This document discusses early hominin species including Australopithecus garhi, Homo habilis, and Homo rudolfensis. A. garhi, found in Ethiopia in 1996, was the earliest known tool-producing hominin dating to between 2.6-2.5 million years ago. H. habilis produced basic stone tools and expanded out of Africa between 2.4-1.5 million years ago. H. rudolfensis, found in Kenya, may be a separate species from H. habilis based on cranial differences. The document also examines the physical characteristics, fossil evidence, locomotion, diet, and basic stone tool production of these early hominins.

1. Homo habilis and Homo erectus
Early Tool Producing Hominims and Expansion in
Africa

3. Australopithecus garhi
The Earliest Tool Producing Hominim

4. Importance of the Species
● A species known as Australopithecus
garhi was found in Ethiopia in 1996
● This species dates between 2.6
million and 2.5 million years; a
broader temporal determination for its
persistence cannot be made at
present because of the paucity of
fossils
● It is particularly significant, though,
because it is the earliest hominim
species that can unequivocally be
demonstrated to have made tools
● Most of the finds have been
concentrated in Ethiopia, at a series of
sites near Gona but also at Bouri
● Although clearly primitive and simple
tools, they show affinities with the
industry at Olduvai Gorge associated
with Homo habilis

5. Dentition and Cranial Capacity
● The traits of A. garhi fossils such as
BOU-VP-12/130 are somewhat
distinctive from traits typically seen in
Australopithecus afarensis and
Australopithecus africanus
● An example of the distinction can be
seen when comparing the Hadar
maxilla (A. afarensis) to the Bouri
specimen of A. gahri
● The cranial capacity of A. garhi
measures 450cc, the same size as
other australopithecines
● Studies made on the premolars and
molar teeth have a few similarities with
those of Paranthropus boisei since
they are larger than any other gracile
form of australopithecine
● It has been suggested that if A. garhi is
ancestral to Homo (ie. Homo habilis)
the maxillary morphology would have
undergone a rapid evolutionary change
in roughly 200,000 and 300,000 years

6. Gona, Ethiopia
● As there is so little skeletal evidence, it
must be expected that the observations of
differences between A. garhi and other
hominims will be refined and expanded
● The main point of discussion concerning A.
garhi is its status as the first hominim to
produce tools
● Excavations at Gona in Ethiopia have
resulted in the discovery of an handful of
sites affording tools that have been dated
between 2.6 million and 1.5 million years
● The earliest tools are associated with A.
garhi, but it is not certain which hominim
was responsible for the manufacture of the
later tool assemblages
● Most of these are based on small cores and
therefore conform to the 'chopper industry'
seen at Olduvai Gorge and elsewhere in the
earliest phases of the Lower Palaeolithic in
Africa

7. Dating the Earliest Tools
● We have little occasion to doubt the
early dates for these tools, nor for
concern over the accuracy of the
dates associated with the remains of
A. garhi, for the stratigraphic
succession affords several horizons of
tephra that permit good dating
opportunities
● The volcanic material also provided
the raw material for the production of
the tools—namely, small pebbles of
trachyte
● It is possible to follow some of the
tephra horizons elsewhere in the
region, and numerous dating assays
have confirmed the chronological
succession
● In short, the tools here are certainly at
least 500,000 years earlier than those
at Olduvai Gorge

8. The Industrial Tradition
● The tools were fashioned from small
pebbles of trachyte, being struck
once or twice, and used as
'choppers'
● We nonetheless also see the use of
small flakes detached from the
pebbles
● Although relatively primitive, they
differ little from the tools made at
Olduvai Gorge by Homo habilis
● The raw material was also
deliberately selected, as there are
other rocks available in the vicinity
● This implies that a conscious
decision was made to choose those
rocks with the best flaking properties
● They were probably used to process
vegetable food

10. Homo habilis and Homo rudolfensis
Physical Characteristics, Sites and Behaviour

11. Significance of Homo habilis
● The importance of Homo habilis
discoveries in the 1960s for the
advancement of our knowledge of
hominid evolution and the stimulation
of excitement and controversy
cannot be understated
● It was the finds of small bone
fragments at Olduvai Gorge
associated with stone tools that
began the process of confirming that
our genus arose in Africa and that
there were fossil remains of
considerable antiquity here
● Because this species was the first
that could be unequivocally
demonstrated to have produced
stone tools, it was named Homo
habilis, or the 'tool-maker'
● Finds from this species span the
period of 2.4 million years and 1.5
million years and its distribution is
restricted to East Africa and South
Africa

