Humans ( Homo sapiens) are the most abundant and widespread species of primate. They are a type of great ape who are characterized by bipedality and exceptional cognitive skills due to a large and complex Human brain. Humans are Sociality and tend to live in complex composed of many cooperating and competing groups, from family and kinship networks to political states. As such, social interactions between humans have established a wide variety of values, social norms, language, and , each of which bolster human society. The desire to understand and influence Phenomenon have motivated humanity's development of science, technology, philosophy, mythology, religion, and other fields of study.
Although some scientists equate the term humans with all members of the genus Homo, in common usage, it generally refers to Homo sapiens, the only Extant taxon member. Anatomically modern humans emerged around 300,000 years ago in Africa, evolving from Homo heidelbergensis or a similar species and migrating out of Africa, gradually replacing or interbreeding with local populations of archaic humans. For most of history, humans were nomadic hunter-gatherers. Humans began exhibiting behavioral modernity about 160,000–60,000 years ago. The Neolithic Revolution, which began in Southwest Asia around 13,000 years ago (and separately in a few other places), saw the emergence of agriculture and permanent human settlement. As populations became larger and denser, forms of governance developed within and between communities, and a number of have risen and fallen. Humans have continued to expand, with a global population of over 8 billion .
and the environment influence human biological variation in visible characteristics, physiology, disease susceptibility, mental abilities, body size, and life span. Though humans vary in many traits (such as genetic predispositions and physical features), any two humans are at least 99% genetically similar. Humans are sexually dimorphic: generally, males have greater body strength and females have a higher body fat percentage. At puberty, humans develop secondary sex characteristics. Females are capable of pregnancy, usually between puberty, at around 12 years, and menopause, around the age of 50.
Humans are omnivorous, capable of consuming a wide variety of plant and animal material, and have used fire and other forms of heat to prepare and cooking food since the time of H. erectus. Humans can survive for up to eight weeks without food and three or four days without water. Humans are generally Diurnality, sleeping on average seven to nine hours per day. Childbirth is dangerous, with a high risk of complications and death. Often, both the mother and the father provide care for their children, who are helpless at birth, as humans are an Altricial.
Humans have a large, highly developed and complex prefrontal cortex, the region of the brain associated with higher cognition. They are highly intelligent, capable of episodic memory, have flexible facial expressions, self-awareness, and a theory of mind. The human mind is capable of introspection, private thought, imagination, volition, and forming views on existence. This has allowed great technological advancements and complex tool development possible through complex reasoning and the transmission of knowledge to subsequent generations. Language, art, and trade are defining characteristics of humans. Long-distance trade routes might have led to cultural explosions and resource distribution that gave humans an advantage over other similar species.
Etymology and definition
All modern humans are classified into the species Homo sapiens
, coined by Carl Linnaeus
in his 1735 work Systema Naturae
The generic name " Homo
" is a learned 18th-century derivation from Latin homō, which refers to humans of either sex.
The word human
can refer to all members of the Homo
although in common usage it generally just refers to Homo sapiens,
the only extant species.
The name " Homo sapiens
" means 'wise man' or 'knowledgeable man'.
There is disagreement if certain extinct members of the genus, namely
, should be included as a separate species of humans or as a subspecies
of H. sapiens
Human is a loanword of Middle English from Old French humain, ultimately from Latin hūmānus, the adjectival form of homō ('man' — in the sense of humankind).
The native English term man can refer to the species generally (a synonym for humanity) as well as to human males. It may also refer to individuals of either sex, though this form is less common in contemporary English.
Despite the fact that the word animal is colloquially used as an antonym for human,
and contrary to a common biological misconception, humans are animals. The word person is often used interchangeably with human, but philosophical debate exists as to whether personhood applies to all humans or all , and further if one can lose personhood (such as by going into a persistent vegetative state).
Humans are apes (Hominoidea
The lineage of apes that eventually gave rise to humans first split from gibbons (family Hylobatidae
), and finally,
). The last split, between the human and chimpanzee–bonobo lineages, took place around 8–4 million years ago, in the late Miocene
During this split, chromosome 2 was formed from the joining of two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes.
Following their split with chimpanzees and bonobos, the Hominini
diversified into many species and at least two distinct genera. All but one of these lineages—representing the genus Homo
and its sole extant species Homo sapiens
—are now extinct.
The genus Homo evolved from Australopithecus.
Though Human fossils from the transition are scarce, the earliest members of Homo share several key traits with Australopithecus. The earliest record of Homo is the 2.8 million-year-old specimen LD 350-1 from Ethiopia, and the earliest named species are Homo habilis and Homo rudolfensis which evolved by 2.3 million years ago. Homo erectus (the African variant is sometimes called Homo ergaster) evolved 2 million years ago and was the first archaic human species to leave Africa and disperse across Eurasia. H. erectus also was the first to evolve a characteristically human body plan. Homo sapiens emerged in Africa around 300,000 years ago from a species commonly designated as either H. heidelbergensis or H. rhodesiensis, the descendants of H. erectus that remained in Africa. H. sapiens migrated out of the continent, gradually replacing or interbreeding with local populations of archaic humans. Humans began exhibiting behavioral modernity about 160,000-70,000 years ago, and possibly earlier.
The "out of Africa" migration took place in at least two waves, the first around 130,000 to 100,000 years ago, the second (Southern Dispersal) around 70,000 to 50,000 years ago.
