todd, Craig Dixon, Antti Sajantila, Ian J. Jackson, Mark A. Birch-Machin, and Jonathan L. Rees (2000). Evidence for variable selective pressures at MC1R. American Journal of Human Genetics 66: 1351–1361.
  9. Robin, Ashley (1991). Biological Perspectives on Human Pigmentation. Cambridge: Cambridge University Press.
  10. LaVelle M (1995). Natural selection and developmental sexual variation in the human pelvis. Am J Phys Anthropol 98 (1): 59-72. PMID 8579191.
  11. Correia H, Balseiro S, De Areia M (2005). Sexual dimorphism in the human pelvis: testing a new hypothesis. Homo 56 (2): 153-60. PMID 16130838.
  12. Rush D (2000). Nutrition and maternal mortality in the developing world.. Am J Clin Nutr 72 (1 Suppl): 212S-240S. PMID 10871588.
  13. Low Birthweight
  14. Khor G (2003). Update on the prevalence of malnutrition among children in Asia.. Nepal Med Coll J 5 (2): 113-22. PMID 15024783.
  15. "Human Development Report 2006," United Nations Development Programme, pp. 363-366, November 9 2006
  16. The World Factbook, U.S. Central Intelligence Agency, retrieved April 2, 2005.
  17. U.N. Statistics on Population Ageing, United Nations press release, February 28, 2002, retrieved April 2, 2005
  18. Urban, Suburban, and Rural Victimization, 1993-98 U.S. Department of Justice, Bureau of Justice Statistics,. Accessed 29 Oct 2006
  19. Scientific American (1998). Evolution and General Intelligence: Three hypotheses on the evolution of general intelligence.
  21. American Association for the Advancement of Science. Foreword. AAAS Atlas of Population & Environment.
  22. Wilson, E.O. (2002). in The Future of Life.
  23. Death and DALY estimates for 2002 by cause for WHO Member States World Health Organisation. Accessed 29 Oct 2006
  24. Murray C, Lopez A (1997). Global mortality, disability, and the contribution of risk factors: Global Burden of Disease Study.. Lancet 349 (9063): 1436-42. PMID 9164317.
  25. Vegetarianism in a Nutshell - Humans are Omnivores - retrieved July 20 2006
  26. Comparison of human anatomy with herbivore anatomy by biologist John Cole - retrieved July 20 2006
  27. 3-D Brain Anatomy, The Secret Life of the Brain, Public Broadcasting Service, retrieved April 3 2005.
  28. Sagan, Carl (1978). The Dragons of Eden. A Balantine Book. ISBN 0-345-34629-7.
  29. Self-recognition in an Asian elephant.. Proc Natl Acad Sci U S A. PMID 17075063.
  30. Consciousness and the Symbolic Universe, by Dr. Jack Palmer, retrieved March 17, 2006.
  31. Researchers home in on how brain handles abstract thought - retrieved July 29, 2006
  32. Dennett, Daniel (1991). Consciousness Explained. Little Brown & Co, 1991, ISBN 0-316-18065-3.
  33. Ned Block: On a Confusion about a Function of Consciousness" in: The Behavioral and Brain Sciences, 1995.
  34. Buss, David M. (2004) "The Evolution of Desire: Strategies of Human Mating". Revised Edition. New York: Basic Books"
  35. Thornhill, R., & Palmer, C. T. (2000). A Natural History of Rape. Biological Bases of Sexual Coercion. Cambridge: MIT Press.
  36. Human evolution: the fossil evidence in 3D, by Philip L. Walker and Edward H. Hagen, Dept of Anthropology, University of California, Santa Barbara, retrieved April 5, 2005.
  37. Human Ancestors Hall: Homo Sapiens - URL retrieved October 13, 2006
  38. Alemseged Z, Coppens Y, Geraads D (2002). Hominid cranium from Omo: Description and taxonomy of Omo-323-1976-896. Am J Phys Anthropol 117 (2): 103-12. PMID 11815945.
  39. Britten RJ (2002). Divergence between samples of chimpanzee and human DNA sequences is 5%, counting indels. Proc Natl Acad Sci U S A 99 (21): 13633-5. PMID 12368483.
  40. Wildman D, Uddin M, Liu G, Grossman L, Goodman M (2003). Implications of natural selection in shaping 99.4% nonsynonymous DNA identity between humans and chimpanzees: enlarging genus Homo.. Proc Natl Acad Sci U S A 100 (12): 7181-8. PMID 12766228.
  41. Ruvolo M (1997). Molecular phylogeny of the hominoids: inferences from multiple independent DNA sequence data sets.. Mol Biol Evol 14 (3): 248-65. PMID 9066793.
  42. Brunet M, Guy F, Pilbeam D, Mackaye H, Likius A, Ahounta D, Beauvilain A, Blondel C, Bocherens H, Boisserie J, De Bonis L, Coppens Y, Dejax J, Denys C, Duringer P, Eisenmann V, Fanone G, Fronty P, Geraads D, Lehmann T, Lihoreau F, Louchart A, Mahamat A, Merceron G, Mouchelin G, Otero O, Pelaez Campomanes P, Ponce De Leon M, Rage J, Sapanet M, Schuster M, Sudre J, Tassy P, Valentin X, Vignaud P, Viriot L, Zazzo A, Zollikofer C (2002). A new hominid from the Upper Miocene of Chad, Central Africa.. Nature 418 (6894): 145-51. PMID 12110880.
  43. Eswaran, Vinayak, Harpending, Henry & Rogers, Alan R. Genomics refutes an exclusively African origin of humans, Journal of Human Evolution, In Press, Corrected Proof, retrieved May 6, 2005.
  44. Boyd, Robert & Silk, Joan B. (2003). How Humans Evolved. New York: Norton & Company. ISBN 0-393-97854-0.
  45. Dobzhansky, Theodosius (1963). Anthropology and the natural sciences-The problem of human evolution, Current Anthropology 4 (2): 138-148.
  46. Templeton, Alan (2002). "Out of Africa again and again" Nature 416: 45 - 51.
  47. The God Delusion by Richard Dawkins, 0593055489, Bantam Press, 2 Oct 2006, .
  48. Royal C, Dunston G (2004). Changing the paradigm from 'race' to human genome variation.. Nat Genet 36 (11 Suppl): S5-7. PMID 15508004.
  49. Jorde L, Watkins W, Bamshad M, Dixon M, Ricker C, Seielstad M, Batzer M (2000). The distribution of human genetic diversity: a comparison of mitochondrial, autosomal, and Y-chromosome data.. Am J Hum Genet 66 (3): 979-88. PMID 10712212.
  50. (2005)The use of racial, ethnic, and ancestral categories in human genetics research.. Am J Hum Genet 77 (4): 519-32. PMID 16175499.
  51. Max Weber's definition of the modern state 1918, by Max Weber, 1918, retrieved March 17, 2006.
  52. Ferguson, Niall. "The Next War of the World." Foreign Affairs, Sep/Oct 2006

External links[]

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