Humans (Homo sapiens) are the most abundant and widespread species of primate, characterized by bipedalism and large, complex brains. This has enabled the development of advanced tools, culture, and language. Humans are highly social and tend to live in complex social structures composed of many cooperating and competing groups, from families and kinship networks to political states. Social interactions between humans have established a wide variety of values, social norms, and rituals, which bolster human society. Curiosity and the human desire to understand and influence the environment and to explain and manipulate phenomena have motivated humanity's development of science, philosophy, mythology, religion, and other fields of study.
|An adult human male (left) and female (Thailand, 2007)|
|Homo sapiens population density (2005)|
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 member. Anatomically modern humans emerged around 300,000 years ago in Africa, evolving from Homo heidelbergensis and migrating out of Africa, gradually replacing local populations of archaic humans. For most of history, all humans were nomadic hunter-gatherers. 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 civilizations have risen and fallen. Humans have continued to expand, with a global population of over 7.9 billion as of March 2022.
Genes 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, men have greater body strength and women have a higher body fat percentage. At puberty, humans develop secondary sex characteristics. Women are capable of pregnancy, and undergo menopause and become infertile at 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 cook food since the time of H. erectus. They can survive for up to eight weeks without food, and three or four days without water. Humans are generally diurnal, 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.
Humans have a large and highly developed prefrontal cortex, the region of the brain associated with higher cognition. They are 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 reason and the transmission of knowledge to future 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 18th-century 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 genus, 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 Neanderthals, 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 sentient beings, and further if one can lose personhood (such as by going into a persistent vegetative state).
Humans are apes (superfamily Hominoidea). The gibbons (family Hylobatidae) and orangutans (genus Pongo) were the first living groups to split from this lineage, then gorillas, and finally, chimpanzees (genus Pan). The splitting date between human and chimpanzee lineages is placed 8–4 million years ago, during the late Miocene epoch, with a more constrained interval 8–7 million proposed by some geneticists. 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.
|Hominoidea (hominoids, apes)||
The genus Homo evolved from Australopithecus. Though 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. H. erectus (the African variant is sometimes called H. 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 local populations of archaic humans.
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 60,000 years ago, Australia around 65,000 years ago, the Americas around 15,000 years ago, and remote islands such as Hawaii, 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-African populations, and Neanderthals and other hominins, such as Denisovans, may have contributed up to 6% of their genome to present-day humans.
Human evolution is characterized by a number of morphological, developmental, physiological, and behavioral 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 hunter-gatherers. 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), China, Papua New Guinea, and the Sahel and West Savanna regions of Africa. Access to food surplus led to the formation of permanent human settlements, the domestication of animals and the use of metal tools 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 city-states, particularly Sumerian 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. Babylonians 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 recorded as a discipline, 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 complex calendars. 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 become 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 Church would become the source of 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 Christian and Islamic worlds would eventually clash, with the Kingdom of England, the Kingdom of France and the Holy Roman Empire declaring a series of holy wars to regain control of the Holy Land from Muslims. 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.
Throughout the early modern period (1500–1800), the Ottomans controlled the lands around the Mediterranean Basin, 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 colonizing of new regions. This includes the British Empire expanding to become the world's 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 of America 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 New World colonies and Europeans continued expansion into Oceania and Africa (where European control went from 10% to almost 90% in less than 50 years). 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, a worldwide economic crisis led to the rise of authoritarian regimes and a Second World War, involving almost all 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 globalized and interconnected.
Habitat and population
|World population||8 billion|
|Population density||16/km2 (40/sq mi) by total area|
53/km2 (138/sq mi) by land area
|Largest cities[n 2]||Tokyo, Delhi, Shanghai, São Paulo, Mexico City, Cairo, Mumbai, Beijing, Dhaka, Osaka, New York-Newark, Karachi, Buenos Aires, Chongqing, Istanbul, Kolkata, Manila, Lagos, Rio de Janeiro, Tianjin, Kinshasa, Guangzhou, Los Angeles-Long Beach-Santa Ana, Moscow, Shenzhen, Lahore, Bangalore, Paris, Jakarta, Chennai, Lima, Bogota, Bangkok|
Early human settlements were dependent on proximity to water and—depending on the lifestyle—other natural resources 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 and desertification. Human settlements continue to be vulnerable 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 adaptable 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, arid desert, extremely cold arctic regions, 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 scientific, 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 and 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. Bubonic plagues, 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 in 2020 there were 7.8 billion humans. 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 slums. Humans have had a dramatic effect on the environment. They are apex predators, 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, the immune, the integumentary, the lymphatic, the musculoskeletal, the reproductive, the respiratory, and the urinary system. The dental formula of humans is: 18.104.22.168. Humans have proportionately shorter palates and much smaller teeth 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 third molars, with some individuals having them congenitally absent.
Humans share with chimpanzees a vestigial tail, appendix, flexible shoulder joints, grasping fingers and opposable thumbs. Apart from bipedalism and brain size, humans differ from chimpanzees mostly in smelling, hearing and digesting proteins. While humans have a density of hair follicles comparable to other apes, it is predominately vellus hair, most of which is so short and wispy as to be practically invisible. Humans have about 2 million sweat glands 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 height for an adult human male is about 171 cm (5 ft 7 in), while the worldwide average height for adult human females is about 159 cm (5 ft 3 in). Shrinkage of stature may begin in middle age in some individuals but tends to be typical in the extremely aged. Throughout history, human populations have universally become taller, probably as a consequence of better nutrition, healthcare, and living conditions. The average mass of an adult human is 59 kg (130 lb) for females and 77 kg (170 lb) 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 diploid and eukaryotic species. Each somatic cell has two sets of 23 chromosomes, each set received from one parent; gametes 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 autosomes 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. Genes 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 mitochondrial DNA, 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 induce early labor or perform a caesarean section if the child needs to be born earlier for medical reasons. In developed countries, infants are typically 3–4 kg (7–9 lb) in weight and 47–53 cm (19–21 in) 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,[n 3] 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. Helpless at birth, 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 infancy, childhood, adolescence, adulthood 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 infertile 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. As of 2018[update], 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 developing 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. 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.
|Human life stages|
|Infant boy and girl||Boy and girl before puberty (children)||Adolescent male and female||Adult man and woman||Elderly man and woman|
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 cook 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 global burden of disease. 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 calories 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, cranial features, facial features, organ systems, eye color, hair color and texture, height and build, and skin color varying across the globe. The typical height of an adult human is between 1.4 and 1.9 m (4 ft 7 in and 6 ft 3 in), 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 sleep patterns.
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 phenotypes 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 to blond to brown to black, which is the most frequent. Hair color depends on the amount of melanin, with concentrations fading with increased age, leading to grey or even white hair. Skin color can range from darkest brown to lightest peach, or even nearly white or colorless in cases of albinism. It tends to vary clinally 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.
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 gonochoric species, meaning they are divided into male and female sexes. 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 males and females is between 1% and 2%. Males on average are 15% heavier and 15 cm (6 in) 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 disorders 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, reasoning, and abstraction. These cognitive processes constitute the mind, and, along with their behavioral 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 intelligent 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 mirror tests 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 diurnal. 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 lucid dreaming, where the dreamer is self-aware. Dreams can at times make a creative thought occur or give a sense of inspiration.
Consciousness and thought
Human consciousness, at its simplest, is "sentience or awareness 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, imagination and volition. It now often includes some kind of experience, cognition, feeling or perception. It may be 'awareness', or 'awareness of awareness', 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 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. The nature of thought is central to psychology and related fields. Cognitive psychology studies cognition, the mental processes 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 and preference 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 neurophysiological changes variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or displeasure. 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 pleasant, such as joy, interest or contentment, contrast with those perceived as unpleasant, 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, erotic, physical, emotional, social, or spiritual 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, moral, ethical, 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 masturbate more often.
Humans can fall anywhere along a continuous scale of sexual orientation, although most humans are heterosexual. While homosexual behavior occurs in some other animals, only humans and domestic 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 sleep, and an intense feeling of excitement.
|Most widely spoken languages||English, Mandarin Chinese, Hindi, Spanish, Standard Arabic, Bengali, French, Russian, Portuguese, Urdu|
|Most practiced religions||Christianity, Islam, Hinduism, Buddhism, folk religions, Sikhism, Judaism, unaffiliated|
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, phoneme structuring 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.
Human arts can take many forms including visual, literary and performing. Visual art can range from paintings and sculptures to film, interaction design and architecture. Literary arts can include prose, poetry and dramas; while the performing arts generally involve theatre, music and dance. Humans often combine the different forms (for example, music videos). Other entities that have been described as having artistic qualities include food preparation, video games and medicine. As well as providing entertainment and transferring knowledge, the arts are also used for political purposes.
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 adapted 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 music genres and ethnic musics; 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 Babylonian 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.
Humans and humanity itself are often the subject of the arts. While most art focuses on individual humans or a small group, in literature, the genre of science fiction is known for tackling issues related to humanity as a whole - for example topics such as human evolution or the future of civilization.
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 cultivated and animals to be domesticated, 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, skyscrapers 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, semiconductors, internal combustion engines, the Internet, nitrogen fixing fertilisers, airplanes, computers, automobiles, contraceptive pills, nuclear fission, the green revolution, radio, scientific plant breeding, rockets, air conditioning, television and the assembly line.
Religion and spirituality
Religion is generally defined as a belief system concerning the supernatural, sacred or divine, and practices, values, institutions and rituals 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 moral 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 professes some variety of religious or spiritual belief. In 2015 the plurality were Christian followed by Muslims, Hindus and Buddhists. 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, scientific laws 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. Aristotle 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 families to nations. The first forms of human social organization were families living in band societies as hunter-gatherers.
The division of humans into male and female gender roles has been marked culturally by a corresponding division of norms, practices, dress, behavior, rights, duties, privileges, status, and power. Cultural differences by gender have often been believed to have arisen naturally out of a division of reproductive labor; the biological fact that women give birth led to their further cultural responsibility for nurturing and caring for children. Gender roles have varied historically, and challenges to predominant gender norms have recurred in many societies.
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 godparents or adoptive children (fictive). 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, language, history, society, culture, nation, religion, 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
The early distribution of political power was determined by the availability of fresh water, fertile soil, and temperate climate of different locations. 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. As communities got bigger the need for some form of governance increased, as all large societies without a government have struggled to function. 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 laws and policies that affect the citizens that they govern. There have been multiple 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 democracies, with 13% being autocracies 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 economies were more likely to be based around gift giving instead of a bartering system. Early money consisted of commodities; 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 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 kill adult humans at a high rate (with infanticide being more common among other animals). It is predicted that 2% of early H. sapiens would be murdered, 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 is 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 appeared due to changing social conditions. While not settled, the current evidence suggests 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.
- The world population and population density statistics are updated automatically from a template that uses the CIA World Factbook and United Nations World Population Prospects.
- Cities with over 10 million inhabitants as of 2018.
- Traditionally this has been explained by conflicting evolutionary pressures involved in bipedalism and encephalization (called the obstetrical dilemma), but recent research suggest it might be more complicated than that.
- Groves CP (2005). Wilson DE, Reeder DM (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. ISBN 0-801-88221-4. OCLC 62265494.
- Spamer EE (29 January 1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758". Proceedings of the Academy of Natural Sciences. 149 (1): 109–14. JSTOR 4065043.
- Porkorny (1959) s.v. "g'hðem" pp. 414–16; "Homo." Dictionary.com Unabridged (v 1.1). Random House, Inc. 23 September 2008. "Homo". Dictionary.com. Archived from the original on 27 September 2008.
- Barras C. "We don't know which species should be classed as 'human'". www.bbc.com. Retrieved 31 March 2021.
- "Definition of HUMAN". www.merriam-webster.com. Retrieved 31 March 2021.
- Spamer EE (1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758". Proceedings of the Academy of Natural Sciences of Philadelphia. 149: 109–114. ISSN 0097-3157. JSTOR 4065043.
- OED, s.v. "human."
- "Man". Merriam-Webster Dictionary. Archived from the original on 22 September 2017. Retrieved 14 September 2017.
Definition 2: a man belonging to a particular category (as by birth, residence, membership, or occupation) —usually used in combination
- "Thesaurus results for HUMAN". www.merriam-webster.com. Retrieved 21 May 2022.
- "Misconceptions about evolution - Understanding Evolution". 19 September 2021. Retrieved 21 May 2022.
- "Concept of Personhood - MU School of Medicine". medicine.missouri.edu. Retrieved 4 July 2021.
- Tuttle RH (4 October 2018). "Hominoidea: conceptual history". In Trevathan W, Cartmill M, Dufour D, Larsen C (eds.). International Encyclopedia of Biological Anthropology. Hoboken, New Jersey, United States: John Wiley & Sons, Inc. pp. 1–2. doi:10.1002/9781118584538.ieba0246. ISBN 978-1-118-58442-2. S2CID 240125199. Retrieved 26 May 2021.
- Tattersall I, Schwartz J (2009). "Evolution of the Genus Homo". Annual Review of Earth and Planetary Sciences. 37 (1): 67–92. Bibcode:2009AREPS..37...67T. doi:10.1146/annurev.earth.031208.100202.
