Fossil Hominins: From Australopithecus to Homo
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Fossil Hominins: From Australopithecus to Homo

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Compares the Fossil Hominins from Australopthecus afarensis to Homo Sapiens

Compares the Fossil Hominins from Australopthecus afarensis to Homo Sapiens

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Fossil Hominins: From Australopithecus to Homo Fossil Hominins: From Australopithecus to Homo Presentation Transcript

  • Fossil Hominins From Australopithecus to Homo
  • Model of Human Evolution: Australopithecus to Homo
    • Australopithecus afarensis to A. africanus : Gracile Australopithecines
    • Paranthropus robustus and boisei: Robust Australopithecines—Dead end?
    • A. africanus to Homo habilis : Rise of tool manufacture?
    • H. habilis to H. erectus: Global spread; increased tool assemblage
    • H. erectus to H. sapiens: Tool specialization and population explosion
    • H. neanderthalensis: Dead end?
  • Fossil Hominins: General Trends
    • Large bulbous cranium
    • Short face compared to ape
    • Vertical carriage of head
    • Hands and Forelimbs Adapted to Tool Making and Use
    • Bipedal Structure of Postcranial Skeleton
  • Fossil Trends: Encephalization (Cranial Capacity Increase)
    • A. afarensis: 390-500 cc; av. 440 cc
    • A. africanus: 435-530 cc; av. 450 cc
    • A./P robustus: 520 cc, one specimen
    • A.P. boisei: 500-530 cc; av. 515 cc.
    • H. habilis: 500-800 cc; av. 680 cc.
    • H. erectus: 750-1250 cc; av. 1000 cc
    • Neanderthal: 1300-1750 cc. av: 1450
    • H. (s.) sapiens: 900-2350 cc. av. 1400
  • Fossil Trends: Forelimbs and Hands
    • Shortened forelimb
    • Hands (manipulation, not locomotion)
    • Enlarged thumb
    • Straight, noncurved finger
    • Enhanced finger sensitivity
  • Fossil Hominins: General Trends--Bipedalism
    • S-shaped vertebrae (backbone)
    • Short, wide, bowl-shaped pelvis
    • Femoral head (ball of femur at pelvis) angled and strengthened
    • Lengthened hindlimb
    • Angle of knee: femur “slopes” to pelvis
    • Platform (arched) structure of foot
    • Nonopposable big toe; toes not curved
  • Lucy ( Australopithecus afarensis ) and Us (Homo sapiens)
    • Note the Following:
    • Shorter (3’6”)
    • Longer arms
    • Curved fingers
    • Shorter lower legs
    • Greater prognathism
    • Sloped forehead
    • Smaller cranial capacity
    • What are the Similarities?
    • Hint: it’s all related to bipedalism
  • Bipedalism: A. afarensis and H. sapiens compared, Fine Points
  • When We Became Bipedal (According to Gary Larson)
    • “ Hey! Look! No hands!”
    • (Does he look like Lucy to you. . .?)
  • Gracile and Robust Australopithecines
    • For A. africanus (top), note:
    • Somewhat rounder skull
    • No Sagittal crest
    • Prognathous jaw
    • For Paranthropus boisei, note:
    • Sagittal crest (ate a lot of veggies)
    • Massive lower jaw (mandible)
    • Flatter face
    • Massive cheek bones (zygomatic arch)
  • Summary of Australopithecines
    • Cranial capacity increased marginally
    • All australopithecines had
    • Sloping foreheads
    • Prominent brow ridges
    • Prognathous lower face and jaws
    • Bipedal postcranial skeletons
    • Robust forms probably were dead ends
    • Graciles likely evolved toward Homo .
  • Australopithecus and Homo Compared—Frontal View
    • Left: A. africanus
    • Right: H. habilis
    • Note:
    • Different Cranial Capacities
    • Brow Ridge Size
  • Australopithecus and Homo Compared—Side View
    • Top: A. africanus
    • Bottom: H. habilis
    • Compare:
    • Mass of Jaws
    • Size of Crania
    • Prognathism
  • Postorbital Constriction
    • Left: Homo erectus
    • Right: Australopithecus africanus
    • Note the narrower constriction of A. africanus’s postorbital constriction than that of H. erectus
  • Homo habilis: The First Known Toolmaker
    • Note the following:
    • Face is much flatter
    • Reduced brow ridge (supraorbital torus)
    • Larger cranial capacity (680 cc.)
