1. Where We Came From & How We Evolved
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.
For a good primer on this subject check out the University of Texas at Austin’s web site:

8. Parallel Toes / Fixed Arches

9. Or WHY WE WALK ON TWO LEGS
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. Let’s 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. 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.

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
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

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
m.y.a.
Possibly bipedal (but not like us)
Small bodied ( lbs); small brained ( 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
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

27. Australopithecus anamensis
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 found Her discovery revolutionized ways of thinking about early hominids.
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)
Left to right: Lucy’s bones, reconstructed Lucy, modern human

30. A. afarensis skull morphology
Male
Female (Lucy)
Cranial capacity: 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 morphology Ground 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
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 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.

36. 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

37. Robust Austraopithecine Morphology
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 = m.y.a
Homo rudolfensis = m.y.a
Homo erectus (aka H. ergaster) = m.y.a.

42. Earliest Members of the Genus Homo
H. Habilis
E. Africa
mya
3 1/2 - 4’ tall
Brain: 510 cc (1 water bottle)
H. rudolfensis
East Africa
mya
/2 feet tall
Brain: 775 cc (1 1/2 water bottles)
H. erectus*
E. Africa
mya
5 1/2 - 6’ tall
Brain: cc
*Sometimes called H. ergaster

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
An early hominid, Homo ergaster, depicted in this diorama from the American Museum of Natural History's Hall of Human Biology and Evolution, lived nearly 2 million years ago in the eastern Rift Valley of Africa.
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.

46. Out of Africa, Part One Homo erectus
Found first in Africa = 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. ergaster East Africa / Georgia
H. georgicus
H. ergaster
East Africa / Georgia
mya
Thinner cranial bones
Less pronounced browridges
H. erectus
Asia
mya
Thicker cranial bones
More pronounced browridges

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 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 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

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: cc (overlaps moderns)
Long, low with receding forehead & large browridges
Midfacial pronathism / powerfully built jaw

52. Boy from Nariokotome Very tall hominid at 1.5 mya
About 8 years old when he died
5’ tall (6 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)
m.y.a.
Late H. habilis or early H. erectus
Brain size: 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 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

56. Homo heidelbergensis
1st appears ca. 1 mya k.y.a. - none later in time than k.y.a.
Africa, Europe (but not Asia)
Brain larger than erectus: cc
Skull more rounded, less robust but still with large brow ridges, receding foreheads & no chins

57. 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.

58. Homo neanderthalensis European descendants of H. heidelbergensis
Female
Dark haired male
Red-headed male
Young boy

59. N E A D R T 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 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
Their bodies' relentless demand for calories, especially in higher latitudes and during colder interludes, probably forced Neanderthal women and children to join in the hunt.

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 Culture Settlements
Open sites, caves, rock-shelters
Built structures / windbreaks
Controlled use of fire: warmth

75. Neanderthal Social Behavior

76. 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

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
Early Anatomically Modern H. sapiens Defined 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 ( )
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. Whole Language