The Human Story
Where We Came From
&
How We Evolved
Identifying the first hominids
• In L.C.A., look for anatomical features shared
by humans and living great apes
• Starting from there, 1st hominids must have
evolved at least one feature that we see only in
modern humans
• Scientists focus on two major areas
– Anatomy related to bipedalism
– Size / shape of canine and 1st premolar teeth
Large brain size, hard evidence for culture, language, etc.,
come much later.
Evidence of Bipedalism
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Placement of foramen magnum
Shape of spine
Shape of pelvic girdle
Bicondylar angle (knock-kneed)
Parallel toes (no divergent big toe)
Two fixed arches in foot
– Side to side / front to back
Placement of
Foramen
Magnum
Shape
of
Spine
Pelvic Girdle & Bicondylar Angle
Anatomical Adaptations for
Habitual Upright Bipedalism
A comparison of
the chimp, human,
and A. afarensis
femurs
demonstrates a
rounder femoral
head and longer
femoral neck
length in
hominids.
Parallel Toes / Fixed Arches
ORIGINS OF BIPEDALISM
Or
WHY WE WALK ON TWO LEGS
Download and read these articles:
The Origins of Habitual Upright Bipedalism
The Origins of Obligate Bipedalism in Hominins
The Whats and Whys of Habitual Upright Bipedalism
If you asked a roomful of anthropologists
why we walk on two legs - not get the
same answer from any two of them.
Specialists cite everything from changing
landscapes to needing to keep cool to
heightening sexual attraction - generally
agreeing only on one point: that everyone
else's hypothesis is wrong.
Let’s take a look at some of these
hypotheses.
Six Major Hypotheses
Hauling Food
A New World
Grabbing A Bite
Keeping Cool
Attracting Mates
Weapons and Tools
Bipedalism:
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Hauling Food
As African landscape shifted from forests toward large
patches of open woodlands & savannahs, food supplies
waned, wannabe hominids descended from trees / became
ground-dwellers.
– Because could no longer feed where lived, were forced to carry food
over long distances back to home bases - tricky task if remained
quadrupeds.
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While some contend early hominids gathered fruits and nuts,
a few argue that they were scavengers.
– Upright stance enabled ancestors to lug carcasses to safer areas for
consumption, also allowing them to see other food sources or potential
danger at greater distances
Bipedalism:
A New World
• As early hominids left forest to explore woodlands /
savannas, no longer needed body structure for
climbing.
– Those who could walk upon two feet better able to survive
• expended less energy / could travel longer distances than knucklewalkers
• better able to see potential dangers lurking in the distance
• Our ancestors developed an upright posture to
– carry food over long distances
– or find it.
Bipedalism:
Attracting Mates
• Sex — specifically males' desire to get more of it — a
direct reason for why we walk upright.
• Upright males better breadwinners
– Those who could walk bipedally freed their arms to carry
more food - made knuckle-walkers far less appealing to
females.
– Their ability to have more food for females (who remained
at the home base to care for the offspring) ensured that
they were able to reproduce, thus leading to future
generations of adept bipeds who in turn were able to pass
on their own genes.
Grabbing A Bite
• Ability to walk upright was in part a serendipitous byproduct of new feeding habits.
• As our ancestors descended from trees to forage on the
ground for low-hanging fruits and berries, they began to
feed from a squatting position.
• Over time, physiological changes occurred in upper
bodies, backbones, pelvic areas, causing weight and
centers of balance to shift to a lower point in the body.
Bipedalism:
Keeping Cool
• Protected early hominids from overheating
– Exposes less of body to direct sunlight on savannahs than
quadrupeds of the same size (60% less heat load)
• Raised bodies above the ground, enabling skin to
come in better contact with cooler / faster-moving
breezes
– Also meant hominids needed only 3 pints of water / day,
whereas quadrupeds needed 5
Bipedalism:ß
Weapons
& tools
• Some hypothesize bipedalism brought forth our
ability to use weapons / tools - others believe the
reverse: advent of tool / weapon use encouraged us to
become bipedal.
