Humans classified with apes and monkeys in primate order. Chimpanzees share 97-99% genetic identity with humans. Primates adapted for arboreal life with grasping hands, opposable thumbs, and forward-facing eyes for depth perception. Primates have larger brains relative to body size than other mammals, enabling complex thought. Primates birth few offspring with long development periods. Over 200 primate species divided into Strepsirrhini and Haplorhini. Strepsirrhines like lemurs rely on smell with tooth combs and produce vitamin C. Haplorhines include tarsiers, New World monkeys, and Catarrhines. New World monkeys have prehensile tails and sideways nostrils. Old World monkeys like baboons are often terrestrial with ischial callosities. Gibbons brachiate with long arms and defend territories vocally. Great apes include orangutans, gorillas, chimps, bonobos, and humans without tails. Orangutans most solitary great apes using tools for food. Gorillas live in troops with extreme male-female size differences eating mostly foliage. Chimpanzees use tools, hunt, and live in large adaptable communities. Bonobos use sex for social bonds and conflict resolution. Humans sole Homo sapiens species from extinct hominin relatives. Hominins split from great apes 6-8 million years ago in Africa. Bipedalism evolved by 7 million years ago enabling energy-efficient walking. Early hominins like Sahelanthropus showed bipedal foramen magnum position. Orrorin tugenensis femur indicates bipedalism despite tree-climbing hands. Ardipithecus mixed ape-human traits with woodland diets. Australopithecus species fully bipedal with ape-like faces and small brains. Au. afarensis footprints prove bipedality 3.6 million years ago. Australopithecines showed sexual dimorphism and ate varied tough foods.