The Physical Basis of SocietyD.Appleton, 1928 - 526 من الصفحات |
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الصفحة 48
... regions have two wet and two dry seasons . Subequatorial and subtropical regions have one wet and one dry season . Deserts lying 25 to 30 degrees from the equator have two brief periods of rain and two hot and dry seasons . In the ...
... regions have two wet and two dry seasons . Subequatorial and subtropical regions have one wet and one dry season . Deserts lying 25 to 30 degrees from the equator have two brief periods of rain and two hot and dry seasons . In the ...
الصفحة 49
... regions so arid that the native animals never seem to drink water but get their supply from the juices of their food , but the higher forms cannot exist under such con- ditions . The farmer waters his stock at frequent intervals , and ...
... regions so arid that the native animals never seem to drink water but get their supply from the juices of their food , but the higher forms cannot exist under such con- ditions . The farmer waters his stock at frequent intervals , and ...
الصفحة 51
... regions with their short summers and short growing seasons . Com- pare the dense tropical forests with their long vines with the little dwarf willows and aspens of the far north . The tem- peratures are quite as great in the United ...
... regions with their short summers and short growing seasons . Com- pare the dense tropical forests with their long vines with the little dwarf willows and aspens of the far north . The tem- peratures are quite as great in the United ...
الصفحة 53
... regions . Animals vary in their re- actions to light . Owls can see by day but prefer to hunt by night . In ponds the snails seek a faint light , being found in the lightest spots on the darkest days . If a cockroach is set free it will ...
... regions . Animals vary in their re- actions to light . Owls can see by day but prefer to hunt by night . In ponds the snails seek a faint light , being found in the lightest spots on the darkest days . If a cockroach is set free it will ...
الصفحة 54
... regions where the days are short and which did not produce seed in the north could be made to set seed by the simple device of covering them and thus shortening the hours of ex- posure to light . There is reason to believe that the ...
... regions where the days are short and which did not produce seed in the north could be made to set seed by the simple device of covering them and thus shortening the hours of ex- posure to light . There is reason to believe that the ...
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acres Africa America appears areas Asia atoms average bacteria believe birds body carbon carbon dioxide cause cent century cephalic index changes characters chromosomes civilization climate color common copper crops cultivated culture danger Darwin death rate destroy disease domestic early earth eggs environment Europe European evidence fact feeble-minded females fish forms germ cells given heredity human Ibid important increase Indians individual inheritance insane insects iron killed known land later light living male man's marriage metals miles natural selection nature Negro neolithic organisms ovum oxygen Pará rubber tree parasites physical population possible pounds present problems produced R. S. LULL race seeds seems social South South America species square mile supply T. H. MORGAN temperature things thousand tion to-day trees tropics types United wild woman women