The Genus Homo: Homo habilis and Homo erectus
Stanford Ch. 11
Which species gave rise to Homo genus?
•Probably Gracile Australopithecines
•Why?
Early Members of the Genus Homo
•Homo habilis
•Homo rudolphensis
•Homo ergaster
•Homo georgicus
•Homo erectus
•Homo antecessor
Homo habilis (“Handy Man”)
•Age 2.3- 1.5 mya
•Eastern and Southern Africa
•Found by
Homo rudolfensis
• 1.8 mya
•Found by Richard Leakey
•Characteristics
•Brain average 610 cc H. habilis
•Brain average 752 cc H. rudolfensis
•Some prognathism
•Molars smaller than Australopithecines
Post cranium
•biped
•still partially arboreal. How?
•Behavior of both H. habilis and H. rudolfensis
•Oldowan tradition
•Percussion flaking: hit two rocks together
•flake and a core
•Lower Paleolithic: first part of the Old Stone Age 2.6 mya
•tools allowed
•Reduction of face and increase brain?
•carnivores and herbivores
•scavengers/ hunters?
•
•likely shared resources
•less sexual dimorphism= less competition
•multimale and multifemale groups?
•Meat: the brain food
•
•social organization
•less time finding food
•
•Trends in hominid evolution
•Expansion of the brain
•tool use? Language? Hunting?
•
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•chewing softer foods
•tools, fire, hunting
Grade vs. Clade
• Grade: A collection of various specimens which exhibit a similar level of adaptation.
•Clade: A formal category in cladistics designating an ancestral species and all its
descendants.
Lumpers vs. Splitters
•Splitters: highlight differences and therefore assign multiple species names to
individual fossil specimens.
•Lumpers: tolerate variations in fossil specimens and thus to recognize fewer fossil
species names as valid.
Homo erectus (as a grade)
•Age 1.8 mya-200 kya
•1.8- 0.8 mya Africa, Europe, W. Asia (first hominid out of Africa?)
•1.8– 200 kya Asia
•Characteristics:
•larger brain 700-1225cc
•short face
•smaller molars
A low, elongated, angular skull, large supraorbital torus (brow ridges), saggital keel
The skull is pentagonal in cross section, widest at the base, with a strong nuchal
(occipital) torus
H. erectus had thick cranial walls. Some specimens showed healed injuries
•skeleton modern but robust
•Some sexual dimorphism
•Tall- modern body proportions
•Nariokatome Boy, Africa
•Behavior
•Lower Paleolithic Culture (2.5 mya-200 kya)
•Acheulean tradition (1.4-200kya)
•hand axe: tear-drop shape with cutting edge around perimeter.
•Symmetrical, standardized tool design
•
•Movius Line: division between had axe- bearing areas and those without hand axes (SE
Asia).
•Bamboo use?
•Adaptation to new environments
•clothing, fire, shelters to survive in cold
•fire? Kao Poh Nam rockshelter
•hunting (and gatherers)
•Schoningen, Germany wooden spears with butchered bones- 400 kya
•Camp sites
•caves or open areas
•Bilzingsleben, Germany 350kya?
•Art?
•Speech?
•near modern development of speech area in brain.
Homo ergaster (“African H. erectus”)
•Africa, W. Asia, Europe
•1.8-0.8 mya
•More rounded, shorter, higher cranium
•Less pronounced supraorbital and occipital tori
•No angularity of skull
•Walls less thick
Why leave Africa?
•Climate Change
•Decreased forests, increased grasslands
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•Hominids took advantage of the new niche
•used stone tools
•meat allowed growth of larger bodies and brains
•could range further
•Did they leave earlier?