H. sapiens proceeded to colonize all the continents and larger islands, arriving in Eurasia 125,000 years ago, Australia around 65,000 years ago, the Americas around 15,000 years ago, and remote islands such as Hawaiian Islands, Easter Island, Madagascar, and New Zealand between the years 300 and 1280 CE.
Human evolution was not a simple linear or branched progression but involved interbreeding between related species.
Genomic research has shown that hybridization between substantially diverged lineages was common in human evolution. DNA evidence suggests that several genes of Neanderthal origin are present among all non sub-Saharan African populations, and Neanderthals and other hominins, such as , may have contributed up to 6% of their genome to present-day non sub-Saharan African humans.
Human evolution is characterized by a number of morphological, developmental, human physiology, and Human behavior changes that have taken place since the split between the last common ancestor of humans and chimpanzees. The most significant of these adaptations are obligate bipedalism, increased brain size and decreased sexual dimorphism (neoteny). The relationship between all these changes is the subject of ongoing debate.
Until about 12,000 years ago, all humans lived as
The Neolithic Revolution (the invention of agriculture
) first took place in Southwest Asia
and spread through large parts of the Old World
over the following millennia.
It also occurred independently in Mesoamerica
(about 6,000 years ago),
Papua New Guinea,
and the Sahel
and Sudanian savanna
regions of Africa.
Access to food surplus led to the formation of permanent
, the domestication
of animals and the Chalcolithic
for the first time in history. Agriculture and sedentary lifestyle led to the emergence of early civilizations
An urban revolution took place in the 4th millennium BCE with the development of , particularly cities located in Mesopotamia.
It was in these cities that the earliest known form of writing, cuneiform script, appeared around 3000 BCE. Other major civilizations to develop around this time were Ancient Egypt and the Indus Valley Civilization. They eventually traded with each other and invented technology such as wheels, plows and sails. Astronomy and mathematics were also developed and the Great Pyramid of Giza was built. There is evidence of a severe drought lasting about a hundred years that may have caused the decline of these civilizations, with new ones appearing in the aftermath. came to dominate Mesopotamia while others, such as Poverty Point cultures, Minoans and the Shang dynasty, rose to prominence in new areas. The Bronze Age suddenly collapsed around 1200 BCE, resulting in the disappearance of a number of civilizations and the beginning of the Greek Dark Ages. During this period iron started replacing bronze, leading to the Iron Age.
In the 5th century BCE, history started being Historiography, which provided a much clearer picture of life at the time.
Between the 8th and 6th century BCE, Europe entered the classical antiquity age, a period when ancient Greece and ancient Rome flourished. Around this time other civilizations also came to prominence. The Maya civilization started to build cities and create Maya calendar. In Africa, the Kingdom of Aksum overtook the declining Kingdom of Kush and facilitated trade between India and the Mediterranean. In West Asia, the Achaemenid Empire's system of centralized governance became the precursor to many later empires, while the Gupta Empire in India and the Han dynasty in China have been described as golden ages in their respective regions.
Following the fall of the Western Roman Empire in 476, Europe entered the Middle Ages.
During this period, Christianity and the Catholic Church would provide centralized authority and education. In the Middle East, Islam became the prominent religion and expanded into North Africa. It led to an Islamic Golden Age, inspiring achievements in architecture, the revival of old advances in science and technology, and the formation of a distinct way of life. The Christendom and would eventually clash, with the Kingdom of England, the Kingdom of France and the Holy Roman Empire declaring a series of crusades to regain control of the Holy Land from . In the Americas, complex Mississippian societies would arise starting around 800 CE, while further south, the Aztecs and Incas would become the dominant powers. The Mongol Empire would conquer much of Eurasia in the 13th and 14th centuries. Over this same time period, the Mali Empire in Africa grew to be the largest empire on the continent, stretching from Senegambia to Ivory Coast. Oceania would see the rise of the Tuʻi Tonga Empire which expanded across many islands in the South Pacific.
The early modern period in Europe and the Near East (c.1450–1800) began with the final defeat of the Byzantine Empire, and the Ottoman Empire.
Meanwhile, Japan entered the Edo period, the Qing dynasty rose in China and the Mughal Empire ruled much of India. Europe underwent the Renaissance, starting in the 15th century, and the Age of Discovery began with the exploring and Colonialism of new regions. This includes the British Empire expanding to become the Largest empire and the colonization of the Americas. This expansion led to the Atlantic slave trade and the genocide of Native American peoples. This period also marked the Scientific Revolution, with great advances in mathematics, mechanics, astronomy and physiology.
The late modern period (1800–present) saw the Technological and Industrial Revolution bring such discoveries as imaging technology, major innovations in transport and energy development.
The United States underwent great change, going from a small group of colonies to one of the global superpowers. The Napoleonic Wars raged through Europe in the early 1800s, Spain lost most of its colonies in the New World, while Europeans continued expansion into Africa—where European control went from 10% to almost 90% in less than 50 years —and Oceania. A tenuous balance of power among European nations collapsed in 1914 with the outbreak of the First World War, one of the deadliest conflicts in history. In the 1930s, Great Depression led to the rise of authoritarian regimes and a Second World War, involving almost all of the world's countries. Following its conclusion in 1945, the Cold War between the USSR and the United States saw a struggle for global influence, including a nuclear arms race and a Space Race. The current Information Age sees the world becoming increasingly Globalization and interconnected.
Habitat and population
Early human settlements were dependent on proximity to water resources
and—depending on the lifestyle—other
used for subsistence
, such as populations of animal prey for hunting
and arable land
for growing crops and grazing livestock.
