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Human evolution. Waikato university site http://sci.waikato.ac.nz/evolution/HumanEvolution.shtml. Main points. Rapid changes as new fossils are found and re-evaluated every year Human and chimp diverged about 7mya in Africa
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Human evolution Waikato university site http://sci.waikato.ac.nz/evolution/HumanEvolution.shtml
Main points • Rapid changes as new fossils are found and re-evaluated every year • Human and chimp diverged about 7mya in Africa • Put lineage is ‘bushy’, with many different species in existence at the same time • Ancestors of modern humans evolved in Africa • Homo erectus populations left Africa about 1.5 mya and moved rapidly across Europe and Asia (out of Africa theory)
Early (Miocene) apes • Apes evolved in Africa 20 mya (proconsul) • Monkey-like traits – backbone, pelvis and forelimb • 17mya land bridges to Eurasia allow migration out of Africa and divered into at least eight groups • 13 mya – major climate change in Eurasia. • Apes that survived – in SE Asia (ancestors of Urang-utan) and in Africa (ancestors of African apes) • human evolution\human_odyssey.pdf
Earliest hominins – already ‘bushy’ lineage • Orrorin tugenensis – 6mya, Kenya, bipedal, ape-like canines • Sahelanthropus tchadensis – 6-7 mya, Chad, might not be bipedal, ape-like skull and dentition, forest environment • Ardipithecus ramidus – Ethiopia, 4.4-5.8 mya, forest environment,
Australopithecines - gracile • A. anamensis – 4.2-3.9 mya. Probably bipedal, ape jaw and teeth • A afarensis (Lucy, foot prints) – 3.9-3 mya, fully bipedal, intermediate human-ape dentition, face and cranium ape like, cranial capacity 375-550cc • A garhi – 2.5 mya, Ethiopia, 450cc cranial capacity, • A. Africanus – 3.2-2 mya, bipedal, 420-500cc cranium,
Australopithecines – robust (Paranthropus) • All have sagittal crest, large jaw, heavy skull, thick enamel on molars • P. robustus – 2-1.5 mya, 530cc cranium, tough, coarse food, might have used tools • P.aethiopicus – 2.6-2.4 mya, heavy face, large crest, 410cc cranium, • P. boisei – huge molars, massive built face and jaw, highly specialised hard food diet
Cut marks on bones –evidence for animal butchering using a tool
Trends in human evolution • Cranial capacity • Bipedalism • Skull – dental arcade facial angle • Sexual dimorphism • Rib cage
Bipedalism • Appears very early- (Maybe up to 7mya) • Gradual change (walking, followed by running) • Earlier genus – position of foramen magnum • Evidence from pelvic structure, knee and foot structure • H. erectus – very efficient movement – very narrow pelvic outlook • Wider pelvic outlet (in Sapiens) might be adaptation to larger infant head size
Cranial capacity • Gradual increase in cranial capacity • Early Australopithecines similar to modern chimp (Around 400cc) • Later australopithecines about 550cc • Homo erectus – 510-1225cc (within modern range) • Neanderthal (1450cc) larger than Homo (1350cc) reflect difference in body size.
Skull morphology • Dental arcade from U (chimp) [with cheek teeth parallel] to V (human) • Decrease in size of teeth (molars ) • Decrease in crest and ridges (sagital – diet, nuchal – posture) • Facial angle becoming flatter (to vertical in Homo)
Other trends • Reduce sexual dimorphism • Rib cage size and shape: Funnel (A. afarensis) Barrel shape (Homo) Funnel shape accommodates the large gut needed for a herbivore (eg – gorilla). Barrel shape and hips – indication of meat in diet.
Homo floresiensis • Discovered 2004, in Indonesia • 18,000yo remains • Tiny – adult female 1 m tall, cranial capacity 380cc, • Tool maker and user • Mix of traits: • Primitive – low cranium, brow ridges, bipedal (narrow pelvis) • Advance - flat face, • Theory – a dwarf form of H. erectus, a case of dwarfism on islands
Homo neanderthalensis • 230,000-30,000 ya, ice age, in Europe and middle east • Robust and heavily built • Cranial capacity – 1450cc • Skull – elongated, receding forehead, weak chin, large nasal cavity • Complex tools (Moustarian) • mDNA evidence – not closely related to Homo sapiens
Cultural evolution • Tools • Fire • Shelter • Clothing • Art • Cooperative behaviour (hunting) • Domestication of plants and animals
Tools (I) • Only stone tools survive • Chimps – modified twigs and rocks, learnt behaviour, regional culture, pre-meditation • A. gahri – 2.5 mya • H. habilis - Oldowan culture [cobble stones, one or more flakes knocked of one side] • H. erectus – Acheulean culture[sharper, straighter edges, smaller flakes removed, worked from many sides, range of uses]
Tools (II) • H. sapiens (archaic) and H. neanderthalensis - Mousterian tools • Stone core is shaped before flakes are removed • Range of uses • Some have tang at the end that suggests a wood or bone handle
Upper palaeolithic industry • Modern H sapiens • Africa – 40,000 – 12,000ya • Wider range of material, regional variation • Uses – fishhooks, harpoon points, needles …