Genus Homo
    Our self-definition is based on intelligence: Homo sapiens =  "intelligent human"
    Genus Homo marks the origin and development of intelligence, and of types of behaviour which are related to intelligence
        Within a species there's no particular correlation between brain size and intelligence.
        Brain size varies between individuals within a species depending upon age, sex, heredity and general size.
        For a species, intelligence correlates roughly to the ratio between its average brain size and its average total body size

Important Factors in  Human Evolution
    Increase in cranial capacity = intelligence
    Size and tooth structure = diet
    Family structure = social organization
    Tools = culture

HOMO HABILIS
    2.2 - 1.6 mya
    East Africa, known from the Olduvai Gorge area of Tanzania
 
Habilis physically resembles Australopiths in having a small body with long arms
    Large adult male may have reached 1.5 m in height and 50 kg; a female would have been closer to 1.2 m and 40 kg
    Teeth resemble those of gracile Australopithecus africanus, with a more "modern" shape to the jaw itself.
Brains were larger in proportion to their bodies than those of Australopithecines
        volume of Habilis brain is 550 - 750 cc, depending on body size
        more than 15% larger than the average for the considerably larger A. robustus.
Habilis' skull higher and more rounded than that of the Australopithecines.
    bony brow ridges
    no hint of an occipital or sagittal crest
    modern-shaped jaw has light muscles - omnivorous diet
The shape of the brain, on the inside of the skull, shows a bulge corresponding to what is called Broca's area of the modern human brain -- area connected with speech patterning. Some degree of vocal communication?

H. habilis evolved into the later H. erectus, which was ancestral to modern humans
After half a million years, H. habilis became extinct due perhaps to conflict with H. erectus, or environmental change at the beginning of the Pleistocene, or it may reflect gradual genetic drift in the entire population through time.

Oldowan tradition -- Earliest tools preserved to the present
     named for Olduvai Gorge
    Mary and Louis Leakey

Oldowan tools are very simple, slightly modified from their original cobble form. The tools were made from rounded stone cobbles which were modified by having one or two pieces of stone (known as flakes) knocked off one or two sides of the stone. Crude choppers, maybe knives. Easily mistaken for natural breakage.

Objects were recognized as tools because their stone material (basalt) doesn't occur in the area in which they were found. Only source of basalt cobbles in the Olduvai Gorge region is more than 30 kilometers distant from the site where the first Oldowan tools were found. Selection, intentional transportation and modification of the stones marks them as tools

Earth stratum from which the Oldowan tools was recovered was covered by a layer of volcanic ash and debris. Site had been occupied by both Australopithecines and H. habilis before the eruption of near-by volcano which covered the site with ash and debris.  eruption -- the same one which bears the footprints at Laetoli -- has been dated using the Potassium-argon technique and the Uranium-decay technique: sometime around 2.2 mya.

What were Oldowan tools used for?
    bola stones
    knives or digging tools
    choppers or cleavers

Who used the Oldowan tools? All H. habilis.

Were other tools used? 
    wood, bone and grass didn't preserve in archaeological record.
    tool kit

"Home base" - centralized area from which individuals carried out daily activities
    toolmaking and butchering animal prey
    the site produced Oldowan tools, debitage (bits and pieces of stone which were knocked off cobbles to make tools)
    broken pieces of animal bone -- large amounts of bone, from many different animals
All concentrated into a comparatively small area