Primates evolved from arboreal insectivores. Reduced olfactory, increased visual capacity. Movement adaptations, adaptation of teeth for omnivorous diet. Nocturnal, large eyes, slightly opposable thumb. Diurnal, flat, hairless face, manipulative hands, large brain.
Humans are more closely related to chimps than chimps are to orangutans.
Increased pair bonding and sexual activity. Prolonged parental care, postnatal growth of brain since prenatal skull size is limited by birth canal size. Compare and contrast Hemichordates with Echinoderms and Chordates.