Modern humans, however, have a great capacity for altering their habitats by means of technology, irrigation
, urban planning
, construction, deforestation
Human settlements continue to be vulnerability
to natural disasters, especially those placed in hazardous locations and with low quality of construction.
Grouping and deliberate habitat alteration is often done with the goals of providing protection, accumulating comforts or material wealth, expanding the available food, improving aesthetics
, increasing knowledge or enhancing the exchange of resources.
Humans are one of the most Adaptation species, despite having a low or narrow tolerance for many of the earth's extreme environments.
Through advanced tools, humans have been able to extend their tolerance to a wide variety of temperatures, humidity, and altitudes. As a result, humans are a cosmopolitan species found in almost all regions of the world, including tropical rainforest, desert, extremely cold , and heavily polluted cities; in comparison, most other species are confined to a few geographical areas by their limited adaptability. The human population is not, however, uniformly distributed on the Earth's surface, because the population density varies from one region to another, and large stretches of surface are almost completely uninhabited, like Antarctica and vast swathes of the ocean. Most humans (61%) live in Asia; the remainder live in the Americas (14%), Africa (14%), Europe (11%), and Oceania (0.5%).
Within the last century, humans have explored challenging environments such as Antarctica, the deep sea, and outer space.
Human habitation within these hostile environments is restrictive and expensive, typically limited in duration, and restricted to Science, military, or industrial expeditions. Humans have briefly visited the Moon and made their presence felt on other celestial bodies through human-made robotic spacecraft. Since the early 20th century, there has been continuous human presence in Antarctica through research stations and, since 2000, in space through habitation on the International Space Station.
Estimates of the population at the time agriculture emerged in around 10,000 BC have ranged between 1 million and 15 million.
Around 50–60 million people lived in the combined eastern and western Roman Empire in the 4th century AD. , first recorded in the 6th century AD, reduced the population by 50%, with the Black Death killing 75–200 million people in Eurasia and North Africa alone. Human population was believed to have reached one billion in 1800. It has since then increased exponentially, reaching two billion in 1930 and three billion in 1960, four in 1975, five in 1987 and six billion in 1999. It passed seven billion in 2011 and passed eight billion in November 2022. It took over two million years of prehistory and human history for the human population to reach one billion and only 207 years more to grow to 7 billion. The combined biomass of the carbon of all the humans on Earth in 2018 was estimated at 60 million tons, about 10 times larger than that of all non-domesticated mammals.
In 2018, 4.2 billion humans (55%) lived in urban areas, up from 751 million in 1950.
The most urbanized regions are Northern America (82%), Latin America (81%), Europe (74%) and Oceania (68%), with Africa and Asia having nearly 90% of the world's 3.4 billion rural population. Problems for humans living in cities include various forms of pollution and crime, especially in inner city and suburban . Humans have had a dramatic effect on the environment. They are , being rarely preyed upon by other species. Human population growth, industrialization, land development, overconsumption and combustion of fossil fuels have led to environmental destruction and pollution that significantly contributes to the ongoing mass extinction of other forms of life. [
] They are the main contributor to global climate change, which may accelerate the Holocene extinction.
Anatomy and physiology
Most aspects of human physiology are closely homologous to corresponding aspects of animal physiology. The human body consists of the legs
, the torso
, the arms, the neck
, and the head. An adult human body consists of about 100 trillion (1014
) cells. The most commonly defined body systems
in humans are the nervous, the cardiovascular, the digestive, the Endocrine system
, the immune, the integumentary, the Lymphatic system
, the musculoskeletal, the reproductive, the respiratory, and the urinary system
The dental formula
of humans is: . Humans have proportionately shorter
and much smaller Human tooth
than other primates. They are the only primates to have short, relatively flush canine teeth
. Humans have characteristically crowded teeth, with gaps from lost teeth usually closing up quickly in young individuals. Humans are gradually losing their wisdom teeth
, with some individuals having them congenitally absent.
Humans share with chimpanzees a Vestigiality tail, appendix, flexible shoulder joints, grasping fingers and .
Apart from bipedalism and brain size, humans differ from chimpanzees mostly in smelling, hearing and digesting proteins. While humans have a density of comparable to other apes, it is predominantly vellus hair, most of which is so short and wispy as to be practically invisible. Humans have about 2 million spread over their entire bodies, many more than chimpanzees, whose sweat glands are scarce and are mainly located on the palm of the hand and on the soles of the feet.
It is estimated that the worldwide average Human height male is about , while the worldwide average height for adult human females is about .
Shrinkage of stature may begin in middle age in some individuals but tends to be typical in the extremely Old age. Throughout history, human populations have universally become taller, probably as a consequence of better nutrition, healthcare, and living conditions. The average Body weight of an adult human is for females and for males. Like many other conditions, body weight and body type are influenced by both genetic susceptibility and environment and varies greatly among individuals.
Humans have a far faster and more accurate throw than other animals.
Humans are also among the best long-distance runners in the animal kingdom, but slower over short distances. Humans' thinner body hair and more productive sweat glands help avoid heat exhaustion while running for long distances.
Like most animals, humans are a ploidy
species. Each somatic cell
has two sets of 23
, each set received from one parent;
have only one set of chromosomes, which is a mixture of the two parental sets. Among the 23 pairs of chromosomes, there are 22 pairs of
and one pair of sex chromosomes. Like other mammals, humans have an XY sex-determination system, so that females have the sex chromosomes XX and males have XY.
and environment influence human biological variation in visible characteristics, physiology, disease susceptibility and mental abilities. The exact influence of genes and environment on certain traits is not well understood.
