Steven Pinker -- How the Mind Works - Hampshire High Italian ...

198 | HOW THE MIND WORKSand were vulnerable to predators (for group living), which then changedtheir means of locomotion to swinging beneath branches (for hands andfor precursors to upright posture), before a climate shift sent them fromthe forest into grasslands (for upright posture and hunting). \Vhat isthe probability that a given planet, even a planet with life, has such a history?SpeciesDateHeightPhysiqueBrainChimp-hominidancestor (if similarto modernchimps)8—6 million yearsago1-1.7 meterslong arms, shortthumbs, curvedfingers and toes;adapted forknuckle-walkingand tree-climbing450 ccArdipithecusramidus4.4 million yearsago?probably bipedal?Australopithecusanamensis4.2-3.9 millionyears ago?bipedal?Australopithecusafarensis (Lucy)4—2.5 millionyears ago1-1.2 metersfully bipedal withmodified handsbut ape-like features:thorax,long arms, curvedfingers and toes400-500 ccHomo habilis(Handyman)2.3-1.6 millionyears ago1-1.5 meterssome specimens:small with longarms; others:robust buthuman500-800 ccHomo erectus1.9 million-300,000 (maybe27,000) years ago1.3-1.5 metersrobust buthuman750-1250 ccArchaic Homosapiens400,000-100,000years ago?robust butmodern1100-1400 ccEarly Homosapiens130,000-60,000years ago1.6-1.85 metersrobust butmodern1200-1700 ccHomo sapiens(Cro-Magnon)45,000-12,000years ago1.6-1.8 metersmodern1300-1600 (cf.today: 1000-2000, average1350)