HUMAN EVOLUTION
Primates 2 Divisions of
Primates 1. Anthropoid
primates 2. Prosimean
primates Characteristics:
Nails (no claws) Prehensile hands and
feet (grasping) Color vision and
depth perception
Anthropoid Primates Include:
marmosets Monkeys Apes Humans
Brain size Large relative
to their body size
Opposable thumbs
Similar dental formula number and
arrangement of teeth
HUMANS Bipedalism – Ability to walk on
2 feet Aligned toes = Bipedalism Enlarged brain =Vertical face Areas for speech in the brain S- shaped spine Bowl-shaped pelvis
Prosimean primates
Include: Lemurs Lorises Tarsiers
Tarsier Skeleton
Gorilla Skeleton
Human Skeleton
Skeleton Comparisons
Draw a Prosimean skeleton, Anthropoid skeleton and a human skeleton
Draw the basic bones Pay special attention to the skulls
Use the same colors for homologous parts in the three skeletons
Highlight the key features of each primate that makes them successful and unique
How does this make them successful?
PALEOANTHROPOLOGISTS
Scientists who study fossil evidence of human evolutionConstruct models of how and when different stages of human evolution occurred
Hominids
Hominids include humans and extinct humanlike primates
The oldest known hominid fossils are between 6 and 7 million years old
First fossils found in Africa
Waves of Hominid Emigration
Two hypotheses have been proposed for the evolution of Homo sapiens“African replacement” hypothesis
Also called Out of Africa, Recent-African-Origin
“Multiregional origin” hypothesis
“African Replacement” Hypothesis
Members of the genus Homo made repeated long-distance migrations out of Africa beginning 1.8 million years ago
H. sapiens emerged from Africa about 150,000 years ago and spread across the Near East, Europe, and Asia
The dispersing H. sapiens populations replaced all other hominids
“Multiregional Origin” Hypothesis
H. erectus emerged from Africa 1.8 million years ago and spread across the Near East, Europe, and Asia
Continued migrations and interbreeding occurred among widespread H. erectus populations
Regional populations of H. erectus evolved into H. sapiens
Australopithecus
Oldest known genus of hominids Lived more than 4 million years ago Knee joints- Allow bipedalism! Australopithecus anamensis Australopithecus afarensis – believed to have
given rise to: A. africanus A. robustus A. boisei Modern Homo sapiens
more than 1 million years ago
A. africanus
!
A. boiser
!
Discovery of Lucy!
Fossils of nearly half complete early hominid Australopithecus afarensis
suggests hominids became bipedal before their brains began to dramatically enlarge
Ardipithecus ramidus
Recent discovery Not clear whether it was bipedal 4.4 million years old
Existence of hominid species not ancestral to modern humans implies…
Hominid phylogenetic tree is very branchy in appearance
Representing species died out, leaving no descendants.
Early Members of the genus HomoH. habilis & H. erectus
Ancestors to modern humans Larger brains than australopithecines May have had speech Started to develop tools Homo erectus- potential first hominid to leave
Africa Homo habilis Homo erectus
Neanderthals
Now extinct Hypothesis- Homo sapiens, being superior to
Neanderthal man, ran him off the planet. New hypothesis- more complicated
Neanderthals may have mixed with the ancestor of modern man
We could be carrying Neanderthal genes. Heavy bones Thick brow ridges Protruding teeth Used shelters, tools, and clothing
Cro-Magnons
Cro-Magnons coexisted with Neanderthals in Europe and the Middle East for as many as 50,000 years
Cro-Magnons had domed heads, smooth brows, and prominent chins
30,000-year-old Cro-Magnon artifacts include: Bone flutes Ivory sculptures Evidence of elaborate burial
ceremonies
Cro-Magnon Cave Painting
Homo sapiens
Evolved about 800,000 years ago A) Neanderthals
Were early Homo sapiens They may be ancestral to modern humans OR They may have died out and been replaced by
modern humans
Some hypotheses:
1. some anthropologist think H. sapiens evolved in PARALLEL from populations of H. erectus all over the world. (interbreeding)
2. some anthropologists propose that H. sapiens DESCENDED from H. erectus in Africa and then dispersed across Earth.