While no humans—not even monozygotic twins—are genetically identical,
two humans on average will have a genetic similarity of 99.5%-99.9%. This makes them more homogeneous than other great apes, including chimpanzees. This small variation in human DNA compared to many other species suggests a population bottleneck during the Late Pleistocene (around 100,000 years ago), in which the human population was reduced to a small number of breeding pairs. The forces of natural selection have continued to operate on human populations, with evidence that certain regions of the genome display directional selection in the past 15,000 years.
The human genome was first sequenced in 2001
and by 2020 hundreds of thousands of genomes had been sequenced. In 2012 the International HapMap Project had compared the genomes of 1,184 individuals from 11 populations and identified 1.6 million single nucleotide polymorphisms. African populations harbor the highest number of private genetic variants. While many of the common variants found in populations outside of Africa are also found on the African continent, there are still large numbers that are private to these regions, especially Oceania and the Americas. By 2010 estimates, humans have approximately 22,000 genes. By comparing mtDNA, which is inherited only from the mother, geneticists have concluded that the last female common ancestor whose genetic marker is found in all modern humans, the so-called mitochondrial Eve, must have lived around 90,000 to 200,000 years ago.
Most human reproduction takes place by internal fertilization via sexual intercourse, but can also occur through assisted reproductive technology procedures.
The average gestation
period is 38 weeks, but a normal pregnancy can vary by up to 37 days.
Embryonic development in the human covers the first eight weeks of development; at the beginning of the ninth week the embryo is termed a fetus
Humans are able to Labor induction
or perform a caesarean section if the child needs to be born earlier for medical reasons.
In developed countries,
are typically in weight and in height at birth.
However, low birth weight is common in developing countries, and contributes to the high levels of infant mortality
in these regions.
Compared with other species, human childbirth is dangerous, with a much higher risk of complications and death.
The size of the fetus's head is more closely matched to the pelvis than other primates. The reason for this is not completely understood, but it contributes to a painful labor that can last 24 hours or more. The chances of a successful labor increased significantly during the 20th century in wealthier countries with the advent of new medical technologies. In contrast, pregnancy and natural childbirth remain hazardous ordeals in developing regions of the world, with maternal death rates approximately 100 times greater than in developed countries.
Both the mother and the father provide care for human offspring, in contrast to other primates, where parental care is mostly done by the mother.
Altricial, humans continue to grow for some years, typically reaching sexual maturity at 15 to 17 years of age. The human life span has been split into various stages ranging from three to twelve. Common stages include Infant, childhood, adolescence, and old age. The lengths of these stages have varied across cultures and time periods but is typified by an unusually rapid growth spurt during adolescence. Human females undergo menopause and become Infertility at around the age of 50. It has been proposed that menopause increases a woman's overall reproductive success by allowing her to invest more time and resources in her existing offspring, and in turn their children (the grandmother hypothesis), rather than by continuing to bear children into old age.
The life span of an individual depends on two major factors, genetics and lifestyle choices.
For various reasons, including biological/genetic causes, women live on average about four years longer than men. , the global average life expectancy at birth of a girl is estimated to be 74.9 years compared to 70.4 for a boy. There are significant geographical variations in human life expectancy, mostly correlated with economic development—for example, life expectancy at birth in Hong Kong is 87.6 years for girls and 81.8 for boys, while in the Central African Republic, it is 55.0 years for girls and 50.6 for boys. The developed world is generally aging, with the median age around 40 years. In the third world, the median age is between 15 and 20 years. While one in five Europeans is 60 years of age or older, only one in twenty Africans is 60 years of age or older. In 2012, the United Nations estimated that there were 316,600 living centenarians (humans of age 100 or older) worldwide.
, preparing a meal]]Humans are omnivorous
, capable of consuming a wide variety of plant and animal material.
Human groups have adopted a range of diets from purely vegan
to primarily carnivorous
. In some cases, dietary restrictions in humans can lead to deficiency diseases; however, stable human groups have adapted to many dietary patterns through both genetic specialization and cultural conventions to use nutritionally balanced food sources.
The human diet is prominently reflected in human culture and has led to the development of food science
Until the development of agriculture approximately 10,000 years ago, Homo sapiens employed a hunter-gatherer method as their sole means of food collection.
This involved combining stationary food sources (such as fruits, grains, tubers, and mushrooms, insect larvae and aquatic mollusks) with wild game, which must be hunted and captured in order to be consumed. It has been proposed that humans have used fire to prepare and cooking food since the time of Homo erectus. Around ten thousand years ago, humans developed agriculture, which substantially altered their diet. This change in diet may also have altered human biology; with the spread of dairy farming providing a new and rich source of food, leading to the evolution of the ability to digest lactose in some adults. The types of food consumed, and how they are prepared, have varied widely by time, location, and culture.
In general, humans can survive for up to eight weeks without food, depending on stored body fat.
Survival without water is usually limited to three or four days, with a maximum of one week. In 2020 it is estimated 9 million humans die every year from causes directly or indirectly related to starvation. Childhood malnutrition is also common and contributes to the Disease burden. However, global food distribution is not even, and obesity among some human populations has increased rapidly, leading to health complications and increased mortality in some developed and a few developing countries. Worldwide, over one billion people are obese, while in the United States 35% of people are obese, leading to this being described as an "obesity epidemic." Obesity is caused by consuming more than are expended, so excessive weight gain is usually caused by an energy-dense diet.
