Early primates thrived in Eurasia leading to the evolution of apes and great apes. It is estimates apes first appeared 22 million years ago. There were more than 20 different species of ape, but they all had similar attributes. They walked on all fours and resemble the modern monkey. Great apes appeared 12 million years ago and they were the descendant of the ape. They were larger, but looked similar to their ancestors.
Bipedal primates were the first of our ancestors to walk on two legs. The bipedal primate with the most evidence for its existence is the Ardipiththecus ramidus which has an estimated age of 4.4 million years old. Early bipedal primates did not resemble Homo sapiens and had long arms and short legs. It wasn't until the Homo erectus 1.89 million years ago that primates began to resemble the modern human.
Homo sapiens are the category of the modern human. meaning "wise man". The earliest homo sapiens date back to 200,000 years ago, evolving mainly in Africa. Homo sapiens have a vaulted skull and vertical forehead in addition to being bipedal. Modern humans have a lighter build and larger brains with smaller teeth and less developed jaws.