    • Toolmaking Technique
    • Hammerstone used to strike
    • A core (lump of stone) to knap
    • A Flake (stone chip)
    • Note: Stone has to be crystalline (so it will fracture predictably)
  • Homo habilis According to Gary Larson
  • Australopithecines and Homo Compared I
    • Cranial capacity
    • Australopithecines: 400-530 cc
    • Homo: 500-2300
    • Maximum braincase width
    • Australopithecines: low on skull
    • Homo: near top
    • Postorbital constriction Australopithecines: marked Homo: moderate to slight
  • Australopithecines and Homo Compared II
    • Supraorbital torus (brow ridge)
    • Australopithecines: large to moderate
    • Homo: large to slight
    • Zygomatic arch
    • Australopithecines: large, flaring
    • Homo: small, not flaring
  • Australopithecines and Homo Compared III
    • Facial size relative to brain case
    • Australopithecines: large
    • Homo: small
    • Jaw
    • A: Massive and prognathic; no chin
    • H: Not massive
    • Prognathism slight to nonexistent;
    • Chin present in sapients
    • Molars and premolars
    • Australopithecines: large; afarensis with diastema
    • Homo: small
  • Australopithecines and Homo Habilis Compared: Skulls
    • General trends
    • Encephalization: Cranial capacity increases
    • Dentition: Cheek teeth are reduced
    • Sagittal Crest (where chewing muscles attach)
    • A./P. robustus and boisei: pronounced
    • A. africanus: sagittal keel or absent
    • H. habilis: absent
  • Australopithecines and Homo Habilis Compared: Skull/Face
    • Braincase
    • A./P. robustus/boisei: less rounded
    • A. africanus: more rounded
    • H. habilis: most rounded of the three
    • Zygomatic arch
    • A./P. robustus/boisei: very pronounced
    • A. africanus: less pronounced
    • H. habilis: far less pronounced than the australopithecines
  • Homo habilis: Hands and Feet
    • Hands
    • Curvature of finger bones are apelike, indicate powerful grip (arboreal)
    • Indications of greater manipulative skill
    • Larger blood supply to hand than earlier hominids
    • Evidence of greater nerve supply
    • Feet: existing fragments indicate modern form:
    • Remains lacked toes
  • Tool Traditions: Oldowan
    • Named after Olduvai Gorge
    • Among the finds at Olduvai:
    • Side chopper, a core tool
    • Several flake tools, including
    • End scraper
    • Side scraper
    • Burin
    • Utilized flakes of unknown function
    • Belongs to Lower Paleolithic
  • Manufacturing Choppers
    • Procedure
    • Knapper strikes a spherical piece of stone
    • Flake falls off opposite side
    • Tool flipped over and procedure repeated
    • Several blows create a cutting edge
    • Requirements reflect Intelligence
    • Planning and foreknowledge of design
    • Knowledge of breakage pattern of rock
    • Hand-eye coordination
  • Oldowan Tradition
    • End chopper
    • Heavy duty scraper
    • Flake scraper
    • Spheroid Hammerstone
    • Chopper
    • Horn core tool or digger
  • Homo habilis and Homo erectus
    • Compared to H. habilis, H erectus had:
    • Larger brain (1000 cc vs 680 cc average)
    • Forehead flatter, less sloping
    • More rounded occipital torus
    • endocasts indicate hemispheric asymmetry
    • Homo erectus and Homo sapiens
  • Homo erectus or ergaster
    • Note:
    • Apelike but larger cranium
    • Postcranial Skeleton
    • Vertebrae: S Shaped
    • Ribcage: Not funnel shaped, now like ours
    • Pelvis: Bowl shaped
    • Angle of Thighbone
  • Homo erectus and Homo Sapiens: Cranium (Braincase)
    • Forehead (Frontal)
    • H. erectus: sloping; low and flat
    • H. sapiens: vertical, indicating frontal lobe
    • Supraorbital torus (brow ridge)
    • H. erectus: prominent--extending as a bar
    • H. sapiens: slight or absent
    • Occipital torus:
    • H. erectus: present
    • H. sapiens: slight or absent
  • Homo erectus and Homo sapiens: Cranium and Face
    • Sagittal keel
    • H. erectus: present; vestige of crest?
