The Genus Homo Flashcards
mastication
chewing
muscles of mastication
▪ temporalis ▪ masseter ▪ medial pterygoid ▪ inferior lateral pterygoid ▪ superior lateral pterygoid
temporalis
muscle fibres get smaller and contract and relax to close the jaw
masseter
tightly packed muscle that contract to close mouth
medial pterygoid
inferior lateral pterygoid
superior lateral pterygoid
prognathism
facial orientation extends beyond the vertical plane
orthognathism
facial orientation does not extend beyond the vertical plane
Miocene (23 - 5.3)
▪ first hominoids (apes)
▪ hominids (great apes)
▪ hominins (species more closely
related to humans)
Australopiths
Pilocene (5.3 - 2.6)
▪ Australopithecus (4.2 –3, 1.9 Ma) ▪ Paranthropus (2.5 –1 Ma) ▪ small brains and bodies ▪ megadont ▪ bipedal with arboreal retentions ▪ long arms ▪ curved phalanges ▪ relatively short legs
Australopithecus
▪ 4.2-3, 1.9 Ma: East Africa, South Africa, Chad
▪ multiple species
▪ prognathic, megadont, large faces
Paranthropus
▪ 3 species: South and East Africa, 2.5 -1 Ma
▪ larger brain size, massive faces
▪ megadont+++
▪ overlaps with Homo
Early Homo: Homo habilis (italics)
▪ East and South Africa, 2.4 –1.4 Ma (maybe 2.8 Ma?)
▪ larger brain (640 cc)
▪ associated with stone tools
▪ more orthognathic
▪ smaller teeth, but still had thick enamel and strong jaws
▪ Still short: 3.5 – 4.5’ in height, 70 lbs average weight
▪ mosaic of morphological features (longer arms, shorter legs, phalanges still somewhat curved)
The First Tool Makers: Stone Tools 101
▪ indicator of human adaptation and technological complexity –material culture
▪ hyper-technological
▪ co-evolution of tools and biology causing reduction of mastication muscles
▪ knapping: hammerstone, core, flake
knapping
making stone tools
▪ hammerstone
▪ core
▪ flake
The First Tool Makers: Extant Analogues
▪ use of animal models/extant analogues ▪ chimpanzee cultures ▪ hammers and anvils ▪ modification of twigs ▪ leaf sponges to drink water ▪ tools focused on food procurement, social display – chimps don’t knap!
The First Tool Makers: Early Homo
▪ Oldowan Industrial Complex
▪ simple, but deliberately manufactured (cores, flakes, retouched flakes)
▪ sourcing stones at a considerable distance
Oldowan Industrial Complex
tools made by the Homo habilis
▪ first tool found in Gona, Ethiopia (2.6 Ma)
Africa and Beyond: Homo erectus
1.8 Ma –143 000 years, potentially even later: Africa, Asia (Indonesia and China), Republic of Georgia
Cranial characteristics of Homo erectus
▪ larger brain size (900 cc) ▪ long, low cranial shape (from front to back) ▪ more orthognathic ▪ supraorbital torus (brow ridge) ▪ sagittal keel ▪ nuchal torus
sagittal keel
rigid of bone that runs from the frontal along the mid line to the back
▪ accommodates the large parietal lobes
nuchal torus
accommodates cranium expansion
Postcranial characteristics of Homo erectus
▪ modern body proportions/stature (orthognathic, small face)
▪ loss of all arboreal retentions
Homo erectus Postcranial
▪ modern body proportions
▪ ↑ in height (4’9’–6’1’”), ↑ in weight (88–150 lbs)
▪ still sexually dimorphic
▪ ↑ in hindlimb length
Nariokotome “Turkana Boy”
▪ 8 year old boy, 1.5 Ma ▪ reduction of upper limb ▪ long lower limbs, large hip joints ▪ would have matured 5’6”–+6’ ▪ 900 cc
Out of Africa: Dmanisi, Republic of Georgia
▪ 1.8 Ma
▪ cranial variability found at the site
▪ primitive tools
▪ why leave Africa – tracking game animals
Acheulean Industrial Complex
▪ created by the H. erectus
▪ 1.7 Ma–160 000 years
▪ hand axes, cleavers
▪ efficient butchering tools
Controlled use of fire
▪ from 1.5 Ma (debated evidence), 1 Ma (still debated), 800 000 years (good evidence), 400 000 years (widespread evidence)
▪ evidence in the form of hearths, burnt bone and artefacts, fire cracked rock
Benefits of fire
▪ cooking (increases digestibility of food → feeds a large and complex brain = language, more complex tools)
▪ social interaction and gatherings
▪ warmth and light (allowed dispersal into colder regions)
▪ protection against predators
