Lecture 12 origins of modern human lifestyle

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Lecture 12 - Origins of the Modern Human Lifestyle

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Lecture 12 origins of modern human lifestyle

  1. 1. Anthro 101: Human Biological Evolution Lecture 12: Origins of the Modern Human Lifestyle – Neandertals & Modern Humans
  2. 2. Using modern foragers as a model to understand the importance of complex foraging technologies
  3. 3. Humans rely more on foods that are hard to get than other apes do 0 20 40 60 80 100 Collected Extracted Hunted PortionofDiet Chimpanzees Human Foragers
  4. 4. Human foragers use wide range of prey and techniques • Prey • Mammals, birds, reptiles, fish • Techniques are variable • Prey type • Season • Snares, traps, calls, tracking • cooperation • Processing • Butchery • Smash bones • Cook • Process plant foods too
  5. 5. Obtaining extractive resources requires skill, strength, and detailed knowledge
  6. 6. For humans, foraging technology takes years to learn
  7. 7. Complexity of foraging tasks may favor bigger brain & slower development • Learn skills & knowledge • long period of learning • Long period for practice Favors • larger brain • Slow development • Longer reliance on parents
  8. 8. Long juvenile period  longer life span • Delays start of reproduction • Invest in growth & learning • Payoff greater if allowed to accumulate RS over longer life span • Longer lifespan means bigger payoff for early investment
  9. 9. High skill tasks favor division of labor and food sharing • Foraging tasks hard to master ==> specialization • Specialization ==> food sharing • In modern foraging societies • Women mainly forage • Men mainly hunt
  10. 10. Resource exchange is extensive in human groups
  11. 11. Sex differences in food production and consumption among the Aché (Paraguayan rainforest) Among modern humans: men commonly share with woman & his children
  12. 12. Meat is a high-variance food source • Meat is a high-quality food source: vitamins, protein, fat • However, meat is a food source with highly variable returns:
  13. 13. Requirements for successful reliance on high variance food: Reciprocal Altruism • Live in large enough groups of hunters to reduce risk and have enough sharing partners • Have cognitive skill to keep track of partners & history of sharing • Be able to prevent people from taking and not giving • In modern hunting societies, riskier foods shared more widely
  14. 14. Food sharing + division of labor may favor reduced sexual dimorphism • Men produce extra calories • support a women & their kids • If kids need males’ contribution • selection favors investing males • selection favors male-female bonds • Reduced male-male competition • Favors reduced sexual dimorphism Efe man with newborn
  15. 15. What does this tell us about foraging in the Pliocene era? • Contemporary foragers rely on complex foraging • Complex foraging linked to important features of human life history • Did Oldowan toolmakers have complex foraging strategies? • Toolmaking suggests they at least began to • First step in transition from ape-like hominins towards more human-like hominins • Morphology and behavior of later species can be explained by this innovation
  16. 16. Did H. erectus have a more modern human lifestyle? • Reduced sexual dimorphism (Yes) • Less male-male competition? • Reduced polygyny, tendency toward pair bonds? • Infant (& adults) brains larger than earlier species (Yes) • Altricial infants - dependent on parental care • Rapid brain growth after birth, slower maturation rate (Yes) • High energy demand on mothers from altricial infants • Selection for paternal investment? • Selection for menopause & female-female cooperation?
  17. 17. The transition to (later) Homo marked by: • Increased reliance on hunted meat and extracted foods • Greater reliance on (more complex) tools • Longer juvenile period to learn foraging and tool use techniques; longer life span • Greater paternal investment  increased pair bonding, reduced dimorphism • Origins of transmitted culture (eg foraging & tool making techniques)
  18. 18. Complex foraging a major part of later hominin evolution • The genus Homo is marked by: • More hunted meat and extracted foods • More complex tools crucial for survival • Longer juvenile period • learn foraging and tool skills • longer life span • Greater paternal investment  increased pair bonding, reduced dimorphism • Origins of transmitted culture • foraging techniques • possibly language
  19. 19. Definite Homo species • Homo ergaster • Homo erectus • Homo floresiensis • Homo heidelbergensis • Homo neanderthalensis • Denisovans • Homo sapiens New Dmanisi skull may alter how we identify species during this time period!
