The chin is the forward pointed part of the anterior mandible ( mental region ) below the lower lip . A fully developed human skull has a chin of between 0.7 cm and 1.1 cm.
99-421: The presence of a well-developed chin is considered to be one of the morphological characteristics of Homo sapiens that differentiates them from other human ancestors such as the closely related Neanderthals . Early human ancestors have varied symphysial morphology, but none of them have a well-developed chin. The origin of the chin is traditionally associated with the anterior–posterior breadth shortening of
198-481: A good luck charm (particularly, children born with them are seen as pleasant, polite and enthusiastic), but can lead to complicated romantic relationships; Haitian mothers gently form indents into newborns' cheek in hopes of molding dimples into the child's face; and a proverb (often incorrectly credited to Pope Paul VI ) argues "A dimple in your cheek/Many hearts you'll seek/A dimple in your chin/The devil within". According to Candy Bites: The Science of Sweets ,
297-415: A multi-layered network of cooperating, distinct, or even competing social groups – from families and peer groups to corporations and political states . As such, social interactions between humans have established a wide variety of values, social norms , languages , and traditions (collectively termed institutions ), each of which bolsters human society . Humans are also highly curious , with
396-668: 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 through complex reasoning and the transmission of knowledge to subsequent generations through language . 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
495-438: A Greek study spanning almost 20 years concluded that 34% of Greek adults had dimples whereas 13% of Greek youths (between 7 and 15 years old) had dimples as well, which might suggest that transient dimples are more common than permanent. Professor John McDonald, citing limited research, concluded that dimples have been mislabeled as genetically inherited and as a dominant trait . It is believed that cheek dimple genes occur on
594-416: A baby born with dimples in their cheeks may lose them as they grow into a child owing to their diminishing baby fat. Dimples are usually located on mobile tissue, and are possibly caused by variations in the structure of the facial muscle known as zygomaticus major . Specifically, the presence of a double or bifid zygomaticus major muscle may explain the formation of cheek dimples. This bifid variation of
693-443: 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
792-479: A dimpled chin: a study from 2010 by the University of Ilorin examined 500 Yoruban Nigerians with both uni- and bilateral cheek dimples, discovering that only 36 (7.2%) had a cleft chin as well. The shape of a person's face can affect the look and form as well: leptoprosopic (long and narrow) faces have long and narrow dimples, and euryprosopic (short and broad) faces have short, circular dimples. People with
891-419: A few other places), saw the emergence of agriculture and permanent human settlement ; in turn, this led to the development of civilization and kickstarted a period of continuous (and ongoing) population growth and rapid technological change . Since then, a number of civilizations have risen and fallen, while a number of sociocultural and technological developments have resulted in significant changes to
990-474: A genetic marker called rs11684042, which is located in chromosome 2 . In Persian literature , the chin dimple is considered a factor of beauty and is metaphorically referred to as "the chin pit" or "the chin well": a well in which the poor lover is fallen and trapped. A double chin is a loss of definition of the jawbone or soft tissue under the chin. There are two possible causes for a double chin, which have to be differentiated. In overweight people, commonly
1089-463: 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
SECTION 10
#17327660306971188-612: A higher body fat percentage. At puberty , humans develop secondary sex characteristics . Females are capable of pregnancy , usually between puberty, at around 12 years old, and menopause , around the age of 50. As omnivorous creatures, they are 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 Homo erectus . Humans can survive for up to eight weeks without food and several days without water . Humans are generally diurnal , sleeping on average seven to nine hours per day. Childbirth
1287-475: A human can lose personhood (such as by going into a persistent vegetative state ). Humans are apes ( superfamily Hominoidea ). The lineage of apes that eventually gave rise to humans first split from gibbons (family Hylobatidae) and orangutans (genus Pongo ), then gorillas (genus Gorilla ), and finally, chimpanzees and bonobos (genus Pan ). The last split, between the human and chimpanzee–bonobo lineages, took place around 8–4 million years ago, in
1386-480: A humanizing touch" in the handsome Denny who had "dimples in conjunction with the physique of a young Greek god[.]" Women without dimples are said to envy the women that have them because dimples are "pitfalls for the men" that "[are] something purely natural and unattainable by art". While it is not possible to give a definite explanation as to why dimples are attractive on a woman, researchers believe this "neutral feature" can be linked to paternity confidence, which