Six Major Hypotheses
Hauling Food
Grabbing A Bite
A New World
Keeping Cool
Attracting Mates
Weapons and Tools
ALL these models may have played a role in the emergence of
habitual upright bipedalism
From Ape to Hominid
• Proto-Hominids (Opportunistic bipeds)
– Sahelanthropus tchandensis / Orrorin tugeninsis
• Transitional Opportunistic-into-Habitual
Bipeds
– Ardipithecus ramidus / Australopithecus anamensis
• First True Habitual Upright Bipeds
– Australopithecus afarensis / A. africanus / A. garhi
– Australopithecus robustus / A. boisei
There is no straight line in the greater
than four million-year-old journey of the
family called HOMINIDAE.
From Ape to Hominid
• Proto-Hominids (Opportunistic bipeds)
– Sahelanthropus techandensis / Orrorin tugeninsis
• Transitional Opportunistic-into-Habitual
Bipeds
– Ardipithecus ramidus / Australopithecus anamensis
• First True Habitual Bipeds
– Australopithecus afarensis / A. africanus / A. garhi
– Australopithecus robustus / A. boisei
Proto-Hominids
• Molecular biology strongly suggests:
– Last common ancestor of chimps & humans
lived 5-8 m.y.a.
• Two recent finds warrant our
attention:
– Sahelanthropus tchadensis
– Orrorin tugenensis
Sahelanthropus tchadensis
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6 - 7 m.y.a.
Brain size: 1/4th of ours
No post-cranial bones
Don’t know if habitual biped
Lived in variety of habitats
Likely ate mainly fruit, with
smaller amounts of other
foods.
Download and read:
The Earliest Possible Hominids
Orrorin tugenensis
• 6 m.y.a.
• Remains fragmentary
• Canines / premolars
extremely ape-like BUT
with thick tooth enamel
(like hominids)
• Maybe bipedal
• Inferior side of femoral
neck (#1 on picture) is
thick (like hominids)
Ardipithecus ramidus
A species of bipedal apes
• 5.8 - 4.4 m.y.a.
• Possibly bipedal (but not like us)
• Small bodied (64-100 lbs); small brained (300350 cc)
• Combo of hominid-like & chimp-like traits
• Diet: unknown (relatively thin tooth enamel)
• Well-watered, forested environment
• Discovery Channel Website About "Ardi"
Ardi Revealed
• Ardi’s skeleton includes many
important bones of the skull,
hands, feet, limbs, and pelvis.
These fossil bones offer key
insights into how 'Ardi' was built,
and how she moved. Her skeleton
demonstrates that she was capable
of both walking upright AND clambering through trees with a
grasping big toe, in a way unlike any other creature known to
science. Ardi shows an unexpected mix of advanced characteristics
and of primitive traits seen in much older apes that were unlike
chimps or gorillas. As such, the skeleton offers a window on what the
last common ancestor of humans and living apes might have been
like.
Interactive webpage: Ardi's Key Skeletal Features
Australopithecus anamensis
• 4.2 - 3.9 m.y.a.
• Fragmentary remains
• Teeth and jaws similar to
fossil apes
• May be earliest
incontrovertible evidence of
bipedalism
• Strongly resembles Austr.
afarensis
• Streamside forests
Australopithecus afarensis
Smallbrained,
bipedal
human
ancestors.
They are the
benchmark by
which the
anatomy of all
other early
hominid
s is
interpreted.
• 4 - 3 mya
• East Africa
• Fully bipedal
• Mix of human-like &
ape-like traits
• Sexually dimorphic
Lucy: 1st afarensis found
Her discovery revolutionized ways of thinking
about early hominids.
