Human origins: rise of the genus homo
Morpholigical differences between early homo and Australopithecines
Feature Early Homo Australopithecines
Sagittal and nuchal crests Absent Present (males)
Brain size Relatively larger Relatively smaller
Face Relatively smaller Relatively larger
Mandible Less robust More robust
Incisors and canines Smaller Larger
Premolars and molars Smaller Larger
* Some of the australopithecines have crest
Homo: bigger brains, smaller teeth
Absolute difference refer to unique features that distinguish one species from
Relative differences typically refer to slight variations in a trait between taxa
Homo habilis and rudolfensis
Habilis – Most complete fossil. 2.3 mya – 16. Mya
• From sites in Tanzania, Kenya, and Ethiopia.
• Species designation: brain size and association with stone tools. • Skeletal morphology similar to contemporaneous australopithecines.
• First species of Homo or junk taxon?
Homo habilis: “handyman”
Type specimen: the original specimen from which the description of a new species
Long forelimbs and robust bones
Homo rudoflensis -
- Koobi Fora, Kenya.
- Originally considered H. habilis.
- H. rudolfensis or H. habilis first representative of our genus?
- Larger brain 750 cc
- No saggital crest
- no subnasl prognathism
- Researches don’t know how vertical the face is because of the of fossils.
- Sizes of the teeth are large.
- Mix of derived and primitive characters
- Mosaic evolution – combo of derived and primitive characteristics
Homo erectus (aisa) and ergaster (Africa)
Ergaster is found in Africa and East Africa
• Earliest African specimens.
• Turkana boy: adult height estimate, limb proportions, and predicted strength. • Limb proportions – arms were shorter and legs were longer. ( proportions look very
much like modern human)
• Debate on H. erectus or H. ergaster as direct ancestor of modern humans.
The first definitive hominin to be found outside Africa
Thicker cranial bones, larger brow ridges, smaller molars and premolars, and more
Homo ergaster skulls, like the skull of KNM-ER 3733 illustrated here, show a
mix of primitive and derived features.
Homo ergaster (Examples WT15000, and ER3733)
Found in Africa at about 1.8 mya
Found in Eurasia (Georgia) at about 1.1 to 1.7 mya
Derived morphological characteristics: large bodies, long legs/short arms,
reduced sexual dimorphism, and large brow ridges.
Unique by having an occipital torus
Cranial capacity approx. 800 - 900 cc
Makers of the Acheulean tool industry which is characterized by the
Slower growth rate is a to derived characteristic and Faster growth rate is primitive
- All early homo do not have a chin *** Homo ergaster and H. erectus differed in a number of ways. Most notably, H.
erectus had a sagittal keel and a more pronounced occipital torus, and the sides
of its skull sloped more than did those of H. ergaster.
Postregmatic depression and sagittal keep in erectus
Homo heidelbergensis and antecessor ( not well accepted)
• Europe and Africa.
• 800–300 KYA.
• Compared to H. erectus, differences in H. heidelbergensis:
Dentition – reduction in the size of the teeth
Brain size – increase in brain size almost as humans
Body size – larger body size and body mass
Heidelbergensis is the new taxonomic designation for specimens that used to be
called archaic homo sapiens
Smaller teeth, divided supraorbital torus, and larger cranial capacity Sometime between 800 kya and 500 kya, hominids with higher, more rounded
crania and larger brains first appear in the fossil record, and by 400 kya Homo
heidelbergensis was common in Africa and western Eurasia. This figure shows two
H. heidelbergensis fossils, one from Kabwe (sometimes called Broken Hill) in
Zambia, and the second from Petralona in Greece. Both are approximately 400,000
Terra Amata – South of France
Evidences of wooden spears of 400,000 ya
Large brow ridges
Length of the face is large but small teeth
Large nasal cavity Homo ergaster is found in Africa and Europe from 1.8 mya until about 1 mya. Homo
heidelbergensis is found at sites in Africa and Europe that date to between 800 kya
and 300 kya. Only H. erectus is found in East Asia during this period.
* Bose basin should be blue and not black
Classic Neanderthals 180, 00 – 30,000 ya ***
- Gene flow and Cold adapter –Contreversey around this.
- Gene flow – Neantherals should be species or sub species to humans.
- **Birdgans rule – body size increasing with decreasing temperature or
- ***Allen Rule : Relative limb length decreases while latitude increases
- Were they cold adapted ? they look like cavemen
• Europe and Middle East.
• 300 – 30 KYA.
• Cranial and dental features.
• Body proportions and presumed strength. • Neanderthal DNA. From fossil bone
No classic Neanderthals - ( phyletic gradualism ) Not relative to this class
Large cc, 1065-1745, strong supraorbital torus, large nose, retromolar gap, weak
chin, and taurodont molars
Retromolar gap: space between the third molar and the rear portion of the
Fluctuations in the ratio of O to O over the last 160,000 years (from a core drilled
in the deepest part of the Greenland ice cap) indicate that about 100 kya the world’s
climate got colder and less stable. In ice cores, more 18O relative to O indicates
higher average global temperatures. (In the deep-sea cores, in contrast, more O 18
relative to O indicates lower temperatures.)
Variation in temperatures
They were adapted to extreme cold weather. • 127,000-27,000 bp (before present) in Europe and portions of western Eurasia.
• Associated with the Mousterian stone tool industry based on the Levallois core
• Buried their dead – indication of culture
• May have cared for injured -
• Occipital bun ( hotdog bun shaped)
• Large brow ridges
• Midfacial prognathism
Retromolar space: space between the third molar and the rear portion of the
mandible ( shared derived chatacteristics)
• No chin
• Taurodont: very large pulp cavities combined with reduced root size. It’s a shared
• Volume of the nose is big
The skulls of Neanderthals, like this one from Shanidar Cave, Iraq, a