Humans are members of a group of mammals that is called the Hominidae, which also includes chimpanzees, gorillas, and orangutans. These animals are closely related and share similar traits.
Our ancestors, known as the Homo genus, emerged about 300,000 years ago and branched off from other apes and other primates in Africa. Our earliest human ancestors walked on two legs, climbed trees, and hunted, gathering food for themselves and their families. This flexibility allowed them to survive in a wide variety of habitats and climates.
During the past 6 million years, humans have developed many characteristics that make us unique among all of the other species on Earth. These include a complex brain, speech, and the ability to build and use tools.
DNA, the genetic code, has played a key role in our evolution. It tells us where our ancestors came from, how they looked and behaved, and how they changed over time.
We have more than six billion people living today, and we are still evolving. The ancestors of modern humans migrated out of Africa and spread around the world.
These humans branched off from other groups of apes and evolved to become modern Homo sapiens (the anatomically modern humans). We have developed more advanced technology, including tools, clothes made from animal hides, a wide range of language, and the complexities of modern society.
Our evolution has been shaped by our social behavior. We are extremely cooperative animals, a trait that is inherited in part from our superior language skills. Compared to other species, we are much more likely to cooperate with others and help them in times of need.
This sense of cooperation begins in childhood, when children are willing to open doors for adults or pick up a dropped item for another child. We also have a natural sense of fairness, which means we are always more likely to help others than to take advantage of them.
The genes that control these behaviors are controlled by a network of cells called the brain. Our brains are made of millions of nerve cells that control and coordinate our movements, thinking, learning, and feelings.
Some neurons in our brains are specialized to work together for special purposes. For example, our cerebellum (the part of our brain that controls movement) is responsible for helping us balance and walk. Other neurons are responsible for helping us recognize images and feel emotion.
All these neurons are connected to each other by a complex system of nerve fibers called the spinal cord. Our spinal cord is one of the longest in all of nature, spanning nearly the entire length of our bodies.
It is this system that gives us the strength and flexibility to move from place to place, climb trees, build our homes, and even grow our own foods! It is also the reason we can communicate with each other by voice.
We also have a large brain that is larger than our ape ancestors, and we are able to think in more abstract ways. These abilities have enriched our lives and made us more intelligent than ever before.