There is biological variation in the human species—with traits such as blood type
, genetic diseases
, Human skull
, Human face
, organ systems
, eye color
, hair color
and hair texture
, Human height
and Body shape
, and skin color varying across the globe. The typical height of an adult human is between , although this varies significantly depending on sex, ethnic origin
, and family bloodlines.
Body size is partly determined by genes and is also significantly influenced by environmental factors such as diet, exercise, and
There is evidence that populations have adapted genetically to various external factors. The genes that allow adult humans to digest lactose are present in high frequencies in populations that have long histories of cattle domestication and are more dependent on cow milk.
Sickle cell anemia, which may provide increased resistance to malaria, is frequent in populations where malaria is endemic. Populations that have for a very long time inhabited specific climates tend to have developed specific that are beneficial for those environments—short stature and stocky build in cold regions, tall and lanky in hot regions, and with high lung capacities or other adaptations at high altitudes. Some populations have evolved highly unique adaptations to very specific environmental conditions, such as those advantageous to ocean-dwelling lifestyles and freediving in the Bajau.
Human hair ranges in color from Red hair to blond to Brown hair to Black hair, which is the most frequent.
Hair color depends on the amount of melanin, with concentrations fading with increased age, leading to Grey hair or even white hair. Skin color can range from Dark skin to Light skin, or even nearly white or colorless in cases of albinism. It tends to vary Clinal variation and generally correlates with the level of ultraviolet radiation in a particular geographic area, with darker skin mostly around the equator. Skin darkening may have evolved as protection against ultraviolet solar radiation. Light skin pigmentation protects against depletion of vitamin D, which requires sunlight to make. Human skin also has a capacity to darken (tan) in response to exposure to ultraviolet radiation. , a Nubians, a Syrian people, and an Egyptians, drawing by an unknown artist after a mural of the tomb of Seti I]]
There is relatively little variation between human geographical populations, and most of the variation that occurs is at the individual level.
Much of human variation is continuous, often with no clear points of demarcation. Genetic data shows that no matter how population groups are defined, two people from the same population group are almost as different from each other as two people from any two different population groups. Dark-skinned populations that are found in Africa, Australia, and South Asia are not closely related to each other.
Genetic research has demonstrated that human populations native to the African continent are the most genetically diverse
and genetic diversity decreases with migratory distance from Africa, possibly the result of bottlenecks during human migration. These non-African populations acquired new genetic inputs from local admixture with archaic populations and have much greater variation from Neanderthals and Denisovans than is found in Africa, though Neanderthal admixture into African populations may be underestimated. Furthermore, recent studies have found that populations in sub-Saharan Africa, and particularly West Africa, have ancestral genetic variation which predates modern humans and has been lost in most non-African populations. Some of this ancestry is thought to originate from admixture with an unknown archaic hominin that diverged before the split of Neanderthals and modern humans.
Humans are a Gonochorism species, meaning they are divided into male and female .
The greatest degree of genetic variation exists between males and females. While the nucleotide genetic variation of individuals of the same sex across global populations is no greater than 0.1%–0.5%, the genetic difference between Man and woman is between 1% and 2%. Males on average are 15% heavier and taller than females. On average, men have about 40–50% more upper body strength and 20–30% more lower body strength than women at the same weight, due to higher amounts of muscle and larger muscle fibers. Women generally have a higher body fat percentage than men. Women have lighter skin than men of the same population; this has been explained by a higher need for vitamin D in females during pregnancy and lactation. As there are chromosomal differences between females and males, some X and Y chromosome-related conditions and Disease only affect either men or women. After allowing for body weight and volume, the male voice is usually an octave deeper than the female voice. Women have a longer life span in almost every population around the world.
The human brain
, the focal point of the central nervous system in humans, controls the peripheral nervous system. In addition to controlling "lower," involuntary, or primarily autonomic activities such as respiration and digestion
, it is also the locus of "higher" order functioning such as thought
, and abstraction
These mental function
constitute the mind
, and, along with their
consequences, are studied in the field of psychology
Humans have a larger and more developed prefrontal cortex than other primates, the region of the brain associated with higher cognition.
This has led humans to proclaim themselves to be more intelligence than any other known species. Objectively defining intelligence is difficult, with other animals adapting senses and excelling in areas that humans are unable to.
There are some traits that, although not strictly unique, do set humans apart from other animals.
Humans may be the only animals who have episodic memory and who can engage in "mental time travel". Even compared with other social animals, humans have an unusually high degree of flexibility in their facial expressions. Humans are the only animals known to cry emotional tears. Humans are one of the few animals able to self-recognize in and there is also debate over to what extent humans are the only animals with a theory of mind.
Sleep and dreaming
Humans are generally Diurnality
. The average sleep requirement is between seven and nine hours per day for an adult and nine to ten hours per day for a child; elderly people usually sleep for six to seven hours. Having less sleep than this is common among humans, even though sleep deprivation can have negative health 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 reduced memory, fatigue, aggression, and bodily discomfort.
During sleep humans dream, where they experience sensory images and sounds. Dreaming is stimulated by the pons and mostly occurs during the REM phase of sleep.
The length of a dream can vary, from a few seconds up to 30 minutes. Humans have three to five dreams per night, and some may have up to seven; however most dreams are immediately or quickly forgotten. They are more likely to remember the dream if awakened during the REM phase. The events in dreams are generally outside the control of the dreamer, with the exception of , where the dreamer is self-aware. Dreams can at times make a Creativity thought occur or give a sense of inspiration.