12. Physical Characteristics
● This species shares many physical
attributes with the gracile
australopithecines, but also evinces
important differences
● Because of differences in cranial
capacity evident in the earlier and
later specimens, some have restricted
the term Homo habilis to refer to those
with a smaller cranial capacity and
those with a larger capacity to Homo
rudolfensis
● It is intriguing that the earlier
specimens, which some authorities do
not believe to have led onward to
other forms in the genus Homo, is that
with the larger cranial capacity
● Nonetheless, this distinction may
reflect temporal differences within the
species rather than the evolutionary
bifurcation of this hominim type

13. Homo rudolfensis
● Homo rudolfensis is a fossil hominin
species discovered by Bernard Ngeneo
Koobi Fora on the east side of Lake
Rudolf (now Lake Turkana) in Kenya
● The scientific name Homo rudolfensis
was proposed in 1986 by V. P. Alekseyev
for the specimen
● Skull 1470 (KNM ER 1470), which has an
estimated age of 1.9 million years
● Originally thought to be a member of the
species Homo habilis, the fossil was the
centre of much debate concerning its
species
● Assigned initially to Homo habilis, the
skull was at first incorrectly dated at
nearly three million years old
● The continuing controversy about whether
this is a distinct species explains some of
the disagreements in the date range of
Homo habilis

14. Another Species ?
● The differences in this skull, when
compared to others of the Homo habilis
species, are too pronounced, leading to the
presumption of a Homo rudolfensis
species, contemporary with Homo habilis
● In the Homo rudolfensis a strong
supraorbital torus on 1813, whereas the
supraorbital torus of 1470 is slight at best,
and does not have the depression behind it
that is seen in 1813
● The face of 1470 is longer than 1813's and
1470's upper jaw is square instead of
rounded-off
● There is a great discrepancy between the
cranial capacities of the two individuals as
well. ER 1470 has a cranial capacity of 775
cm3, where ER 1813 has a cranial capacity
of only 510 cm3 (which is above the
australopithecine average, but well below
the accepted 600 cm3 cut-off for Homo)

15. The Principal Fossils
● KNM ER 1813 is a relatively complete
cranium which dates to 1.9 million
years old, discovered at Koobi Fora,
Kenya by Kamoya Kimeu in 1973.
The brain capacity is 510 cm3, not as
impressive as other early specimen
and forms of Homo habilis discovered.
However, some scientists conclude
that KNM-ER 1813 is a near perfect
Homo erectus, except for its small
brain and size, and that it could be an
erectus that was small or even be a
Homo ergaster.
● OH 7 dates to 1.75 million years old
and was discovered by Jonathan
Leakey on 4 November , 1960, at
Olduvai Gorge, Tanzania. It is the
type specimen. It has a lower jaw
complete with a number of teeth and
the left parietal is nearly completed.
The brain size attributed to this
specimen (assumed to be a young
boy) ranges from 590-710 cm3

16. Principal Fossils, continued
● OH 24 (AKA 'Twiggy') is a deformed
cranium dating 1.8 million years old,
discovered in October 1968, at Olduvai
Gorge, Tanzania by Peter Nzube. It was
found in a very fractured state,
cemented in limestone rock, and had to
be reconstructed, but over 100 small
fragments could not be assigned a
location in the reconstruction. An
estimate of 590 cm3 is given for the
brain volume. A reduction in a
protruding face is present compared to
members of more primitive
Australopithecines.
● KNM ER 1805 is a specimen of an adult
Homo habilis made of 3 pieces of
cranium dating 1.74 million years old
from Koobi Fora, Kenya. Previous
assumptions were that this specimen
belonged to Homo erectus based on the
degree of prognathism and overall
cranial shape

17. Reconstructions
● The reconstructions of Homo habilis and
Homo rudolfensis are based on the fossil
evidence, but additionally, there are
suppositions made concerning the thickness
of skin and muscles and assumptions
regarding the prevalence of body hair
● Ultimately, these reconstructions are
unreliable, representing a series of
postulates regarding their intermediate
status between the higher primates and
humans
● Some general postulates are, however,
probably relatively accurate: the skin colour
was likely dark, being well adapted to the
high UV radiation of the regions in Africa
which they occupied
● Less is known about body hair, given the
lack of clothing evidence, but some possibly
remained although this may have rapidly
been lost as they expanded their ranges
outwith Africa and into more temperate
regions