- Goodman M, Tagle DA, Fitch DH, Bailey W, Czelusniak J, Koop BF, et al. (March 1990). "Primate evolution at the DNA level and a classification of hominoids". Journal of Molecular Evolution. 30 (3): 260–6. Bibcode:1990JMolE..30..260G. doi:10.1007/BF02099995. PMID 2109087. S2CID 2112935.
- Ruvolo M (March 1997). "Molecular phylogeny of the hominoids: inferences from multiple independent DNA sequence data sets". Molecular Biology and Evolution. 14 (3): 248–65. doi:10.1093/oxfordjournals.molbev.a025761. PMID 9066793.
- Brahic C (2012). "Our True Dawn". New Scientist. 216 (2892): 34–37. Bibcode:2012NewSc.216...34B. doi:10.1016/S0262-4079(12)63018-8.
- MacAndrew A. "Human Chromosome 2 is a fusion of two ancestral chromosomes". Evolution pages. Archived from the original on 9 August 2011. Retrieved 18 May 2006.
- Strait DS (September 2010). "The Evolutionary History of the Australopiths". Evolution: Education and Outreach. 3 (3): 341–352. doi:10.1007/s12052-010-0249-6. ISSN 1936-6434. S2CID 31979188.
- Dunsworth HM (September 2010). "Origin of the Genus Homo". Evolution: Education and Outreach. 3 (3): 353–366. doi:10.1007/s12052-010-0247-8. ISSN 1936-6434. S2CID 43116946.
- Kimbel WH, Villmoare B (July 2016). "From Australopithecus to Homo: the transition that wasn't". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 371 (1698): 20150248. doi:10.1098/rstb.2015.0248. PMC 4920303. PMID 27298460. S2CID 20267830.
- Villmoare B, Kimbel WH, Seyoum C, Campisano CJ, DiMaggio EN, Rowan J, et al. (March 2015). "Paleoanthropology. Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia". Science. 347 (6228): 1352–1355. Bibcode:2015Sci...347.1352V. doi:10.1126/science.aaa1343. PMID 25739410.
- Zhu Z, Dennell R, Huang W, Wu Y, Qiu S, Yang S, et al. (July 2018). "Hominin occupation of the Chinese Loess Plateau since about 2.1 million years ago". Nature. 559 (7715): 608–612. Bibcode:2018Natur.559..608Z. doi:10.1038/s41586-018-0299-4. PMID 29995848. S2CID 49670311.
- Hublin JJ, Ben-Ncer A, Bailey SE, Freidline SE, Neubauer S, Skinner MM, et al. (June 2017). "New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens" (PDF). Nature. 546 (7657): 289–292. Bibcode:2017Natur.546..289H. doi:10.1038/nature22336. PMID 28593953.
- "Out of Africa Revisited". Science (This Week in Science). 308 (5724): 921. 13 May 2005. doi:10.1126/science.308.5724.921g. ISSN 0036-8075. S2CID 220100436.
- Stringer C (June 2003). "Human evolution: Out of Ethiopia". Nature. 423 (6941): 692–3, 695. Bibcode:2003Natur.423..692S. doi:10.1038/423692a. PMID 12802315. S2CID 26693109.
- Johanson D (May 2001). "Origins of Modern Humans: Multiregional or Out of Africa?". actionbioscience. Washington, DC: American Institute of Biological Sciences. Retrieved 23 November 2009.
- Posth C, Renaud G, Mittnik A, Drucker DG, Rougier H, Cupillard C, et al. (March 2016). "Pleistocene Mitochondrial Genomes Suggest a Single Major Dispersal of Non-Africans and a Late Glacial Population Turnover in Europe". Current Biology. 26 (6): 827–33. doi:10.1016/j.cub.2016.01.037. hdl:2440/114930. PMID 26853362. S2CID 140098861.
- Karmin M, Saag L, Vicente M, Wilson Sayres MA, Järve M, Talas UG, et al. (April 2015). "A recent bottleneck of Y chromosome diversity coincides with a global change in culture". Genome Research. 25 (4): 459–66. doi:10.1101/gr.186684.114. PMC 4381518. PMID 25770088.
- Armitage SJ, Jasim SA, Marks AE, Parker AG, Usik VI, Uerpmann HP (January 2011). "The southern route "out of Africa": evidence for an early expansion of modern humans into Arabia". Science. 331 (6016): 453–6. Bibcode:2011Sci...331..453A. doi:10.1126/science.1199113. PMID 21273486. S2CID 20296624. Archived from the original on 27 April 2011. Retrieved 1 May 2011.
- Rincon P (27 January 2011). "Humans 'left Africa much earlier'". BBC News. Archived from the original on 9 August 2012.
- Clarkson C, Jacobs Z, Marwick B, Fullagar R, Wallis L, Smith M, et al. (July 2017). "Human occupation of northern Australia by 65,000 years ago". Nature. 547 (7663): 306–310. Bibcode:2017Natur.547..306C. doi:10.1038/nature22968. hdl:2440/107043. PMID 28726833. S2CID 205257212.
- Lowe DJ (2008). "Polynesian settlement of New Zealand and the impacts of volcanism on early Maori society: an update" (PDF). University of Waikato. Archived (PDF) from the original on 22 May 2010. Retrieved 29 April 2010.
- Appenzeller T (May 2012). "Human migrations: Eastern odyssey". Nature. 485 (7396): 24–6. Bibcode:2012Natur.485...24A. doi:10.1038/485024a. PMID 22552074.
- Reich D, Green RE, Kircher M, Krause J, Patterson N, Durand EY, et al. (December 2010). "Genetic history of an archaic hominin group from Denisova Cave in Siberia". Nature. 468 (7327): 1053–60. Bibcode:2010Natur.468.1053R. doi:10.1038/nature09710. hdl:10230/25596. PMC 4306417. PMID 21179161.
- Hammer MF (May 2013). "Human Hybrids" (PDF). Scientific American. 308 (5): 66–71. Bibcode:2013SciAm.308e..66H. doi:10.1038/scientificamerican0513-66. PMID 23627222. Archived from the original (PDF) on 24 August 2018.
- Yong E (July 2011). "Mosaic humans, the hybrid species". New Scientist. 211 (2823): 34–38. Bibcode:2011NewSc.211...34Y. doi:10.1016/S0262-4079(11)61839-3.
- Ackermann RR, Mackay A, Arnold ML (October 2015). "The Hybrid Origin of "Modern" Humans". Evolutionary Biology. 43 (1): 1–11. doi:10.1007/s11692-015-9348-1. S2CID 14329491.
- Noonan JP (May 2010). "Neanderthal genomics and the evolution of modern humans". Genome Research. 20 (5): 547–53. doi:10.1101/gr.076000.108. PMC 2860157. PMID 20439435.
- Abi-Rached L, Jobin MJ, Kulkarni S, McWhinnie A, Dalva K, Gragert L, et al. (October 2011). "The shaping of modern human immune systems by multiregional admixture with archaic humans". Science. 334 (6052): 89–94. Bibcode:2011Sci...334...89A. doi:10.1126/science.1209202. PMC 3677943. PMID 21868630.
- Boyd R, Silk JB (2003). How Humans Evolved. New York City: Norton. ISBN 978-0-393-97854-4.
- Garcea E (4 July 2013). Hunter-Gatherers of the Nile Valley and the Sahara Before 12,000 Years Ago. Oxford University Press. doi:10.1093/oxfordhb/9780199569885.013.0029.
- Colledge S, Conolly J, Dobney K, Manning K, Shennan S (2013). Origins and Spread of Domestic Animals in Southwest Asia and Europe. Walnut Creek: Left Coast Press. pp. 13–17. ISBN 978-1-61132-324-5. OCLC 855969933.
- Scanes CG (January 2018). "The Neolithic Revolution, Animal Domestication, and Early Forms of Animal Agriculture". In Scanes CG, Toukhsati SR (eds.). Animals and Human Society. pp. 103–131. doi:10.1016/B978-0-12-805247-1.00006-X. ISBN 9780128052471.
- He K, Lu H, Zhang J, Wang C, Huan X (7 June 2017). "Prehistoric evolution of the dualistic structure mixed rice and millet farming in China". The Holocene. 27 (12): 1885–1898. Bibcode:2017Holoc..27.1885H. doi:10.1177/0959683617708455. S2CID 133660098.
- Lu H, Zhang J, Liu KB, Wu N, Li Y, Zhou K, et al. (May 2009). "Earliest domestication of common millet (Panicum miliaceum) in East Asia extended to 10,000 years ago". Proceedings of the National Academy of Sciences of the United States of America. 106 (18): 7367–72. Bibcode:2009PNAS..106.7367L. doi:10.1073/pnas.0900158106. PMC 2678631. PMID 19383791.
- Denham TP, Haberle SG, Lentfer C, Fullagar R, Field J, Therin M, et al. (July 2003). "Origins of agriculture at Kuk Swamp in the highlands of New Guinea". Science. 301 (5630): 189–93. doi:10.1126/science.1085255. PMID 12817084. S2CID 10644185.
- Scarcelli N, Cubry P, Akakpo R, Thuillet AC, Obidiegwu J, Baco MN, et al. (May 2019). "Yam genomics supports West Africa as a major cradle of crop domestication". Science Advances. 5 (5): eaaw1947. Bibcode:2019SciA....5.1947S. doi:10.1126/sciadv.aaw1947. PMC 6527260. PMID 31114806.
- Winchell F (October 2017). "Evidence for Sorghum Domestication in Fourth Millennium BC Eastern Sudan: Spikelet Morphology from Ceramic Impressions of the Butana Group" (PDF). Current Anthropology. 58 (5): 673–683. doi:10.1086/693898. S2CID 149402650.
- Manning K (February 2011). "4500-Year old domesticated pearl millet (Pennisetum glaucum) from the Tilemsi Valley, Mali: new insights into an alternative cereal domestication pathway". Journal of Archaeological Science. 38 (2): 312–322. doi:10.1016/j.jas.2010.09.007.
- Noble TF, Strauss B, Osheim D, Neuschel K, Accamp E (2013). Cengage Advantage Books: Western Civilization: Beyond Boundaries. ISBN 978-1-285-66153-7. Retrieved 11 July 2015.
- Spielvogel J (1 January 2014). Western Civilization: Volume A: To 1500. Cenpage Learning. ISBN 978-1-285-98299-1. Archived from the original on 5 September 2015. Retrieved 11 July 2015.
- Thornton B (2002). Greek Ways: How the Greeks Created Western Civilization. San Francisco, CA: Encounter Books. pp. 1–14. ISBN 978-1-893554-57-3.
- Garfinkle SJ, Bang PF, Scheidel W (1 February 2013). Bang PF, Scheidel W (eds.). Ancient Near Eastern City-States. The Oxford Handbook of the State in the Ancient Near East and Mediterranean. doi:10.1093/oxfordhb/9780195188318.001.0001. ISBN 9780195188318. Retrieved 16 April 2021.
- Woods C (28 February 2020). "The Emergence of Cuneiform Writing". In Hasselbach-Andee R (ed.). A Companion to Ancient Near Eastern Languages (1st ed.). Wiley. pp. 27–46. doi:10.1002/9781119193814.ch2. ISBN 978-1-119-19329-6. S2CID 216180781.
- Robinson A (October 2015). "Ancient civilization: Cracking the Indus script". Nature. 526 (7574): 499–501. Bibcode:2015Natur.526..499R. doi:10.1038/526499a. PMID 26490603. S2CID 4458743.
- Crawford H (2013). "Trade in the Sumerian world". The Sumerian World. Routledge. pp. 447–61. ISBN 978-1-136-21911-5.
- Bodnár M (2018). "Prehistoric innovations: Wheels and wheeled vehicles". Acta Archaeologica Academiae Scientiarum Hungaricae. 69 (2): 271–298. doi:10.1556/072.2018.69.2.3. ISSN 0001-5210. S2CID 115685157.
- Pryor FL (1985). "The Invention of the Plow". Comparative Studies in Society and History. 27 (4): 727–743. doi:10.1017/S0010417500011749. ISSN 0010-4175. JSTOR 178600. S2CID 144840498.
- Carter R (2012). "19. Watercraft". In Potts DT (ed.). A companion to the archaeology of the ancient Near East. Chichester, West Sussex: Wiley-Blackwell. pp. 347–354. ISBN 978-1-4051-8988-0. Archived from the original on 28 April 2015. Retrieved 8 February 2014.
- Pedersen O (1993). "Science Before the Greeks". Early physics and astronomy: A historical introduction. CUP Archive. p. 1. ISBN 978-0-521-40340-5.
- Robson E (2008). Mathematics in ancient Iraq: A social history. Princeton University Press. pp. xxi.
- Edwards JF (2003). "Building the Great Pyramid: Probable Construction Methods Employed at Giza". Technology and Culture. 44 (2): 340–354. doi:10.1353/tech.2003.0063. ISSN 0040-165X. JSTOR 25148110. S2CID 109998651.
