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Human

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Humans are members of the species Homo sapiens, a name meaning "wise man" or "knowledgeable man."

Carl von Linné
Carl von Linné

As primates, we are the most widespread and abundant species in our biological group. Humans are defined by several key physical and mental traits. We practice bipedality, which is the ability to walk upright on two legs. We also possess large, complex brains that allow for advanced tool use and culture. These traits enable us to build highly social structures. These structures range from small kinship networks to massive political states.

Sweet Baby Kisses Family Love
Sweet Baby Kisses Family Love

Our intelligence is driven by a highly developed prefrontal cortex. This is the region of the brain responsible for higher cognition, or complex thinking. This area allows for episodic memory and self-awareness. It also enables a "theory of mind," which is the ability to understand that others have their own thoughts. Humans can use flexible facial expressions to communicate. We can engage in introspection, which is the act of looking inward at our own private thoughts. This mental depth allows us to use imagination and volition to influence our environment.

Human evolution is a complex process of biological change. We belong to the family of apes, sharing a lineage with gibbons, orangutans, gorillas, and chimpanzees. The last split between humans and the chimpanzee-bonobo lineage occurred around 8 to 4 million years ago. During this time, our ancestors underwent a chromosomal change. While other apes have 24 pairs of chromosomes, humans have only 23 pairs. This happened because two chromosomes joined together to form chromosome 2. We evolved from the genus Australopithecus into the genus Homo.

Tree of life
Tree of life

The genus Homo emerged through various species over millions of years. The earliest record is a 2.8 million-year-old specimen from Ethiopia. Species like Homo habilis and Homo rudolfensis appeared by 2.3 million years ago. Homo erectus evolved about 2 million years ago and was the first to leave Africa. Homo sapiens specifically emerged in Africa at least 300,000 years ago. We migrated out of Africa in at least two major waves. The first wave occurred between 130,000 and 100,000 years ago. The second, known as the Southern Dispersal, happened around 70,000 to 50,000 years ago.

Early migrations mercator
Early migrations mercator

As humans migrated, they settled across almost every continent. We reached Eurasia 125,000 years ago and Australia around 65,000 years ago. Humans arrived in the Americas approximately 15,000 years ago. Eventually, humans reached remote islands like Hawaii and New Zealand between 300 and 1280 CE. For most of our history, we lived as hunter-gatherers. This changed about 12,000 years ago during the Neolithic Revolution. This was the invention of agriculture, which allowed for permanent settlements.

Silk route
Silk route

Agriculture led to food surpluses and the rise of early civilizations. In the 4th millennium BCE, an urban revolution created city-states in Mesopotamia. Sumerian cities developed cuneiform, the earliest known form of writing, around 3000 BCE. Other major civilizations included Ancient Egypt and the Indus Valley. These groups traded and invented technologies like the wheel and the plow.

All Gizah Pyramids
All Gizah Pyramids

Humans also developed complex systems of mathematics and astronomy. These advancements allowed for massive projects, such as the Great Pyramid of Giza. Over time, civilizations rose and fell due to factors like drought or conflict.

Dunhuang star map
Dunhuang star map

Biologically, humans show both great similarity and interesting variation. On average, two humans are more than 99% genetically similar. The most genetically diverse populations are found in Africa. Variation occurs in body size, mental abilities, and disease susceptibility. There is also significant variation between males and females. For example, men generally have greater body strength. Women often have a higher body fat percentage and live longer lifespans.

Hair colors
Hair colors

Despite these differences, we remain a single, highly connected species. As of 2026, the human population exceeds 8.3 billion people.

Population Density, v4.11, 2020 (48009093621)
Population Density, v4.11, 2020 (48009093621)
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🖼️ Images & Media (40)
File:Early migrations mercator.svg
Early migrations mercator.svg
File:Tree of life.svg
Tree of life.svg
File:A Man on the Moon, AS11-40-5903 (cropped).jpg
A Man on the Moon, AS11-40-5903 (cropped).jpg
File:All Gizah Pyramids.jpg
All Gizah Pyramids.jpg
File:Sweet Baby Kisses Family Love.jpg
Sweet Baby Kisses Family Love.jpg
File:Baby with Aerobie flying ring.jpg
Baby with Aerobie flying ring.jpg
File:Hair colors.jpg
Hair colors.jpg
File:Baby playing with yellow paint. Work by Dutch artist Peter Klashorst entitled "Experimental".jpg
Baby playing with yellow paint. Work by...
File:Ethnie dong 6511a.jpg
Ethnie dong 6511a.jpg
File:Population Density, v4.11, 2020 (48009093621).jpg
Population Density, v4.11, 2020 (48009093621).jpg
File:Into the Jaws of Death 23-0455M edit.jpg
Into the Jaws of Death 23-0455M edit.jpg
File:Carl von Linné.png
Carl von Linné.png

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