Consciousness and thought
Human consciousness, at its simplest, is sentience
of internal or external existence.
Despite centuries of analyses, definitions, explanations and debates by philosophers and scientists, consciousness remains puzzling and controversial,
being "at once the most familiar and most mysterious aspect of our lives".
The only widely agreed notion about the topic is the intuition that it exists.
Opinions differ about what exactly needs to be studied and explained as consciousness. Some philosophers divide consciousness into phenomenal consciousness, which is sensory experience itself, and access consciousness, which can be used for reasoning or directly controlling actions.
It is sometimes synonymous with 'the mind', and at other times, an aspect of it. Historically it is associated with introspection
, private thought
It now often includes some kind of experience
. It may be 'awareness', or 'Meta-cognition
', or self-awareness
There might be different levels or orders of consciousness,
or different kinds of consciousness, or just one kind with different features.
The process of acquiring knowledge and understanding through thought, experience, and the senses is known as cognition.
The human brain perception the external world through the , and each individual human is influenced greatly by his or her experiences, leading to subjectivity views of existence and the passage of time. The nature of thought is central to psychology and related fields. Cognitive psychology studies cognition, the mental function underlying behavior. 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. Psychologists have developed intelligence tests and the concept of intelligence quotient in order to assess the relative intelligence of human beings and study its distribution among population.
Motivation and emotion
Human motivation is not yet wholly understood. From a psychological perspective, Maslow's hierarchy of needs is a well-established theory that can be defined as the process of satisfying certain needs in ascending order of complexity.
From a more general, philosophical perspective, human motivation can be defined as a commitment to, or withdrawal from, various goals requiring the application of human ability. Furthermore, incentive
are both factors, as are any perceived links between incentives and preferences. Volition may also be involved, in which case willpower is also a factor. Ideally, both motivation and volition ensure the selection, striving for, and realization of goals in an optimal manner, a function beginning in childhood and continuing throughout a lifetime in a process known as socialization
Emotions are biological states associated with the nervous system
brought on by Neurophysiology changes variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or Suffering. They are often intertwined with mood, temperament, personality, disposition, creativity, and motivation. Emotion has a significant influence on human behavior and their ability to learn. Acting on extreme or uncontrolled emotions can lead to social disorder and crime, with studies showing criminals may have a lower emotional intelligence than normal.
Emotional experiences perceived as pleasure, such as joy, interest or contentment, contrast with those perceived as suffering, like anxiety, sadness, anger, and despair.
Happiness, or the state of being happy, is a human emotional condition. The definition of happiness is a common philosophical topic. Some define it as experiencing the feeling of positive emotional affects, while avoiding the negative ones. Others see it as an appraisal of life satisfaction or quality of life. Recent research suggests that being happy might involve experiencing some negative emotions when humans feel they are warranted.
Sexuality and love
For humans, sexuality involves biological
, physical, emotional, social
, or Spirituality
feelings and behaviors.
Because it is a broad term, which has varied with historical contexts over time, it lacks a precise definition.
The biological and physical aspects of sexuality largely concern the human reproductive functions, including the human sexual response cycle.
Sexuality also affects and is affected by cultural, political, legal, philosophical, Morality
, and religious aspects of life.
Sexual desire, or libido
, is a basic mental state present at the beginning of sexual behavior. Studies show that men desire sex more than women and Masturbation
Humans can fall anywhere along a continuous scale of sexual orientation,
although most humans are heterosexual. While homosexuality behavior occurs in some other animals, only humans and Sheep have so far been found to exhibit exclusive preference for same-sex relationships. Most evidence supports nonsocial, biological causes of sexual orientation, as cultures that are very tolerant of homosexuality do not have significantly higher rates of it. Research in neuroscience and genetics suggests that other aspects of human sexuality are biologically influenced as well.
Love most commonly refers to a feeling of strong attraction or emotional attachment. It can be impersonal (the love of an object, ideal, or strong political or spiritual connection) or interpersonal (love between humans).
When in love dopamine, norepinephrine, serotonin and other chemicals stimulate the brain's pleasure center, leading to side effects such as increased heart rate, loss of appetite and Insomnia, and an Euphoria.
Humanity's unprecedented set of intellectual skills were a key factor in the species' eventual technological advancement and concomitant domination of the biosphere.
Disregarding extinct hominids, humans are the only animals known to teach generalizable information,
innately deploy recursive embedding
to generate and communicate complex concepts,
engage in the "folk physics
" required for competent tool design,
or cook food in the wild.
Teaching and learning preserves the cultural and ethnographic identity of human societies.
Other traits and behaviors that are mostly unique to humans include starting fires,
and vocal learning
While many species communicate, language
is unique to humans, a defining feature of humanity, and a cultural universal.
Unlike the limited systems of other animals, human language is open—an infinite number of meanings can be produced by combining a limited number of symbols.
Human language also has the capacity of displacement, using words to represent things and happenings that are not presently or locally occurring but reside in the shared imagination of interlocutors.
Language differs from other forms of communication in that it is modality independent; the same meanings can be conveyed through different media, audibly in speech, visually by sign language or writing, and through tactile media such as braille.
Language is central to the communication between humans, and to the sense of identity that unites nations, cultures and ethnic groups. There are approximately six thousand different languages currently in use, including sign languages, and many thousands more that are extinct language.