  20. 20. Transition to later Homo occurred between the Pliocene & the Pleistocene @ 1.8 mya Lower Pleistocene Middle 1.8 mya .9 .3 Upper Sharp cooling trend Glaciers cover much of Europe Major climatic fluctuations
  21. 21. The shift towards more modern Homo begins about 1.8 mya (not modern humans yet) • Hominins in Africa with: • Skull similar to earlier hominins • Taller body • Long legs and short arms • Slower growth rate, longer childhood • Reduced sexual dimorphism • Made Mode 2 tools • Acheulean hand axes H. ergaster KNM ER 3733
  22. 22. The shift towards more modern Homo begins about 1.8 mya (not modern humans yet) • Similar finds in C. Africa, S. Africa, Asia • first hominin found in Asia • Classified as Homo erectus or ergaster • We will call them erectus, but • earlier forms in Africa sometimes called ergaster • later forms in Asia sometimes called erectus H. ergaster KNM ER 3733
  23. 23. Homo erectus combined ancestral and derived traits • Ancestral features • receding forehead • no chin • narrowing behind eyes • Post-orbital constriction Dmanisi KNM-ER 3733
  24. 24. Homo erectus combined ancestral and derived traits Derived features • Occipital torus • Thick brow ridges • Thick skull • Smaller, less protruding face • Higher skull • Smaller teeth • Sagittal keel • Shovel-shaped incisors • Large orbits • Wide lower skull • Brain size ranged from 700 - 1200 cc KNM-ER 3733
  25. 25. Some derived features of skull linked to diet(?) • All teeth smaller, especially molars • tearing and biting with canines & incisors • Occipital torus & brow = thick ridges - buttress • chewing and biting strength • NOT muscle attachments • Sagittal keel? • Shovel-shaped incisors indicate heavy use of teeth P. boisei H. erectus
  26. 26. Shovel-shaped incisors Krapina Neandertal maxilla K, photograph © Milford Wolpoff
  27. 27. Post-cranial skeletons tell us a lot about H. erectus • Nariokotome boy - East Africa • Most complete skeleton • Tall adults (male 6’, female 5’) • Long limbs • Narrow hips ==> infants born with small brains, slow development • Tooth age indicate faster maturing than modern humans, though • Narrow shoulders • Thick bones ==> heavily muscled • Sexual dimorphism reduced, still > Hs  Body proportions like modern humans in tropics KNM-WT 1500
  28. 28. H. erectus mastered new subsistence skills • First (so far known) to leave Africa • More complicated stone tool kit - Acheulean tools • Controlled fire (possibly very early, definitely later) 1-2 mya • Relied more heavily on hunting - ate more meat
  29. 29. H. erectus 1st hominin to leave Africa in Lower Pleistocene 1.8 mya 1.7 mya 1.8 mya Why now and not earlier?
  30. 30. Technologically more advanced • 1.8 mya using Oldowan tools • 1.7 - 1.4 mya bifaces added to toolkit • Bifaces = round cores shaped to make flatter with longer cutting edge all around • Hand axe & cleaver • Acheulean = Bifaces = Mode 2 • Acheulean + Oldowan = Early Stone Age Hand ax Cleaver
  31. 31. Hand axes reveal something about minds and habits • All have same Height:Width:Thickness proportions • Unchanged for 1.5 million years • common plan in heads of toolmakers • Used for specific purposes in standard ways • Knowledge passed along by teaching and imitation
  32. 32. Hand axes probably used to butcher carcasses • well suited for cutting, dismembering animal carcass • Wear patterns support meat processing • Pointed end cuts through meat, rounded end fits in palm • Flakes maybe also used for cutting • Biface holds sharp edge longer than flakes • Longer cutting edge than a flake
  33. 33. Late Homo species • Homo ergaster • Homo erectus • Homo floresiensis • Homo heidelbergensis • Homo neanderthalensis • Denisovans • Homo sapiens
  34. 34. Complex foraging a major part of later hominin evolution • The genus Homo is marked by: • More hunted meat and extracted foods • More complex tools crucial for survival • Longer juvenile period • learn foraging and tool skills • longer life span • Greater paternal investment  increased pair bonding, reduced dimorphism • Origins of transmitted culture • foraging techniques • possibly language
  35. 35. Major climatic changes occurred during Pleistocene Lower Pleistocene Middle 1.8 mya .9 .3 Upper Sharp cooling trend Glaciers cover much of Europe Major climatic fluctuations Homo erectus Homo heidelbergensis Homo neanderthalensis
  36. 36. Middle Pleistocene (900 – 300 kya) • Long, cold glacial periods • Short, warmer interglacial periods • Great variability in climate • Next stage in hominin evolution occurred during this stage • More like modern humans than Homo erectus
  37. 37. Figure 13.12a
  38. 38. Figure 13.12b
  39. 39. Emergence of modern features begins with H. heidelbergensis (approx. 800kya) • Ancestral features • Large brow ridges • Thick cranial bones • Large, prognathic face • No chin • Robust bodies • Derived features • Brain size 1200-1300 cc • Higher foreheads • More rounded skull • Sides of skull more vertical
