Ardipithecus-Lived in 5.8 - 4.4 Mya(the end of the Miocene & beginning of the Pliocene epoch)-Probably ancestral to Australopithecus Afarensis-Brain volume was about the size of a modern chimpanzee-Tim White of Berkeley, the anatomist says:"Ramidus is the first species this side of our common ancestor with chimpanzees."
CHAPTER 1: AUSTRALOPITHECINES MORPHOLOGY-Lived in East and South Africa between 4.4 and 1.4 Mya(The Pliocene & the beginning of Pleistocene epoch)-Trend toward larger brain size-Brain enlargement probably arose in response to changes in foods habitat-Brain volumes ranges from 435 to 650 cc-Between 1.2 to 1.4 m tall-Sexual dimorphism in earlier creature-The normal lifespan was about 25-30 years-Ate meat & plants(friuts.nuts,roots,eggs,lizard,fishs,carrions,...)-Lived with: saber-thoothed tiger,lion,hyraxes,rats,baboons,pigs,monkeys,hippos,...
1. Change in diet - less “tree” food - more open ground foraging, e.g. seeds, grasses, roots2. Change in dentition - smaller canine teeth - male canines became as small as those of females
CHAPTER 2:AUSTRALOPITHECINES SPECIES Gracile Species Location • Australopithecus Anamensis Kenya • Australopithecus Afarensis Ethiopia & Tanzania • Australopithecus Africanus South Africa • Australopithecus Garhi Ethiopia Robust Species Location • Australopithecus Robustus South Africa • Australopithecus Aethiopicus Kenya • Australopithecus Boisei Kenya Australopithecus BahrelGhazali East Africa Australopithecus Sediba Chad
Gracile Species:3.9 to 2 Mya in East Africa3.5 to 2.3 Mya in South AfricaErect bipeds, about 1-1.5 m. in statureApelike skull morphologyTeeth for chewing food in a hominin fashion
Earlier fossils show dental features similar to some late Miocene apes; later South African fossils do not Sexually dimorphic, in body size and canine tooth size
Foramen magnum is forward and downward- looking, as in genus Homo Brain is about a third of a modern human brain in size, and three times larger than Miocene apes Endocasts suggest that the human cerebral reorganization has not yet occurred Blood drainage system for the brain is significantly different from genus Homo
South Africa 1.8 to 1 million years ago Thick bones for their size, with prominent muscle markings Sagittal crest, for huge temporal muscles (more evident in males) – an example of convergent evolution in gorillas and hominins In South Africa the robusts were either an offshoot of the East African lineage, or convergent evolution from a South African ancestor
East Africa 2.5 to 1.3 million years ago More massive skull and larger body size than South African relatives Enormous molars, premolars, mandible and palate East African robust forms likely evolved from earlier gracile forms in east Africa
Australopithecus Afarensis Body Ground or tree-dweller?• Slightly curved hand & foot bones• Relatively long and powerful arms• Bowl-shaped pelvis• Knock-kneed (knee joint angled inward)• Heel bone heavily built (like ours)
Anatomical Adaptations forHabitual Upright Bipedalism A comparison of the chimp, human, and A. afarensis femurs demonstrates a rounder femoral head and longer femoral neck length in hominids.
• 3.5 - 2.0 m.y.a.• Mainly S. Africa• Mixture of habitats• Fruit, salads, insects, small easily captured prey• Sexual dimorphism• (male:1.3m&41kg - female:1.1m & 30 kg)• Brain size: 1/3rd ours• Relationship to other hominids? UnknownThis species slightly different from A. afarensis: slightly taller, less facialprognathism, slightly larger brain. Also lived in drier habitats (especially dryscrublands and perhaps open grasslands), and thus may have exploiteddifferent resources.
• 3.0 - 2.0 M.y.a.• Eastern Africa (the site of Bouri, Middle Awash, Ethiopia)• Fruit, salads, insects, small easily captured prey• Brain size: About 450 cc• The dental arcade is U-shaped• link between the genus of Australopithecus and Homo
NutCracker Man!• 2.3 - 1.2 m.y.a.• Ethiopia, Tanzania, and Kenya in East Africa.• Face is more vertically set, more orthognathic• Low forehead• Foramen magnum located more anteriorly• Sexual dimorphism• (male:1.3m&68kg - female:under 1.05m & 45 kg)• Low vaulted brain case• Brain size: 500- 550cc• The biggest, flattest cheek teeth and the thickest enamel of any known hominin
Chapter 10: Australopithecus Bahrelghazali• 3.5 – 3 M.y.a.• Central Chad in Africa• May be closely related to A.afarensis• Jaw and teeth features to other australopithecines• Probably similar in size to modern chimpanzees• Large incisiform canines and molars• Premolars with 3 roots• Brain size: 400- 550cc
• 1.95 – 1.78 M.y.a.• Southern Africa (South Africa)• brain of the juvenile was human-like in shape,but still much smaller than in Homo specie• generally thinner and lighter jaw, smaller teeth• the legs are quite long• pelvis appears to be more adapted for walking• Brain size: 430 cc