Human arts can take many forms including Visual arts
, Literary arts
and Performing arts
. Visual art can range from
, interaction design and architecture
Literary arts can include prose
; while the performing arts generally involve theatre
Humans often combine the different forms (for example, music videos).
Other entities that have been described as having artistic qualities include Culinary arts
, video games and medicine
As well as providing entertainment and transferring knowledge, the arts are also used for political purposes.
tablet of the Gilgamesh
epic in Akkadian]]
Art is a defining characteristic of humans and there is evidence for a relationship between creativity and language.
The earliest evidence of art was shell engravings made by Homo erectus 300,000 years before modern humans evolved. Art attributed to H. sapiens existed at least 75,000 years ago, with jewellery and drawings found in caves in South Africa. There are various hypotheses as to why humans have Adaptation to the arts. These include allowing them to better problem solve issues, providing a means to control or influence other humans, encouraging cooperation and contribution within a society or increasing the chance of attracting a potential mate. The use of imagination developed through art, combined with logic may have given early humans an evolutionary advantage.
Evidence of humans engaging in musical activities predates cave art and so far music has been practiced by virtually all known human cultures.
There exists a wide variety of and ; with humans' musical abilities being related to other abilities, including complex social human behaviours. It has been shown that human brains respond to music by becoming synchronized with the rhythm and beat, a process called entrainment. Dance is also a form of human expression found in all cultures and may have evolved as a way to help early humans communicate. Listening to music and observing dance stimulates the orbitofrontal cortex and other pleasure sensing areas of the brain.
Unlike speaking, reading and writing does not come naturally to humans and must be taught.
Still, literature has been present before the invention of words and language, with 30,000-year-old paintings on walls inside some caves portraying a series of dramatic scenes. One of the oldest surviving works of literature is the Epic of Gilgamesh, first engraved on ancient tablets about 4,000 years ago. Beyond simply passing down knowledge, the use and sharing of imaginative fiction through stories might have helped develop humans' capabilities for communication and increased the likelihood of securing a mate. Storytelling may also be used as a way to provide the audience with moral lessons and encourage cooperation.
Tools and technologies
Stone tools were used by proto-humans at least 2.5 million years ago.
The use and manufacture of tools has been put forward as the ability that defines humans more than anything else
and has historically been seen as an important evolutionary step.
The technology became much more sophisticated about 1.8 million years ago,
with the controlled use of fire beginning around 1 million years ago.
The wheel and wheeled vehicles appeared simultaneously in several regions some time in the fourth millennium BC.
The development of more complex tools and technologies allowed land to be Arable land
and animals to be Domestication
, thus proving essential in the development of agriculture
—what is known as the Neolithic Revolution.
China developed paper, the printing press, gunpowder, the compass and other important inventions.
The continued improvements in smelting allowed forging of copper, bronze, iron and eventually steel, which is used in railways, and many other products. This coincided with the Industrial Revolution, where the invention of automated machines brought major changes to humans' lifestyles. Modern technology is observed as progressing exponentially, with major innovations in the 20th century including: electricity, penicillin, , internal combustion engines, the Internet, Fertilizer, , , Car, contraceptive pills, nuclear fission, the Green Revolution, radio, scientific plant breeding, , air conditioning, television and the assembly line.
Religion and spirituality
Religion is generally defined as a belief
system concerning the supernatural
, and practices, values
, institutions and
associated with such belief. Some religions also have a moral code
. The evolution and the history of the first religions have recently become areas of active scientific investigation.
While the exact time when humans first became religious remains unknown, research shows credible evidence of religious behaviour from around the Middle Paleolithic era (45-200 thousand years ago).
It may have evolved to play a role in helping enforce and encourage cooperation between humans.
There is no accepted academic definition of what constitutes religion.
Religion has taken on many forms that vary by culture and individual perspective in alignment with the geographic, social, and linguistic diversity of the planet. Religion can include a belief in life after death (commonly involving belief in an afterlife), the origin of life, the nature of the universe (religious cosmology) and its ultimate fate (eschatology), and what is morality or immoral. A common source for answers to these questions are beliefs in transcendent divine beings such as deities or a singular God, although not all religions are theistic.
Although the exact level of religiosity can be hard to measure,
a majority of humans profess some variety of religious or spiritual belief. In 2015 the plurality were Christians followed by Muslims, Hindus and Buddhism. As of 2015, about 16%, or slightly under 1.2 billion humans, were irreligious, including those with no religious beliefs or no identity with any religion.
Science and philosophy
An aspect unique to humans is their ability to transmit knowledge from one generation to the next and to continually build on this information to develop tools,
and other advances to pass on further.
This accumulated knowledge can be tested to answer questions or make predictions about how the universe functions and has been very successful in advancing human ascendancy.
has been described as the first scientist,
and preceded the rise of scientific thought through the Hellenistic period.
Other early advances in science came from the Han Dynasty in China and during the Islamic Golden Age.
The scientific revolution, near the end of the Renaissance
, led to the emergence of modern science
A chain of events and influences led to the development of the scientific method, a process of observation and experimentation that is used to differentiate science from pseudoscience.
An understanding of mathematics is unique to humans, although other species of animals have some numerical cognition. All of science can be divided into three major branches, the formal sciences (e.g., logic and mathematics), which are concerned with formal systems, the applied sciences (e.g., engineering, medicine), which are focused on practical applications, and the empirical sciences, which are based on empirical observation and are in turn divided into natural sciences (e.g., physics, chemistry, biology) and social sciences (e.g., psychology, economics, sociology).