- Voosen P (August 2018). "New geological age comes under fire". Science. 361 (6402): 537–538. Bibcode:2018Sci...361..537V. doi:10.1126/science.361.6402.537. PMID 30093579. S2CID 51954326.
- Saggs HW (2000). Babylonians. Univ of California Press. p. 7. ISBN 978-0-520-20222-1.
- Sassaman KE (1 December 2005). "Poverty Point as Structure, Event, Process". Journal of Archaeological Method and Theory. 12 (4): 335–364. doi:10.1007/s10816-005-8460-4. ISSN 1573-7764. S2CID 53393440.
- Lazaridis I, Mittnik A, Patterson N, Mallick S, Rohland N, Pfrengle S, et al. (August 2017). "Genetic origins of the Minoans and Mycenaeans". Nature. 548 (7666): 214–218. Bibcode:2017Natur.548..214L. doi:10.1038/nature23310. PMC 5565772. PMID 28783727.
- Keightley DN (1999). "The Shang: China's first historical dynasty". In Loewe M, Shaughnessy EL (eds.). The Cambridge History of Ancient China: From the Origins of Civilization to 221 BC. Cambridge University Press. pp. 232–291. ISBN 978-0-521-47030-8.
- Kaniewski D, Guiot J, van Campo E (2015). "Drought and societal collapse 3200 years ago in the Eastern Mediterranean: a review". WIREs Climate Change. 6 (4): 369–382. doi:10.1002/wcc.345. S2CID 128460316.
- Drake BL (1 June 2012). "The influence of climatic change on the Late Bronze Age Collapse and the Greek Dark Ages". Journal of Archaeological Science. 39 (6): 1862–1870. doi:10.1016/j.jas.2012.01.029.
- Wells PS (2011). "The Iron Age". In Milisauskas S (ed.). European Prehistory: A Survey. Interdisciplinary Contributions to Archaeology. New York, NY: Springer. pp. 405–460. doi:10.1007/978-1-4419-6633-9_11. ISBN 978-1-4419-6633-9.
- Hughes-Warrington M (2018). "Sense and non-sense in Ancient Greek histories". History as Wonder: Beginning with Historiography. United Kingdom: Taylor & Francis. ISBN 978-0-429-76315-1.
- Beard M (2 October 2015). "Why ancient Rome matters to the modern world". The Guardian. Retrieved 17 April 2021.
- Vidergar AB (11 June 2015). "Stanford scholar debunks long-held beliefs about economic growth in ancient Greece". Stanford University. Retrieved 17 April 2021.
- Inomata T, Triadan D, Vázquez López VA, Fernandez-Diaz JC, Omori T, Méndez Bauer MB, et al. (June 2020). "Monumental architecture at Aguada Fénix and the rise of Maya civilization". Nature. 582 (7813): 530–533. Bibcode:2020Natur.582..530I. doi:10.1038/s41586-020-2343-4. PMID 32494009. S2CID 219281856.
- Milbrath S (March 2017). "The Role of Solar Observations in Developing the Preclassic Maya Calendar". Latin American Antiquity. 28 (1): 88–104. doi:10.1017/laq.2016.4. ISSN 1045-6635. S2CID 164417025.
- Benoist A, Charbonnier J, Gajda I (2016). "Investigating the eastern edge of the kingdom of Aksum: architecture and pottery from Wakarida". Proceedings of the Seminar for Arabian Studies. 46: 25–40. ISSN 0308-8421. JSTOR 45163415.
- Farazmand A (1 January 1998). "Administration of the Persian achaemenid world-state empire: implications for modern public administration". International Journal of Public Administration. 21 (1): 25–86. doi:10.1080/01900699808525297. ISSN 0190-0692.
- Ingalls DH (1976). "Kālidāsa and the Attitudes of the Golden Age". Journal of the American Oriental Society. 96 (1): 15–26. doi:10.2307/599886. ISSN 0003-0279. JSTOR 599886.
- Xie J (2020). "Pillars of Heaven: The Symbolic Function of Column and Bracket Sets in the Han Dynasty". Architectural History. 63: 1–36. doi:10.1017/arh.2020.1. ISSN 0066-622X. S2CID 229716130.
- Marx W, Haunschild R, Bornmann L (2018). "Climate and the Decline and Fall of the Western Roman Empire: A Bibliometric View on an Interdisciplinary Approach to Answer a Most Classic Historical Question". Climate. 6 (4): 90. doi:10.3390/cli6040090.
- Brooke JH, Numbers RL, eds. (2011). Science and Religion Around the World. New York: Oxford University Press. p. 72. ISBN 978-0-195-32819-6.
- Renima A, Tiliouine H, Estes RJ (2016). "The Islamic Golden Age: A Story of the Triumph of the Islamic Civilization". In Tiliouine H, Estes RJ (eds.). The State of Social Progress of Islamic Societies: Social, Economic, Political, and Ideological Challenges. International Handbooks of Quality-of-Life. Cham: Springer International Publishing. pp. 25–52. doi:10.1007/978-3-319-24774-8_2. ISBN 978-3-319-24774-8.
- Vidal-Nanquet P (1987). The Harper Atlas of World History. Harper & Row Publishers. p. 76.
- Asbridge T (2012). "Introduction: The world of the crusades". The Crusades: The War for the Holy Land. Simon and Schuster. ISBN 978-1849837705.
- Adam King (2002). "Mississippian Period: Overview". New Georgia Encyclopedia. Retrieved 15 November 2009.
- Conrad G, Demarest AA (1984). Religion and Empire: The Dynamics of Aztec and Inca Expansionism. Cambridge University Press. p. 2. ISBN 0521318963.
- May T (2013). The Mongol Conquests in World History. Reaktion Books. p. 7. ISBN 978-1-86189-971-2.
- Canós-Donnay S (25 February 2019). "The Empire of Mali". Oxford Research Encyclopedia of African History. Oxford University Press. doi:10.1093/acrefore/9780190277734.013.266. ISBN 978-0-19-027773-4. Retrieved 7 May 2021.
- Canela SA, Graves MW. "The Tongan Maritime Expansion: A Case in the Evolutionary Ecology of Social Complexity". Asian Perspectives. 37 (2): 135–164.
- Brady T, Oberman T, Tracy JD, eds. (1 January 1994). "Ottomans and Europe". Handbook of European History 1400-1600: Late Middle Ages, Renaissance and Reformation. Brill. pp. 589–635. doi:10.1163/9789004391659_019. ISBN 978-90-04-39165-9. Retrieved 17 April 2021.
- Goree R (19 November 2020). "The Culture of Travel in Edo-Period Japan". Oxford Research Encyclopedia of Asian History. Oxford University Press. doi:10.1093/acrefore/9780190277727.013.72. ISBN 978-0-19-027772-7. Retrieved 7 May 2021.
- Mosca MW (2010). "CHINA'S LAST EMPIRE: The Great Qing". Pacific Affairs. 83.
- Suyanta S, Ikhlas S (19 July 2016). "Islamic Education at Mughal Kingdom in India (1526-1857)". Al-Ta Lim Journal. 23 (2): 128–138. doi:10.15548/jt.v23i2.228. ISSN 2355-7893.
- Kirkpatrick R (2002). The European Renaissance, 1400-1600. Harlow, England. p. 1. ISBN 978-1-317-88646-4. OCLC 893909816.
- Arnold D (2002). The Age of Discovery, 1400-1600 (Second ed.). London. pp. xi. ISBN 978-1-136-47968-7. OCLC 859536800.
- Palan R (14 January 2010). "International Financial Centers: The British-Empire, City-States and Commercially Oriented Politics". Theoretical Inquiries in Law. 11 (1). doi:10.2202/1565-3404.1239. ISSN 1565-3404. S2CID 56216309.
- Dixon EJ (January 2001). "Human colonization of the Americas: timing, technology and process". Quaternary Science Reviews. 20 (1–3): 277–299. Bibcode:2001QSRv...20..277J. doi:10.1016/S0277-3791(00)00116-5.
- Lovejoy PE (1989). "The Impact of the Atlantic Slave Trade on Africa: A Review of the Literature". The Journal of African History. 30 (3): 365–394. doi:10.1017/S0021853700024439. ISSN 0021-8537. JSTOR 182914. S2CID 161321949.
- Cave AA (2008). "Genocide in the Americas". In Stone D (ed.). The Historiography of Genocide. London: Palgrave Macmillan UK. pp. 273–295. doi:10.1057/9780230297784_11. ISBN 978-0-230-29778-4.
- Delisle RG (September 2014). "Can a revolution hide another one? Charles Darwin and the Scientific Revolution". Endeavour. 38 (3–4): 157–8. doi:10.1016/j.endeavour.2014.10.001. PMID 25457642.
- "Greatest Engineering Achievements of the 20th Century". National Academy of Engineering. Archived from the original on 6 April 2015. Retrieved 7 April 2015.
- Herring GC (2008). From colony to superpower : U.S. foreign relations since 1776. New York: Oxford University Press. p. 1. ISBN 978-0-19-972343-0. OCLC 299054528.
- O'Rourke KH (March 2006). "The worldwide economic impact of the French Revolutionary and Napoleonic Wars, 1793–1815". Journal of Global History. 1 (1): 123–149. doi:10.1017/S1740022806000076. ISSN 1740-0228.
- Zimmerman AF (November 1931). "Spain and Its Colonies, 1808-1820". The Hispanic American Historical Review. 11 (4): 439–463. doi:10.2307/2506251. JSTOR 2506251.
- Raudzens G (2004). "The Australian Frontier Wars, 1788-1838 (review)". The Journal of Military History. 68 (3): 957–959. doi:10.1353/jmh.2004.0138. ISSN 1543-7795. S2CID 162259092.
- David S (2011). "British History in depth: Slavery and the 'Scramble for Africa'". www.bbc.co.uk. Retrieved 5 May 2021.
- Clark CM (2012). "Polarization of Europe, 1887-1907". The sleepwalkers : how Europe went to war in 1914. London: Allen Lane. ISBN 978-0-7139-9942-6. OCLC 794136314.
- Robert Dahl (1989). Democracy and Its Critics. Yale UP. pp. 239–40. ISBN 0300153554.
- McDougall WA (May 1985). "Sputnik, the space race, and the Cold War". Bulletin of the Atomic Scientists. 41 (5): 20–25. Bibcode:1985BuAtS..41e..20M. doi:10.1080/00963402.1985.11455962. ISSN 0096-3402.
- Plous S (May 1993). "The Nuclear Arms Race: Prisoner's Dilemma or Perceptual Dilemma?". Journal of Peace Research. 30 (2): 163–179. doi:10.1177/0022343393030002004. ISSN 0022-3433. S2CID 5482851.
- Sachs JD (April 2017). "Globalization—In the Name of Which Freedom?". Humanistic Management Journal. 1 (2): 237–252. doi:10.1007/s41463-017-0019-5. ISSN 2366-603X. S2CID 133030709.
- "World". The World Factbook. CIA. 17 May 2016. Retrieved 2 October 2016.
- "World Population Prospects: The 2017 Revision" (PDF). United Nations, Department of Economic and Social Affairs, Population Division. 2017. p. 2&17.
- "The World's Cities in 2018" (PDF). United Nations.
- Rector RK (2016). The Early River Valley Civilizations (First ed.). New York, NY. p. 10. ISBN 978-1-4994-6329-3. OCLC 953735302.
- "How People Modify the Environment" (PDF). Westerville City School District. Retrieved 13 March 2019.
- "Natural disasters and the urban poor" (PDF). World Bank. October 2003. Archived (PDF) from the original on 9 August 2017.
- Habitat UN (2013). The state of the world's cities 2012 / prosperity of cities. [London]: Routledge. pp. x. ISBN 978-1-135-01559-6. OCLC 889953315.
- Piantadosi CA (2003). The biology of human survival : life and death in extreme environments. Oxford: Oxford University Press. pp. 2–3. ISBN 978-0-19-974807-5. OCLC 70215878.
- O'Neil D. "Human Biological Adaptability; Overview". Palomar College. Archived from the original on 6 March 2013. Retrieved 6 January 2013.
- "Population distribution and density". BBC. Archived from the original on 23 June 2017. Retrieved 26 June 2017.
- Bunn SE, Arthington AH (October 2002). "Basic principles and ecological consequences of altered flow regimes for aquatic biodiversity". Environmental Management. 30 (4): 492–507. doi:10.1007/s00267-002-2737-0. hdl:10072/6758. PMID 12481916. S2CID 25834286.
- Heim BE (1990–1991). "Exploring the Last Frontiers for Mineral Resources: A Comparison of International Law Regarding the Deep Seabed, Outer Space, and Antarctica". Vanderbilt Journal of Transnational Law. 23: 819.
- "Mission to Mars: Mars Science Laboratory Curiosity Rover". Jet Propulsion Laboratory. Archived from the original on 18 August 2015. Retrieved 26 August 2015.
- "Touchdown! Rosetta's Philae probe lands on comet". European Space Agency. 12 November 2014. Archived from the original on 22 August 2015. Retrieved 26 August 2015.
- "NEAR-Shoemaker". NASA. Archived from the original on 26 August 2015. Retrieved 26 August 2015.