  40. 40. H. Heidelbergensis identified as a new species of hominin (by some) • More Derived features (compared to H. erectus) • Less prognathic • Smaller teeth • Smaller brow ridges, one over each eye • Flexed base of skull • Reduced postorbital constriction • Rounded occipital bone Bodo
  41. 41. H. heidelbergensis hunted big game • On island of Jersey, piles of bones of mammoths and wooly rhino found at base of cliff • Some are adults, too big for most predators • Carcasses have been butchered with stone tools • Skull cavity opened, to extract brain tissue • Bones have been sorted by body parts • Have also found wooden spears alongside masses of horse bones
  42. 42. H. heidelbergensis began making new kinds of tools • Continued to make Mode 2 till 150 kya • Oldowan & Acheulean • cores flaked along sides to extend cutting edge • 300 kya, H. heidelbergensis started making flake tools Mode 3
  43. 43. Levallois technique (Mode 3) • Involves striking flakes from a prepared core • A striking platform is formed at one end • Core's edges are trimmed by flaking off pieces around the outline of the intended flake • Large, symmetrical flakes are struck off of the core • This method provides much greater control over the size and shape of the final flake • More efficient use of available stone • Greater level of planning & abstract thinking
  44. 44. A variety of tool innovations Some of these tools were hafted • Wear patterns on tools suggest some were attached to a handle • Greater force & greater safety • Spears Lots of new materials and shapes • Soft hammers (bone, wood) • Retouched edges • Stylized tool shapes • Wider variety in toolkit
  45. 45. Social life of H. heidelbergensis • H. erectus were hunters, also still scavengers • H. heidelbergensis were definitely hunters • If their life was similar to modern hunting people, then: • Male-male cooperation during hunting • Sexual division of labor • Food sharing • Knowledge, skill, learning • Male aggressiveness (?) • Interdependence of men & women to raise children • Pair-bonding • How well does the evidence fit the theory?
  46. 46. Social life of H. heidelbergensis • Group size calculated to 131 people • As group size increases, takes more time to monitor relationships • Intelligence & language could make this easier • H. heidelbergensis brain much larger than H. erectus • NOT clear WHY (social, ecological, technology) • Do have more sophisticated tools • What about language?
  47. 47. Physical adaptations for language • Cranial base flexed • Longer larynx • Range of vowels • Other species vowels more limited • Can produce nasally • Mammals • Lower their larynx while vocalizing • Same freedom of movement to produce range of sounds
  48. 48. Homo erectus language? • Humans = flexed cranial base • H. erectus = flatter • Short pharynx • Vowels limited • Neanderthals also a bit flatter than modern humans H. Erectus (java)
  49. 49. Physical adaptations for language • Vertebral canals • Space in bone of vertebrae for nerves • Nerves in rib cage control breathing • Chimps & some Homo erectus fossils have small openings • Suggest limited breath control • 2006 Dmanisi vertebra within modern human range
  50. 50. Homo erectus language? • Dmanisi on left, similar to modern human canal • H. erectus from Kenya on right, smaller like a chimp canal
  51. 51. Possible Language in H. heidelbergensis • Some evidence suggests could have used language • Breath control • vertebral canals larer • Tongue innervations (lots of nerves to control it) • canals in mandible & skull • Length of pharynx • Flexed base of skull
  52. 52. Social life of H. heidelbergensis • Male parenting & pair-bonding? • Large brain size, narrow pelvis • Altricial offspring take lots of energy • Females limited in foraging by offspring ➔ Cooperation & division of labor necessary • Male-male competition? • Evidence for cannibalism • Bones processed same way as deer bones at site in Spain • Territorial aggression & eating of enemy? Eating own group members? • Sexual dimorphism slight, like modern humans • Hunting large game with hand held spears… ➔ Cooperation & sharing necessary
  53. 53. The Hominin lineage – 1.8 mya to present • H. erectus --> H. heidelbergensis = 800 kya • Speciation & divergence in Africa • H. erectus survived in Asia • H. erectus extinct in Africa • H. heidelbergensis the 2nd species to leave Africa • Southern Europe 800 kya, northern Europe 500 kya • India & China by 600 kya • H. heidelbergenesis gave rise to: • H. Neanderthalensis 300-150 kya • H. sapiens 200 kya H. heidelbergensis H. floresensis H. sapiens H. erectus H. Neanderthalensis
  54. 54. Around 300 kya, morphology of H. heidelbergensis in Europe began to change • Site = Sima de los Huesos, Spain • 2000 bones from > 24 individuals • Unique skull traits • Bulge in middle of face • Brow ridges arch over each eye • Skull with rounded back • Cranial capacity = 1390 cc • Considerable variation in population
