After the Seventh Day

acres Africa agriculture already America ancient animals Arctic Asia Asia Minor atomic ayllu Aztecs became become biotic potential Britain building Byblos canals Carthage cent century B.C. China civilization climate countries crops cultivation culture desert developed disease earth East Egypt empire energy engineering Eskimos Euphrates evidence experts farmers farming feet fertility fields fire fish floods forest grain Greece Greek heat human hunting Inca India Indians Indus industrial irrigation islands Kon-Tiki Lake land living locusts malaria materials means Mesopotamia metal methods migration miles minerals modern mosquitoes mountains Nabataeans nature Negev Nile nomads North peasants Persian Persian plateau plants plateau plow population primitive produce pyramids radioactive reactors region rice river rock Roman Sahara salt seeds settlement silt slaves snow soil square miles stone Sumerian supply surface temple tion trade tree tritium tsetse fly uranium Valley wealth wheel