Early Homo

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Early Homo
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Homo Begins

• Contemporaneous (2 m.y.a.) sets of teeth, very
  different in size comprise the earliest evidence
  of a generic split the larger set is attributed
  to A. boisei, the smaller to H. habilis, the
  first species of the genus, Homo.
• The distinctive early Homo trends are a rapid
  increase in brain size, increasingly elaborate
  tool-making, and an increasing emphasis on
  hunting, but there remains considerable debate as
  to when and in what population these trends led
  to speciation (from an australopithecine to Homo
  habilis).
• Johanson and White propose that A. afarensis
  effectively produced two populations, one of
  which evolved into the other australopithecines,
  the other evolving into Homo habilis.
• H. habilis was transitional and co-existed with
  A. boisei.

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Homo habilis
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Homo habilis

• 612 cc brain
• 2.3 - 1.6 mya
• first toolmaker
• prognathic face, brow ridge
• probable meat-eater
• possibly arboreal
• discovered in 1960 by Leakeys
• no speech

Artists representation of a Homo habilis band as
it might have existed two million years ago.
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Homo rudolfensis

• 781cc brain
• 2.4 - 1.6 mya roughly contemporaneous with H.
  habilis
• recent classification by Bernard Wood to
  differentiate from less specialized H. habilis
• larger teeth than H. habilis, ate tougher foods
• feet more like modern humans than like H. habilis

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H. habilis vs. H. erectus

• Finds in east Africa indicate the Homo habilis
  was not very different from the
  australopithecines in terms of body size and
  shape.
• The earliest Homo erectus remains indicate rapid
  biological change.
• The fossil record for the transition from H.
  habilis to H. erectus supports the punctuated
  equilibrium model of evolution.
• H. erectus was considerably taller and had a
  larger brain than H. habilis.

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Homo erectus

• 1891 - Eugene Dubois discovers H. erectus in Java
• Dubois calls it Pithecanthropus erectus
  initially, also dubbed Java Man
• finds in China called Sinanthropus
• dates from 1.9 mya to 27,000 years B.P.
• 994 cc brain size (compare to 612 for H. habilis)
• Acheulean tool industry

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Homo erectus - Skulls
Rear views of three skulls of H. erectus and one
of Archaic Homo sapiens.
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H. erectus Skull
Reconstruction of one of the H. erectus fossils
from Zhoukoudian, China.
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Homo erectus
Photograph of Nariokotome boy, an early Homo
erectus found near Lake Turkana, Kenya.
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Homo erectus Evolutionary Success

• Less sexual dimorphism possible pair bonds,
  marriage
• Less hair on body wearing of furs, other
  clothing
• Wearing of furs ability to live further north
• Quick adaptation to environment without physical
  changes
• Culture is main reason H. erectus was so
  successful
• organization for hunting
• ability to protect against predators
• control of fire?
• possible campsites
• tools (Acheulean industry)

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H. erectus Culture/Biology Synergy

• Acheulian tools and essentially modern bipedalism
  aided hunting.
• H. erectus average brain size (1,000 cc) is
  double that of the australopithecines.
• Larger skulls select for neotony, because of the
  constraints bipedalism puts on the size of the
  birth canal.
• Neotony causes a long dependency period, which
  allows for the emphasis on cultural transmission
  of information.
• Dependent children create an environment which
  increasingly selects for interdependent social
  groups.

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H. erectus Distribution
The sites of discovery of Homo erectus and its
possible maximum distribution.
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H. erectus Evolution and Expansion

• Major H. erectus Sites
• East, West Turkana, Kenya, dated 1.6 m.y.a.
  (Leakey)
• Upper Bed II, Olduvai, dated 1 m.y.a.
• Trinil, Java, Indonesia, dated approximately
  700,000 years ago (Dubois)
• Zhoukoudian, China (a.k.a. Peking Man) is a
  massive site, dated 500,000-350,000 years ago
• Europe has non-skeletal remains dating 700,000
  years ago, and skeletal remains dated at 500,000
• The vast environmental differences encompassed by
  the H. erectus sites, and the associated lack of
  physical variation attest to the success of
  culture as an adaptive strategy.

