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 (2.5
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