Competition, Interspecific (see also 

 Competition; Predation): 



among grass- eating mammals, 

 127-28 



among island species, 155 



among rodents for grassland 

 vegetation, 127 



and social despotism, 184 



as highly developed in tropical 

 rain forests, 346 



Darwin's view of as instrument 

 for segregating species into 

 different niches, 251-252 



due to saturation of habitats, 253 



Cause's rule or "competitive 

 exclusion principle" as 

 describing, 253-254 



geographical variations in amount 

 of, 253 



increase in during stress or crisis, 

 253 



occurrence of in simultaneously 

 occupied habitats when one 

 species increases in abundance, 

 253 



patterns of with two species of 

 similar niche requirements, 

 254 



reduction of: 

 by differing adaptations to cli- 

 mate, of related insect species, 

 253 

 during critical stages of life 



cycle, 253 

 or elimination of when require- 

 ments of species less than 

 supply available, 252 

 through lowering of populations 



by predation, 252-253 

 through setting up of mutually 

 exclusive territorial relations, 

 253 



removal of and expansion of 



species beyond limits of niche, 

 252 



restriction of population to opti- 

 mum niche as effect of, 252 

 Conditioning {see also Water- Con- 

 ditioning): 



and transmission of behavior 

 patterns, 251 



as "trial and error" form of 

 learning, 15 



of carnivores to new species as 

 prey, 192 



of insect larvae and production 

 of new strain, 261 



of water, 172-173 

 Continental Drift Theory: 



as possible explanation of distri- 

 bution of fauna in Neotropical 

 region, 270 



ex/jl allied. 150-51 



Continent(s) {see also North 



America): 

 animal communities in deciduous 



forest biociation of European, 



298-299 

 approximate coincidence of with 



regions, 268-269 

 Asia: 

 animal communities in deciduous 



forest biociation of, 299 

 dispersal of fauna of to North 



America, 155, 318 

 Bering land bridge as connecting 



North American and Asian, 272 

 connection of to islands by land 



bridges, 155 

 distinctiveness of fauna of 



Australian and designation of 



Australia as zoological realm, 



268-269 

 evolution and spread of horses 



across, 272 

 fauna in of Neotropical region, 270 

 fauna of African, 271 

 isolation of prerequisite to develop- 

 ment of orders and families, 



272 

 land bridges between as dispersal 



pathways, 151 

 logic of using as basis for first 



major subdivision of fauna, 



268-269 

 northern: 

 concentration of, 151 

 periods of aridity and glaciation 



in, 151 

 periods of warm, moist uniform 



climates in, 151 

 repeated flooding of, 151 

 South America: 

 dispersal of fauna of to North 



America, 156 

 distinctiveness of fauna of, and 



designation as zoological 



realm, 268-269 

 temperature of as influenced by 



currents of sea, 354 

 theories about drifting of, 150-151 

 Convergence, 22-23, 154 

 Cooperation, Interspecific {see 



Commensalism; Mutualism) 

 Cooperation, Intraspecific: 

 aggregation by bees as method of 



raising body temperatures in, 



74-75 

 among muskox and bison, 175 

 and negative social facilitation, 



175 

 and positive social facilitation, 175 

 ant societies as examples of, 175- 



176 

 division of labor in colonization as, 



174 



Cooperation, Intraspecific 



(Conliniied) 

 effects of size of aggregation on, 



175 

 grouping of free- living protozoans 



as, 174 

 increasing amounts of in increas- 

 ingly complex societies, 175-176 

 in huddling of mice, 175 

 in roosting of bob-white quails, 175 

 m wolf packs, 175 

 need for specialized behavior in, 



176 

 of aquatic organisms, 175 

 persistence of aggregation of 



individuals as, 174 

 termite societies as examples of, 



175-76 

 Creeks, defined, 42 

 Cycles {sec also Catastrophes; 



Plagues; Populations): 

 and changes in physiological vigor, 



241-242 

 and vitamin content of food con- 

 sumed, 241 

 and ultra-violet intensities, 244 

 as causing variations in species 



through survivors, 262 

 better understood as oscillations, 



237-238 

 criteria used to determine real 



peaks of, 238 

 defined. 237 

 epizootics in, and theory of general 



cause of cycles, 241 

 explanation of causes of for 



particular species, 240-241 

 extreme fluctuations between 



peaks and lows in, 238 

 extrinsic factors as necessarily 



affecting intrinsic factors in, 



242-243 

 five- six year, species occurring 



in, 237 

 hidden periodicities in, 237 

 in heights of ionosphere and ozone 



layers as affecting populations, 



243 

 in mathematical usage, 237-238 

 in plankton populations, 358 

 in predator populations: 

 and ability to shift from one 



region to another, 240 

 as dependent on that of herbivores, 



241 

 as dependent on that of prey, 239 

 in sunspots: 

 and relation to ultraviolet light, 



244 

 and weather, 243 

 correlated with population cycles, 



243 



lnde> 



41 1 