1485-509: A mesoprosopic face are more likely to have dimples in their cheeks than any other face shape. Singaporean plastic surgeon Khoo Boo-Chai (1929–2012) determined that a cheek dimple occurs on the intersecting line between the corner of the mouth and the outer canthi of the eye, (nicknamed the "KBC point" in dimple surgery) but people with natural dimples do not always have their dimples on the KBC point. The other common type of facial dimple form near
1584-581: A more barrel-shaped chests in contrast to the funnel shape of other apes, an adaptation for bipedal respiration. 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 predominantly 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
1683-504: 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
1782-524: A paragraph about Molly wondering whether she was beautiful as she looked in her mirror, which was followed by: "She would have been sure if, instead of inspecting herself with such solemnity, she had smiled her own sweet merry smile, and called out the gleam of her teeth, and the charm of her dimples." Scarlett O'Hara exploited her cheek dimples in Gone with the Wind when she was flirting to get her own way, to
1881-451: 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
1980-639: A similar species. Migrating out of Africa , they gradually replaced and interbred with local populations of archaic humans. Multiple hypotheses for the extinction of archaic human species such as Neanderthals include competition, violence , interbreeding with Homo sapiens , or inability to adapt to climate change . Humans began exhibiting behavioral modernity about 160,000–60,000 years ago. For most of their history, humans were nomadic hunter-gatherers. The Neolithic Revolution , which began in Southwest Asia around 13,000 years ago (and separately in
2079-515: A simple linear or branched progression but involved interbreeding between related species . Genomic research has shown that hybridization between substantially diverged lineages was common in human evolution. DNA evidence suggests that several genes of Neanderthal origin are present among all non sub-Saharan-African populations, and Neanderthals and other hominins, such as Denisovans , may have contributed up to 6% of their genome to present-day non sub-Saharan-African humans. Human evolution
SECTION 20
#17327660306972178-451: 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
2277-406: 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
2376-511: 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
2475-485: 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
2574-424: Is a population decline in the winter months of this realm. Humans established nation-states in the other seven realms, such as South Africa , India , Russia , Australia , Fiji , United States and Brazil (each located in a different biogeographical realm). By using advanced tools and clothing , humans have been able to extend their tolerance to a wide variety of temperatures, humidities , and altitudes. As
2673-462: Is also a classic example of variable penetrance with environmental factors or a modifier gene possibly affecting the phenotypical expression of the actual genotype . Cleft chins can be presented in a child when neither parent presents a cleft chin. Cleft chins are common among people originating from Europe, the Middle East and South Asia. There is a possible genetic cause for cleft chins,
2772-402: 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 hairlessness , obligate bipedalism, increased brain size and decreased sexual dimorphism ( neoteny ). The relationship between all these changes
2871-456: 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 in other primates. The reason for this is not completely understood, but it contributes to a painful labor that can last 24 hours or more. The chances of
2970-421: 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, highly developed, and complex prefrontal cortex , the region of the brain associated with higher cognition. Humans are highly intelligent and capable of episodic memory ; they have flexible facial expressions, self-awareness , and
3069-479: 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. In 2012, the United Nations estimated that there were 316,600 living centenarians (humans of age 100 or older) worldwide. Humans are omnivorous , capable of consuming
Chin - Misplaced Pages Continue
3168-443: 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
3267-408: 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
3366-460: Is never seen upon the most extravagant jests to disorder her countenance with the ruffle of a smile [but] very rarely takes the freedom to sink her cheek into a dimple" implying that dimples are alluring due to demure women that have them. The Englishwoman's Magazine from 1866 featured an article named "The Human Form Divine: Dimples and Wrinkles", which associated cheek dimples with youth. On transient dimples, it wrote: "But generally, dimples mark
3465-521: 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