- Kraft R (11 December 2010). "JSC celebrates ten years of continuous human presence aboard the International Space Station". JSC Features. Johnson Space Center. Archived from the original on 16 February 2012. Retrieved 13 February 2012.
- Tellier LN (2009). Urban world history: an economic and geographical perspective. p. 26. ISBN 978-2-7605-1588-8.
- Thomlinson R (1975). Demographic problems; controversy over population control (2nd ed.). Ecino, California: Dickenson Pub. Co. ISBN 978-0-8221-0166-6.
- Harl KW (1998). "Population estimates of the Roman Empire". Tulane.edu. Archived from the original on 7 May 2016. Retrieved 8 December 2012.
- Zietz BP, Dunkelberg H (February 2004). "The history of the plague and the research on the causative agent Yersinia pestis". International Journal of Hygiene and Environmental Health. 207 (2): 165–78. doi:10.1078/1438-4639-00259. PMC 7128933. PMID 15031959.
- "World's population reaches six billion". BBC News. 5 August 1999. Archived from the original on 15 April 2008. Retrieved 5 February 2008.
- "World Population: 2020 Overview | YaleGlobal Online". yaleglobal.yale.edu. Retrieved 18 April 2021.
- Bar-On YM, Phillips R, Milo R (June 2018). "The biomass distribution on Earth". Proceedings of the National Academy of Sciences of the United States of America. 115 (25): 6506–6511. doi:10.1073/pnas.1711842115. PMC 6016768. PMID 29784790.
- "68% of the world population projected to live in urban areas by 2050, says UN". United Nations Department of Economic and Social Affairs (DESA). 16 May 2018. Retrieved 18 April 2021.
- Duhart DT (October 2000). Urban, Suburban, and Rural Victimization, 1993–98 (PDF). U.S. Department of Justice, Bureau of Justice Statistics. Retrieved 1 October 2006.
- Roopnarine PD (March 2014). "Humans are apex predators". Proceedings of the National Academy of Sciences of the United States of America. 111 (9): E796. Bibcode:2014PNAS..111E.796R. doi:10.1073/pnas.1323645111. PMC 3948303. PMID 24497513.
- Stokstad E (5 May 2019). "Landmark analysis documents the alarming global decline of nature". Science. AAAS. Retrieved 9 May 2021.
For the first time at a global scale, the report has ranked the causes of damage. Topping the list, changes in land use—principally agriculture—that have destroyed habitat. Second, hunting and other kinds of exploitation. These are followed by climate change, pollution, and invasive species, which are being spread by trade and other activities. Climate change will likely overtake the other threats in the next decades, the authors note. Driving these threats are the growing human population, which has doubled since 1970 to 7.6 billion, and consumption. (Per capita of use of materials is up 15% over the past 5 decades.)
- Pimm S, Raven P, Peterson A, Sekercioglu CH, Ehrlich PR (July 2006). "Human impacts on the rates of recent, present, and future bird extinctions". Proceedings of the National Academy of Sciences of the United States of America. 103 (29): 10941–6. Bibcode:2006PNAS..10310941P. doi:10.1073/pnas.0604181103. PMC 1544153. PMID 16829570.* Barnosky AD, Koch PL, Feranec RS, Wing SL, Shabel AB (October 2004). "Assessing the causes of late Pleistocene extinctions on the continents". Science. 306 (5693): 70–5. Bibcode:2004Sci...306...70B. CiteSeerX 10.1.1.574.332. doi:10.1126/science.1101476. PMID 15459379. S2CID 36156087.
- "Climate Change 2001: Working Group I: The Scientific Basis". grida.no/. Archived from the original on 1 June 2007. Retrieved 30 May 2007.
- Lewis OT (January 2006). "Climate change, species-area curves and the extinction crisis". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 361 (1465): 163–71. doi:10.1098/rstb.2005.1712. PMC 1831839. PMID 16553315.
- Roza G (2007). Inside the human body : using scientific and exponential notation. New York: Rosen Pub. Group's PowerKids Press. p. 21. ISBN 978-1-4042-3362-1.
- "Human Anatomy". Inner Body. Archived from the original on 5 January 2013. Retrieved 6 January 2013.
- Collins D (1976). The Human Revolution: From Ape to Artist. p. 208. ISBN 978-0714816760.
- Marks JM (2001). Human Biodiversity: Genes, Race, and History. Transaction Publishers. p. 16. ISBN 978-0-202-36656-2.
- O'Neil D. "Humans". Primates. Palomar College. Archived from the original on 11 January 2013. Retrieved 6 January 2013.
- "How to be Human: The reason we are so scarily hairy". New Scientist. 2017. Retrieved 29 April 2020.
- Sandel AA (September 2013). "Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness". American Journal of Physical Anthropology. 152 (1): 145–50. doi:10.1002/ajpa.22333. hdl:2027.42/99654. PMID 23900811.
- Kirchweger G (2 February 2001). "The Biology of Skin Color: Black and White". Evolution: Library. PBS. Archived from the original on 16 February 2013. Retrieved 6 January 2013.
- Roser M, Appel C, Ritchie H (8 October 2013). "Human Height". Our World in Data.
- "Senior Citizens Do Shrink – Just One of the Body Changes of Aging". News. Senior Journal. Archived from the original on 19 February 2013. Retrieved 6 January 2013.
- Bogin B, Rios L (September 2003). "Rapid morphological change in living humans: implications for modern human origins". Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology. 136 (1): 71–84. doi:10.1016/S1095-6433(02)00294-5. PMID 14527631.
- "Human weight". Articleworld.org. Archived from the original on 8 December 2011. Retrieved 10 December 2011.
- Schlessingerman A (2003). "Mass Of An Adult". The Physics Factbook: An Encyclopedia of Scientific Essays. Archived from the original on 1 January 2018. Retrieved 31 December 2017.
- Kushner R (2007). Treatment of the Obese Patient (Contemporary Endocrinology). Totowa, NJ: Humana Press. p. 158. ISBN 978-1-59745-400-1. Retrieved 5 April 2009.
- Adams JP, Murphy PG (July 2000). "Obesity in anaesthesia and intensive care". British Journal of Anaesthesia. 85 (1): 91–108. doi:10.1093/bja/85.1.91. PMID 10927998.
- Lombardo MP, Deaner RO (March 2018). "Born to Throw: The Ecological Causes that Shaped the Evolution of Throwing In Humans". The Quarterly Review of Biology. 93 (1): 1–16. doi:10.1086/696721. ISSN 0033-5770. S2CID 90757192.
- Parker-Pope T (27 October 2009). "The Human Body Is Built for Distance". The New York Times. Archived from the original on 5 November 2015.
- John B. "What is the role of sweating glands in balancing body temperature when running a marathon?". Livestrong.com. Archived from the original on 31 January 2013. Retrieved 6 January 2013.
- Therman E (1980). Human Chromosomes: Structure, Behavior, Effects. Springer US. pp. 112–24. doi:10.1007/978-1-4684-0107-3. ISBN 978-1-4684-0109-7. S2CID 36686283.
- Edwards JH, Dent T, Kahn J (June 1966). "Monozygotic twins of different sex". Journal of Medical Genetics. 3 (2): 117–23. doi:10.1136/jmg.3.2.117. PMC 1012913. PMID 6007033.
- Machin GA (January 1996). "Some causes of genotypic and phenotypic discordance in monozygotic twin pairs". American Journal of Medical Genetics. 61 (3): 216–28. doi:10.1002/(SICI)1096-8628(19960122)61:3<216::AID-AJMG5>3.0.CO;2-S. PMID 8741866.
- Jonsson H, Magnusdottir E, Eggertsson HP, Stefansson OA, Arnadottir GA, Eiriksson O, et al. (January 2021). "Differences between germline genomes of monozygotic twins". Nature Genetics. 53 (1): 27–34. doi:10.1038/s41588-020-00755-1. PMID 33414551. S2CID 230986741.
- "Genetic – Understanding Human Genetic Variation". Human Genetic Variation. National Institute of Health (NIH). Archived from the original on 25 August 2013. Retrieved 13 December 2013.
Between any two humans, the amount of genetic variation—biochemical individuality—is about 0.1%.
- Levy S, Sutton G, Ng PC, Feuk L, Halpern AL, Walenz BP, et al. (September 2007). "The diploid genome sequence of an individual human". PLOS Biology. 5 (10): e254. doi:10.1371/journal.pbio.0050254. PMC 1964779. PMID 17803354.
- Race, Ethnicity, and Genetics Working Group (October 2005). "The use of racial, ethnic, and ancestral categories in human genetics research". American Journal of Human Genetics. 77 (4): 519–32. doi:10.1086/491747. PMC 1275602. PMID 16175499.
- "Chimps show much greater genetic diversity than humans". Media. University of Oxford. Archived from the original on 18 December 2013. Retrieved 13 December 2013.
- Harpending HC, Batzer MA, Gurven M, Jorde LB, Rogers AR, Sherry ST (February 1998). "Genetic traces of ancient demography". Proceedings of the National Academy of Sciences of the United States of America. 95 (4): 1961–7. Bibcode:1998PNAS...95.1961H. doi:10.1073/pnas.95.4.1961. PMC 19224. PMID 9465125.
- Jorde LB, Rogers AR, Bamshad M, Watkins WS, Krakowiak P, Sung S, et al. (April 1997). "Microsatellite diversity and the demographic history of modern humans". Proceedings of the National Academy of Sciences of the United States of America. 94 (7): 3100–3. Bibcode:1997PNAS...94.3100J. doi:10.1073/pnas.94.7.3100. PMC 20328. PMID 9096352.
- Wade N (7 March 2007). "Still Evolving, Human Genes Tell New Story". The New York Times. Archived from the original on 14 January 2012. Retrieved 13 February 2012.
- Pennisi E (February 2001). "The human genome". Science. 291 (5507): 1177–80. doi:10.1126/science.291.5507.1177. PMID 11233420. S2CID 38355565.
- Rotimi CN, Adeyemo AA (February 2021). "From one human genome to a complex tapestry of ancestry". Nature. 590 (7845): 220–221. Bibcode:2021Natur.590..220R. doi:10.1038/d41586-021-00237-2. PMID 33568827. S2CID 231882262.
- Altshuler DM, Gibbs RA, Peltonen L, Altshuler DM, Gibbs RA, Peltonen L, et al. (September 2010). "Integrating common and rare genetic variation in diverse human populations". Nature. 467 (7311): 52–8. Bibcode:2010Natur.467...52T. doi:10.1038/nature09298. PMC 3173859. PMID 20811451.
- Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes". Science. 367 (6484): eaay5012. doi:10.1126/science.aay5012. PMC 7115999. PMID 32193295. "Populations in central and southern Africa, the Americas, and Oceania each harbor tens to hundreds of thousands of private, common genetic variants. Most of these variants arose as new mutations rather than through archaic introgression, except in Oceanian populations, where many private variants derive from Denisovan admixture."
- Pertea M, Salzberg SL (2010). "Between a chicken and a grape: estimating the number of human genes". Genome Biology. 11 (5): 206. doi:10.1186/gb-2010-11-5-206. PMC 2898077. PMID 20441615.
- Cann RL, Stoneking M, Wilson AC (1987). "Mitochondrial DNA and human evolution". Nature. 325 (6099): 31–6. Bibcode:1987Natur.325...31C. doi:10.1038/325031a0. PMID 3025745. S2CID 4285418.
- Soares P, Ermini L, Thomson N, Mormina M, Rito T, Röhl A, et al. (June 2009). "Correcting for purifying selection: an improved human mitochondrial molecular clock". American Journal of Human Genetics. 84 (6): 740–59. doi:10.1016/j.ajhg.2009.05.001. PMC 2694979. PMID 19500773.
- "University of Leeds | News > Technology > New 'molecular clock' aids dating of human migration history". 20 August 2017. Archived from the original on 20 August 2017.
- Poznik GD, Henn BM, Yee MC, Sliwerska E, Euskirchen GM, Lin AA, et al. (August 2013). "Sequencing Y chromosomes resolves discrepancy in time to common ancestor of males versus females". Science. 341 (6145): 562–5. Bibcode:2013Sci...341..562P. doi:10.1126/science.1237619. PMC 4032117. PMID 23908239.
- Shehan CL (2016). The Wiley Blackwell Encyclopedia of Family Studies, 4 Volume Set. John Wiley & Sons. p. 406. ISBN 978-0-470-65845-1. Archived from the original on 10 September 2017.
- Jukic AM, Baird DD, Weinberg CR, McConnaughey DR, Wilcox AJ (October 2013). "Length of human pregnancy and contributors to its natural variation". Human Reproduction. 28 (10): 2848–55. doi:10.1093/humrep/det297. PMC 3777570. PMID 23922246.
- Klossner NJ (2005). Introductory Maternity Nursing. p. 103. ISBN 978-0-7817-6237-3.
The fetal stage is from the beginning of the 9th week after fertilization and continues until birth
- World Health Organization (November 2014). "Preterm birth Fact sheet N°363". who.int. Archived from the original on 7 March 2015. Retrieved 6 March 2015.
