Australopithecines: anatomy, dietary adaptations: size of teeth, chewing muscles: musseter and temporalis.
Gracile and robust australopithecines.
Gracile (A. afarensis, A. anamensis, A. africanus, A.garhi) diet: roots and tubers
Robust (A. aethiopicus, A. robustus, A. boisei) diet: seeds and nuts. Had huge molars and premolars, large chewing muscles, sagittal crests, very large postorbital constriction and flared out cheek bones for temporalis muscle to fit through.
Kenyanthropus platyops (3.5 mya) – bipedal, small brain, small teeth.
Genus Homo (increased brain size, smaller molars, parabolic dental row, reduced temporal muscles, reduced masseter muscles, stone tools)
Genus Homo includes several species:
Homo habilis, Homo erectus, Homo sapiens and some other
Homo sapiens includes several subspecies:
H. s. heidelbergensis, H. s. neanderthalensis, and H. s. sapiens
Human reproductive strategies: concealed ovulation, rotational birth, loss of baculum; K vs. r reproductive strategies
- max breadth of skull is higher than in neanderthals
Behaviorally modern humans and the great leap forward: infinitely variable tool kit
- pressure flaking (allows to detach long thin flakes from the core), invasive retouching on both sides of the tool; art, burial, ritual;
- Blombos cave (South Africa); Aurignacian stone tool technology – Upper Paleolithic
Having large brains means giving birth to babies with large heads. Homo had to develop adaptations to giving birth to large brain babies: 1) wider birth canal, 2) rotational birth, 3) babies are born with underdeveloped brain – require a lot of care from their mothers
=> women become economically dependant from men => monogamy or limited polygamy
Adaptations to cold: small surface/volume ratio in cold climate helps to conserve heat;
short extremities, esp. short tibias and digits help to conserve heat in cold climate. Animals in hot climates tend to have long extremities
Models of Homo sapiens sapiens origin:
Multiregional evolution vs. Single Origin
Multirigeaonal evolution - traces all populations to humans first leaving Africa over 1.7 – 1.5 mya. This model suggests that all populations of Homo erectus evolved towards Homo sapiens in Asia, Africa, and Europe.
Single Origin – suggests that Homo sapiens sapiens evolved in Africa around 100,000 years ago from a population of Homo sapiens heidelbergensis and then spread into Europe in Asia, replacing archaic Homo sapiens.