3564-416: Is prominently reflected in human culture and has led to the development of food science . Dimple This is an accepted version of this page A dimple , also called a gelasin (from Latin gelasinus , from Ancient Greek γελασῖνος ( gelasînos ) ), and a fovea buccalis , is a small natural indentation in the flesh on a part of the human body, most notably in
3663-808: Is the ability of a man to easily distinguish his own offspring. This has led to artificial attempts to create them: the Ohio-based Dolly Dimpler company advertized in Photoplay about a device that created dimples in customers' cheeks; in 1936, Isabella Gilbert invented the Dimple Maker, a face-fitting brace which pushed dents into the cheeks to emulate dimples, but it is unknown whether the artificial dimples could last this way (the American Medical Association argued that frequent users could develop cancer); and in
3762-445: Is the subject of ongoing debate. Hylobatidae ( gibbons ) Pongo abelii Pongo tapanuliensis Pongo pygmaeus Gorilla gorilla Gorilla beringei Pan troglodytes Pan paniscus Homo sapiens (humans) 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
3861-654: 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 ,
3960-548: The British Empire expanded to become the world's largest empire . 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 of the world's countries . The war's destruction led to
4059-580: The Caral–Supe civilization is the oldest complex civilization in the Americas. 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
Chin - Misplaced Pages Continue
4158-451: The Church would provide centralized authority and education. In the Middle East, Islam became the prominent religion and expanded into North Africa. It led to an Islamic Golden Age , inspiring achievements in architecture , the revival of old advances in science and technology, and the formation of a distinct way of life. The Christian and Islamic worlds would eventually clash, with
4257-474: The Homo genus. 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
4356-579: 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, between 200 and 900 CE Mesoamerica was in its Classic Period , while further north, complex Mississippian societies would arise starting around 800 CE. The Mongol Empire would conquer much of Eurasia in the 13th and 14th centuries. Over this same time period,
4455-854: 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. By the late 15th century, the Aztecs and Inca had become the dominant power in Mesoamerica and the Andes , respectively. The early modern period in Europe and
4554-587: 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
4653-652: The Poverty Point culture , Minoans and the Shang dynasty , rose to prominence in new areas. The Late Bronze Age collapse around 1200 BCE resulted 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
4752-499: The cheek . Numerous cultures believe that cheek dimples are a good luck charm that entices people who perceive them as physically attractive, but they are also associated with heroism and innocence, which has been included in literature for many centuries. Medical research debates whether cheek dimples can be inherited or which type of allele they are, but it is certain that humans with cheek dimples are more likely to have them in both cheeks. Depth and length appearances are affected by
4851-795: The colonization of the Americas and the Columbian Exchange . 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 . Influenced by Enlightenment ideals,
4950-422: The dental arch or tooth row; however, its general mechanical or functional advantage during feeding, developmental origin, and link with human speech, physiology, and social influence are highly debated. Robinson (1913) suggests that the demand to resist masticatory stresses triggered bone thickening in the mental region of the mandible and ultimately formed a prominent chin. Moreover, Daegling (1993) explains
5049-473: The prenatal period , but the chin does not become prominent until the early postnatal period . This later modification happens by bone remodeling processes ( bone resorption and bone deposition ). Coquerelle et al. show that the anteriorly positioned cervical column of the spine and forward displacement of the hyoid bone limit the anterior–posterior breadth in the oral cavity for the tongue, laryngeal , and suprahyoid musculatures. Accordingly, this leads
SECTION 50
#17327660306975148-438: The 21st century, people undergo dimple surgery . The sentiments appear in fiction: authors have described dimples in their characters for centuries to show beauty, especially in women, which has been seen as part of their sex appeal. This is possibly why cheek dimples have been identified with female characters: Anne from Anne of Green Gables envied other female characters' dimples, whereas Wives and Daughters featured
5247-468: The 5th chromosome , whereas cleft chin genes occur on the 16th. However, the University of Utah considers dimples an "irregular" dominant trait that is probably controlled mostly by one gene but is influenced by other genes. Having bilateral dimples (dimples in both cheeks) is the most common form of cheek dimples. In a 2018 study of 216 people aged 18–42 with both unilateral (one dimple) and bilateral, 120 (55.6%) had dimples in both of their cheeks. It
