Human Evolution

CENOZOIC ERA= 66 m.y.a ; rise of mammals and primates Primates = group of mammals including monkeys, apes and humans

Primates

Primate Characteristics 1. strong hands, long fingers, opposable thumb 2. arms move freely at the shoulder joint 3. Binocular vision = eyes positioned on the front of the face (accurately judge distance) 4. intelligent animals with relatively large brains 5. complex social skills with extended parental care of their young

Characteristics Unique to Humans 1. walking upright = Bipedalism 2. larger brain 3. use of speech and language

Primate Evolution= divided into 2 groups about 40 million years ago 1. Prosimians = small, monkey-like primates with large, forward facing eyes; grasping digits, most are nocturnal, feed on fruits “pre-monkey” Examples: Lemurs, Lorises, Tarsiers

2. Anthropoids = “human-like” primates ; monkeys, apes, humans; Diurnal = active during the day; complex socially

Two separate groups of monkeys evolved: 1. New World Monkeys = 30 Million years ago migrated to American Continents (South America); evolved in isolation,strong, flexible, prehensile tails (grasp branches), arboreal, flat spreading noses

2. Old World Monkeys = 25 Million years ago Europe-Asia-Africa; long prominent noses, no prehensile tail Apes = larger brains, no tails (gorilla, chimpanzee, orangutan)

The Hominids Early Hominids = all the Anthropoids that belong to the human family; ancestors to modern humans

The First Hominid? Considerable controversy exists Originally thought to be Ramapithecus - found in 1932 in India = 8 million year old jaw with teeth

None found in Africa (Ramapithecus) More complete fossils discovered suggest that it is more closely related to the Orangutan

Consensus Now... Proconsul - has many characteristics of Old World Monkeys but lacks a tail Approximately 5-10 million years old

Human vs. Ape Anatomy 1. Human vertebral column is more curved than an apes 2. Human spinal cord exits from the bottom of the skull (Apes exits from the rear) 3. Human pelvis is broader and more bowl shaped 4. Human legs bow in from the hip to the knee, apes are straighter 5. Ape arms disproportionate to their legs

What is the controversy? 1. Skeleton fragments ONLY have been found of the earliest human ancestors 2. The “Missing Link” has yet to be discovered (an ape like creature with a larger brain) 3. Religion vs. Science 4. Relative short time frame for Evolution of Man 5. Personal Bias tends to influence discoveries

Australopithecus Australopithecus= “Southern Ape” oldest hominid fossil dates to 3.5 - 4.4 million years ago • Australopithecus africanus= 2.7 - 2.1 m.y.a • Australopithecus afarensis= “Lucy” 40% complete fossil (female based on pelvis shape) 3 - 4 m.y.a. • A. robustus , A. boisei = 2 m.y.a. ; side branches of human family tree that became extinct Characteristics common to all Australopithecus: walked upright, apelike characteristics (long arms compared to legs), small brains, found only in Africa

Homo habilis= “Handy man” first hominids to use tools and weapons (2 Homo habilis= “Handy man” first hominids to use tools and weapons (2.5 m.y.a)

Homo erectus = “Upright man” first to migrate out of Africa & into Asia , built fires, hunters and gatherers

Homo sapiens= “Wise man” 500,000 - 300,000 years ago Neanderthals = brains as large as modern humans, speech, ritual burials, decorated tools, lived until about 34,000 yrs. ago Cro-Magnon = cave paintings, lived during the Ice Age, complex dwellings, likely evolved into modern humans of today, lived to about 10,000 yrs. ago

Human Races Humans have differentiated as they spread throughout the world Skin pigmentation changes with proximity to the equator Isolation has kept races homogeneous Cultural, behavioral, religious and other isolation mechanisms have and do exist