- Kiserud T, Benachi A, Hecher K, Perez RG, Carvalho J, Piaggio G, Platt LD (February 2018). "The World Health Organization fetal growth charts: concept, findings, interpretation, and application". American Journal of Obstetrics and Gynecology. 218 (2S): S619–S629. doi:10.1016/j.ajog.2017.12.010. PMID 29422204. S2CID 46810955.
- "What is the average baby length? Growth chart by month". www.medicalnewstoday.com. 18 March 2019. Retrieved 18 April 2021.
- Khor GL (December 2003). "Update on the prevalence of malnutrition among children in Asia". Nepal Medical College Journal. 5 (2): 113–22. PMID 15024783.
- Rosenberg KR (1992). "The evolution of modern human childbirth". American Journal of Physical Anthropology. 35 (S15): 89–124. doi:10.1002/ajpa.1330350605. ISSN 1096-8644.
- Pavličev M, Romero R, Mitteroecker P (January 2020). "Evolution of the human pelvis and obstructed labor: new explanations of an old obstetrical dilemma". American Journal of Obstetrics and Gynecology. 222 (1): 3–16. doi:10.1016/j.ajog.2019.06.043. PMID 31251927. S2CID 195761874.
- Barras C (22 December 2016). "The real reasons why childbirth is so painful and dangerous". BBC.
- Kantrowitz B (2 July 2007). "What Kills One Woman Every Minute of Every Day?". Newsweek. Archived from the original on 28 June 2007.
A woman dies in childbirth every minute, most often due to uncontrolled bleeding and infection, with the world's poorest women most vulnerable. The lifetime risk is 1 in 16 in sub-Saharan Africa, compared to 1 in 2,800 in developed countries.
- Rush D (July 2000). "Nutrition and maternal mortality in the developing world". The American Journal of Clinical Nutrition. 72 (1 Suppl): 212S–240S. doi:10.1093/ajcn/72.1.212S. PMID 10871588.
- Laland KN, Brown G (2011). Sense and Nonsense: Evolutionary Perspectives on Human Behaviour. Oxford University Press. p. 7. ISBN 978-0-19-958696-7.
- Kail RV, Cavanaugh JC (2010). Human Development: A Lifespan View (5th ed.). Cengage Learning. p. 296. ISBN 978-0-495-60037-4.
- Schuiling KD, Likis FE (2016). Women's Gynecologic Health. Jones & Bartlett Learning. p. 22. ISBN 978-1-284-12501-6.
The changes that occur during puberty usually happen in an ordered sequence, beginning with thelarche (breast development) at around age 10 or 11, followed by adrenarche (growth of pubic hair due to androgen stimulation), peak height velocity, and finally menarche (the onset of menses), which usually occurs around age 12 or 13.
- Phillips DC (2014). Encyclopedia of Educational Theory and Philosophy. Sage Publications. pp. 18–19. ISBN 978-1-4833-6475-9.
On average, the onset of puberty is about 18 months earlier for girls (usually starting around the age of 10 or 11 and lasting until they are 15 to 17) than for boys (who usually begin puberty at about the age of 11 to 12 and complete it by the age of 16 to 17, on average).
- Mintz S (1993). "Life stages". Encyclopedia of American Social History. 3: 7–33.
- Soliman A, De Sanctis V, Elalaily R, Bedair S (November 2014). "Advances in pubertal growth and factors influencing it: Can we increase pubertal growth?". Indian Journal of Endocrinology and Metabolism. 18 (Suppl 1): S53-62. doi:10.4103/2230-8210.145075. PMC 4266869. PMID 25538878.
- Walker ML, Herndon JG (September 2008). "Menopause in nonhuman primates?". Biology of Reproduction. 79 (3): 398–406. doi:10.1095/biolreprod.108.068536. PMC 2553520. PMID 18495681.
- Diamond J (1997). Why is Sex Fun? The Evolution of Human Sexuality. New York City: Basic Books. pp. 167–70. ISBN 978-0-465-03127-6.
- Peccei JS (2001). "Menopause: Adaptation or epiphenomenon?". Evolutionary Anthropology. 10 (2): 43–57. doi:10.1002/evan.1013. S2CID 1665503.
- Marziali C (7 December 2010). "Reaching Toward the Fountain of Youth". USC Trojan Family Magazine. Archived from the original on 13 December 2010. Retrieved 7 December 2010.
- Kalben BB (2002). "Why Men Die Younger: Causes of Mortality Differences by Sex". Society of Actuaries. Archived from the original on 1 July 2013.
- "Life expectancy at birth, female (years)". World Bank. 2018. Retrieved 13 October 2020.
- "Life expectancy at birth, male (years)". World Bank. 2018. Retrieved 13 October 2020.
- Conceição P, et al. (2019). Human Development Report (PDF). United Nations Development Programme. ISBN 978-92-1-126439-5.
- "Human Development Report 2019" (PDF). United Nations Development Programme.
- "The World Factbook". U.S. Central Intelligence Agency. Archived from the original on 12 September 2009. Retrieved 2 April 2005.
- "U.N. Statistics on Population Ageing". United Nations. 28 February 2002. Archived from the original on 8 December 2005. Retrieved 2 April 2005.
- Haenel H (1989). "Phylogenesis and nutrition". Die Nahrung. 33 (9): 867–87. PMID 2697806.
- Cordain L (2007). "Implications of Plio-pleistocene diets for modern humans". In Ungar PS (ed.). Evolution of the human diet: the known, the unknown and the unknowable. pp. 264–65.
"Since the evolutionary split between hominins and pongids approximately 7 million years ago, the available evidence shows that all species of hominins ate an omnivorous diet composed of minimally processed, wild-plant, and animal foods.
- American Dietetic Association (June 2003). "Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets". Journal of the American Dietetic Association. 103 (6): 748–65. doi:10.1053/jada.2003.50142. PMID 12778049.
- Crittenden AN, Schnorr SL (2017). "Current views on hunter-gatherer nutrition and the evolution of the human diet". American Journal of Physical Anthropology. 162 (S63): 84–109. doi:10.1002/ajpa.23148. PMID 28105723.
- Cordain L, Eaton SB, Sebastian A, Mann N, Lindeberg S, Watkins BA, et al. (February 2005). "Origins and evolution of the Western diet: health implications for the 21st century". The American Journal of Clinical Nutrition. 81 (2): 341–54. doi:10.1093/ajcn.81.2.341. PMID 15699220.
- Ulijaszek SJ (November 2002). "Human eating behaviour in an evolutionary ecological context". The Proceedings of the Nutrition Society. 61 (4): 517–26. doi:10.1079/PNS2002180. PMID 12691181.
- Harrington SP (July–August 1997). "Earliest Agriculture in the New World". Archaeology Newsbriefs. 50 (4). Archived from the original on 3 June 2010.
- Balter M (13 February 2007). "Double Cropping the Earliest Agriculture". ScienceNOW Daily News. American Association for the Advancement of Science. Archived from the original on 16 February 2007.
- Morelle R (2 June 2006). "Ancient fig clue to first farming". BBC News. Archived from the original on 2 June 2006. Retrieved 19 February 2007.
- Krebs JR (September 2009). "The gourmet ape: evolution and human food preferences". The American Journal of Clinical Nutrition. 90 (3): 707S–711S. doi:10.3945/ajcn.2009.27462B. PMID 19656837.
- Holden C, Mace R (October 1997). "Phylogenetic analysis of the evolution of lactose digestion in adults". Human Biology. 69 (5): 605–28. PMID 9299882.
- Gibbons A. "The Evolution of Diet". National Geographic. Retrieved 18 April 2021.
- Ritchie H, Roser M (20 August 2017). "Diet Compositions". Our World in Data.
- Lieberson AD (2004). "How Long Can a Person Survive without Food?". Scientific American. Retrieved 18 April 2021.
- Spector D (9 March 2018). "Here's how many days a person can survive without water". Business Insider Australia. Retrieved 18 April 2021.
- Holmes J. "Losing 25,000 to Hunger Every Day". United Nations. Retrieved 18 April 2021.
- Mai HJ (2020). "U.N. Warns Number Of People Starving To Death Could Double Amid Pandemic". NPR.org. Retrieved 18 April 2021.
- Murray CJ, Lopez AD (May 1997). "Global mortality, disability, and the contribution of risk factors: Global Burden of Disease Study". Lancet. 349 (9063): 1436–42. doi:10.1016/S0140-6736(96)07495-8. PMID 9164317. S2CID 2569153.
- Haslam DW, James WP (October 2005). "Obesity". Lancet. 366 (9492): 1197–209. doi:10.1016/S0140-6736(05)67483-1. PMID 16198769. S2CID 208791491.
- Catenacci VA, Hill JO, Wyatt HR (September 2009). "The obesity epidemic". Clinics in Chest Medicine. 30 (3): 415–44, vii. doi:10.1016/j.ccm.2009.05.001. PMID 19700042.
- de Beer H (March 2004). "Observations on the history of Dutch physical stature from the late-Middle Ages to the present". Economics and Human Biology. 2 (1): 45–55. doi:10.1016/j.ehb.2003.11.001. PMID 15463992.
- O'Neil D. "Adapting to Climate Extremes". Human Biological Adaptability. Palomar College. Archived from the original on 6 January 2013. Retrieved 6 January 2013.
- Rask-Andersen M, Karlsson T, Ek WE, Johansson Å (September 2017). "Gene-environment interaction study for BMI reveals interactions between genetic factors and physical activity, alcohol consumption and socioeconomic status". PLOS Genetics. 13 (9): e1006977. doi:10.1371/journal.pgen.1006977. PMC 5600404. PMID 28873402.
- Beja-Pereira A, Luikart G, England PR, Bradley DG, Jann OC, Bertorelle G, et al. (December 2003). "Gene-culture coevolution between cattle milk protein genes and human lactase genes". Nature Genetics. 35 (4): 311–3. doi:10.1038/ng1263. PMID 14634648. S2CID 20415396.
- Hedrick PW (October 2011). "Population genetics of malaria resistance in humans". Heredity. 107 (4): 283–304. doi:10.1038/hdy.2011.16. PMC 3182497. PMID 21427751.
- Weatherall DJ (May 2008). "Genetic variation and susceptibility to infection: the red cell and malaria". British Journal of Haematology. 141 (3): 276–86. doi:10.1111/j.1365-2141.2008.07085.x. PMID 18410566. S2CID 28191911.
- Shelomi M, Zeuss D (5 April 2017). "Bergmann's and Allen's Rules in Native European and Mediterranean Phasmatodea". Frontiers in Ecology and Evolution. 5. doi:10.3389/fevo.2017.00025. ISSN 2296-701X. S2CID 34882477.
- Panesar NS (September 2008). "Why are the high altitude inhabitants like the Tibetans shorter and lighter?". Medical Hypotheses. 71 (3): 453–6. doi:10.1016/j.mehy.2008.04.005. PMID 18495367.
- Ilardo MA, Moltke I, Korneliussen TS, Cheng J, Stern AJ, Racimo F, et al. (April 2018). "Physiological and Genetic Adaptations to Diving in Sea Nomads". Cell. 173 (3): 569–580.e15. doi:10.1016/j.cell.2018.03.054. PMID 29677510.
- Rogers AR, Iltis D, Wooding S (2004). "Genetic variation at the MC1R locus and the time since loss of human body hair". Current Anthropology. 45 (1): 105–08. doi:10.1086/381006. S2CID 224795768.
- Roberts D (2011). Fatal Invention. London, New York: The New Press.
- Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology. 33: 585–623. doi:10.1146/annurev.anthro.33.070203.143955.
- Jablonski NG, Chaplin G (May 2010). "Colloquium paper: human skin pigmentation as an adaptation to UV radiation". Proceedings of the National Academy of Sciences of the United States of America. 107 (Supplement_2): 8962–8. Bibcode:2010PNAS..107.8962J. doi:10.1073/pnas.0914628107. PMC 3024016. PMID 20445093.
- Jablonski NG, Chaplin G (July 2000). "The evolution of human skin coloration" (PDF). Journal of Human Evolution. 39 (1): 57–106. doi:10.1006/jhev.2000.0403. PMID 10896812. Archived from the original (PDF) on 14 January 2012.
- Harding RM, Healy E, Ray AJ, Ellis NS, Flanagan N, Todd C, et al. (April 2000). "Evidence for variable selective pressures at MC1R". American Journal of Human Genetics. 66 (4): 1351–61. doi:10.1086/302863. PMC 1288200. PMID 10733465.
- Robin A (1991). Biological Perspectives on Human Pigmentation. Cambridge: Cambridge University Press.
- "The Science Behind the Human Genome Project". Human Genome Project. US Department of Energy. Archived from the original on 2 January 2013. Retrieved 6 January 2013.
Almost all (99.9%) nucleotide bases are exactly the same in all people.
- O'Neil D. "Ethnicity and Race: Overview". Palomar College. Archived from the original on 6 January 2013. Retrieved 6 January 2013.
- Keita SO, Kittles RA, Royal CD, Bonney GE, Furbert-Harris P, Dunston GM, Rotimi CN (November 2004). "Conceptualizing human variation". Nature Genetics. 36 (11 Suppl): S17-20. doi:10.1038/ng1455. PMID 15507998.
