Humans belong to a group of mammals called primates. It includes apes, monkeys and several much smaller animals such as lemurs and bush babies. As much as 50 million years ago, back in the Eocene Period, there were traces of primate-like animals. They were small and looked rather like squirrels, but their eyes faced forwards like modern monkeys and they had grasping hands and feet.
These animals evolved into monkey-like animals, but remains of primates are scarce and the fossil record contains many gaps. Those few remains that have been found are of tree-living monkeys that are very similar to monkeys living today.
Where did humans probably evolve?
The early ancestors of humans were called hominids, and they appear to have evolved in Africa where many of their remains have been discovered.
The earliest remains of what were probably our ancestors are those of human-like apes called Australopithecus, which date back more than three million years. These creatures walked erect and looked similar to us, but their brain capacity was small. Several forms of Australopithecus have been found. All of them were much shorter than modern humans, and their teeth show that they had a vegetarian diet.
What remains of ancient humans have been found?
The first true human appeared around two million years ago in Africa. It has been named Homo habilis (‘handy man’) because it used primitive stone tools. It was still rather ape-like, however, and was soon replaced by Homo erectus, which looked very much like us. It had a much heavier jaw, bony ridges over the eyes and a sloped-back forehead. Homo erectus appeared about 1.6 million years ago. Only a few incomplete fossils of these early humans have been found, but their tools have been discovered in large numbers.
When did our ancestors begin to walk upright?
Some of the earliest remains of our ancestors are more than three million years old. They show very clearly that these creatures walked upright. The development of an upright posture, walking on two legs, is thought to have followed climatic changes. As the forest areas retreated our ancestors were forced to live on open grasslands. An upright posture would then be an advantage, because it allows an animal to travel more quickly. It also frees the hands for carrying food, babies and, eventually, weapons and tools.
When did the first modern human appear?
Modern humans appeared between 300,000 and 150,000 years ago, probably in Africa. The first ones were known as the Cro-Magnons, and they rapidly migrated throughout Asia and Europe. They did not reach North America until 12,000 years ago. Some of these ancient humans were the artists who made cave paintings showing extinct animals such as the mammoth and the cave bear. They were also almost certainly responsible for the extinction of many of these ancient animals, which quickly followed their migration into new hunting areas.
How closely related are we to modern apes?
Research shows that 99 percent of our genetic material is identical to that of the chimpanzee, which means that we not only resemble one another, but often share the same diseases. Some of the tropical diseases emerging from Africa are thought to have crossed over from chimpanzees to humans very recently. In addition to the physical resemblance, chimpanzees share with us the abilities to develop social systems and to communicate complex messages. Some of them have also developed the ability to make and use simple tools. We do know from fossilized teeth that there was once a huge ape called Gigantopithecus that was around three times the size of modern gorillas.
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