Philosophy is a field of study where humans seek to understand fundamental truths about themselves and the world in which they live.
Philosophical inquiry has been a major feature in the development of humans' intellectual history. It has been described as the "no man's land" between definitive scientific knowledge and dogmatic religious teachings. Philosophy relies on reason and evidence, unlike religion, but does not require the empirical observations and experiments provided by science. Major fields of philosophy include metaphysics, epistemology, logic, and axiology (which includes ethics and aesthetics).
Society is the system of organizations and institutions arising from interaction between humans. Humans are highly social and tend to live in large complex social groups. They can be divided into different groups according to their income, wealth, power, reputation
and other factors. The structure of social stratification and the degree of social mobility
differs, especially between modern and traditional societies.
Human groups range from the size of Family
to nations. The first form of human social organization is thought to have resembled hunter-gatherer Band society
Human societies typically exhibit Gender identity
that distinguish between Masculinity
characteristics and prescribe the range of acceptable behaviours and attitudes for their members based on their sex
The most common categorisation is a gender binary
Many societies recognise a third gender
or less commonly a fourth or fifth.
In some other societies, non-binary is used as an umbrella term for a range of gender identities that are not solely male or female.
Gender roles are often associated with a division of social norm, practices, clothing, social behavior, rights, duty, privileges, social status, and power, with men enjoying more rights and privileges than women in most societies, both today and in the past. As a social construct,
gender roles are not fixed and vary historically within a society. Challenges to predominant gender norms have recurred in many societies. Little is known about gender roles in the earliest human societies. Early modern humans probably had a range of gender roles similar to that of modern cultures from at least the Upper Paleolithic, while the were less sexually dimorphic and there is evidence that the behavioural difference between males and females was minimal.
All human societies organize, recognize and classify types of social relationships based on relations between parents, children and other descendants (consanguinity
), and relations through marriage
(affinity). There is also a third type applied to
). These culturally defined relationships are referred to as kinship. In many societies, it is one of the most important social organizing principles and plays a role in transmitting status and inheritance
All societies have rules of incest taboo
, according to which marriage between certain kinds of kin relations are prohibited, and some also have rules of preferential marriage with certain kin relations.
Human ethnic groups are a social category that identifies together as a group based on shared attributes that distinguish them from other groups. These can be a common set of traditions, ancestry
, or social treatment within their residing area.
Ethnicity is separate from the concept of race, which is based on physical characteristics, although both are socially constructed.
Assigning ethnicity to a certain population is complicated, as even within common ethnic designations there can be a diverse range of subgroups, and the makeup of these ethnic groups can change over time at both the collective and individual level.
Also, there is no generally accepted definition of what constitutes an ethnic group.
Ethnic groupings can play a powerful role in the social identity
and solidarity of ethnopolitical units. This has been closely tied to the rise of the nation state
as the predominant form of political organization in the 19th and 20th centuries.
Government and politics
As farming populations gathered in larger and denser communities, interactions between these different groups increased. This led to the development of governance within and between the communities.
Humans have evolved the ability to change affiliation with various social groups relatively easily, including previously strong political alliances, if doing so is seen as providing personal advantages.
This cognitive flexibility allows individual humans to change their political ideologies, with those with higher flexibility less likely to support authoritarian and nationalistic stances.
Governments create and policies that affect the citizens that they govern. There have been many forms of government throughout human history, each having various means of obtaining power and the ability to exert diverse controls on the population.
As of 2017, more than half of all national governments are democracy, with 13% being autocracy and 28% containing elements of both. Many countries have formed international political organizations and alliances, the largest being the United Nations with 193 member states.
Trade and economics
Trade, the voluntary exchange of goods and services, is seen as a characteristic that differentiates humans from other animals and has been cited as a practice that gave Homo sapiens
a major advantage over other hominids.
Evidence suggests early H. sapiens
made use of long-distance trade routes to exchange goods and ideas, leading to cultural explosions and providing additional food sources when hunting was sparse, while such trade networks did not exist for the now extinct Neanderthals.
Early trade likely involved materials for creating tools like obsidian
The first truly international trade routes were around the spice trade
through the Roman and medieval periods.
Early human Economy were more likely to be based around Gift economy instead of a system.
Early money consisted of Commodity money; the oldest being in the form of cattle and the most widely used being cowrie shells. Money has since evolved into governmental issued coins, Paper money and electronic money. Human study of economics is a social science that looks at how societies distribute scarce resources among different people. There are massive inequalities in the division of wealth among humans; the eight richest humans are worth the same monetary value as the poorest half of all the human population.
Humans commit violence on other humans at a rate comparable to other primates, but have an increased preference for killing adults, infanticide being more common among other primates.
It is predicted that 2% of early H. sapiens
, rising to 12% during the medieval period, before dropping to below 2% in modern times.
There is great variation in violence between human populations with rates of homicide in societies that have legal systems
and strong cultural attitudes against violence at about 0.01%.
The willingness of humans to kill other members of their species en masse through organized conflict (i.e., war) has long been the subject of debate. One school of thought holds that war evolved as a means to eliminate competitors, and has always been an innate human characteristic. Another suggests that war is a relatively recent phenomenon and has appeared due to changing social conditions.
While not settled, current evidence indicates warlike predispositions only became common about 10,000 years ago, and in many places much more recently than that. War has had a high cost on human life; it is estimated that during the 20th century, between 167 million and 188 million people died as a result of war.
List of human evolution fossils