- O'Neil D. "Models of Classification". Modern Human Variation. Palomar College. Archived from the original on 6 January 2013. Retrieved 6 January 2013.
- Jablonski N (2004). "The evolution of human skin and skin color". Annual Review of Anthropology. 33: 585–623. doi:10.1146/annurev.anthro.33.070203.143955.
- Palmié S (May 2007). "Genomics, divination, 'racecraft'". American Ethnologist. 34 (2): 205–22. doi:10.1525/ae.2007.34.2.205.
- "Genetic – Understanding Human Genetic Variation". Human Genetic Variation. National Institute of Health (NIH). Archived from the original on 25 August 2013. Retrieved 13 December 2013.
In fact, research results consistently demonstrate that about 85 percent of all human genetic variation exists within human populations, whereas about only 15 percent of variation exists between populations.
- Goodman A. "Interview with Alan Goodman". Race Power of and Illusion. PBS. Archived from the original on 29 October 2012. Retrieved 6 January 2013.
- Marks J (2010). "Ten facts about human variation". In Muehlenbein M (ed.). Human Evolutionary Biology (PDF). New York: Cambridge University Press. Archived from the original (PDF) on 15 April 2012. Retrieved 5 September 2013.
- Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology. 33: 585–623. doi:10.1146/annurev.anthro.33.070203.143955.
genetic evidence [demonstrate] that strong levels of natural selection acted about 1.2 mya to produce darkly pigmented skin in early members of the genus Homo
- O'Neil D. "Overview". Modern Human Variation. Palomar College. Archived from the original on 5 November 2012. Retrieved 6 January 2013.
- Jorde LB, Watkins WS, Bamshad MJ, Dixon ME, Ricker CE, Seielstad MT, Batzer MA (March 2000). "The distribution of human genetic diversity: a comparison of mitochondrial, autosomal, and Y-chromosome data". American Journal of Human Genetics. 66 (3): 979–88. doi:10.1086/302825. PMC 1288178. PMID 10712212.
- "New Research Proves Single Origin Of Humans In Africa". Science Daily. 19 July 2007. Archived from the original on 4 November 2011. Retrieved 5 September 2011.
- Manica A, Amos W, Balloux F, Hanihara T (July 2007). "The effect of ancient population bottlenecks on human phenotypic variation". Nature. 448 (7151): 346–348. Bibcode:2007Natur.448..346M. doi:10.1038/nature05951. PMC 1978547. PMID 17637668.
- Chen L, Wolf AB, Fu W, Li L, Akey JM (February 2020). "Identifying and Interpreting Apparent Neanderthal Ancestry in African Individuals". Cell. 180 (4): 677–687.e16. doi:10.1016/j.cell.2020.01.012. PMID 32004458. S2CID 210955842.
- Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes". Science. 367 (6484): eaay5012. doi:10.1126/science.aay5012. PMC 7115999. PMID 32193295. "An analysis of archaic sequences in modern populations identifies ancestral genetic variation in African populations that likely predates modern humans and has been lost in most non-African populations."
- Durvasula A, Sankararaman S (February 2020). "Recovering signals of ghost archaic introgression in African populations". Science Advances. 6 (7): eaax5097. Bibcode:2020SciA....6.5097D. doi:10.1126/sciadv.aax5097. PMC 7015685. PMID 32095519. "Our analyses of site frequency spectra indicate that these populations derive 2 to 19% of their genetic ancestry from an archaic population that diverged before the split of Neanderthals and modern humans."
- Pierce BA (2012). Genetics: A Conceptual Approach. Macmillan. p. 75. ISBN 978-1-4292-3252-4.
- Muehlenbein MP (29 July 2010). Jones J (ed.). Human Evolutionary Biology. Cambridge University Press. p. 74. ISBN 978-0-521-87948-4.
- Fusco G, Minelli A (10 October 2019). The Biology of Reproduction. Cambridge University Press. p. 304. ISBN 978-1-108-49985-9.
- Gustafsson A, Lindenfors P (October 2004). "Human size evolution: no evolutionary allometric relationship between male and female stature". Journal of Human Evolution. 47 (4): 253–66. doi:10.1016/j.jhevol.2004.07.004. PMID 15454336.
- Ogden CL, Fryar CD, Carroll MD, Flegal KM (October 2004). "Mean body weight, height, and body mass index, United States 1960-2002" (PDF). Advance Data (347): 1–17. PMID 15544194. Archived from the original (PDF) on 23 February 2011.
- Miller AE, MacDougall JD, Tarnopolsky MA, Sale DG (1993). "Gender differences in strength and muscle fiber characteristics". European Journal of Applied Physiology and Occupational Physiology. 66 (3): 254–62. doi:10.1007/BF00235103. hdl:11375/22586. PMID 8477683. S2CID 206772211.
- Bredella MA (2017). "Sex Differences in Body Composition". In Mauvais-Jarvis F (ed.). Sex and Gender Factors Affecting Metabolic Homeostasis, Diabetes and Obesity. Advances in Experimental Medicine and Biology. Vol. 1043. Cham: Springer International Publishing. pp. 9–27. doi:10.1007/978-3-319-70178-3_2. ISBN 978-3-319-70177-6. PMID 29224088.
- Rahrovan S, Fanian F, Mehryan P, Humbert P, Firooz A (September 2018). "Male versus female skin: What dermatologists and cosmeticians should know". International Journal of Women's Dermatology. 4 (3): 122–130. doi:10.1016/j.ijwd.2018.03.002. PMC 6116811. PMID 30175213.
- Easter C. "Sex Linked". National Human Genome Research Institute. Retrieved 18 April 2021.
- Puts DA, Gaulin SJ, Verdolini K (July 2006). "Dominance and the evolution of sexual dimorphism in human voice pitch". Evolution and Human Behavior. 27 (4): 283–96. doi:10.1016/j.evolhumbehav.2005.11.003.
- "Gender, women, and health". Reports from WHO 2002–2005. Archived from the original on 25 June 2013.
- "3-D Brain Anatomy". The Secret Life of the Brain. Public Broadcasting Service. Archived from the original on 5 September 2017. Retrieved 3 April 2005.
- Stern P (22 June 2018). "The human prefrontal cortex is special". Science. 360 (6395): 1311–1312. Bibcode:2018Sci...360S1311S. doi:10.1126/science.360.6395.1311-g. ISSN 0036-8075. S2CID 149581944.
- Erickson R (22 September 2014). "Are Humans the Most Intelligent Species?". Journal of Intelligence. 2 (3): 119–121. doi:10.3390/jintelligence2030119. ISSN 2079-3200.
- "Humans not smarter than animals, just different, experts say". phys.org. Retrieved 24 October 2020.
- Robson D. "We've got human intelligence all wrong". www.bbc.com. Retrieved 24 October 2020.
- Owen J (26 February 2015). "Many Animals—Including Your Dog—May Have Horrible Short-Term Memories". National Geographic News. Retrieved 6 September 2020.
- Schmidt KL, Cohn JF (2001). "Human facial expressions as adaptations: Evolutionary questions in facial expression research". American Journal of Physical Anthropology. 116 (S33): 3–24. doi:10.1002/ajpa.20001. PMC 2238342. PMID 11786989.
- Moisse K (5 January 2011). "Tears in Her Eyes: A Turnoff for Guys?". ABC News (American). Retrieved 22 April 2020.
- Deleniv S (2018). "The 'me' illusion: How your brain conjures up your sense of self". New Scientist. Retrieved 22 April 2020.
- Beck J (2019). "Can We Really Know What Animals Are Thinking?". Snopes. Retrieved 22 April 2020.
- Grandner MA, Patel NP, Gehrman PR, Perlis ML, Pack AI (August 2010). "Problems associated with short sleep: bridging the gap between laboratory and epidemiological studies". Sleep Medicine Reviews. 14 (4): 239–47. doi:10.1016/j.smrv.2009.08.001. PMC 2888649. PMID 19896872.
- Ann L (27 January 2005). "HowStuffWorks "Dreams: Stages of Sleep"". Science.howstuffworks.com. Archived from the original on 15 May 2012. Retrieved 11 August 2012.
- Hobson JA (November 2009). "REM sleep and dreaming: towards a theory of protoconsciousness". Nature Reviews. Neuroscience. 10 (11): 803–13. doi:10.1038/nrn2716. PMID 19794431. S2CID 205505278.
- Empson J (2002). Sleep and dreaming (3rd ed.). New York: Palgrave/St. Martin's Press.
- Cherry K (2015). "10 Facts About Dreams: What Researchers Have Discovered About Dreams". About Education: Psychology. About.com. Archived from the original on 21 February 2016.
- Lite J (29 July 2010). "How Can You Control Your Dreams?". Scientific America. Archived from the original on 2 February 2015.
- Domhoff W (2002). The scientific study of dreams. APA Press.
- "Consciousness". Merriam-Webster. Retrieved 4 June 2012.
- van Gulick R (2004). "Consciousness". Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University.
- Schneider S, Velmans M (2008). "Introduction". In Velmans M, Schneider S (eds.). The Blackwell Companion to Consciousness. Wiley. ISBN 978-0-470-75145-9.
- Searle J (2005). "Consciousness". In Honderich T (ed.). The Oxford companion to philosophy. Oxford University Press. ISBN 978-0-19-926479-7.
- Block N (June 1995). "On a confusion about a function of consciousness". Behavioral and Brain Sciences. 18 (2): 227–47. doi:10.1017/S0140525X00038474. S2CID 246244859.
- Jaynes J (2000) . The Origin of Consciousness in the Breakdown of the Bicameral Mind (PDF). Houghton Mifflin. ISBN 0-618-05707-2. Archived from the original (PDF) on 7 August 2019. Retrieved 25 October 2020.
- Rochat P (December 2003). "Five levels of self-awareness as they unfold early in life". Consciousness and Cognition. 12 (4): 717–31. doi:10.1016/s1053-8100(03)00081-3. PMID 14656513. S2CID 10241157.
- Carruthers P (15 August 2011). "Higher-Order Theories of Consciousness". Stanford Encyclopedia of Philosophy. Retrieved 31 August 2014.
- Antony MV (2001). "Is consciousness ambiguous?". Journal of Consciousness Studies. 8: 19–44.
- "Cognition". Lexico. Oxford University Press and Dictionary.com. Retrieved 6 May 2020.
- Glattfelder JB (2019). "The Consciousness of Reality". In Glattfelder JB (ed.). Information—Consciousness—Reality: How a New Understanding of the Universe Can Help Answer Age-Old Questions of Existence. The Frontiers Collection. Cham: Springer International Publishing. pp. 515–595. doi:10.1007/978-3-030-03633-1_14. ISBN 978-3-030-03633-1. S2CID 189379814.
- "American Psychological Association (2013). Glossary of psychological terms". Apa.org. Retrieved 13 August 2014.
- "Developmental Psychology Studies Human Development Across the Lifespan". www.apa.org. Archived from the original on 9 July 2014. Retrieved 28 August 2017.
- Burman E (2017). Deconstructing Developmental Psychology. New York, NY: Routledge. ISBN 978-1-138-84695-1.
- Colom R (1 January 2004). "Intelligence Assessment". Encyclopedia of Applied Psychology: 307–314. doi:10.1016/B0-12-657410-3/00510-9. ISBN 9780126574104.
- McLeod S (20 March 2020). "Maslow's Hierarchy of Needs". Simplypsychology.org. Simply Scholar Limited. Retrieved 4 April 2020.
Maslow's hierarchy of needs is a motivational theory in psychology comprising a five-tier model of human needs, often depicted as hierarchical levels within a pyramid. Needs lower down in the hierarchy must be satisfied before individuals can attend to needs higher up.
- Heckhausen J, Heckhausen H (28 March 2018). Motivation and Action. Introduction and Overview: Springer, Cham. p. 1. doi:10.1007/978-3-319-65094-4_1. ISBN 978-3-319-65093-7.
- Damasio AR (May 1998). "Emotion in the perspective of an integrated nervous system". Brain Research. Brain Research Reviews. 26 (2–3): 83–6. doi:10.1016/s0165-0173(97)00064-7. PMID 9651488. S2CID 8504450.
- Ekman P, Davidson RJ (1994). The Nature of emotion : fundamental questions. New York: Oxford University Press. pp. 291–93. ISBN 978-0-19-508944-8.
Emotional processing, but not emotions, can occur unconsciously.
- Cabanac M (2002). "What is emotion?". Behavioural Processes. 60 (2): 69–83. doi:10.1016/S0376-6357(02)00078-5. PMID 12426062. S2CID 24365776.
Emotion is any mental experience with high intensity and high hedonic content (pleasure/displeasure)
- Scirst DL (2011). Psychology Second Edition. New York, NY: Worth Publishers. p. 310. ISBN 978-1-4292-3719-2.
- Averill JR (April 1999). "Individual differences in emotional creativity: structure and correlates". Journal of Personality. 67 (2): 331–71. doi:10.1111/1467-6494.00058. PMID 10202807.
- Tyng CM, Amin HU, Saad MN, Malik AS (2017). "The Influences of Emotion on Learning and Memory". Frontiers in Psychology. 8: 1454. doi:10.3389/fpsyg.2017.01454. PMC 5573739. PMID 28883804.
