australopithecines tool mfg
DESCRIPTION
Social Science, AnthropologyTRANSCRIPT
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The Australopithecines
For classroom purposes only
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Australopithecus anamensis
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Australopithecus anamensis
More chimp-like
Not as exciting as the others
Probably not a tool user
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Australopithecus afarensis
Most well known hominid fossil
Primitive characters:
Small braincase (420 cc)
Relatively large, pointed canines
Bipedal, but with ape tendencies
Long arms, curved fingers, toes
Reconstruction of Australopithecine
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Australopithecus
afarensis
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Many Reconstructions
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A recent find at the site of Lomekwi in Kenya has seen the addition of a new genus and species, Kenyanthropus platyops.
Leakey et al., 2001
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Kenyanthropus
platyops
Kenyanthropus platyops
3.5 Ma
Kenya
Bipedal
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Early Hominids
Late Miocene Early Pliocene hominins show transitional features
Relatively small brains
Relatively primitive dentition intermediate
Bipedal - probable arboreal behaviours
A. afarensis
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Summary of Early Hominid Species
Species
Time Period
(million years B.P.) Distribution
Sahelanthropus tchadensis
Orrorin tugenensis
Ardipithecus ramidus kadabba
Ardipithecus ramidus
Australopithecus anamensis
Australopithecus afaransis
Kenyanthropus platyops
Australopithecus bahrelghazalia
Australopithecus africanus
Australopithecus garhi
Paranthropus aethiopicus
Paranthropus biosei
Paranthropus robustus
Sometimes also called
Australopithecus
7-6
6.2-5.6
5.8-5.2
4.4
4.2-39.
3.9-3.0
3.5
3.5-3.0
3.5-2.5
2.5
2.5
2.3-1.4
1.9-1.0
Central Africa
East Africa
East Africa
East Africa
East Africa
East Africa
East Africa
North Central Africa
South Africa
East Africa
East Africa
East Africa
South Africa
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Hominids as Erect Bipeds
The postcranial skeletons of Australopithecus and Paranthropus are those of erect bipeds.
Evidence includes the shape of the pelvis, the position of the foramen magnum, the presence of a lumbar
curve, the way the femurs are angled in, the anatomy
of the foot, and the Laetoli footprints.
Many hypothesis have been proposed to explain the advantages of erect bipedalism. These benefits include
raising the line of sight, freeing the hands, and assisting
the body in maintaining a proper body temperature.
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Gracile vs. Robust
Body Types
Robust = full of strength, powerfully built, like Neanderthals
Gracile = graceful, slender, like Modern Humans
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Gracile Australopithecines
Cranial Capacity - 450-530 cc
Fully Bipedal
Arises around 4 million years ago and lasts till around 1 million years ago
Two types Gracile and Robust
Begin making tools around 2.5 million years ago
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Later
Australopithecines
At 3-2 myr hominins are
increasingly diverse
Paranthropus robusts
heavier build, larger toothed
A side branch, extinct by 1 myr
Australopithecus gracile
lighter build, smaller toothed
thought to be ancestral to Homo
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The Early Hominids of South Africa
An early fossil find was a juvenile skull found at the Taung quarry and placed in the species Australopithecus africanus.
Fossils found in the Sterkfontein Valley belong to both Australopithecus africanus and Paranthropus robustus.
Australopithecus africanus Sts 5, from Sterkfontein, South Africa
Paranthropus robustus SK 48, from Swartkrans, South Africa
1985 David L. Brill 1985 David L. Brill
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A clear biped foramen magnum
Australopithecus africanus
Teeth & mandible are human-like
Small canines
Large, flat molars
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Australopithecus
africanus
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The Early Hominids of East Africa
Olduvai Gorge in Tanzania, associated with the Leakey family, has been the site of finds of Paranthropus boisei and early members of the genus Homo.
West Lake Turkana was where Paranthropus aethiopicus was discovered.
Australopithecus anamensis was found at the site of Kanapoi in Kenya.
Hadar in northern Ethiopia was the site of the discovery of Lucy, who belongs to the species Australopithecus afarensis.
Fossilized footprints dating between 3.8 and 3.6 million B.P. have been found at the site of Laetoli.
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Robust Australopithicines
(Paranthropus) Huge teeth and jaws
Huge muscles for these jaws with special crests to attach these muscles to.
Survived until around 1 million years ago
Slightly larger cranial capacity
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The Paranthropus Skull
Paranthropus is characterized by specialized chewing apparatus that includes large premolars and molars associated with a thick,
deep mandible.
