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The Human Story

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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 ... – PowerPoint PPT presentation

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Title: The Human Story


1
The Human Story
  • Where We Came From
  • How We Evolved

2
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.
3
Evidence of Bipedalism
  • 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

4
Placement of Foramen Magnum
5
Shape of Spine
6
Pelvic Girdle Bicondylar Angle
7
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.
8
Parallel Toes / Fixed Arches
9
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
10
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. Lets take a look at some
of these hypotheses.
11
Six Major Hypotheses
Hauling Food
Grabbing A Bite
A New World
Keeping Cool
Attracting Mates
Weapons and Tools
12
Bipedalism 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.
  • 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

13
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 knuckle-walkers
  • 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.

14
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.

15
Grabbing A Bite
  • Ability to walk upright was in part a
    serendipitous by-product 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.

16
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

17
Bipedalismß
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.

18
Six Major Hypotheses
Grabbing A Bite
Hauling Food
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
19
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

20
There is no straight line in the greater than
four million-year-old journey of the family
called HOMINIDAE.
21
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

22
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

23
Sahelanthropus tchadensis
  • 6 - 7 m.y.a.
  • Brain size 1/4th of ours
  • No post-cranial bones
  • Dont 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
24
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)

25
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 (300-350
    cc)
  • Combo of hominid-like chimp-like traits
  • Diet unknown (relatively thin tooth enamel)
  • Well-watered, forested environment
  • Discovery Channel Website About "Ardi"

26
Ardi Revealed
  • Ardis 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
27
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

28
Australopithecus afarensis
Small-brained, bipedal human ancestors. They are
the benchmark by which the anatomy of all other
early hominids is interpreted.
  • 4 - 3 mya
  • East Africa
  • Fully bipedal
  • Mix of human-like ape-like traits
  • Sexually dimorphic

29
Lucy 1st afarensis foundHer discovery
revolutionized ways of thinking about early
hominids.
  • 1974 - Hadar, Ethiopia
  • About 38 tall 55 lbs
  • Long arms / short legs
  • Mid-20s when died
  • Teeth small unspecialized, indicating a mixed,
    omnivorous diet of mostly soft foods (fruits)

Left to right Lucys bones, reconstructed Lucy,
modern human
30
A. afarensis skull morphology
Male
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)

31
afarensis body morphologyGround or tree-dweller?
  • 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?)

32
A. afarensis footprints
  • Laetoli, Tanzania home to a footprint trail 3.5
    m.y. old
  • Probably a trackway of A. afarensis

33
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

34
Australopithecus africanus
  • 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.
35
Australopithecus garhiA 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 garhis remains. Such marks are signs of
    stone tools being used to carve up animal
    carcasses. Cant say for sure IF garhi was maker,
    maker-user, user (or none of these) of tools.

36
The Robust AustralopithecinesDietary 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

37
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
  • Extremely large molars / premolars
  • Dished face
  • Extremely large chewing muscles
  • Wide-flaring cheekbones
  • Pronounced pinching-in behind the eye orbits
  • Prominent sagittal crest

38
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

39
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.
40
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
  • 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

41
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.

42
Earliest Members of the Genus Homo
43
Early Homo Behavior
  • Stone tools 1st appear ca. 2.5 mya
  • Most often attributed to H. habilis ( maybe A.
    garhi)
  • Earliest tools (Oldowan tradition)
  • 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


44
Making / Using Oldowan Tools
Hominids often traveled up to 10 km to acquire
right kind of stone from which to make tools.
45
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 predators kill.
46
Out of Africa, Part OneHomo erectus
  • 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

47
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

48
H. ergaster vs. H. erectus
H. georgicus
49
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
  • 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

50
Homo erectusWhy 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

51
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

52
Boy from NariokotomeVery tall hominid at 1.5 mya
  • About 8 years old when he died
  • 5 tall (6 feet _at_ 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

53
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

54
THE RISE OF MODERN HUMANS
  • From
  • Homo erectus
  • To
  • Homo sapiens
  • Via
  • Homo heidelbergensis

55
Homo heidelbergensisAncestor 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
56
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 1200-1500 cc
  • Skull more rounded, less robust but still with
    large brow ridges, receding foreheads no chins

57
Homo heidelbergensisFirst 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.
58
Homo neanderthalensisEuropean descendants of H.
heidelbergensis
Female
Dark haired male
Red-headed male
Young boy
59
N E A N D E R T A L
W O R L D
60
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.
61
Neanderthals Earlier Views
Until very recently, Neanderthals were most often
depicted as brutish, dimwitted, half man . . .
half beast.
62
Neanderthals Recent Views
63
Neanderthals Recent Views
64
Neanderthal Cranial Morphology
65
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

66
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

67
A Comparison Side by Side With A Relative
  • 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

68
Us vs. Them
69
Explanation for Neanderthal Morphology
  • Cold weather harsh climate adaptations
  • Strenuous hunting

70
Neanderthal culture
71
Neanderthal Culture Stone tools
  • 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)

72
Levallois Flint Knapping
  • Careful retouching of flakes taken off cores
  • Specific uses of flakes
  • Animal butchering
  • Woodworking
  • Bone antler carving
  • Working of animal hides

73
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)

74
Neanderthal CultureSettlements
  • Open sites, caves, rock-shelters
  • Built structures / windbreaks
  • Controlled use of fire warmth

75
Neanderthal Social Behavior
76
Neandertal CannibalismRitualistic 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

77
Burying the Dead
  • Intentional
  • Some grave offerings stone tools, animal bones
    (flowers?)

78
Burying The Dead
  • Intentional human burials
  • Some graves contain offerings - stone tools,
    animal bones (flowers?)
  • Reasons for burial?

79
The Fate of the Neanderthals Part I
  • By 30 k.y.a. no more Neanderthals. Why?
  • Sudden climatic change
  • Large game dying out and Neanderthals hunting
    methods not suitable?
  • Out competed by anatomically modern H. sapiens?
  • Better energy extraction methods
  • Shorter gestation periods
  • 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?

80
The Fate of the Neanderthals Part II
  • Interbred with anatomically modern H. sapiens to
    produce modern Europeans?
  • Four-year-old child buried in a Portuguese
    rock-shelter 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
81
In Our Own Image
  • Idaltu Ethiopia / 160,000 y.a.
  • Cro-Magnon Europe / 45,000 y.a.

82
Early Anatomically Modern H. sapiensDefined
Morphologically, Not Behaviorally
  • 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

83
Complexity of Culture Begins about 50 k.y.a.
  • 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
  • Ubiquitous burial of the dead
  • Postmortem modification common
  • Art and symbolism

84
Spreading Out
85
Art
Cave paintings and venus figurines
86
Origins of Moderns
  • Lots of debate
  • Several major theories
  • Recent African origin
  • Multiregional origins
  • Multiple dispersal origins

87
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