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Left to right: Lucy’s bones,
reconstructed Lucy, modern human
1974 - Hadar, Ethiopia
About 3’8” tall; 55 lbs
Long arms / short legs
Mid-20s when died
Teeth: small &
unspecialized, indicating a
mixed, omnivorous diet of
mostly soft foods (fruits)
A. afarensis skull morphology
Male
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Female
(Lucy)
Cranial capacity: 350 -500 cc (2/3rds - 1 water bottle
Small sagittal crest in males
Slightly projecting upper canine teeth in males
Parallel rows of cheek teeth (like apes)
A. afarensis body morphology
Ground or tree-dweller?
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Slightly curved hand & foot bones
Relatively long and powerful arms
Bowl-shaped pelvis
Knock-kneed (knee joint angled
inward)
• Heel bone heavily built (like ours)
• Foot may have
had high, fixed
arches (Laetoli?)
A. afarensis footprints
• Laetoli, Tanzania: home to a footprint trail 3.5 m.y. old
• Probably a trackway of A. afarensis
An afarensis 3 yr old baby girl
• Ethiopia (Hadar)
• Lived 3.3 m.y.ago
• Ape-like scapula
• Human-like knees
• Finger bones partially
curved
• Heel bone well-developed
• Endocast shows delayed
brain growth (like us)
• Chimp-like hyoid bone
Australopithecus africanus
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3.5 - 2.0 m.y.a.
Mainly S. Africa
Mixture of habitats
Fruit, salads, insects, small
easily captured prey
• Brain size: 1/3rd ours
• Relationship to other hominids?
Unknown
This species slightly different from A. afarensis: slightly taller,
less facial prognathism, slightly larger brain. Also lived in drier
habitats (especially dry scrublands and perhaps open grasslands),
and thus may have exploited different resources.
Australopithecus garhi:
A stone tool using australopithecine?
• Ethiopia
• 2.5 million years old
• Mostly fragments of
skulls, some post-cranial
remains
• Most intriguing: cut-marked animal bones found near garhi’s
remains. Such marks are signs of stone tools being used to carve
up animal carcasses. Can’t say for sure IF garhi was maker,
maker-user, user (or none of these) of tools.
The Robust Australopithecines
Dietary specialists?
• One of most fascinating
branches of human family
tree
• Reveal radically different
way of being hominid
• About 2.5 m.y.a they diverged from our own lineage
• Came to be defined by an adaptation to eating hard
foods like nuts, seeds, and roots
Robust Austraopithecine Morphology
• 2.5 - 1 m.y.a.
• South and East Africa
• 3 species - united by suite of
features related to eating tough
foods:
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Extremely large molars / premolars
Dished face
Extremely large chewing muscles
Wide-flaring cheekbones
Pronounced pinching-in behind the
eye orbits
– Prominent sagittal crest
Robust australopithecine behavior
Digging sticks used by
modern chimpanzees.
While such tools have not
been found with robust
australopithecine fossils,
it is possible they used
such tools
• Omnivores, but relied on hard to chew foods (nuts, roots,
seeds)
• Probably used tools (bones/horns showing polishing, maybe
used for digging up roots)
• Lived in (open) woodlands and savannas
• Evolutionary dead end
Australopithecine Foraging Behavior
Foraging (the systematic
search for food and other
provisions) was THE
lifeway of all hominids
from the earliest
australopithecines until
about 10,000 years ago (the
start of agricultural modes
of subsistence.
Foraging by australopithecines and early species of Homo most likely
consisted of collecting roots, berries, seeds, nuts, salad greens, insects,
etc. Around 2 m.y.a meat, obtained by scavenging, became part of the
foraging way of life. Eventually fish and shellfish would be added.
Major adaptive shifts in hominid
evolution ca. 2 m.y.a.
• Australopithecine lineage
– Intensification of adaptation to hard object feeding
• Emergence of Homo lineage
– Several new species appear on African landscape
– Physically / behaviorally different from earlier &
contemporary australopithecines
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Flatter faces
Brain reorganized (lateralization & language regions)
Unquestioned manufacture/use of stone tools (bone/horn/wood?)
