human evolution: genus homo
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HUMAN EVOLUTION: GENUS HOMO. Time-Line of Hominid Evolution: 5 Adaptive Radiations. 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 - PowerPoint PPT PresentationTRANSCRIPT
HUMAN EVOLUTION: GENUS HOMO
Time-Line of Hominid Evolution:5 Adaptive Radiations
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. Homo habilis2. Homo ergaster3. Homo erectus4. Homo antecessor (“archaic”
Homo sapiens)5. Homo heidelbergensis
(“archaic” Homo sapiens)6. Homo neanderthalensis
Cranial capacity for Genus Homo
Homo habilis
http://www.archaeologyinfo.com/homohabilis.htm
1. Homo habilis
2.3-1.5 mya
East Africa (Kenya, Tanzania, Ethiopia) & southern Africa
Increased brain size (680-800ml)
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
1.8-1.6 mya
Lake Turkana, Kenya
Increased Brain Size (800-880 ml)
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 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 (900-1600 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. 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 pre-modern forms of H. sapiens
AFRICAN ARCHAICS
EUROPEAN ARCHAICS
Kabwe, Zambia Bodo, Ethiopia
Arago, France Petroloma, Greece
4. Homo antecessor 780,000 ya
Gran Dolina, Spain (oldest fossil humans in EU!)
Increased Brain Size (1000 ml)
Direct ancestor of H. heidelbergensis & H. neanderthalensis (?)
• 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
Homo antecessor
5. Homo heidelbergensis 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 Germany1st archaic cranium discovered in Europe
Homo neanderthalensis
http://www.archaeologyinfo.com/homoneaderthalensis.htm
6. Homo neanderthalensis
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
African European-SW Asian East Asian Australian
Modern Human Regional Variation
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 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.
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)
• 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
Recent Research: “Mungo Man”