Primates and Human Origins Ch. 32.3

PRIMATES/PRIMATA (order) means FIRST Increased ability to use eyes and front limbs to perform tasks Binocular vision, well-developed cerebrum, fingers and toes, rotating arms around shoulder joints

Fingers, Toes, and Shoulders: 5 flexible fingers that can curl Flexible toes that help with climbing and swinging Arms are well adapted to climbing because they can rotate in broad circles Thumb and big toe are opposable to other digits

Well-Developed Cerebrum: cerebral cortex enables more complex behaviors –Social behaviors

Binocular Vision: both eyes face forward with overlapping fields of view Ability to merge visual images from both eyes –Provides depth perception and 3D view of the world

Evolution of Primates Came from a common ancestor 65 mya Split into several groups –Earliest groups are PROSIMIANS (monkeys) –Humans and apes are ANTHROPOIDS –SEE VIDEO/CLADOGRAM

PROSIMIANS: small, nocturnal primates with large eyes for seeing in the dark Doglike snouts –Bush babies, lemurs, lorises, tarsiers

ANTHROPOIDS: humans, apes, and most monkeys –2 major branches NEW WORLD MONKEYS (squirrel monkeys and spider monkeys) live in trees Strong flexible arms for swinging, long PREHENSILE (coil tightly) TAILS

Other group evolved in Africa and Asia (OLD WORLD  macaques and baboons) –Spend time in trees but no prehensile tail GREAT APES: HOMINOIDS (gibbons, orangutans, gorillas, chimpanzees, and humans) –We share 98% of our DNA with chimps

What is a hominid? Walked upright and developed thumbs for grasping BIPEDAL: walked on 2 feet (freed hands to use as tools) OPPOSABLE THUMBS: grasped objects (see activity)

Early Hominids 5 genera: Ardipithecus, Australopithecus, Paranthropus, Kenyanthropus, and Homo Covers about 4.5 million years Not all of these species are human ancestors (See detailed picture)

The Road to Modern Humans Genus Homo: means man Homo hablilis was one of the 1 st to be found with tools –Found in Africa –Evolved into H. ergaster and H. erectus Eventually migrated from Africa to all across Asia (see map) No concrete evidence as to how H.sapien was found all over the world (see diagram)