Added meat to diet (scavenging)
Some species have brains as large as 750 cc
Earliest Homo species
• Contentiousness regarding who belongs to
early Homo
(Question: If one of the gracile australopithecine species is ancestral to Homo, how does one
tell a late gracile australopith from an early Homo?)
• At least 3 (perhaps more) Homo species
– Homo habilis = 2 - 1.5 m.y.a
– Homo rudolfensis = 2 - 1.8 m.y.a
– Homo erectus (aka H. ergaster) = 1.8 - 1.0 m.y.a.
Earliest Members of the Genus Homo
H. Habilis
H. rudolfensis
H. erectus*
E. Africa
2 - 1.5 mya
3 1/2 - 4’ tall
East Africa
2 - 1.8 mya
5 - 5 1/2 feet tall
Brain: 510 cc (1
Brain: 775 cc (1 1/2
E. Africa
1.8 - 1.0 mya
5 1/2 - 6’ tall
Brain: 800-1200 cc
*Sometimes called H.
ergaster
water bottle)
water bottles)
Early Homo Behavior
• Stone tools 1st appear ca. 2.5 mya
– Most often attributed to H. habilis ( maybe A. garhi)
– Earliest tools (Oldowan tradition)
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Flakes (cutting/scraping)
Chopper / chopping tools (“smashers / bashers”)
Hammerstones
Some bone/horn w/scratches (digging?)
• Meat eating takes on increasing importance after 2.5
m.y.a.
• Several types of sites: quarries, food processing
locations
Making / Using Oldowan Tools
Hominids often traveled up to 10 km
to acquire right kind of stone from
which to make tools.
Early Homo Scavenging Behavior
Can a hominid eat meat obtained like this and not get sick?
Perhaps if one gets there within a few hours of a predator’s kill.
Out of Africa, Part One
Homo erectus
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Found first in Africa = 1.8 - 1.0 m.y.a.
Perhaps Rep. of Georgia = 1.7 m.y.a. (H. georgicus?)
Island SE Asia = 1.8 m.y.a.
Continental Asia = 1.4 m.y.a
Out of Africa, Part 2
• Homo erectus
– By 1.5 m.y.a develops a more sophisticated tool
technology (Acheulian)
– African forms sometimes called H. ergaster
– Georgian forms sometimes called H. georgicus
– Asian and southeast Asian forms always called
H. erectus
H. ergaster vs. H. erectus
H. georgicus
H. ergaster
East Africa / Georgia
1.8 - 1.0 mya
Thinner cranial bones
Less pronounced
browridges
H. erectus
Asia
1.8 - .05 mya
Thicker cranial bones
More pronounced
browridges
Homo erectus
(Prometheus Unbound)
• Invented new tool: handaxe
– Larger tools, required more preparation than Oldowan choppers
• First hominids to make tools to a predetermined shape
• First hominids to make task-specific tools
– Some tools used for butchering animal carcasses; others for working
with wood; still others for use with veggies
• Probably the first hominids to use, perhaps even control, fire
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Hints of use at South African site between 1.5 - 1.0 m.y.a.
Fire allows cooking foods (makes meat and veggie consumption easier)
Useful to lengthen the day into the night
Keeps predators away
Warmth
Homo erectus
Why are these hominids so important?
• ?? FIRST TO LEAVE AFRICA ??
• COMPETENT TOOLMAKERS: Acheulean
– 1st appeared 1.5 m.y.a.
– Shaping entire stone to stereotyped form
– Bifacial flaking
– Butcher animal carcasses / digging tools /
cutting & scraping
• FIRST to USE/CONTROL FIRE (ca. 1 m.y.a.)