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Homo ergaster

• Classification created in the 1980s based on
  anatomical differences in H. erectus specimens
• cranial proportions
• thin, arched brow ridge
• eye sockets more rounded
• face is more vertical
• Andrew Kramers study showed that 16 H. erectus
  skulls are no more variable than a sample from
  modern H. sapiens and therefore not a separate
  species.

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Tool-making

• The oldest known manufactured tools are dated at
  2.6-2 m.y.a., were found in various parts of
  Africa, and are grouped under the name Oldowan
  pebble tools, given them by the Leakeys in 1931.
• There is some speculation that relatively
  advanced tool-making by Homo ancestors might have
  created the environment which produced the
  generic Homo-Australopithecus split.
• H. habilis may be as old as 2.4 m.y.a., which
  means it existed close to the time of the origin
  of stone tools.
• Based on circumstantial evidence, it was likely
  that Australopithecines also made tools, if less
  well and of less permanent material than later
  Homo groups.
• 1.6-1.8 m.y.a. saw a dramatic increase in the
  hunting efficacy of Homo and during this period
  P. boisei may have been forced into an
  exclusively vegetarian niche, providing an
  example of competitive exclusion.

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Oldowan Tool Industry

• found primarily with H. habilis (Latin for
  handyman) remains from over 2 mya
• largest number of tools found at Olduvai Gorge,
  Tanzania, by Louis and Mary Leakey
• choppers
• unmodified flakes
• earliest found at Omo and Hadar, Ethiopia (2.4
  mya) and in the Democratic Republic of the Congo

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Tool-making
Evolution in tool making, from chopper (far left)
to flake (far right).
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Acheulean Tool Industry

• first appeared 1.5 mya, lasted over 1 million
  years
• associated with H. erectus
• more refined than Oldowan
• bifaces, picks, cleavers used for butchering,
  digging, prehistoric Swiss Army knife
• Acheulean didnt reach Asia?

Acheulean hand axes from Kenya
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Paleolithic Tools

• Three Paleolithic Divisions
• Lower Paleolithic (Homo erectus) - Acheulean
• Middle Paleolithic (archaic Homo sapiens) -
  Mousterian
• Upper Paleolithic (up to 15,000 years ago) -
  Aurignacian, Chatelperronian, Solutrean,
  Magdalenian
• Technique Differentiation
• Paleolithic stone tool-making was marked by
  advancing refinement of technique, recognizable
  groupings of which are called tool-making
  traditions.
• A basic distinction is between core and flake
  tools.

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New Discoveries - Fire

• fire drives (hunting)
• H. erectus probably first controlled fire
• date of mastery
• 1.4 mya (proposed from Kenya)
• 500,000 yBP (definite from Zhoukoudian)
• fire uses
• cooking
• keeping predators away

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New Discoveries - Campsite

• Acheulean tools near water sources
• Some camps found in caves
• Possible built structures
• Terra Amata, France (on Riviera)
• 450,000 to 380,000 yBP
• stake holes, line of stones
• roughly 30 by 15 foot huts
• central hearth

Reconstruction of hut at Terra Amata
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H. erectus Food Procurement

• H. erectus bipedalism, the de-emphasis on
  chewing (smaller molars) compared to
  australopithecines, and the emphasis on the front
  teeth (possibly for eating flesh) all suggest
  hunting and gathering as its primary adaptive
  strategy.
• The skeletal evidence for hunting and gathering
  is supported by site remains, such as those found
  at Terra Amata (approximately 300,000 years ago).

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H. erectus Language

• No evidence clearly supporting H. erectus use of
  language exists.
• Some researchers argue that Acheulian tools and
  apparent, complex hunting techniques, which do
  exist in the fossil record, support the
  possibility of rudimentary speech.
• Nariokotome boy has small intercostal muscles
  (ribs), which may not have controlled fine motor
  movement for speech vertebral canal narrow
• larynx was moving to human-like position
• incipient basicranial flexion
• H. erectus only capable of baby talk?

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Ritual and Religion

• red ochre - oxidized clay, often used for burials
  or as a status symbol
• no evidence that H. erectus buried their dead
• evidence of ritual cannibalism at Zhoukoudian?

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Emergence of Modern Humans