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89-477: Fire is an essential tool for human survival and the use of fire was important in early human cultural history since the Lower Paleolithic . Today, it is a key component of Scouting and bushcraft . Evidence for fire making dates to at least the early Middle Paleolithic , with dozens of Neanderthal hand axes from France exhibiting use-wear traces suggesting these tools were struck with

178-406: A Diesel engine works, rapid compression of air heats the interior to 400–700 °F, well above the tinder's autoignition temperature . Tinder that holds an ember such as charcloth must be used. After compression, the piston is opened quickly and the ember is transferred to a larger pile of tinder. Sunlight can be concentrated using a lens (such as a burning glass ) to focus the energy from

267-494: A drill , to make holes on solid materials such as wood , stone , bone , or teeth , and as a fire drill to start a fire . The spindle can be held into a fixed frame, or by a hand-held block (the hand piece or thimble ) with a hole into which the top of the shaft is inserted. Some lubricant should be used to reduce friction between these two parts, otherwise, it could lead to some trouble when doing it too fast. A popular campcraft book of 1920 attributed this invention to

356-415: 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

445-668: 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

534-508: A built-in striking blade which provides an easy method for sparking with one hand. Another common type has the ferro rod attached to a magnesium bar that can be scraped with a knife to make a powdered tinder that will burn for a few seconds. Hiking stores sell both magnesium starters, firelighter blocks, and other specialist tinder . Lighters typically use a percussion-type sparking device to ignite gas/liquid fuels such as butane or naphtha/gasoline. These are simple to light, often using

623-443: 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

712-419: 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

801-535: A fire would have been to use the hot ashes or burning wood from a forest or grass fire, and then to keep the fire or coals going for as long as possible by adding more combustible material. Fire can be created through friction by rapidly grinding pieces of solid combustible material (such as wood ) against each other (or a hard surface) which are heated and create an ember. Successfully creating fire by friction involves skill, fitness, knowledge, and acceptable environmental conditions. Some techniques involve crafting

890-463: 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

979-449: A hard, glassy stone such as quartz , jasper , agate or flint cleaves small, hot, oxidizing metal particles that can ignite tinder. The steel should be high carbon, non-alloyed, and hardened. Similarly, two pieces of iron pyrite or marcasite when struck together can create sparks. The use of flint in particular became the most common method of producing flames in pre-industrial societies (see also fire striker ). Travelers up to

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1068-612: 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

1157-475: 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

1246-581: 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

1335-504: 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

1424-459: A pile of magnesium or ferrocerium shavings is common; and a moisture-resistant DIY tinder features cotton balls impregnated with petroleum jelly. A feather stick can be made from available branches or twigs with a knife . Autoignition temperatures of common tinder: Tinder is preserved within a tinderbox , which today is often a plastic bag. Tinder, when formed into a tight bundle, can also be used to preserve/carry an ember. Often in

1513-451: 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

1602-639: 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

1691-515: 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

1780-451: 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

1869-409: A system of interlocking pieces that give the practitioner an improved mechanical advantage; these techniques require more skill and knowledge but less fitness, and work in less ideal conditions. Once hot enough, the ember is introduced to the tinder, more oxygen is added by blowing and the result is ignition. The hand drill is the most widespread among indigenous cultures, characterized by the use of

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1958-441: A thin, straightened wooden shaft or reed to be spun with the hands, grinding within a notch against the soft wooden base of a fire board (a wooden board with a carved notch in which to catch heated wood fibers created by friction). This repeated spinning and downward pressure causes black dust to form in the notch of the fireboard, eventually creating a hot, glowing coal. The coal is then carefully placed among dense, fine tinder, which

2047-414: A wheel mechanism that when spun with the thumb creates friction on the internal rod of ferrocerium "flint" and throws a shower of white-hot sparks into the gas or wick. Alternately, an electric spark ignites the fuel. With almost 2 billion lighters sold each year, this is the most popular means to light fires today. A fire piston ignites a combustible substance by rapid compression of air. Similar to how

2136-406: 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

2225-511: 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

2314-529: Is a material that combusts first (as an ember or flame ) and in doing so heats other material (heavier tinder, twigs, kindling, etc.) until it burns (as a flame). Fine tinder is characterized by its ability to combust from a spark, friction, or other action from the below methods. Many forms of tinder are available – charcloth is preferred by many; tinder fungus and other species such as Phellinus igniarius have been used as firestarter ; most friction methods using wood generate their own fine tinder; today

2403-485: 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

2492-424: 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

2581-568: Is absent and the cord is kept taut by pulling the ends with both hands, while moving them left and right at the same time. In the absence of a frame, the thimble is shaped so that it can be held with the chin or the mouth. The bow lathe used for traditional woodturning uses the same principle as the bow drill. Bow drills with green jasper bits were used in Mehrgarh between the 4th and 5th millennium BC to drill holes into lapis lazuli and carnelian . Similar drills were found in other parts of

2670-443: Is believed to have been invented by World War 2 POWs . A German survival expert named Rüdiger Nehberg wrote about this method in one of his books. A small amount of wood ash is rolled up in a piece of cotton like a cigar. The cotton is then placed between two boards and rolled back and forth. Pressure and speed are both gradually increased. With proper technique ignition can occur in seconds. A fire striker or firesteel when hit by

2759-402: 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

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2848-456: 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