• FIRST SYSTEMATIC HUNTING of
medium-size game animals
Homo erectus Morphology
• Body Size and Shape
– Basically modern, but more muscled and robust
– Some individuals very tall (boy from Nariokotome, Lake
Turkana) = 6 feet tall when an adult
Large brain: 700 - 1200 cc
(overlaps moderns)
Long, low with receding
forehead & large browridges
Midfacial pronathism /
powerfully built jaw
Boy from Nariokotome
Very tall hominid at 1.5 mya
• About 8 years old when he died
• 5’ tall (6 feet @ maturity)
• Legs relatively long in proportion to body
as compared to earlier hominids
• Well adapted to staying cool in hot, dry
climates
• Face, molar teeth, chewing muscles smaller
than earlier hominids (softer, high-quality perhaps cooked - foods)
• Skull-to-pelvis proportions of females: give
birth to relatively immature infants
– Implications: long infancy-childhood
dependency period: good for learning
Homo georgicus
?? 1st Hominid to Leave Africa ??
• Dmanisi, Georgia (Caucasus
Mtns)
• 1.7 - 1.8 m.y.a.
• Late H. habilis or early H. erectus
• Brain size: 600-750 cc
• Stature: 1.5 m
• Oldowan tool technology
THE RISE OF MODERN HUMANS
From
Homo erectus
To
Homo sapiens
Via
Homo heidelbergensis
Homo heidelbergensis
Ancestor to Neanderthals and Us
Name given to a range of specimens from about
800,000 years ago to the appearance of Homo
neanderthalensis in Europe and anatomically
modern Homo sapiens in Africa
Homo heidelbergensis
• 1st appears ca. 1 mya - 800 k.y.a.
- none later in time than 500 300 k.y.a.
• Africa, Europe (but not Asia)
• Brain larger than erectus: 12001500 cc
• Skull more rounded, less robust
but still with large brow ridges,
receding foreheads & no chins
Homo heidelbergensis
First BIG GAME hunters
• By 500 k.y.a. using wooden
spears to hunt large game
• Bodybuilder physiques
– Pronounced muscle
markings
– Thick layers of hard bone
around central marrow
cavities
While heidelbergensis lived in Africa, other hominid
species lived elsewhere: H. erectus continued
successfully in eastern Asia and in Europe H.
antecessor was living in Spain by 800,000 years ago.
Homo neanderthalensis
European descendants of H. heidelbergensis
Female
Dark haired male
Young boy
Red-headed male
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Neanderthals: Ancestors Or Dead
Ends?
• Unique species that lived
in Europe, southwest Asia,
central Asia between
200,000 0 30,000 years ago
(k.y.a.)
• Much controversy over
their fate AND their
relationship to
anatomically modern
humans (H. sapiens)
No other aspect of human
evolution has generated
as much public interest
for so long a time as the
story of the Neanderthals.
Neanderthals: Earlier Views
Until very recently, Neanderthals were
most often depicted as brutish,
dimwitted, “half man . . . half beast.”
Neanderthals: Recent Views
Neanderthals: Recent Views
Neanderthal Cranial Morphology
Neanderthal Cranial Morphology
• Cranial cap: 1400 cc
• Large midface / very big nose
that projects forward
• Large gap behind 3rd molar
• Large protruding occipital
bone
• Marked neck muscle
attachments on skull
• Very large incisor teeth
• No chin
• Double-arched brow ridge
Neanderthals & Modern Humans Compared
Modern human child (left) and Neanderthal child (right)
• Neanderthals differ from anatomically modern H. sapiens in a
suite of cranial features:
– low but elongated and broadened braincase
– prominent brow ridges
– Occipital bun
– a depression on the surface of the occipital bone at the
back of the skull
– large face with rounded orbits, wide nasal aperture
– mandible with a receding chin region
– retromolar space in adult individuals
A Comparison: Side by Side
With A Relative
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Brain case: low vs. high
Nasal opening: large vs. narrow
Collarbone: long vs. shorter
Rib cage: conical vs. cylindrical
Limb bones: thick-walled vs.
thin-walled
Hand bones: robust vs. slender
Trunk: short vs. long
Hips: flaring vs. narrow
Joint surfaces: large vs. smaller
Lower leg: shorter vs. longer
Bowed limbs vs. straight limbs
Us vs. Them
Explanation for Neanderthal Morphology
• Cold weather & harsh
climate adaptations
• Strenuous hunting
Neanderthal culture
Neanderthal Culture: Stone tools
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Mousterian toolkit
– Effective but simple
– Changed little over 100,000 yrs.
