October 12, Lecture Notes, Anthropology
LOWER PLEISTOCENE HOMININS (1.8 mya - 400 kya)
(or HOMO ERECTUS / HOMO ERGASTER)
- it was called such because at the time it was thought that these were the first to be bipedal
- one species or two?
- lived during a dramatic period in terms of climate, a COOLING PERIOD
- especially in northern africa
- impacts the evolution of humans
- LARGER BODY (same height as modern humans)
- in the span of a million years the brain expands from 800cc to 1200cc's
- regional differences in terms of these brain sizes.
- more muscular than homo habilines. robustly built, bulking up.
- less sexual dimorphism, this decline begins with homo erectus. species in general is getting
larger but females are catching up to males. Why would that be? the larger brain size of babies is
causing women wiht larger birth canals to be selected for.
- size of birth canal is increasing rapidly
- HIGHER SKULL (forehead)
- LESS PROGNATHIC (facial out-jutting)
- the endocasts of the interior skull looking at brain impressions on the skull, we can see that
australopithecines brains look like chimpanzees, homo erectus is beginning to look more like
humans. the frontal lobe is increasing faster than the other parts.
- SMALLER JAWSAND TEETH like humans
- they still have relatively large SUPRAORBITAL TORUS (ridges over the eyes)
Why are the bones of the skull thicker in the Homo Erectus?
- to protect their brains better. they are much stronger and bigger so perhaps they are doing
certain dangerous things and their brains need more protection
- they have a much larger OCCIPITAL TORUS than humans, ridge around base of skull where
neck muscles connect.
- one interesting feature in their teeth: their incisors are "shovel-shaped", as if scooped from the
inside. we find these for the very first time in the HOMO ERECTUS, still found in some modern
HOMO ERECTUS BEHAVIOURS
- first to migrate out ofAfrica?
- until discovery of DMANISI fossils in Georgia in 2000, we thought Homo Erectus to be the
first to wander out of Africa.
- north africa was getting dryer so species of all sorts start to wander to find environments more
suited to them. not millions of individuals, but small groups looking for water, following rain patterns.
- we know for sure that erectus is the first ones found WIDELY outside of africa
- more advanced stone tools called: ACHEULEAN TOOLS
- lots of debates about whether they were hunters or still scavangers. Did they hunt or scavange?
- none of the tools that have been preserved are hunting tools...
- homo erectus must have eaten a lot of meat because of the large brains.
- teeth don't tell us much.
- very difficult to find DIRECT evidence of hunting but there is plenty of INDIRECT ev