Relative brain size

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Relative brain size
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Homo ergaster / H. erectus

• Oldest fossils c. 2 mya
• Pleistocene (Ice Ages)
• Duration 1.8 mya -- 10,000 ya.
• Alternation of warm and cold climates
• With glacial advances - lowering of sea level -
• land bridges
• Facilitated dispersal of Homo out of Africa 1.5 -
  1.2 mya

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Homo ergaster / Homo erectus sites
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Differences in brain size and skull
characteristics

• Cranial capacity
• Homo habilis 650 cc (500 800)
• Homo erectus 950 cc (750 - 1,250)
• Thick skull
• Large, solid brow ridges
• Occipital bun (torus)
• Reduction in relative tooth size

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Brain size / time relationship
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Homo sapiens
Homo erectus
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Homo ergaster
Noriokotome boy
Kenya, Africa 1.6 mya c. 11 years old 56
tall Estimation would have been 6 had he
survived to maturity
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A basic tool of Homo erectus Acheulian
biface hand axe
1.4 - 400,000 ybp entire stone flaked Acheulian
technique
Tool kit
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Homo ergaster / Homo erectus sites
No beach huts!
featured in Out of Africa 1. use of fire? 2.
regional evolution of H. sapiens?
early Homo? 1.75 mya
1.8 mya and 27-53,000 ybp !
1.78 mya
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Zhoukoudian site China Evidence for use of fire?
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• Homo erectus, Homo heidelbergensis, and the
  Neandertal problem

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Archaic Homo sapiens

• Classification complex unresolved
• Archaic H. sapiens appears c. 700,000 ybp
• Wide distribution, in the Old World excluding the
  far north
• Brow ridges still prominent - but less dense
• Later forms have higher cranial vault and reduced
  tooth size.
• Cranial capacity increased to 1,300 cc in
  Neandertals

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A hypothetical phylogeny
?
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archaic Homo sapiens sites
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Archaic Homo sapiens showing erectus-like
features
Petralona, Greece Bodo, Ethiopia
Dali, China
Oldest 500,000 ybp, Bodo, Ethiopia Homo
heidelbergensis (to 700,000 ybp)
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Neandertals recent archaics

• Lived in a time-range 100,000 - 28,000 ya
• Shared Europe with modern H. sapiens for c.
  12,000 yrs.
• Brain was, on average, larger than that of modern
  humans 1410 vs. 1330 cc
• Height 4.9 - 5.6 ft.
• Weight 110 - 143 lb.
• Heavier bones, more muscular
• Differ in skull and extremities

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How to classify?
?
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Skull differences




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A neandertal
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Neandertal sites Note not in Africa
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Mousterian stone culture Neandertals
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Artifacts of teeth and ivory Dated at 45,000
ya From a site in France Neandertal