18. Cranial Capacity and Dentition
● Homo habilis had a cranial capacity was (on
average 50 percent larger than
australopithecines), but considerably
smaller than the 1350 cm to 1450 cm3
3
range of modern Homo sapiens
● Little is known about the teeth of Homo
habilis, but the available evidence indicates
that the teeth of Homo habilis are larger
than those of modern humans
● In addition, the shape of the premolars of
this species were more elongated than were
those of their ancestors and, thus, much
more similar in appearance to those of
modern humans
● This implies that the dentition began to
change from one largely suited to the
processing of tough vegetable foods, to
teeth well adapted to a more omnivorous
diet
● Is this associated with hunting and the
discovery of fire ?

19. Locomotion and Stature
● Hands and feet enable us to perform a
variety of functions, such as digging soil,
grasping objects, and even hanging from
the stems of trees
● Unexpectedly, a fossil belonging to this
species, dating from approximately 1.75
MYA, was found at Olduvai; this fossil
was complete except that the back of the
heel and terminal bones of the toes were
missing
● It displays modern human characteristics:
the stout basal bone of the big toe is
aligned with the other toes, whereas in
apes the big toe is larger and more robust
● Additionally, the hands show a capacity for
gripping and precision permitting tool
manipulation and production
● This species reached heights of 1.2 to 1.4
metres, but its bones and pelvic structure
were quite robust and suggests an heavy
musculature that indicates significant
power in short running bursts

20. Subsistence and Social Structure
● The best evidence for the diet of Homo habilis
is afforded by the dentition of the specimens
found
● As the arrangement of teeth and chewing
muscles does not necessarily reflect the actual
diet, given the time-lag between evolution and
behaviour, it is most apposite to consider the
evidence of tooth wear
● The site of the fossils found at Olduvai Gorge
indicates that this species inhabited open
grasslands near the edge of a lake
● Other animals that also resided in this area
include elephants, giraffes, wild pigs, various
species of antelope, rabbits, baboons, hyenas,
lizards, tortoises, and birds
● Among these animals, early members in the
human lineage preyed on lizards, tortoises,
pigs, rabbits, young antelope and fish from the
nearby lake. In addition, they probably
depended on carrion left by larger predators,
like lions

21. Lithic Industry
● The tools characteristic of the earliest
sites are called 'choppers'
● This term describes the existence of
cores, produced mainly on pebbles,
that have had flakes struck from them
to produce primitive chopping or
cutting implements
● In some instances, the flakes (those
pieces detached from the cores) were
also used as tools
● Sometimes this early chopper industry
is term 'Oldowan' after the type-sites
of the Oldowan Gorge, but it is also
called the 'Omo' industry or 'Mode I'
industries to distinguish them from the
slightly more complex implements
produced later
● The later complexity in production
may, however, reflect access to better
raw materials than an actual
development in technique to produce
implements

22. Distinguishing the Chopper Industries
● Although the chopper industries are
primitive, in the sense that they represent
the most simple form of lithic reduction,
they are clearly produced by hominims
● Most important are the signs of flaking:
this produced flakes (the material
removed from a larger pebble or cobble)
with the distinctive 'bulb of percussion'
● This rarely occurs naturally—only the
most unusual conditions of pebbles
striking one another would result in a
flake being struck off
● The discovery of many of these flakes in
a restricted area, along with the signs of
multiple flakes being struck from the
pebbles, confirms that they were
produced by hominim agency
● All these criteria were met at the sites
affording tools at Olduvai Gorge and
elsewhere

24. Homo ergaster in Africa
The First Colonists: Expansion of Hominim Range

25. Distribution and Nomenclature
● The designation of Homo ergaster is
relatively recent, and is intended to
distinguish the early forms of Homo
erectus from the later forms
● This has met with some resistance from
specialists, for those that are opposed to
this distinction see no justification for
positing a different species
● Irrespective of the controversies
amongst the palaeoanthropologists,
there is evidence of a change in the
anatomy and behaviour in the species
that is considered by some as Homo
ergaster
● Our earliest finds derive from East
Africa, sometimes at the sites where
Homo habilis was found in older layers
● It is clear that Homo ergaster/Homo
erectus was an extremely successful
species and was the first to colonise
regions outside of Africa

