Cycles (Coiiliiiiied) 

 in weather: 

 and failure of crops during dry 



years, 330 

 and variations in solar radiation, 



243 

 as not absolutely synchronous in 



large areas, 243 

 evidence for in annual rings of 



giant sequoias, 243 

 length of, 243 

 thirty-five year, 243 

 lack of correspondence between, 

 and random number cycles when 

 conspicuous peaks considered, 

 238 

 life, critical periods in and effects 



of solar radiation, 244 

 nine- ten year: 

 as better expressed in southerly 

 latitudes than in far North, 237 

 seen as modification of short- 

 term cycles, 237 

 species demonstrating, 237 

 nutrition and rate of reproduction 



in, 241 

 obtained from plotting random 

 numbers compared to animal 

 population, 238 

 occurrence of in population of 

 single prey and predator in 

 limited area, 239-240 

 of herbivores: 

 and relations with plants during, 



241 

 and variations in mineral salts 



of plants, 241 

 as basic to cycles of other 

 organisms, 241 

 of lemmings and predators, 240 

 periods of among invertebrates, 



237 

 periodicities of best established, 



237 

 role of stress in reduction of 



populations as cause of, 241 

 short-term: 

 coefficient of variation in, 238 

 length of, 238 

 theories about, 237 

 sustaining of in populations of 

 predator and prey through 

 introduction of cover, food 

 and immigration, 240 

 synchrony in: 

 and isolated local populations, 



238 

 as consideration in testing 



reality of, 238 

 local and regional fluctuations 



of, 238 

 of rodents and lemmings, 238-239 

 testing oscillations for randomness 

 before designation as, 238 



Cycles (Continued) 

 three-four year: 

 as better expressed in far North 



than southerly latitudes, 237 

 species demonstrating, 237 

 use of term justified, 237-233 

 variations in tempo of in different 

 parts of the world, 238 

 Cyclomorphosis, 60 



Desert(s): 

 adaptations in: 

 of animals to lack of water, 338 

 of animals to soil, 339 

 of plants to lack of water, 333 

 age of North American, 283 

 appearance of during Tertiary era, 



334 

 areas of occurrence of, 332 

 as usually occurring on lee side of 

 mountains and continents with 

 respect to prevailing winds, 332 

 avoidance of hot ground surface by 



animals of, 338 

 basin sage biociation in: 

 birds of, 337 

 invertebrates of, 337 

 overlap of species between desert 



scrub and, 336-337 

 populations of small mammals in, 



337 

 reptiles of, 337 



species of mammals in, 336-337 

 subspecies of as contrasting 

 sharply with scrub biociation 

 species, 336-337 

 biociations of other than North 



American, 337-338 

 biotic succession in vegetation of, 



333 

 cause of development of in Great 



Basin of North America, 281 

 characteristic animals of, 338 

 characteristics of soils of, 172 

 cold blooded animals of as 



hibernating, 339 

 description of areas defined as, 



332 

 differentiation of vegetation of 

 during Pliocene and Pleistocene 

 eras, 334-335 

 distinct nature of species of fish 



in pools of, 339 

 evaporation in, 332, 333 

 inactivity of birds during prolonged 



droughts in, 348 

 invasion of organisms from into 



woodland, 311-312 

 kinds of vegetation in, 333 

 most arid grassland association 

 considered as, 325 



Desert(s) (Continued) 

 most important environmental 



factors of, 338 

 nocturnal habits of animals of to 

 avoid high temperatures, 33 3 

 oases in, 339 

 physiographic succession in 



vegetation of, 333 

 plant and animal activity in with 



abundant rain, 333-339 

 plant associations of in North 



America, 333-334 

 precipitation in, 332 

 protective devices of plants in, 192 

 relation of species of to Eurasian 



forms, 334-335 

 scrub biociation in: 

 absence of large mammals from, 



335 

 birds in, 335-336 

 home ranges of small mammals 



in, 335-336 

 invertebrate populations in, 336 

 level of bird populations in, 336 

 mammals in, 335 

 reptiles in, 336 

 semi-deserts, carrying capacity 



of land, 339 

 semi-fertility of soil of where 



irrigation possible, 339 

 species of as occurring in grass- 

 land, 326-327 

 temperatures of, 332-333 

 topography of, 333 

 tropical thorn forest considered 



as, 334 

 use of shady nesting areas by 



animals of, 338 

 vegetation of originating from 



hardy species of Tertiary floras, 

 334-335 

 Detritus, 54-55, 55, 58, 73, 74, 87, 

 92, 114, 130, 188, 195, 196, 

 356-357 

 Developmental Life Histories, 



defined, 16 

 Diel Rhythms: 

 in marine plankton, 358-359 

 kinds of, 100-101 

 Disease [see also Parasites; 

 Parasitism): 

 as stabilizing factor in populations: 

 of muskrats, 232-233 

 with occurrence of epizootics, 

 228 

 as uncommon among primitive 



bison herds, 328 

 epizootics of: 

 among wild animals and high 



population densities, 228-229 

 as rarely occurring in inferior 



habitats, 231 

 defined. 228 

 factors in occurrence of, 228 



412 Index 