5346-518: The Americas and Europe experienced a period of political revolutions known as the Age of Revolution . The Napoleonic Wars raged through Europe in the early 1800s, Spain lost most of its colonies in the New World , while Europeans continued expansion into Africa – where European control went from 10% to almost 90% in less than 50 years – and Oceania. In the 19th century,
5445-511: The Human Chin , evolutionary anthropologists James Pampush and David Daegling discuss various theories that have been raised to solve the puzzle of the chin. They conclude that "each of the proposals we have discussed falter either empirically or theoretically; some fail, to a degree, on both accounts… This should serve as motivation, not discouragement, for researchers to continue investigating this modern human peculiarity… perhaps understanding
5544-876: The Mediterranean. In West Asia, the Achaemenid Empire 's system of centralized governance became the precursor to many later empires, while the Gupta Empire in India and the Han dynasty in China have been described as golden ages in their respective regions. Following the fall of the Western Roman Empire in 476, Europe entered the Middle Ages . During this period, Christianity and
5643-832: The Near East ( c. 1450 –1800) began with the final defeat of the Byzantine Empire , and the rise of the Ottoman Empire . Meanwhile, Japan entered the Edo period , the Qing dynasty rose in China and the Mughal Empire ruled much of India. Europe underwent the Renaissance , starting in the 15th century, and the Age of Discovery began with the exploring and colonizing of new regions. This included
5742-478: 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. Currently the species is present in all eight biogeographical realms , although their presence in the Antarctic realm is very limited to research stations and annually there
5841-561: 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. Compared to other apes, the human heart produces greater stroke volume and cardiac output and the aorta is proportionately larger. 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
5940-447: The chin (lower or inferior part) is depository in its nature. These coordinated bone growth and modeling processes mold the vertical symphysis present at birth into the prominent shape of the chin. Recent research on the development of the chin suggests that the evolution of this unique characteristic was formed not by mechanical forces such as chewing but by evolutionary adaptations involving reduction in size and change in shape of
6039-402: The chin as a functional adaptation to resist masticatory stress that causes vertical bending stresses in the coronal plane . Others have argued that the prominent chin is adapted to resisting wishboning forces, dorso-ventral shear forces, and generally a mechanical advantage to resist lateral transverse bending and vertical bending in the coronal plane. On the contrary, others have suggested that
SECTION 60
#17327660306976138-483: The chin in turn will not project forward enough to give the impression of a defined jawline and chin. Despite low amounts of fat in the area, it can appear as if the chin is melting into the neck. The extent of this deficiency can vary drastically and usually has to be treated surgically. In some patients, the aesthetic deficit can be overcome with genioplasty alone; in others, the lack of forward growth might warrant orthognathic surgery to move one or two jaws forward. If
6237-399: The chin will reveal some unexpected insight into what it means to be human." The terms cleft chin, chin cleft, dimple chin, or chin dimple refer to a dimple on the chin. It is a Y-shaped fissure on the chin with an underlying bony peculiarity. Specifically, the chin fissure follows the fissure in the lower jaw bone that resulted from the incomplete fusion of the left and right halves of
6336-665: The collapse of most global empires, leading to widespread decolonization. Following the conclusion of the Second World War in 1945, the United States and the USSR emerged as the remaining global superpowers . This led to a Cold War that saw a struggle for global influence, including a nuclear arms race and a space race , ending in the collapse of the Soviet Union. The current Information Age , spurred by
6435-787: 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 is believed to have reached one billion in 1800. It has since then increased exponentially, reaching two billion in 1930 and three billion in 1960, four in 1975, five in 1987 and six billion in 1999. It passed seven billion in 2011 and passed eight billion in November 2022. It took over two million years of human prehistory and history for
6534-478: The continent, gradually replacing or interbreeding with local populations of archaic humans. Humans began exhibiting behavioral modernity about 160,000–70,000 years ago, and possibly earlier. This development was likely selected amidst natural climate change in Middle to Late Pleistocene Africa. The "out of Africa" migration took place in at least two waves, the first around 130,000 to 100,000 years ago,
