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Anthro 101: Human Biological Evolution
Lecture 12: Origins of the Modern Human Lifestyle – Neandertals & Modern Humans
Using modern foragers as a model to understand the importance of complex foraging technologies
Humans rely more on foods that are hard to get than other apes do
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
Obtaining extractive resources requires skill, strength, and detailed knowledge
For humans, foraging technology takes years to learn
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
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
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
Resource exchange is extensive in human groups
Sex differences in food production and consumption among the Aché (Paraguayan rainforest)
Among modern humans: men commonly share with woman & his children
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:
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
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
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
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?
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)
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
Definite Homo species
• Homo ergaster• Homo erectus• Homo floresiensis• Homo heidelbergensis• Homo neanderthalensis
• Denisovans• Homo sapiens
New Dmanisi skull may alter how we identify speciesduring this time period!
Transition to later Homo occurred between the Pliocene & the Pleistocene @ 1.8 mya
Upper
Lower Pleistocene Middle
1.8 mya .9 .3
Upper
Sharp cooling trend
Glaciers cover much of Europe
Major climaticfluctuations
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
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 erectusH. ergaster KNM ER 3733
Homo erectus combined ancestral and derived traits
• Ancestral features• receding forehead• no chin• narrowing behind eyes
• Post-orbital constriction
Dmanisi
KNM-ER 3733
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
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
Shovel-shaped incisors
Krapina Neandertal maxilla K, photograph © Milford Wolpoff
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
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
H. erectus 1st hominin to leave Africa in Lower Pleistocene
1.8 mya
1.7 mya
1.8 mya
Why now and not earlier?
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
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
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
Late Homo species
• Homo ergaster• Homo erectus• Homo floresiensis• Homo heidelbergensis• Homo neanderthalensis
• Denisovans• Homo sapiens
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
Major climatic changes occurred during Pleistocene
Lower Pleistocene Middle
1.8 mya .9 .3
Upper
Sharp cooling trend
Glaciers cover much of Europe
Major climaticfluctuations
Homo erectusHomo heidelbergensis
Homo neanderthalensis
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
Figure 13.12a
Figure 13.12b
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
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
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
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
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
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
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?
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?
Physical adaptations for language
• Cranial base flexed• Longer larynx• Range of vowels
• Other species vowelsmore limited• Can produce nasally
• Mammals• Lower their larynx while vocalizing• Same freedom of movement to
produce range of sounds
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)
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 vertebrawithin modern humanrange
Homo erectus language?
• Dmanisi on left, similar to modern human canal• H. erectus from Kenya on right, smaller like a chimp canal
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
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
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
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
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
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
People in warm climates tend to have long limbs in proportion to height
Neanderthals were short and stocky, but not stupid
• Cranial capacity ave. = 1520 cc
(modern humans ave. = 1400 cc)• Modern hyoid bone, language likely
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
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
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
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
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?
Burials preserve rare skeletons of children
2-year old Infant
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
Some Neanderthals survived serious injuries and illnesses
• implies that Neanderthals cared for the ill and injured
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
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
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
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?
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
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