Title: The Earliest Dispersal of the Genus Homo: Homo erectus and Contemporaries
1Chapter 9
- The Earliest Dispersal of the Genus Homo Homo
erectus and Contemporaries
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3Left Homo Erectus (1mya)Center
Australopithicus afarensis (2.5mya)Right Homo
Neandertalensis (100,000-32,000ya)
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5Homo erectus
- Discoveries from East Africa have established
Homo erectus by 1.8 m.y.a. - Some researchers see anatomical differences
between the African and Asian discoveries. - They place African fossils into the Homo ergaster
species. - Analyses show that H. erectus/ergaster represents
closely related species and possibly geographical
varieties of a single species
6BECOMING HUMAN PART II
7First Dispersal of the Hominins
- Close to 2 million years ago, hominins expanded
out of Africa into other areas of the Old World. - Since the early hominin fossils have been found
only in Africa, it seems that hominins were
restricted to this continent for as long as 5
million years.
8First Dispersal of the Hominins
- After 2 mya, theres less diversity in these
hominins than in their pre-australopith and
australopith predecessors. - There is universal agreement that the hominins
found outside of Africa are members of genus
Homo. - Homo erectus is the species for which there is
the most evidence.
9Homo erectus A New Kind of Hominin
- The first hominin to expand into new regions of
the Old World. - As a species, H. erectus existed over 1 million
years. - We can understand its success as a hominid
species based on behavioral capacities (i.e.)
more elaborate tool use) and physical changes
(i.e. larger).
10Grade
- H.erectus hominins represent a different grade of
evolution than their African predecessors. - Grade refers to a grouping of organisms sharing a
similar adaptive pattern. - Grade implies nothing directly about shared
ancestry, but implies general adaptive aspects
of a group of animals
11Morphology of Homo erectus
- Living in different environments over much of the
Old World, H. erectus populations shared several
common physical traits including
12Body Size
- Adult weight gt100 lbs, average adult height of
ca. 5 feet 6 inches - Sexually dimorphic, weight and height varied
according to sex - Increased robusticity (heavily built body) that
dominated hominin evolution until anatomically
modern H. sapiens
13Brain Size
?Homo Sapien Skulls?
- Cranial capacities 700 cm3 to 1250 cm3
- Brain size closely linked with overall body size
- H. erectus is larger-bodied than early Homo
sample but relative brain size is about the same - Relative brain size of H. erectus is considerably
less encephalized than later members of genus Homo
1. Australopithecus afarensis 2.
Australopithecus africanus
3. Homo habilis 4. Homo erectus 5. Homo
Neandertalensis
14Cranial Shape
- Thick cranial bone, large browridges
(supraorbital tori), and projecting nuchal torus - Braincase long and low, with little forehead
development - Cranium wider at base, compared with earlier and
later species - Sagittal keel, a small ridge from front to back
along the sagittal suture, reflects bone
buttressing in a very robust skull, rather than a
specific function
15Homo Erectus findsAfrica, Asia, Indonesia, Europe
16Homo erectus from Africa
- Homo erectus evolved first in Africa, supported
by evidence of - Earlier hominins prior to the appearance of H.
erectus occurring in Africa. - 1.8 mya fossils at East Turkana, in Kenya, and
not long after at other sites in East Africa. - Though, 1.75 mya populations in southeastern
Europe 1.6 mya populations in Indonesia,
suggesting quick migrations
17TURKANA BOYa.k.a. Nariokotome Skeleton WT 15000
- In 1984, Kamoya Kimeu discovered a small piece of
skull on the west side of Lake Turkana at the
site known as Nariokotome. - The excavations produced the most complete H.
erectus skeleton ever found - Facial bones, a pelvis, and most of the limb
bones, ribs, and vertebrae.
18TURKANA BOYNariokotome Skeleton
- The Nariokotome skeleton is dated to about 1.6
mya. - The skeleton is that of a boy about 12 years of
age with an estimated height of 5 feet 3 inches.
19Olduvai Gorge
- Find by Louis Leakey in 1960, includes
well-preserved cranial vault with small part of
upper face. - Dated at 1.4 mya, the cranial capacity is the
largest of all the African H. erectus specimens. - The browridge is the largest known for any
hominin, but the walls of the braincase are thin.
- Similar to East African H. erectus specimens
differs from thick cranial bones in Asian H.
erectus.
20Gona Evidence
- Ethiopia find dated to appx. 1.3 mya
- Female pelvis with very wide birth canal,
indicating large-brained infants in utero - Perhaps newborn H. erectus with a brain that was
comparable to typical modern human baby - Suggests, when compared with Nariokotome pelvis,
considerable sexual dimorphism in skeletal
anatomy is linked to reproduction and body size
21Daka Evidence
- Middle Awash of Ethiopia find dated to appx. 1
mya - Complete cranium more like Asian H. erectus than
most earlier East African remains discussed - Discounts argument that East African fossils are
different species than Asian H. erectus
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23The Earliest African Emigrants
- Why they left is a mystery
- A greater range of physical variation in
specimens outside of Africa at about 1.8 mya - Into Java, Indonesia by 1.6 mya
- Equates to less than 200,000 years to travel from
East Africa to Southeast Asia
24The Dmanisi Hominins
- The discovery of the Dmanisi materials in the
Republic of Georgia began in the early 1990s. - The most informative specimens are four
well-preserved crania, with one recently
discovered being almost complete. - The remains are the best-preserved hominins of
this age found anywhere outside of Africa.
25The Dmanisi Hominins
- The most complete specimen has a less robust and
thinner browridge, a projecting lower face, and a
large upper canine. - All three Dmanisi crania have small cranial
capacities. - A number of stone tools, similar to Olduwan
industry from Africa, have been recovered at
Dmanisi. - Remains from four individuals allows comparisons
with H. erectus from other areas
26Dmanisi Diagnostic Characteristics
- Estimated height ranging from ca 4 feet 9 inches
to 5 feet 5 inches, smaller than full H. erectus
specimens from East Africa or Asia - Body proportions, however, similar to H. erectus
(and H. sapiens) and different from earlier
hominins