The Physical Basis of Society

acre Africa America appeared Asia average bacteria beetles believe birds body breeding carbon carbon dioxid carnivora cattle cause cent century changes characters chromosomes civilization climate color considered crops cultivated Darwin death destroyed discovered discoveries disease early earth eggs elements elm-leaf beetle environment Europe European evidence evolution existence fact favorable feeble-minded female fish forms germ cells groups growth hence heredity Hessian fly human Ibid important Inasmuch inches increase individuals influence inheritance insects Kallikak Family killed known Lamarck large numbers larvæ less living lower malaria male man's mated natural selection nature normal organisms ovum oxygen parents physical plants and animals population possible produced race reason seeds smallpox social society soil species square mile substances survive temperature theory thought tion trees tropics tuberculosis United women yellow yellow fever