  55. 55. Homo neanderthalensis: 150 - 30 kya • Distinctive features • Massive brows • Low forehead, long cranial vault • Very large face, mid-face bulge • Occipital bun at back of skull • Large, heavily worn incisors • Fused roots on molars • Shovel-shaped incisors • Short, muscular bodies • No chin • Gap behind 3rd molar
  56. 56. Neanderthals look like modern creatures in very cold places • Animals in cold places are large and stocky, with short limbs • Animals in hot places are smaller, thinner, longer limbed M. fuscata, Japan M. sinica, Sri Lanka
  57. 57. People in warm climates tend to have long limbs in proportion to height
  58. 58. Neanderthals were short and stocky, but not stupid • Cranial capacity ave. = 1520 cc (modern humans ave. = 1400 cc) • Modern hyoid bone, language likely
  59. 59. Why such a prognathic face and big nose? • Warmed air on intake? • BUT, modern populations in cold climates have narrow noses • Stronger biting force? • BUT, typically face is flatter in animals with strong bite force • Genetic drift without adaptive purpose - most likely • Continues trend of larger faces seen in archaic H. sapiens • Isolated population during glacial periods • Genetic drift of genes for large faces
  60. 60. Neanderthals may have matured quickly • Rate of enamel development on teeth • Faster in Neanderthals than humans • Neanderthals fully grown by 15 years old • May have evolved to start reproduction sooner • High adult mortality rate
  61. 61. Neanderthals were skilled toolmakers • Made Mode 3 tools (Mousterian industry/ Levoillois technique) • Continued to use Mode 2 (Acheulean tools) • Wood spears • hafted spear points • Retouched edges • Efficient use of stone • Large variety of tool types • Little bone or antler used at most sites
  62. 62. Neanderthals hunted big game: diet high in meat • Bones of red deer (elk), deer, bison, aurochs, goats, sheep, horses • At many sites, one kind of prey species predominates • Prime-aged adult prey common • Some sites at foot of cliffs have huge piles of bones • Chemical analyses of fossils = diet high in meat • Close-range hunting
  63. 63. Neanderthals buried their dead • Lots of nearly complete skeletons • Lots of children found • Maybe to avoid scavenging of bodies, maybe held cultural significance • Some controversial evidence of ritual or ceremony at burial • Ochre? • Grave goods? • Fetal position?
  64. 64. Burials preserve rare skeletons of children 2-year old Infant
  65. 65. Neanderthal life was hard and short • 40-45 years maximum lifespan • Many skeletons show evidence of disease, injuries • Arthritis, gum disease, fractured skull & neck, stab wounds, withered limbs • Run-ins with prey & predators? Spear hole in skull Gum disease & missing teeth
  66. 66. Some Neanderthals survived serious injuries and illnesses • implies that Neanderthals cared for the ill and injured
  67. 67. Neanderthals may have practiced cannibalism sometimes • Modern cannibalism = ritual • No ritual in Neanderthals • Krapina, Croatia - 130 kya • Long bones cracked for marrow • Cut marks on some bones • Some bones burned • France - 100 kya • 78 hominind bone fragments + hundreds of red deer bone fragments • Lots of cut marks • Long bones broken = extract marrow • Deer and hominin bones treated the same Cut marks on skull from Krapina, Croatia
  68. 68. A beginning of art and modern culture? • Red & yellow ochre • No representational carvings • Perforated & grooved animal bones & teeth • Maybe art, maybe natural causes • One site of Neanderthal remains + Chatelperronian industry 40 - 27 kya • (usually modern human) • Bone tools • Carved bone pendant • Pierced bones & teeth • Blade tools • Shelter construction
  69. 69. A beginning of art and modern culture? • Shell jewelry found in Slovenia 50 kya • Pierced, indicating worn as jewelry • Pre-dates arrival of modern humans • Evidence of pigment on shells - painted
  70. 70. A beginning of art and modern culture? • Slovenia site 82 - 43 kya • Possible flute = Evenly spaced holes in bone • Or random gnawing and punctures by carnivores?
  71. 71. Second species of nearly modern humans • Denisovans • Split from Neanderthal lineage 350kya • Very large molars • Lived in Eastern Eurasia • DNA passed to modern human populations in SE Asia • 1 pinkie bone (40kya) • 1 molar
  72. 72. Neanderthals are NOT ancestral to modern humans • Homo heidelbergensis 800 - 150 kya led to both… • Neanderthals (Homo Neanderthalensis) • Limited to Europe & western Asia • 150 - 30 kya • Homo sapiens (modern humans) • Separate species from Neanderthals • Overlapped in time with Neanderthals • Evidence for interbreeding & gene flow • Modern humans descended from group in Africa living at about the same time as Neanderthals

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