6633-517: The dent in Junior Mints is based on this belief, arguing that a unilateral dimple is more attractive than bilateral. Richard Steele wrote that a dimpled laugh "is practised to give a grace to the features, and is frequently made a bait to entangle a gazing lover; this was called by the ancients the Chian laugh." He added: "The prude hath a wonderful esteem for the Chian laugh or dimple [...] and
6732-435: The departure of youth, and fade away at the approach of crow's feet "; "Did you ever see a pretty child's face without dimples in it? Dimples in the cheek—temping dimples—and a dimple in the chin that gave a roguish smartness to the face?" British boxer-turned-Hollywood actor Reginald Denny had his cheek dimples gushed about in a Photoplay article, which Professor Michael Williams inferred that "dimples might also provide
6831-423: The desire to understand and influence phenomena having motivated humanity's development of science , technology , philosophy , mythology , religion , and other frameworks of knowledge ; humans also study themselves through such domains as anthropology , social science , history , psychology , and medicine . There are estimated to be more than eight billion living humans . Although some scientists equate
6930-516: The development of the Internet and Artificial Intelligence systems, sees the world becoming increasingly globalized and interconnected. 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
7029-640: 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 . All modern humans are classified into the species Homo sapiens , coined by Carl Linnaeus in his 1735 work Systema Naturae . The generic name " Homo " is a learned 18th-century derivation from Latin homō , which refers to humans of either sex. The word human can refer to all members of
7128-685: 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 Civilisation . They eventually traded with each other and invented technology such as wheels, plows and sails. Emerging by 3000 BCE,
7227-430: The face. Holton et al. claim that this adaptation occurred as the face became smaller compared to that of other ancient humans. Robert Franciscus takes a more anthropological viewpoint: he believes that the chin was formed as a consequence of the change in lifestyle humans underwent approximately 80,000 years ago. As humans' hunter-gatherer societies grew into larger social networks, territorial disputes decreased because
7326-566: 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
7425-595: 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
7524-443: The human lifestyle. 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, humans are among the least genetically diverse species. Any two humans are at least 99.5% genetically similar. Humans are sexually dimorphic : generally, males have greater body strength and females have
7623-555: The human population to reach one billion and only 207 years more to grow to 7 billion. The combined biomass of the carbon of all the humans on Earth in 2018 was estimated at 60 million tons, about 10 times larger than that of all non-domesticated mammals. In 2018, 4.2 billion humans (55%) lived in urban areas, up from 751 million in 1950. The most urbanized regions are Northern America (82%), Latin America (81%), Europe (74%) and Oceania (68%), with Africa and Asia having nearly 90% of
7722-517: 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
7821-420: The jaw bone, or muscle, during the embryonal and fetal development. It can also develop during the later mandibular symphysis , due to growth of the mental protuberance during puberty, or as a result of acromegaly . In some cases, one mental tubercle may grow more than another, which can cause facial asymmetry. A cleft chin is an inherited trait in humans and can be influenced by many factors. The cleft chin
7920-567: The late Miocene epoch. During this split, chromosome 2 was formed from the joining of two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes. Following their split with chimpanzees and bonobos, the hominins diversified into many species and at least two distinct genera. All but one of these lineages – representing the genus Homo and its sole extant species Homo sapiens – are now extinct. The genus Homo evolved from Australopithecus . Though fossils from
8019-422: The layer of subcutaneous fat around the neck sags down and creates a wrinkle , creating the appearance of a second chin. This fat pad is occasionally surgically removed and the corresponding muscles under the jaw shortened (hyoid lift). Another cause can be a bony deficiency, commonly seen in people of normal weight. When the jaw bones ( mandible and by extension the maxilla ) do not project forward enough,
8118-498: The mouth in three types: lower para-angle (underneath the mouth and lips), para-angle ("around the mouth angle"), and upper para-angle (above the mouth and lips). Cheek dimples are often associated with youth and beauty and are seen as an attractive quality in a person's face, accentuating smiles and making the smile look more cheerful and memorable. Throughout numerous cultures and history, there have been superstitions based on dimples: Chinese culture believes that cheek dimples are