26. Affixing the Age of Homo ergaster
● Nevertheless, in this lecture we shall
consider the evidence only from East
Africa, where this species presumably
diversified from Homo habilis and explore
the later diffusion inside Africa and into
Asia in the following lecture
● The paucity of sites affording remains of
Homo ergaster renders it difficult to
determine the age range of this species
● It is, however, commonly thought to have
flourished between 2.0 million and 1.6
million years ago
● Some have suggested that it is
significantly younger, emerging only at
1.7 million years
● The dates from the site of Dmanisi in
Georgia have affixed the occupation by
Homo ergaster here to 1.88 million years,
so presumably it must be older in Africa

27. Physical Characteristics
● No agreement exists on which features
distinguish Homo ergaster from Homo
erectus
● This renders the determination of this
species rather arbitrary; hence the
controversy regarding its status
● An enlargement of cranial capacity and a
slightly smaller set of teeth does, however,
distinguish Homo ergaster and early forms
of Homo erectus from Homo habilis
● It is widely accepted that this form of
hominim evolved out of Homo habilis,
although there are some that select Homo
rudolfensis as a probable direct ancestor
● We are able to study the inter-relationship of
cultural behaviour and evolution with this
species (and Homo erectus) better than with
any other preceding hominim form because
of the larger data-set but also the expansion
of the range of settlement which implies
certain social and technological features of
culture

28. Cranial Capacity
● Homo ergaster shows an increase in
cranial capacity (700-900 cm3) from that
of Homo habilis
● The skull bones are thinner and lack an
obvious depression, or sulcus, on the
surface, which may be the most-
distinguishing characteristic between
Homo ergaster and Homo erectus skulls
● Also, the face of Homo ergaster is less
robust (more gracile) than is that of Homo
erectus
● Homo ergaster skulls also display
increased cranial breadth across the
parietal bones, as well as an increase in
the length of the occipital bone
● A broadening in the nasal bones and
nasal openings also can be seen
● Homo ergaster skulls also show a shorter
cranial base and greater development of
the mandibular symphysis

30. Dentition and Diet
● The dentition of Homo ergaster is
similar to that of Homo sapiens, but
the teeth of the former were slightly
larger to that of the latter
● However, Homo ergaster shows
some dental reduction when
compared to earlier Homo species
● The interesting feature of Homo
ergaster teeth is located on the
backside of the incisors
● These teeth are ‘scooped’ in
appearance and referred to as
‘shovel-shaped'
● Some scholars have suggested that
such teeth constitute an adaptation
for hunter-gatherers to process food,
and this is indeed a distinguishing
characteristic of the Native
American populations

31. Locomotion and Stature
● It is indisputable that Homo ergaster
was fully bipedal—the pelvis, joints
and vertebral column demonstrate this
● This species was slightly taller than
Homo habilis, but the small fossil
sample renders it difficult to make any
statements regarding diversity in size
● Altogether, the species is more gracile
and was probably faster than Homo
habilis
● The long arms of Homo habilis have
vanished, and there is more
proportion in the body, possibly a
result of evolutionary adaptations
associated with full bipedalism and
also a greater endurance for long-
range movement
● Rather than having the ability to run
quickly, Homo ergaster seems better
suited for walking long distances

32. Social Structure and Behaviour
● We can be certain that Homo ergaster was
capable of producing fire, for this was a
necessity in their expansion within and
beyond Africa
● This undoubtedly began to accelerate the
transformation of dentition, the digestive
tract, and the range of foods that could be
consumed
● Moreover, it may have also permitted a
more developed social structure focusing
on the hearth and the communal sharing
and preparation of food
● Expansion of range also suggests slightly
larger population numbers, perhaps even
an adaptive advantage over Homo habilis
in that this species never appeared to have
colonised new territories
● A question of climatic change, too, is also
relevant to the triggers for Homo ergaster
expansion, but it is probable that social
structure, technological innovation, and
dietary flexibility were essential for the
expansion to have been successful

33. Lithic Industry
● After roughly 1.6 million years, a new lithic
industry emerges in Africa known as the
Acheulean
● This refers to a tool-kit based on the
production of bifacially manufactured
handaxes
● Although a relatively simple type of tool to
produce, it was highly practical and was
distributed throughout the Old World and
persisted until at least the end of the
Middle Palaeolithic (ca. 35,000 BP)
● Its production implies a good grasp of
causality, but also a sense of symmetry
that can possibly be explained with
reference to the development of
mechanisms coordinating the function of
the two sides of the brain, namely, a
change in the frontal cortex
● This industry completely supplants the
chopper industry in Africa, but the chopper
industry continues to flourish elsewhere—
in East Asia, handaxes do not occur at all