Human evolution

People have changed over a long time.

Long ago, our ancestors lived in forests. Some lived in trees. They even built nests to sleep in.

Slowly, these groups began to change. Some learned to walk on two feet. This helped them move in new ways.

Other groups grew bigger brains. This helped them use stone tools.

Modern humans first appeared in Africa. We learned to use complex ways to talk. This helped us live in groups.

It is amazing to see how we grew. We are part of a big story.

Humans belong to a group called primates. This group includes great apes.

Over millions of years, humans changed in many ways. We learned to walk on two feet. This is called bipedalism.

We also developed complex language and better hand skills.

Long ago, humans and chimpanzees shared an ancestor. They split apart between 9 and 7 million years ago.

One group led to gorillas. Another group led to chimpanzees. A third group led to humans.

An early group was the Australopithecines. They lived in Africa around 4 million years ago.

Some were good at climbing trees. They might have built nests to sleep in.

Later, the genus Homo appeared. This group includes our direct ancestors.

Early members used stone tools. Over time, their brains grew much larger. This is called encephalization. Modern humans emerged in Africa about 300,000 years ago.

Our history is not a straight line. It is more like a web of many different groups.

Humans belong to a group of animals called primates. This group includes all the great apes.

Over a very long time, humans changed in many ways. We developed bipedalism, which is the ability to walk on two feet.

We also gained better hand skills and the ability to use complex language. These changes helped our ancestors live in new ways. Scientists study these changes using many tools. They use paleontology to study fossils and genetics to look at DNA.

Our history began with many different branches. Long ago, humans and chimpanzees shared a common ancestor.

This split happened between 9 and 7 million years ago. One branch led to gorillas. Another branch led to chimpanzees. A third branch led to the human line. This process was not a straight line. Instead, it was more like a web where different groups met and mixed.

One important group was the Australopithecines. They lived in eastern Africa around 4 million years ago.

Some members, like "Little Foot," were good at climbing trees.

They might have built nests in trees to stay safe at night. There were many different kinds of these early relatives. Some were more built for strength, while others were more slender. They lived across the African continent before they eventually went extinct.

Later, the genus Homo appeared in the fossil record. The Ledi jaw is a very old example from about 2.8 million years ago.

These early humans were among the first to use stone tools. Over time, a thing called encephalization happened. This means their brains grew much larger.

For example, the brain size of Homo erectus was much bigger than earlier ancestors. This growth helped them solve new problems and use tools more effectively.

Modern humans, known as Homo sapiens, emerged in Africa about 300,000 years ago. We are part of a long story of change. Our ancestors traveled to many different places.

They met other types of humans along the way. This shows how connected our history really is. Even though we are different from other apes today, we share a very deep history with them. Studying these fossils helps us understand how we became who we are today.

Human evolution is the long history of how our species emerged. Humans are part of the hominid family, which includes all the great apes.

Over millions of years, our ancestors developed specific traits. These include bipedalism, which is walking on two feet. They also gained dexterity, or better hand skills. Finally, they developed complex language. Scientists study this history using several different fields. Physical and evolutionary anthropology look at our bodies. Paleontology studies ancient fossils. Genetics looks at our DNA. Together, these tools help us map our origins.

The story begins with primates. Primates diverged from other mammals about 65 million years ago.

Early fossils appeared during the Paleocene period. These early primates were widespread in Eurasia and Africa. Some early species include Plesiadapis from North America and Archicebus from China. Other species like Altiatlasius lived in Africa. These early primates eventually led to the ape superfamily. This group includes the gibbon and hominid families. These two families diverged about 15 to 20 million years ago.

Different branches of the ape family tree split at different times. The lineage of gibbons split from the great apes about 18 to 12 million years ago. The orangutan lineage, known as the Ponginae subfamily, split about 12 million years ago.

African hominids, the Homininae subfamily, split from orangutans about 14 million years ago. The human line, or hominins, parted from the Gorillini tribe, which includes gorillas, between 8 and 9 million years ago. Finally, the Australopithecine group separated from the Pan genus, which includes chimpanzees and bonobos, about 4 to 7 million years ago.

Genetic data shows that humans and chimpanzees share a common ancestor. This split likely happened between 9 and 7 million years ago. Human DNA is about 98.4% identical to chimpanzee DNA when comparing single nucleotide polymorphisms.

This similarity shows our close connection. However, the fossil record for chimpanzees is limited. Acidic rainforest soils often dissolve bones, making fossils hard to find. Some scientists believe early hominins adapted to drier environments outside the equatorial belt. In these areas, they lived alongside animals like elephants, horses, and hyenas.

The genus Australopithecus lived in eastern Africa about 4 million years ago.

They spread across Africa before going extinct 2 million years ago. Many different species existed, such as A. afarensis and A. africanus. Some scientists group certain species into a "robust" category. Others call them "gracile" australopiths. A famous specimen is "Little Foot," which is 3.67 million years old.

Little Foot had an opposable big toe. This suggests he was a good climber. He may have built nests in trees for safety, similar to modern chimpanzees.

The genus Homo appeared later in the fossil record. The Ledi jaw is one of the earliest examples, dating to about 2.8 million years ago.

These early humans likely used stone tools. A major change in this genus was encephalization. This is the process of the brain growing larger. Early Homo habilis had brains similar to chimpanzees. However, later species like Homo erectus saw their cranial capacity double to 850 cm3.

This rapid growth helped our ancestors solve complex problems.

Anatomically modern humans, or Homo sapiens, emerged in Africa about 300,000 years ago. Our evolution was not a straight line. Instead, it was a web-like process. Modern humans interbred with archaic humans as they moved.

This means our ancestors met and mixed with different human groups. This complex history shows how many different paths led to the humans we are today.