Homo Sapiens

**Humans** (***Homo sapiens***) are the most abundant and widespread species of primate. They are a type of great ape that is characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. 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. As such, social interactions between humans have established a wide variety of values, social norms, languages, and rituals, each of which bolsters human society. The desire to understand and influence phenomena has motivated humanity's development of science, technology, philosophy, mythology, religion, and other fields of study.

Although some scientists equate the term "*humans*" with all members of the genus *Homo*, in common usage it generally refers to *Homo sapiens*, the only extant member. Anatomically modern humans emerged around 300,000 years ago in Africa, evolving from *Homo heidelbergensis* or a similar species and migrating out of Africa, gradually replacing or interbreeding with local populations of archaic humans. For most of history, humans were nomadic hunter-gatherers. Humans began exhibiting behavioral modernity about 160,000–60,000 years ago. The Neolithic Revolution, which began in Southwest Asia around 13,000 years ago (and separately in a few other places), saw the emergence of agriculture and permanent human settlement. As populations became larger and denser, forms of governance developed within and between communities, and a number of civilizations have risen and fallen. Humans have continued to expand, with a global population of over 8 billion as of 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, males have greater body strength and females have a higher body fat percentage. At puberty, humans develop secondary sexual characteristics. Females are capable of pregnancy, usually between puberty, at around 12 years old, and menopause, around the age of 50.

Humans are omnivorous, capable of consuming a wide variety of plant and animal material, and have used fire and other forms of heat to prepare and cook food since the time of *Homo erectus*. Humans 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, highly developed, and complex prefrontal cortex, the region of the brain associated with higher cognition. They are highly intelligent, capable of episodic memory, have flexible facial expressions, self-awareness, and a theory of mind. The human mind is capable of introspection, private thought, imagination, volition, and forming views on existence. This has allowed great technological advancements and complex tool development to be possible through complex reasoning and the transmission of knowledge to subsequent generations. Language, art, and trade are defining characteristics of humans. Long-distance trade routes might have led to cultural explosions and resource distribution that gave humans an advantage over other similar species.

## Etymology and definition

Further information: Names for the human species and Human taxonomy

All modern humans are classified into the species *Homo sapiens*, coined by Carl Linnaeus in his 1735 work *Systema Naturae*. The generic name "*Homo*" is a learned 18th-century derivation from Latin *homō*, which refers to humans of either sex. The word *human* can refer to all members of the *Homo* 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).

## Evolution

Main article: Human evolution

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 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.