– Trimmed flint nodules
• Strike-off lots of flakes
– predetermined form retouched)
– Tool specialization
• Skin & meat preparation
• Hunting
• Woodworking
• Hafting
– Some wooden tools (including
thrusting spears)
Levallois Flint Knapping
• Careful retouching of
flakes taken off cores
• Specific uses of flakes
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Animal butchering
Woodworking
Bone & antler carving
Working of animal hides
Neanderthal Culture: Subsistence
• Extremely successful hunters
– Jabbing spears (not thrown) w/ hafted stone points
– No long-distance hunting (locally available game)
• Cave bear, Deer, Woolly rhinoceros, mammoth, wild cattle,
reindeer, horse, wild ass, ibex, saiga
– Neanderthal skeletons often show fractures
• Fairly efficient gatherers
– Berries, greens, roots - limited time frame (few weeks)
Neanderthal Culture
Settlements
• Open sites, caves, rock-shelters
• Built structures / windbreaks
• Controlled use of fire: warmth
Neanderthal Social Behavior
Neandertal Cannibalism
Ritualistic or Nutritional Purposes
• Possible evidence
– France & Croatia
– Fragmentary bones show stone-tool cut marks
similar to those found on butchered game animals
– Some long bones smashed to get marrow
Burying the Dead
• Intentional
• Some grave offerings: stone tools, animal bones
(flowers?)
Burying The Dead
• Intentional human
burials
• Some graves
contain offerings
- stone tools,
animal bones
(flowers?)
• Reasons for
burial?
The Fate of the Neanderthals: Part I
By 30 k.y.a. no more Neanderthals. Why?
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Sudden climatic change
– Large game dying out and Neanderthals
hunting methods not suitable?
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Out competed by anatomically modern H.
sapiens?
– Better energy extraction methods
– Shorter gestation periods
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Died due to diseases brought by
anatomically modern H. sapiens?
Genetically absorbed into anatomically
modern H. sapiens populations without
significant genetic contributions to modern
populations?
The Fate of the Neanderthals: Part II
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Interbred with anatomically modern H. sapiens to
produce modern Europeans?
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Four-year-old child buried in a Portuguese rockshelter 25,000 to 24,500 years ago
Czech Republic, male, mixture of Neanderthal and
a.m. Homo sapiens features
Recent genetic data indicates no admixture
In Our Own Image
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Idaltu: Ethiopia / 160,000 y.a.
Cro-Magnon: Europe / 45,000 y.a.
Early Anatomically Modern H. sapiens
Defined Morphologically, Not Behaviorally
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Tall, almost vertical forehead
Smallest teeth (relative to body size) of all the hominids)
Small to minimal brow ridges
No retromolar gap (we get impacted wisdom teeth)
Cranial cap.: 1350 (1000 - 2000)
There is a chin, a uniquely modern human trait
High rounded cranium : widest point on sides of parietals
Complexity of Culture
Begins about 50 k.y.a.
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Blade tools: increased technological
abilities
Atlatl
Small bone & ivory tools
Fishhooks
Tailored skin clothing
Bow and arrow
Nets, snares
Expansion into new eco-niches
– Especially plant foods / marine foods
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Ubiquitous burial of the dead
Postmortem modification common
Art and symbolism
Spreading Out
Art
Cave paintings
and
“venus” figurines
Origins of Moderns
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
• Lots of debate
• Several major theories
– Recent African origin
– Multiregional origins
– Multiple dispersal origins
Whole Language