8217-527: The muscle originates as a single structure from the zygomatic bone . As it travels anteriorly, it then divides with a superior bundle that inserts in the typical position above the corner of the mouth. An inferior bundle inserts below the corner of the mouth. Cheek dimples can occur in any person, but some studies have suggested that dimples (both cheek and chin) are more common in females. They can be either permanent, or transient (aging makes dimples appear/disappear due to facial development and muscle growth):
8316-401: The new social structure promoted building alliances in order to exchange goods and belief systems. Franciscus believes that this change in the human environment reduced hormone levels, especially in men, resulting in the natural evolution of the chin. Overall, human beings are unique in the sense that they are the only species among primates who have chins. In the paper The Enduring Puzzle of
8415-559: The ongoing mass extinction of other forms of life. 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 visited the Moon and made their presence known on other celestial bodies through human-made robotic spacecraft . Since
8514-442: 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 . Humans also have
8613-474: 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
8712-783: The patient suffers from sleep apnea , early maxillomandibular advancement is usually the only causal treatment and necessary to preserve normal life expectancy. Homo sapiens Humans ( Homo sapiens , meaning "thinking man" or "wise man") or modern humans are the most common and widespread species of primate , and the last surviving species of the genus Homo . They are great apes characterized by their hairlessness , bipedalism , and high intelligence . Humans have large brains , enabling more advanced cognitive skills that enable them to thrive and adapt in varied environments, develop highly complex tools , and form complex social structures and civilizations . Humans are highly social , with individual humans tending to belong to
8811-515: 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%). Estimates of the population at the time agriculture emerged in around 10,000 BC have ranged between 1 million and 15 million. Around 50–60 million people lived in
8910-433: The presence of the chin is not related to mastication. The presence of thick bone in the relatively small mandible may indicate better force resistance capacity. However, the question stands of whether the chin is an adaptive or nonadaptive structure. Recent works on the morphological changes of the mandible during development have shown that the human chin, or at least the inverted-T shaped mental region, develops during
9009-404: The second ( Southern Dispersal ) around 70,000 to 50,000 years ago. H. sapiens proceeded to colonize all the continents and larger islands, arriving in Eurasia 125,000 years ago, Australia around 65,000 years ago, the Americas around 15,000 years ago, and remote islands such as Hawaii , Easter Island , Madagascar , and New Zealand in the years 300 to 1280 CE. Human evolution was not
9108-547: The sense of humanity). 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. 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
9207-463: The shape of the skull and dimples can appear and disappear due to age. There are four types of facial dimples, including cheek, and the cleft chin (sometimes nicknamed a "chin dimple"). Cheek dimples when present, show up when a person makes a facial expression, such as smiling, whereas a chin dimple is a small line on the chin that stays on the chin without making any specific facial expressions. Dimples may appear and disappear over an extended period;
9306-433: The term "humans" with all members of the genus Homo , in common usage it generally refers to Homo sapiens , the only extant member. All other members of the genus Homo , which are now extinct, are known as archaic humans , and the term "modern human" is used to distinguish Homo sapiens from archaic humans. Anatomically modern humans emerged around 300,000 years ago in Africa, evolving from Homo heidelbergensis or
9405-427: 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
9504-411: The upper parts of the mandible ( alveolar process ) to retract posteriorly, following the posterior movement of the upper tooth row, while the lower part of the symphysis remained protruded to create more space, thereby creating the inverted-T shaped mental relief during early ages and the prominent chin later. The alveolar region (upper or superior part of the symphysis) is sculpted by bone resorption, but
9603-440: 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 . Most aspects of human physiology are closely homologous to corresponding aspects of animal physiology. The dental formula of humans is: 2.1.2.3 2.1.2.3 . Humans have proportionately shorter palates and much smaller teeth than other primates. They are
9702-468: Was originally concluded that 60% of people with one dimple likely have it in their left cheek, but later research concluded that 53% were on the right, however, this may be due to differing cultures. Dimples are analogous and how they form in cheeks varies from person to person. Dimple depth and size can also vary; unilateral dimples are usually large, and a possible 12.8% of bilateral people have dimples positioned asymmetrically. They are not linked with
9801-402: 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
#696303