- Van Gelder JL (November 2016). "Emotions in Criminal Decision Making". In Wright R (ed.). Oxford Bibliographies in Criminology. Oxford University Press.
- Sharma N, Prakash O, Sengar KS, Chaudhury S, Singh AR (2015). "The relation between emotional intelligence and criminal behavior: A study among convicted criminals". Industrial Psychiatry Journal. 24 (1): 54–8. doi:10.4103/0972-6748.160934. PMC 4525433. PMID 26257484.
- Fredrickson BL (March 2001). "The role of positive emotions in positive psychology. The broaden-and-build theory of positive emotions". The American Psychologist. 56 (3): 218–26. doi:10.1037/0003-066X.56.3.218. PMC 3122271. PMID 11315248.
- Haybron DM (August 2013). "The proper pursuit of happiness". Res Philosophica. 90 (3): 387–411. doi:10.11612/resphil.2013.90.3.5.
- Haybron DM (13 April 2014). "Happiness and Its Discontents". The Opinion Pages. The New York Times.
I would suggest that when we talk about happiness, we are actually referring, much of the time, to a complex emotional phenomenon. Call it emotional well-being. Happiness as emotional well-being concerns your emotions and moods, more broadly your emotional condition as a whole. To be happy is to inhabit a favorable emotional state.... On this view, we can think of happiness, loosely, as the opposite of anxiety and depression. Being in good spirits, quick to laugh and slow to anger, at peace and untroubled, confident and comfortable in your own skin, engaged, energetic and full of life.
- Graham MC (2014). Facts of Life: ten issues of contentment. Outskirts Press. pp. 6–10. ISBN 978-1-4787-2259-5.
- "Secret to happiness may include more unpleasant emotions: Research contradicts idea that people should always seek pleasure to be happy". ScienceDaily. American Psychological Association. 14 August 2017. Retrieved 25 October 2020.
- Greenberg JS, Bruess CE, Oswalt SB (2016). Exploring the Dimensions of Human Sexuality. Jones & Bartlett Publishers. pp. 4–10. ISBN 978-1-284-08154-1. Retrieved 21 June 2017.
Human sexuality is a part of your total personality. It involves the interrelationship of biological, psychological, and sociocultural dimensions. [...] It is the total of our physical, emotional, and spiritual responses, thoughts, and feelings.
- Bolin A, Whelehan P (2009). Human Sexuality: Biological, Psychological, and Cultural Perspectives. Taylor & Francis. pp. 32–42. ISBN 978-0-7890-2671-2.
- Younis I, Abdel-Rahman SH (2013). "Sex difference in libido". Human Andrology. 3 (4): 85–89. doi:10.1097/01.XHA.0000432482.01760.b0. S2CID 147235090.
- "Sexual orientation, homosexuality and bisexuality". American Psychological Association. Archived from the original on 8 August 2013. Retrieved 10 August 2013.
- Bailey JM, Vasey PL, Diamond LM, Breedlove SM, Vilain E, Epprecht M (September 2016). "Sexual Orientation, Controversy, and Science". Psychological Science in the Public Interest. 17 (2): 45–101. doi:10.1177/1529100616637616. PMID 27113562.
- LeVay S (2017). Gay, Straight, and the Reason Why: The Science of Sexual Orientation. Oxford University Press. pp. 8, 19. ISBN 978-0-19-975296-6.
- Balthazart J (2012). The Biology of Homosexuality. Oxford University Press. pp. 13–14. ISBN 978-0-19-983882-0.
- Buss DM (2003). The Evolution of Desire: Strategies of Human Mating (Revised ed.). New York City: Basic Books. ISBN 978-0-465-00802-5.
- Fromm E (2000). The art of loving. New York: Harper Perennial. ISBN 978-0-06-095828-2.
- "Love, Actually: The science behind lust, attraction, and companionship". Science in the News. 14 February 2017. Retrieved 25 October 2020.
- "What are the top 200 most spoken languages?". Ethnologue: Languages of the World. 2020.
- World. The World Factbook (Report). Central Intelligence Agency. Retrieved 15 November 2021.
- "The Changing Global Religious Landscape". Pew Research Center. 5 April 2017.
- Ord T (2020). The Precipice: Existential Risk and the Future of Humanity. New York: Hachette Books. ISBN 978-0-316-48489-3.
Homo sapiens and our close relatives may have some unique physical attributes, such as our dextrous hands, upright walking and resonant voices. However, these on their own cannot explain our success. They went together with our intelligence...
- Goldman JG (2012). "Pay attention… time for lessons at animal school". bbc.com. Retrieved 22 April 2020.
- Winkler M, Mueller JL, Friederici AD, Männel C (November 2018). "Infant cognition includes the potentially human-unique ability to encode embedding". Science Advances. 4 (11): eaar8334. Bibcode:2018SciA....4.8334W. doi:10.1126/sciadv.aar8334. PMC 6248967. PMID 30474053.
- Johnson-Frey SH (July 2003). "What's so special about human tool use?". Neuron. 39 (2): 201–4. doi:10.1016/S0896-6273(03)00424-0. PMID 12873378. S2CID 18437970.
- Emery NJ, Clayton NS (February 2009). "Tool use and physical cognition in birds and mammals". Current Opinion in Neurobiology. 19 (1): 27–33. doi:10.1016/j.conb.2009.02.003. PMID 19328675. S2CID 18277620.
In short, the evidence to date that animals have an understanding of folk physics is at best mixed.
- Lemonick MD (3 June 2015). "Chimps Can't Cook, But Maybe They'd Like To". National Geographic News. Retrieved 22 April 2020.
- Vakhitova T, Gadelshina L (2 June 2015). "The Role and Importance of the Study of Economic Subjects in the Implementation of the Educational Potential of Education". Procedia - Social and Behavioral Sciences. The Proceedings of 6th World Conference on educational Sciences. 191: 2565–2567. doi:10.1016/j.sbspro.2015.04.690. ISSN 1877-0428.
- McKie R (9 October 2018). "The Book of Humans by Adam Rutherford review – a pithy homage to our species". The Guardian. Retrieved 22 April 2020.
- Nicholls H (29 June 2015). "Babblers speak to the origin of language". The Guardian. Retrieved 22 April 2020.
- Dasgupta S (2015). "Can any animals talk and use language like humans?". bbc.com. Retrieved 22 April 2020.
Most animals are not vocal learners.
- Scott-Phillips TC, Blythe RA (18 September 2013). "Why is language unique to humans?". Royal Society. Retrieved 24 October 2020.
- Pagel M (July 2017). "Q&A: What is human language, when did it evolve and why should we care?". BMC Biology. 15 (1): 64. doi:10.1186/s12915-017-0405-3. PMC 5525259. PMID 28738867.
- Fitch WT (4 December 2010). "Language evolution: How to hear words long silenced". New Scientist. 208 (2789): ii–iii. Bibcode:2010NewSc.208D...2F. doi:10.1016/S0262-4079(10)62961-2. ISSN 0262-4079.
- Lian A (2016). "The Modality-Independent Capacity of Language: A Milestone of Evolution". In Lian A (ed.). Language Evolution and Developmental Impairments. London: Palgrave Macmillan UK. pp. 229–255. doi:10.1057/978-1-137-58746-6_7. ISBN 978-1-137-58746-6.
- "Culture | United Nations For Indigenous Peoples". www.un.org. 5 June 2015. Retrieved 24 October 2020.
- Comrie B, Polinsky M, Matthews S (1996). The Atlas of Languages: The Origin and Development of Languages Throughout the World. New York City: Facts on File. pp. 13–15. ISBN 978-0-8160-3388-1.
- Mavrody S (2013). Visual Art Forms: Traditional to Digital. Sergey's HTML5 & CSS3. ISBN 978-0-9833867-5-9.
- "Types of Literary Arts and Their Understanding – bookfestivalscotland.com". Bookfestival Scotland. 2020. Retrieved 5 May 2021.
- "Bachelor of Performing Arts" (PDF). University of Otago.
- Brown S (24 October 2018). "Toward a Unification of the Arts". Frontiers in Psychology. 9: 1938. doi:10.3389/fpsyg.2018.01938. ISSN 1664-1078. PMC 6207603. PMID 30405470.
- "Culinary arts - How cooking can be an art". Northern Contemporary Art. 21 October 2019. Retrieved 5 May 2021.
- Smuts A (1 January 2005). "Are Video Games Art?". Contemporary Aesthetics (Journal Archive). 3 (1).
- Cameron IA, Pimlott N (September 2015). "Art of medicine". Canadian Family Physician. 61 (9): 739–40. PMC 4569099. PMID 26371092.
- Bird G (7 June 2019). "Rethinking the role of the arts in politics: lessons from the Négritude movement". International Journal of Cultural Policy. 25 (4): 458–470. doi:10.1080/10286632.2017.1311328. ISSN 1028-6632. S2CID 151443044.
- Morriss-Kay GM (February 2010). "The evolution of human artistic creativity". Journal of Anatomy. 216 (2): 158–76. doi:10.1111/j.1469-7580.2009.01160.x. PMC 2815939. PMID 19900185.
- Joordens JC, d'Errico F, Wesselingh FP, Munro S, de Vos J, Wallinga J, et al. (February 2015). "Homo erectus at Trinil on Java used shells for tool production and engraving". Nature. 518 (7538): 228–31. Bibcode:2015Natur.518..228J. doi:10.1038/nature13962. PMID 25470048. S2CID 4461751.
- St Fleur N (12 September 2018). "Oldest Known Drawing by Human Hands Discovered in South African Cave". The New York Times. Retrieved 20 September 2018.
- Radford T (16 April 2004). "World's oldest jewellery found in cave". The Guardian. ISSN 0261-3077. Retrieved 23 September 2020.
- Dissanayake E (2008). "The Arts after Darwin: Does Art have an Origin and Adaptive Function?". In Zijlmans K, van Damme W (eds.). World Art Studies: Exploring Concepts and Approaches. Amsterdam: Valiz. pp. 241–263.
- Morley I (2014). "A multi-disciplinary approach to the origins of music: perspectives from anthropology, archaeology, cognition and behaviour". Journal of Anthropological Sciences = Rivista di Antropologia. 92 (92): 147–77. doi:10.4436/JASS.92008. PMID 25020016.
- Trost W, Frühholz S, Schön D, Labbé C, Pichon S, Grandjean D, Vuilleumier P (December 2014). "Getting the beat: entrainment of brain activity by musical rhythm and pleasantness". NeuroImage. 103: 55–64. doi:10.1016/j.neuroimage.2014.09.009. PMID 25224999. S2CID 4727529.
- Karpati FJ, Giacosa C, Foster NE, Penhune VB, Hyde KL (March 2015). "Dance and the brain: a review". Annals of the New York Academy of Sciences. 1337 (1): 140–6. Bibcode:2015NYASA1337..140K. doi:10.1111/nyas.12632. PMID 25773628. S2CID 206224849.
- Chow D (22 March 2010). "Why Do Humans Dance?". livescience.com. Retrieved 21 September 2020.
- Krakauer J (26 September 2008). "Why do we like to dance--And move to the beat?". Scientific American. Retrieved 21 September 2020.
- Prior KS (21 June 2013). "How Reading Makes Us More Human". The Atlantic. Retrieved 23 September 2020.
- Puchner M. "How stories have shaped the world". www.bbc.com. Retrieved 23 September 2020.
- Dalley S (2000). Myths from Mesopotamia: Creation, the Flood, Gilgamesh, and Others (revised ed.). Oxford University Press. p. 41. ISBN 978-0-19-283589-5.
- Hernadi P (2001). "Literature and Evolution". SubStance. 30 (1/2): 55–71. doi:10.2307/3685504. ISSN 0049-2426. JSTOR 3685504.
- Gunn J (2005). "Humanity". In Westfahl G (ed.). The Greenwood Encyclopedia of Science Fiction and Fantasy: Themes, Works, and Wonders. Greenwood Publishing Group. pp. 399–401. ISBN 978-0-313-32951-7.
- McCurry J (21 April 2015). "Japan's Maglev Train Breaks World Speed Record with 600 km/h Test Run". The Guardian (U.S. ed.). New York.
- Clark JD, de Heinzelin J, Schick KD, Hart WK, White TD, WoldeGabriel G, et al. (June 1994). "African Homo erectus: old radiometric ages and young Oldowan assemblages in the Middle Awash Valley, Ethiopia". Science. 264 (5167): 1907–10. Bibcode:1994Sci...264.1907C. doi:10.1126/science.8009220. PMID 8009220.
- Choi CQ (11 November 2009). "Human Evolution: The Origin of Tool Use". livescience.com. Retrieved 9 October 2020.
- Orban GA, Caruana F (2014). "The neural basis of human tool use". Frontiers in Psychology. 5: 310. doi:10.3389/fpsyg.2014.00310. PMC 3988392. PMID 24782809.
