HUMAN EVOLUTION: GENUS HOMO
Time-Line of Hominid Evolution:
5 Adaptive Radiations
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First Adaptive Radiation: 6-7 mya in the
late Miocene, potential last common
ancestors
Second Adaptive Radiation: 4-5 mya in
early Pliocene, first true hominids
Third Adaptive Radiation: 3-4 mya in
middle Pliocene, more hominids
Fourth Adaptive Radiation: 2-3 mya in late
Pliocene, more & “robust” hominids
Fifth Adaptive Radiation: 2-1.8 mya in late
Pliocene & early ice age, genus Homo
Rise of the genus Homo
•
Earliest fossils from same African sites as Australopithecines
•
Most date between 2.4 and 1.8 mya
•
Homo habilis means “handy man”
•
Growing consensus that there may have been 2 or more species
of Homo living at the same time by about 2 mya
6 SPECIES OF GENUS HOMO
1.
2.
3.
4.
5.
6.
Homo habilis
Homo ergaster
Homo erectus
Homo antecessor (“archaic” Homo
sapiens)
Homo heidelbergensis (“archaic”
Homo sapiens)
Homo neanderthalensis
Cranial capacity for Genus Homo
Homo habilis
http://www.archaeologyinfo.com/homohabilis.htm
1. Homo habilis
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2.3-1.5 mya
East Africa (Kenya, Tanzania,
Ethiopia) & southern Africa
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Increased brain size (680-800ml)
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Stone tools
Homo habilis
Homo habilis at Olduvai Gorge, Tanzania
Brain size & face
showed
advances
towards more
human-like form
Skeletal remains
discovered at
Olduvai Gorge in
1986 by Don
Johanson revealed
limb sizes and
proportions nearly
identical to
australopithecines
Homo ergaster
http://www.archaeologyinfo.com/homoergaster.htm
2. Homo ergaster
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1.8-1.6 mya
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Lake Turkana, Kenya
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Increased Brain Size (800-880 ml)
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Thinner Skull with smaller facial
bones (than Homo erectus)
Turkana Boy Skeleton
• 90% of skeleton
of adolescent male
found west of Lake
Turkana in the mid
1980s
•1.6 mya, very
modern skeleton,
similar to that of
fully modern
human
Homo erectus
http://www.archaeologyinfo.com/homoerectus.htm
3. Homo erectus
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1.8 mya – 33,000 ya
First hominid to migrate out of
Africa! Africa, then Russia, China,
Java, Italy, etc. (p. 270-71)
50% increased brain size (9001600 ml)
Fire, clothing, shelters, cooking
Homo erectus Facial Morphology
EXAMPLE: Peking Man Reconstruction
Archaic Homo sapiens
•
Hominids with larger brains
& more modern cranial
features than classic H.
AFRICAN ARCHAICS
erectus
•
Recently divided into Homo
antecessor &
heidelbergensis
•
Taxonomy is problematic:
some fossils could be H.
erectus, others could be
direct ancestors of later
Neanderthals or premodern forms of H. sapiens
Kabwe, Zambia
Bodo, Ethiopia
EUROPEAN ARCHAICS
Arago, France
Petroloma, Greece
4. Homo antecessor
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780,000 ya
Gran Dolina, Spain (oldest fossil
humans in EU!)
Increased Brain Size (1000 ml)
Direct ancestor of H. heidelbergensis
& H. neanderthalensis (?)
Homo antecessor
• Mixture of
"archaic" and
"modern" traits,
with especially
modern-looking
mid-face
• Other features are
not unique & could
be considered a
form of European
H. erectus
5. Homo heidelbergensis
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130,000 ya – 700,000 ya
Germany, China, Ethiopia, Greece,
Hungary, Zambia, etc. (p.289)
Increased Brain Size (1000-1400 ml)
“Prepared Core” tools, wooden
spears, dealt with changing
environments
The Steinheim Cranium
The Steinheim specimen
excavated in the 1930s from
Germany
1st archaic cranium discovered
in Europe
Homo neanderthalensis
http://www.archaeologyinfo.com/homoneaderthalensis.htm
6. Homo neanderthalensis
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28,000 ya – 225,000 ya
Belgium, Croatia, Germany, France, Iraq,
Israel, Italy (p.297)
Increased Brain Size (1200-1700 ml)
“Retouched flakes” (tool use), big game
hunters, buried dead, cave art, early
language?, compassion
Original Neanderthal Skullcap
Neanderthal Features
Neanderthal Adaptations
Modern Human Regional Variation
African
European-SW Asian
East Asian
Australian
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Out of Africa (Single Region)
About 130,000 years ago, the first
anatomically modern Homo sapiens
evolved in East Africa (probably
from H. erectus)
then migrated out of Africa to
Europe, Asia, and the rest of the
world.
At this point, H. sapiens may have
interbred with or out-competed
other existing species, such as H.
erectus and H. neanderthalensis.
Multiregional Hypothesis
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1.8 mya, Homo erectus evolved in East
Africa and then began to migrate to
Europe and Asia (due to lack of water
and shelter)
A very successful species, H. erectus
survived until 33,000 years ago! So…the
Multiregional hypothesis argues that
modern H. sapiens evolved from the
different H. erectus stocks in different
regions (continents) at the same time.
After H. sapiens evolved in these
different regions, may have been
interbreeding, thus sharing of genes.
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Compromise (Mostly Out of Africa)
About 130,000 years ago, the first
anatomically modern Homo sapiens
evolved in East Africa (probably from H.
erectus) and then migrated out of Africa
to Europe, Asia, & rest of world.
At this point, H. sapiens did interbreed
with members of other species (H.
erectus & H. Neanderthalensis)
Recent Research: “Mungo Man”
• Part of mDNA extracted recently from bones of a
60,000 year old modern Homo sapiens skeleton found in
1974 on the shores of Lake Mungo in Australia
• Oldest DNA extracted from a human so far!
• Comparison of this DNA with that of 9 other ancient
Australian skeletons, 2 Neanderthals, and 3,453
contemporary people from around the world indicates:
"Mungo Man" had a unique genetic marker
• Indicates that a now lost genetic line of modern Homo
sapiens existed in Australia BEFORE arrival of later
Australian Aborigines
• This evidence provides significant support for rejecting
the "out of Africa" complete replacement model of
modern Homo sapiens evolution