AP BIOLOGY

Detailed explanation-1: -Bipedalism, or upright walking, is argued by many to be the hallmark of being a hominin. Humans are unique among all living primates in the way that they move around.

Detailed explanation-2: -The earliest hominid with the most extensive evidence for bipedalism is the 4.4-million-year-old Ardipithecus ramidus. In 2009, researchers announced the results of more than 15 years of analysis of the species and introduced the world to a nearly complete skeleton called Ardi.

Detailed explanation-3: -Chimpanzees, gorillas and gibbons, macaques, spider monkeys, capuchins, and others are all frequent bipedal walkers. To define humans categorically as “bipedal” is not enough; to describe them as habitually bipedal is nearer the truth, but habit as such does not leave its mark on fossil bones.

Detailed explanation-4: -The possible reasons for the evolution of human bipedalism include the freeing of the hands to use and carry tools, threat displays, sexual dimorphism in food gathering, and changes in climate and habitat (from jungle to savanna).