- Berna F, Goldberg P, Horwitz LK, Brink J, Holt S, Bamford M, Chazan M (May 2012). "Microstratigraphic evidence of in situ fire in the Acheulean strata of Wonderwerk Cave, Northern Cape province, South Africa". Proceedings of the National Academy of Sciences of the United States of America. 109 (20): E1215-20. doi:10.1073/pnas.1117620109. PMC 3356665. PMID 22474385.
- Gowlett JA (June 2016). "The discovery of fire by humans: a long and convoluted process". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 371 (1696): 20150164. doi:10.1098/rstb.2015.0164. PMC 4874402. PMID 27216521.
- Damiano J (2018). "Neolithic Era Tools: Inventing a New Age". MagellanTV. Retrieved 9 October 2020.
- Deng Y, Wang P (2011). Ancient Chinese inventions. Cambridge, UK: Cambridge University Press. pp. 13–14. ISBN 978-0-521-18692-6. OCLC 671710733.
- Schifman J (9 July 2018). "The Entire History of Steel". Popular Mechanics. Retrieved 5 May 2021.
- National Geographic Society (9 January 2020). "Industrial Revolution and Technology". National Geographic Society. Retrieved 9 October 2020.
- Roser M, Ritchie H (11 May 2013). "Technological Progress". Our World in Data.
- Fallows J (23 October 2013). "The 50 Greatest Breakthroughs Since the Wheel". The Atlantic. Retrieved 5 May 2021.
- "Evolutionary Religious Studies: A New Field of Scientific Inquiry". Archived from the original on 17 August 2009.
- Boyer P (October 2008). "Being human: Religion: bound to believe?". Nature. 455 (7216): 1038–9. Bibcode:2008Natur.455.1038B. doi:10.1038/4551038a. PMID 18948934. S2CID 205040781.
- Emmons RA, Paloutzian RF (2003). "The psychology of religion". Annual Review of Psychology. 54 (1): 377–402. doi:10.1146/annurev.psych.54.101601.145024. PMID 12171998.
- King BJ (29 March 2016). "Chimpanzees: Spiritual But Not Religious?". The Atlantic. Retrieved 8 October 2020.
- Culotta E (November 2009). "Origins. On the origin of religion". Science. 326 (5954): 784–7. Bibcode:2009Sci...326..784C. doi:10.1126/science.326_784. PMID 19892955.
- Atkinson QD, Bourrat P (2011). "Beliefs about God, the afterlife and morality support the role of supernatural policing in human cooperation". Evolution and Human Behavior. 32 (1): 41–49. doi:10.1016/j.evolhumbehav.2010.07.008. ISSN 1090-5138.
- Idinopulos TA (1998). "What Is Religion?". CrossCurrents. 48 (3): 366–380. ISSN 0011-1953. JSTOR 24460821.
- Walker GC (1 August 2000). "Secular Eschatology: Beliefs about Afterlife". OMEGA - Journal of Death and Dying. 41 (1): 5–22. doi:10.2190/Q21C-5VED-GYW6-W091. ISSN 0030-2228. S2CID 145686249.
- Bautista JS, Herrera VE, Miranda RC (2017). "Scientific and Religious Beliefs about the Origin of Life and Life after Death: Validation of a Scale". Universal Journal of Educational Research. 5 (6): 995–1007. doi:10.13189/ujer.2017.050612. ISSN 2332-3205.
- McKay R, Whitehouse H (March 2015). "Religion and morality". Psychological Bulletin. 141 (2): 447–73. doi:10.1037/a0038455. PMC 4345965. PMID 25528346.
- "Summary of Religions and Beliefs". www.bolton.ac.uk. Retrieved 8 October 2020.
- Ball P (2015). "Complex societies evolved without belief in all-powerful deity". Nature News. doi:10.1038/nature.2015.17040. S2CID 183474917.
- Hall DE, Meador KG, Koenig HG (June 2008). "Measuring religiousness in health research: review and critique". Journal of Religion and Health (Submitted manuscript). 47 (2): 134–63. doi:10.1007/s10943-008-9165-2. PMC 8823950. PMID 19105008. S2CID 25349208.
- Sherwood H (27 August 2018). "Religion: why faith is becoming more and more popular". The Guardian. ISSN 0261-3077. Retrieved 8 October 2020.
- Hackett C, McClendon D (2017). "Christians remain world's largest religious group, but they are declining in Europe". Pew Research Center. Retrieved 8 October 2020.
- "The Changing Global Religious Landscape". Pew Research Center's Religion & Public Life Project. 5 April 2017. Retrieved 8 October 2020.
- Di Christina M. "A Very Human Story: Why Our Species Is Special". Scientific American. Retrieved 27 September 2020.
- Andersen H, Hepburn B (2020). "Scientific Method". In Zalta EN (ed.). The Stanford Encyclopedia of Philosophy (Winter 2020 ed.). Metaphysics Research Lab, Stanford University. Retrieved 8 October 2020.
- Lo Presti R (2014). "History of science: The first scientist". Nature. 512 (7514): 250–251. Bibcode:2014Natur.512..250L. doi:10.1038/512250a. ISSN 1476-4687. S2CID 4394696.
- Russo L (2004). The forgotten revolution : how science was born in 300 BC and why it had to be reborn. Berlin. p. 1. ISBN 978-3-642-18904-3. OCLC 883392276.
- Needham J, Wang L (1954). Science and civilisation in China. Cambridge [England]. p. 111. ISBN 0-521-05799-X. OCLC 779676.
- Henry J (2008). "Renaissance and Revolution". The scientific revolution and the origins of modern science (3 ed.). Houndsmills, Basingstoke, Hampshire: Palgrave Macmillan. ISBN 978-1-137-07904-6. OCLC 615209781.
- Hansson SO (2017). Zalta EN (ed.). "Science and Pseudo-Science". Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 11 June 2017. Retrieved 3 July 2017.
- Olmstead MC, Kuhlmeier VA (2015). Comparative Cognition. Cambridge University Press. pp. 209–10. ISBN 978-1-107-01116-8.
- "Branches of Science" (PDF). University of Chicago. Archived from the original (PDF) on 23 April 2017. Retrieved 26 June 2017.
- "What is Philosophy?". Department of Philosophy. Florida State University. Retrieved 8 October 2020.
- "Philosophy". Definition, Systems, Fields, Schools, & Biographies. Encyclopedia Britannica. Retrieved 8 October 2020.
- Kaufmann F, Russell B (1947). "A History of Western Philosophy and its Connection with Political and Social Circumstances from the Earliest Times to the Present Day". Philosophy and Phenomenological Research. 7 (3): 461. doi:10.2307/2102800. JSTOR 2102800.
- Messerly JG (25 March 2016). "What is the Difference Between Philosophy, Science, and Religion?". ieet.org. Retrieved 8 August 2020.
- Hassan NR, Mingers J, Stahl B (4 May 2018). "Philosophy and information systems: where are we and where should we go?". European Journal of Information Systems. 27 (3): 263–277. doi:10.1080/0960085X.2018.1470776. ISSN 0960-085X. S2CID 64796132.
- Schizzerotto A. "Social Stratification" (PDF). University of Trento. Archived from the original (PDF) on 20 March 2018. Retrieved 3 July 2017.
- Fukuyama F (2012). The origins of political order : from prehuman times to the French Revolution. Farrar, Straus and Giroux. p. 53. ISBN 978-0-374-53322-9. OCLC 1082411117.
- Ridgeway CL (2001). International Encyclopedia of the Social & Behavioral Sciences. ISBN 978-0-08-043076-8.
- Alters S, Schiff W (2009). Essential Concepts for Healthy Living. Jones & Bartlett Publishers. p. 143. ISBN 978-0763756413. Retrieved 3 January 2018.
- Fortin N (2005). "Gender Role Attitudes and the Labour Market Outcomes of Women Across OECD Countries". Oxford Review of Economic Policy. 21 (3): 416–438. doi:10.1093/oxrep/gri024.
- "The Nature of Kinship: Overview". www2.palomar.edu. Retrieved 24 October 2020.
- Itao K, Kaneko K (February 2020). "Evolution of kinship structures driven by marriage tie and competition". Proceedings of the National Academy of Sciences of the United States of America. 117 (5): 2378–2384. doi:10.1073/pnas.1917716117. PMC 7007516. PMID 31964846.
- Chandra K (2012). Constructivist theories of ethnic politics. Oxford University Press. pp. 69–70. ISBN 978-0-19-989315-7. OCLC 829678440.
- People J, Bailey G (2010). Humanity: An Introduction to Cultural Anthropology (9th ed.). Wadsworth Cengage learning. p. 389.
In essence, an ethnic group is a named social category of people based on perceptions of shared social experience or one's ancestors' experiences. Members of the ethnic group see themselves as sharing cultural traditions and history that distinguish them from other groups. Ethnic group identity has a strong psychological or emotional component that divides the people of the world into opposing categories of “us” and “them.” In contrast to social stratification, which divides and unifies people along a series of horizontal axes based on socioeconomic factors, ethnic identities divide and unify people along a series of vertical axes. Thus, ethnic groups, at least theoretically, cut across socioeconomic class differences, drawing members from all strata of the population.
- Blackmore E (22 February 2019). "Race and ethnicity: How are they different?". Culture. Retrieved 24 October 2020.
- Chandra K (2006). "What is Ethnic Identity and Does It Matter?". Annual Review of Political Science. 9 (1): 397–424. doi:10.1146/annurev.polisci.9.062404.170715. ISSN 1094-2939.
- Smith AD (1999). Myths and Memories of the Nation. Oxford University Press. pp. 4–7.
- Banton M (2007). "Max Weber on 'ethnic communities': a critique". Nations and Nationalism. 13 (1): 19–35. doi:10.1111/j.1469-8129.2007.00271.x.
- Delanty G, Kumar K (2006). The SAGE Handbook of Nations and Nationalism. London: SAGE. p. 171. ISBN 978-1-4129-0101-7.
- Holslag J. A political history of the world: three thousand years of war and peace. pp. 24–25. ISBN 978-0-241-38466-4. OCLC 1080190517.
- Christian D (2004). Maps of Time. University of California Press. ISBN 978-0-520-24476-4.
- Nuwer R. "Why governments are broken – and how to fix them". www.bbc.com. Retrieved 24 October 2020.
- Cronk L, Leech BL (20 September 2017). "How Did Humans Get So Good at Politics?". SAPIENS. Retrieved 24 October 2020.
- Zmigrod L, Rentfrow PJ, Robbins TW (May 2018). "Cognitive underpinnings of nationalistic ideology in the context of Brexit". Proceedings of the National Academy of Sciences of the United States of America. 115 (19): E4532–E4540. doi:10.1073/pnas.1708960115. PMC 5948950. PMID 29674447. S2CID 4993139.
- Melina R (14 February 2011). "What Are the Different Types of Governments?". livescience.com. Retrieved 24 October 2020.
- DeSilver D. "Despite global concerns about democracy, more than half of countries are democratic". Pew Research Center. Retrieved 24 October 2020.
- National Geographic Society (23 December 2012). "international organization". National Geographic Society. Retrieved 24 October 2020.
- Horan RD, Bulte E, Shogren JF (1 September 2005). "How trade saved humanity from biological exclusion: an economic theory of Neanderthal extinction". Journal of Economic Behavior & Organization. 58 (1): 1–29. doi:10.1016/j.jebo.2004.03.009. ISSN 0167-2681.
- Gibbons J (11 August 2015). "Why did Neanderthals go extinct?". Smithsonian Insider. Retrieved 11 October 2020.
- University of Wyoming (24 March 2005). "Did Use of Free Trade Cause Neanderthal Extinction?". www.newswise.com. Retrieved 11 October 2020.
- Polianskaya A (15 March 2018). "Humans may have been trading with each for as long as 300,000 years". inews.co.uk. Retrieved 11 October 2020.
- Henriques M. "How spices changed the ancient world". www.bbc.com. Retrieved 11 October 2020.
- Strauss IE (26 February 2016). "The Myth of the Barter Economy". The Atlantic. Retrieved 11 October 2020.
- "The History of Money". www.pbs.org. Retrieved 11 October 2020.
- "Why do we need economists and the study of economics?". Federal Reserve Bank of San Francisco. Retrieved 23 October 2020.
- Sheskin M. "The inequality delusion: Why we've got the wealth gap all wrong". New Scientist. Retrieved 24 October 2020.
- Yong E (28 September 2016). "Humans: Unusually Murderous Mammals, Typically Murderous Primates". The Atlantic. Retrieved 7 May 2021.
- Gómez JM, Verdú M, González-Megías A, Méndez M (October 2016). "The phylogenetic roots of human lethal violence". Nature. 538 (7624): 233–237. Bibcode:2016Natur.538..233G. doi:10.1038/nature19758. PMID 27680701. S2CID 4454927.
- Pagel M (October 2016). "Animal behaviour: Lethal violence deep in the human lineage" (PDF). Nature. 538 (7624): 180–181. Bibcode:2016Natur.538..180P. doi:10.1038/nature19474. PMID 27680700. S2CID 4459560.
- Ferguson RB (1 September 2018). "War Is Not Part of Human Nature". Scientific American.
- Ferguson N (September–October 2006). "The Next War of the World". Foreign Affairs.