8 - later human evolution Flashcards
Geological time
pleistocene and pliocene
Homo species continued
Homo erectus - 1.8mya - 50,000ya
Homo ergaster (1.8 mya - c50,000ya)
Homo heidelbergensis (800,000ya-c.200,000ya)
Hom neanderthalensis (127,000ya-30,000ya)
Homo sapiens (130,000ya-present)
Homo floresiensis (c50,000ya)
Homo erectus: a big shift
postcranialy very different from homo habilis
abrupt changes to anatomy:
- fully bipedal
- much bigger brain
behaviour differences
- meat eating
- possible use of fire
- first hominin to leave Africa
homo erectus morphology postcranium
tall and thin (adults up to 6ft)
lower limbs long/arms shorter)
narrow hips and shoulders
very muscular - long thick bones
e.g. WT 15000 ‘turkana boy’
Homo erectus and Homo ergaster same species?
geographic distinction and differences in crania:
Homo erectus (Asia)
- pronounced brow ridge
- pronounced sagittal keel
Homo ergaster (Africa)
- less pronounced brow ridge
- No sagittal keel
Dmanisi, Georgia
1991 - Dmanisi, Republic of Georgia
1.8 mya - Homo erectus?
small brains, less than 800cc
found with oldowan tools
extreme morphological variation in the one location
H.ergaster/erectus technology
Early H.ergaster - oldowan tools
- found between 1.8-1.5mya
Dmanisi tools are oldowan
Later Homo ergaster/erectus
- Acheulean technology
new type of stone tool technology
- found between 1.4 mya - 250,000ya
- hand axes and more complexity
- also called mode 2 technology
Homo floresiensis ‘the hobbit’
remains of 7 individuals - island of Flores, Indonesia (2004)
- LB1 (female adult partial skeleton) Nicknamed the hobbit
- c50,000ya
LOTs of debate of what they are?
-dwarved homo erectus?
-new species of hominin?
- pathological human?
Homo floresiensis cranium morphology
-very small cranial capacity c400cc
- receding foreheads
-vertical face with no snout
- no chin
Homo floresiensis postcranium morphology
- very small stature c 1m tall
- human-like scapula
- ape like wrists
- relatively short legs and big feet
- mix of primitive and derived characteristics
Homo heidelbergensis
- variability in specimens due to fluctuations in world temperatures
- Earliest specimens date 800,000-500,000ya
- Zambia, Ethiopia, Germany, Greece
- Later specimens c 200,000 ya - Dali, China
Possibly one or more species?
Homo heidelbergensis (europe)
rhodesiensis (africa)
antecessor (Europe)
homo heidelbergensis cranium and postcranium
cranium:
-larger cranial capacity 1200-1500 cc
- higher forehead
- massive brow ridges
- maximum width of cranium above ears
postcranium
- e.f. Boxgrove, England c500,000ya
- left tibia
- tall (possible >1.8m)
- robustly built
H. heidelbergensis technology
Africa and Europe
- early h.heidelbergensis - acheulean tradition
- to about 150,000 ya
Direct evidence of hunting
- wooden spears from schoningen Germany, c400,000 ya
- simple sharpened poles
- butchered horses found at same site
neanderthal origins and location
late middle Pleistocene, early upper pleistocene. Europe in glacial period
found in Western Europe, also found in the levant, in the Near East
Not found in Africa or East Asia
Neanderthal cranial characteristics
Cranium:
- large brain c1200-1750cc
- large double-arched brow bridges
- mid facial prognathism
- wide and large noses
- nasal bones almost horizontal from face
- large orbits
elongated mandible:
- retromolar space
- no chin
neanderthal postcrania
very robust
- broad chest
- robust scapulae with muscle marking
- arms strong and one more powerful than the other
compact and stocky
- forearm and shin short
cold climate adaptations
- short stature
- stocky build
- bergmann and allens rule
neanderthal mousterian stone tool industry
neanderthals association with mousterian stone tools
- greater reliance on small flaked tools than in Acheulean
- Southern France - Neanderthals found with upper palaeolithic tool kit - the chatelperronian
neanderthal burial of dead?
skeletons remarkably complete and often found in caves. symbolic or disposal?
1950s - Sganidar IV Burial, Northern Iraq c50-5000ya
- large amount of wildflower pollen
- but not clear this was deliberate?
neanderthal art and ritual?
find example
Homo sapiens
Homo sapiens morphology
cranium
-flat faces
- nasal bones more vertical
- orbits and nasal aperture smaller
- hugh vaulted and rounded braincase, and shorter braincase
postcranium
-tall and less robust
- long legs and short arms
Upper paleolithic technology
no correlation between Homo sapiens and new tool kits, like neanderthals
Later modern humans are associated with upper palaeolithic tools
- e.g. aurignacian
- shift to manufacture of blade tools
- more efficient use of raw materials
- include more types of tools and materials
origins of Homo sapiens?
Historical theories of Homo sapiens:
- multiregional model
- out of Africa model (or recent African origins model)
multiregional model
multiple geographic origins for Homo sapiens
- c 1.5mya - single species from H. erectus to H. sapiens
- speciation prevented by extensive gene flow
- Homo sapiens evolves in many regions
Differences in fossil record due to:
- selection pressures and local adaptations
- rate of evolution
Transitional specimens in fossil record in different regions
multiregional model supporting evidence
- mainly fossil evidence
- continuity of certain morphological characters is claimed
- geographical continuity of morphology
- Wolpoff argues late Pleistocene specimens from java resemble modern Australians (read up)
Recent African origin model
main proponent = Chris stringer
All people descend from Africa Homo sapiens:
- A single speciation event c 200,00 ya
- Homo sapiens migrated out of Africa
- Replaced local archaic populations
- no gene flow between archaic and modern
only find transitional fossils in Africa, no continuity in local regions
recent African model - supporting evidence
Fossil:
-earliest homo sapien fossils are found in Africa
- evidence outside of Africa not until much later
- no ‘transitional’ specimens
Mitochondrial DNA (mtDNA)
- greatest variation in Africans (Cann et al, 1987) - but some problems with this study
- common ancestor of all living people in Africa
- mitochondrial eve dated to c166,000-250,000
Genome Data
Green et al (2010) - complete nuclear genome
compared neanderthal genome to recent human genomes
Findings:
- neanderthal nuclear DNA more similar to non-african individuals
- interbreeding between H.sapiens and local archaic populations in Europe and asia
- proportion of neanderthal ancestry for non African populations today 1-4%
Denisovans
Denisova cave, siberia (area occupied by neanderthals and Homo sapiens)
finger bone & molar
date c 50-30,00 ya
distinct mtDNA lineage
compared genome with 53 modern human populations. share 4-6% DNA with Melanesians
Denisovans and neanderthals
13 year old female c90,000 ya
mother- neanderthal ancestry
father - denisovan ancestry BUT also some traces of neanderthal ancestry
suggests mixing between late Pleistocene hominin groups was common