    • H. sapiens: slight or absent
    • Postorbital constriction
    • H. erectus: pronounced
    • H. sapiens: slight or nonexistent
  • Homo erectus and Homo sapiens: Facial Skeleton
    • Facial skeletion
    • H. erectus: Relatively large, with large orbits and nasal opening
    • H. sapiens: Relatively small, with small orbits and nasal opening
    • Prognathism (jutting jaw)
    • H. erectus: Pronounced
    • H. sapiens: minimal or nonexistent
  • Homo erectus and Homo sapiens skulls
    • Compare:
    • Brow ridges (supraorbital tori)
    • Prognathism
    • Constriction behind eye sockets (postorbital constriction)
    • Presence versus absence of chin
  • Tool Traditions: Acheulean
    • Named after St. Acheul
    • Characteristics of Acheulean handaxe
    • Bifacial: both sides knapped
    • Symmetrical in breadth
    • Shaped to a point on one end
    • The edge is thin and sharp
    • Broad end is curved, but edge is still sharp
    • Part of Lower Paleolithic
  • Acheulean Axe as “Swiss Army Knife”; Abbevillean variation
    • Swiss Army Rock?
    • Sharp tip: used for piercing
    • Thin edge: used for cutting (hide or meat off bone)
    • Broad end: used for chopping or scraping
    • Abbevillean Variation:
    • Bifacial, like the Acheulean
    • Not quite so symmetrical
    • Olduvai specimen: transitional type?
  • Manufacturing Acheulean Handaxes
    • A demanding task
    • Symmetrical, finely shaped
    • Dozens of flakes removed, from 25 to 75
    • Each flake blow must be precisely positioned
    • Core must be turned over again and again
    • to maintain symmetry
    • to keep edge straight
    • All the exterior rind ( cortex ) was removed
  • Abbevillian and Acheulean Handaxes
    • Left: Abbevillian. Note asymmetry, rough retouch
    • Right: Acheulean. Note symmetry, fine retouch
  • Homo heidelbergensis or “Archaic” Homo sapiens
    • Left: Skull. Note heavy brow ridge, prognathism
    • Right: Mandible. Note arc-like dental arcade, absence of diastema, absence of chin
  • Manufacturing Levallois Cores and Flakes
    • Knappers
    • Draw outline of flake on stone module
    • Strikes flake of desired shape
    • Requires knowledge of breakage pattern of rock
    • Prepares rock beforehand to control how rock breaks when struck
    • Ensure right shape (e.g. cutting, perforation, piercing) is struck
  • Levallois Flake and Flaking Technique
  • Homo neanderthalensis : Skeleton
    • Left: Homo neanderthalensis
    • Right : Homo sapiens
    • Compare
    • Relative thickness of bones
    • Breadth of ribcages
    • Size of skulls
  • Homo neanderthalensis: Cranium
    • Left: H. neanderthalensis : note larger cranial size, occipital bun, prognathism, brow ridge
    • Right : H. sapiens : Note rounded cranium, presence of chin, absence of prognathism and brow ridge
  • Mousterian Tradition
    • Positively identified with Neanderhals
    • Le Moustier, France is a Neanderthal site
    • Belongs to Middle Paleolithic
    • More sophisticated than Oldowan or Acheulean, both Lower Paleolithic
  • Mousterian Tool Assemblage
    • Sample includes Scrapers, Points, and Handaxes
  • Upper Paleolithic: The Great Leap Forward?
    • Probably begins about 50,000 BP
    • Primary Attributes
    • Shift from flake tools to blades
    • Subsistence on greater range of animal and plant species
    • Larger sites
    • Increase of bone, antler, ivory, shell, and other materials for tools
  • Upper Paleolithic: Associated Attributes
    • Associated Attributes
    • Greater use of “imported” goods:
    • raw materials obtainable only from
    • great distances from inhabited sites
    • which suggests trade
    • More elaborate burials, with grave goods
    • Appearance and elaborate use of symbols and works of art.
  • Upper Paleolithic: The Blades
    • Blades begin roughly 40,000 Years BP
    • Comparative efficiency
    • Levallois cores may produce 5 flakes
    • Many more blades could be produced from same core--and with longer cutting edge
    • Unlike other traditions, blade traditions are shorter lived
    • Oldowan: from ca.2.5 m. yrs BP
    • Acheulean: from ca 1.9 m. yrs BP
  • Upper Paleolithic Assemblage
    • Upper Paleolithic Tools (left to right): biconical bone point, Perigordian flint blade, prismatic blade core, Soluterean Willow leaf point, double-row barbed harpoon point (various sites in France)
  • To Sum Up: Representatives of Five Species
    • The species:
    • 1. Australopithecus afarensis
    • 2. Australopithecus africanus
    • 3. Homo habilis
    • 4. Homo erectus
    • 5. Homo neanderthalensis