2937-421: 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

3026-479: 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

3115-443: 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

3204-408: 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

3293-521: 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

3382-433: Is pressed against it as one blows directly onto the coal until the tinder begins burning and eventually catches into flame. The advantage of the hand drill technique is that it requires no rope. The bow drill uses the same principle as the hand drill (friction by rotation of wood on wood) but the spindle is shorter, wider (about the size of a human thumb) and driven by a bow, which allows longer, easier strokes and protects

3471-418: Is prominently reflected in human culture and has led to the development of food science . Bow drill A bow drill is a simple hand-operated type of tool , consisting of a rod (the spindle or drill shaft ) that is set in rapid rotary motion by means of a cord wrapped around it, kept taut by a bow which is pushed back and forth with one hand. This tool of prehistoric origin has been used both as

3560-445: 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

3649-654: 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 ,

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3738-548: 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

3827-580: 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

3916-511: 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

4005-474: 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

4094-466: The Indus Valley civilization and Iran one millennium later. For use as a fire drill , the shaft should have a blunt end, which is placed into a small cavity of a stationary piece of wood (the fireboard ). Turning the shaft with high speed and downward pressure generates heat, which eventually creates powdered charcoal and ignites it forming a small ember . For drilling, the lower end of

4183-511: The Inuit . In Mehrgarh ( Pakistan ) it has been dated between the 4th-5th millennium BCE. The string of the bow is wrapped once around the spindle, so that it is tight enough not to slip during operation. In a variation called the Egyptian bow drill , the cord is wound around the shaft multiple times, or is fixed to it by a knot or a hole. The strap drill is a simpler version, where the bow

4272-579: 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,

4361-854: 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

4450-587: 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

4539-652: 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

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4628-795: 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,

4717-518: 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,

4806-876: 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

4895-832: 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

4984-478: 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

5073-561: 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

5162-665: 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

5251-787: 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

5340-609: The contact of an electrically heated object to tinder. A current is run through the object until it is red hot, like the burners on an electric stove , and it is brought into contact with the tinder, lighting it. For example, a foil-paper chewing gum wrapper will heat-up and ignite; or a flashlight battery coming into contact with a thin wire mesh (such as steel wool) may produce enough heat to ignite charcloth or other tinder. Larger batteries can generate sparks when its leads touch. Human Humans ( Homo sapiens , meaning "thinking man" or "wise man") or modern humans are

5429-478: 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,

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5518-423: 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

5607-516: 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

5696-640: 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

5785-685: 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,

5874-535: The form of a cigar and made of compacted tinder materials held within a tinderbox, a smouldering ember could safely be saved inside. Fire occurs naturally as a result of volcanic activity , meteorites , and lightning strikes . Many animals are aware of fire and adapt their behavior to it. Plants, too, have adapted to the natural occurrence of fire (see Fire ecology ). Thus, humans encountered and were aware of fire, and later its beneficial uses, long before they could make fire on demand. The first and easiest way to make

5963-566: 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

6052-595: 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

6141-437: The groove of the second piece in a "plowing" motion, to produce hot dust which creates an ember. A split is often made down the length of the grooved piece, so that oxygen can flow freely to the coal/ember. A fire-saw is a method by which a piece of wood is sawed through a notch in a second piece or pieces to generate friction. The tinder may be placed between two slats of wood with the third piece or "saw" drawn over them above

6230-443: 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

6319-555: 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

6408-517: 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

6497-567: 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

6586-419: The late 19th century would often use self-contained kits known as tinderboxes to start fires. Some fire-starting systems use a ferrocerium rod and a hard scraper to create hot sparks by manually scratching the ferro rod with a knife or sharp object to ignite man-made or natural tinder. Fire starters based upon ferrocerium are popular with bushcraft hobbyists and survivalists . Similar sparking devices have

6675-584: The mineral pyrite to produce sparks around 50,000 years ago. At the Neolithic site of La Draga , researchers have found that fungi were used as tinder. Hearths are one of the most common features found at archaeological sites. Ötzi , a well-preserved natural mummy of a man who lived in the Ötztal Alps between 3400 and 3100 BCE , carried material to make a fire ( tinder fungus along with flint and pyrite for creating sparks). Fires start from increasing tinder's temperature until it combusts. Tinder

6764-501: 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

6853-559: 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

6942-442: 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

7031-474: 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

7120-426: The palms. Additional downward pressure is generated by the handhold. A pump drill is a variant of the bow drill that uses a coiled rope around a cross-section of wooden stake spin the shaft by pumping up and down a cross-member. The fire plough or fireplow consists of a stick cut to a dull point, and a long piece of wood with a groove cut down its length. The stake is pressed down hard and rubbed quickly against

7209-515: 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

7298-404: 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

7387-547: 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

7476-410: The sun onto tinder. A concave mirror can also concentrate the sun's rays onto tinder. An exothermic chemical reaction can generate enough heat as to catch itself or tinder on fire. Matches are small sticks of wood or stiff paper with a coating that undergoes an exothermic reaction when triggered by friction. Other reactions that can be used to start fires include: Electrical firemaking involves

7565-433: 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

7654-400: The tinder so as to catch a coal, but there is more than one configuration. A fire-thong uses a non-melting cord, ratan , or flexible strip of wood to 'saw' the wood creating friction. On the board, opposite side the cord, is a well with a hole through the board to gathered the charred, soon-to-smoke, wood dust. The Rudiger roll friction fire method , also known as the "fire roll" method,

7743-427: 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

7832-440: 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

7921-402: 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

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