... non-biological model of human geographical expansion, one that would have been independent of natural Human range expansions, contractions and extinctions 41 selection Given that humans behaved as ... 1987) In the east, Human range expansions, contractions and extinctions 47 the barriers of the Taurus, Pontic, Zagros and Caucasus would have checked the expansion of the tropical humans (Finlayson ... more restricted geographic Human range expansions, contractions and extinctions 49 ranges would have been most prone to extinction whereas those with greater mobility and behavioural diversity...