Many features of the skull are related to the development of powerful chewing muscles.
The zygomatic arch is long and powerfully built, flaring away from the skull.
A small sagittal crest appears on the top of most specimens for attachment of the powerful temporalis muscle.
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Paranthropus
Lived from 2.5 to 1.2 myr
Differentiated from Australopithecus
Our close relatives
But not our direct ancestors
Went extinct by 1 myr!
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Australopithecus aethiopicus
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Anatomy reflects heavy muscular forces
Paranthropus
Characterised as megadontic
Large molars
Heavy, buttressed mandibles
Small anterior teeth
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Australopithecus
boisei
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Johanson & Edgar, 1996.
Paranthropus boisei OH5
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Robust Hominids of East Africa
Australopithecus afarensis Top and side views of the mandible
LH 4 from Laetoli, Tanzania
Paranthropus aethiopicus WT 17000, the Black skull, from Lomekwi, West Lake Turkana, Kenya
Paranthropus boisei
OH 5, from Olduvai Gorge, Tanzania
1985 David L. Brill
Tim White
Alan Walker/National Museums of Kenya
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Australopithecus robustus
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Other Hominids
A recent find at the site of Lomekwi in Kenya has seen the
addition of a new genus and
species, Kenyanthropus platyops.
A find discovered in Chad, located in north central Africa, has been
placed in the species
Australopithecus bahrelghazalia.
National Museums of Kenya
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Kenyanthropus platyops
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Brain size is a critical criterion for assignment into Homo
Range in Brain Size
Australopithecines (400 to 545 cc)
Homo (509 to 1,880 cc)
Slight overlap between genera
Homo
Australopithecus
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Hominin Brain Size
Australopithecines show a slight change through time
Homo shows a rapid increase
Homo shows substantial brain size increase over 2 myr
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Early Hominid
Dentition In general, the dentition of
Australopithecus and
Paranthropus resembles that
of Homo. Yet early species
of Australopithecus show
many nonhominid features,
and Paranthropus evolved
rather specialized dentition.
For example, many features of the dentition of A.
afarensis are intermediate
between that of modern
humans and apes.
The dentition of Paranthropus is highly
specialized for heavy
grinding with the back teeth.
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Tools and Dentition
Reduction in dentition
Lower chewing and grinding forces
Coincides with increasing evidence for tool use
Increasing dependence on culture
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Early Hominid Tool Use
The earliest hominid tools were probably made of perishable tools such as wood, bark, leaves, and fiber. However, the evidence for tool use in the archaeological record consists primarily of stone objects.
The first concrete evidence of stone tool manufacture comes from a site in Ethiopia dated at 2.6 million B.P.
Further evidence for early hominid tool use stems from the anatomy of the hand. The hand anatomy of Paranthropus robustus introduced the possibility that members of this species were capable of a precision grip and complex toolmaking.
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Chimpanzees are regular tool users with brain sizes avg. 370 cc
Brains and Tools
By 2 myr hominin brain sizes exceed the Great Apes
Hominins were
sufficiently
intelligent
to use tools
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The Early Hominid Brain and Skull
The cranial capacities of Australopithecus and Paranthropus vary from 400 to 530 cubic centimeters, compared to an average of 1350 for modern humans.
The structure of the skull reflects a small cranium associated with large dentition and powerful chewing muscles.
The Australopithecus skull shows prognathism and the bones are pneumatized. The expansion of the temporalis muscle is reflected in the presence of a temporal-nuchal crest. The top views shows postorbital constriction.
The forehead, behind brow ridges, is low and flat.
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Chimp Comparisons
Chimps show tool use
but do not equate with the Oldowan
Chimps create sites
but the density and nature of Oldowan sites is far different
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Emergence of Tool Use
Earliest known tools are 2.5 myr old
Most occur from 2-1.5 myr
Oldowan Technology
Contemporary with early Homo
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Lokalalei, Kenya
2.34 myr
Reassembly of stone tools
Shows a sequence of
flaking actions
Refit Stone Tools
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Selected materials
knowledge of raw materials
Lokalalei, Kenya
Shows some forethought and knowledge of rock mechanics
Applied controlled flaking
required dextrous motor skills
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Visibility of Tool Use
Behaviours become visible at 2.5 myr Witnessing an intensification of tool use
Oldowan Tools and
Sites
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Oldowan Sites
Oldowan sites show diversity of types
Stone tool scatters Dense concentrations of stone tools
Stone tools with associated fossils
Site types imply different activities over the landscape
The Oldowan represents new adaptations and a dietary shift