Human evolution is the lengthy process by which human beings developed on Earth from now-extinct primates. Scientific evidence shows that the physical and behavioral traits shared by human beings originated from apelike ancestors and evolved over a period of approximately six million years in Africa. We humans are Homo sapiens, a culture-bearing, upright-walking species that lives on the ground. One of the earliest defining human traits, bipedalism, the ability to walk on two legs evolved over 4 million years ago and other important human characteristics such as a large and complex brain, the capacity for language, the ability to make and use tools developed more recently. Many advanced traits including complex symbolic expression, art, and elaborate cultural diversity emerged mainly during the past 100,000 years.