Dispersal Pathways (Continued) 

 over advancing and retreating 



glaciers, 284 

 "sweepstakes routes," defined as, 



151 

 taken by cold-blooded vertebrates, 



151-153 

 theories about: 

 based on hypotheses about conti- 

 nents, 150 

 to explain occurrence of related 



forms in South America, 



Australia and Africa, 270 

 toward southern land extensions 



during cold period in northern 



continents, 151 

 tropical species and Bering land 



bridge as, 153-154, 154 

 warm temperate species and 



Bering land bridge as, 153-154 

 Distribution: 

 as affected by zonation of vegeta- 

 tion, 295 

 basic concepts in understanding 



ecological system in, 285 

 biotic province concept in, 272 

 ecological and zoogeographical 



approaches to compared, 276 

 factors in of marine organisms, 



351, 372 

 faunistic system for of J. A. Allen 



(1892), 272-273 

 in deciduous forest biociation of 



Asia, 299 

 in deciduous forest biociation of 



Europe, 298-299 

 in deciduous forest biociation of 



North America, 295 

 of birds, 296 



of invertebrates, 296-297 

 of mammals, 295-296 

 of reptiles and amphibians, 296- 



297 

 in deciduous forest- edge biociation 



of North America, 297 

 of birds, 297-298 

 of mammals, 297-298 

 of reptiles, 297-298 

 in serai stage communities too 



wide for definition of biome, 



276 

 life- zone system of, 272, 274 

 new approaches to study of, 274- 



276 

 of aquatic organisms, knowledge of 



Great Lakes necessary to under- 

 standing of, 288 

 of Arcto- tertiary flora, 282 

 of coastal chaparral, 312 

 of coniferous forests, 301 

 of deserts, 332 



of grassland in North America, 325 

 of marine tropical fauna, 370 



Distribution (Continued) 

 of mixed biocies in southeastern 



North America, 298 

 of organisms in large geographic 



units and problem of geographic 



ecology, 268 

 of organisms into realms and 



regions, best system of, 268-269 

 of petran bush, 312 

 of plant associations of North 



America, 302 

 of plant species, concept of 



biociation as useful for analysis 



of, 276-279 

 of temperature, deciduous forests, 



293 

 of tropical biomes, 340 

 of vegetation in deciduous forest 



biome, 293-294 

 of species over wide area and 



genetic diversification, 261-262 

 of tundra species in post- Pleisto- 

 cene era, 317 

 of woodland, 311 

 restricted in climax communities, 



276 

 summary of aspects of two sets of 



factors controlling, 279 

 Diurnal Animals (see also Diurna- 



tion): 

 birds as, 99-100 

 color vision in, 101 

 in tropical rain forests, 349 

 major period of activity of, 100-101 

 Diurnation {see also Diurnal 



Animals): 

 as reducer of competition: 

 among birds, 247 

 among butterflies, 247 

 between white and black crappie, 



247 

 Dominance (see also Dominants; 



Predominants): 

 as exerted through plant reaction, 



163 

 defined in communities, 18-19 

 expressed through "coaction," 19 

 in balanoid-gastropod-thallophyte 



biome of sea, 364 

 in pelecypod-annelid biome of 



sea, 366 

 in Sargasso Sea, 359 

 lack of in streams, 43 

 reversal of because of temperature 



changes, 246 

 Dominants {see also Dominance; 



Predominants): 

 fifty per cent rule. 29 

 as key to recognition of communi- 

 ties, 27 

 as modifiers of effect of environ- 

 ment for other organisms in 



community, 7 



Dominants (Continued) 

 bison as examples of, 7 

 changes in as affecting community, 



21 

 chestnut blight as example of, 19 

 defined. 18-19 

 in coral reef biome, 367 

 in deserts, large number of dif- 

 ferent life-forms among, 332 

 in temperate deciduous forest 



biome, 293-94 

 life- forms of as determining 



biome, 276 

 of Eurasian plant associations, 307 

 perennial grasses as in climax 



grassland, 325 

 plant, as key to recognition of 



ecesis, 161-162 

 plant, as most important climax 



species on land, 276 

 plant, disregarded by biociation 



concept in establishing divisions 



of biome for animals, 276-279 

 shifts in due to geologic succession, 



24-26 



Ecad, defined. 7 

 Ecesis: 



absolute growth rate in, defined, 

 160 



and plotting of sigmoid curve, 

 160-161 



and relation to dispersal, 159 



defined, 159, 162 



environmental factors influencing 

 rate of growth in, 161 



factors causing inhibiting phase of 

 growth in, 161 



favorable conditions for, 159 



following of logistic curve in at 

 every level of species organi- 

 zation, 161 



growth of populations in as follow- 

 ing sigmoid or logistic curve, 

 159-160 



instantaneous growth rate in, 

 defined, 160 



of plant communities, rate of more 

 rapid than in animal communi- 

 ties, 161-162 



population growth curves in and 

 productivity yield, 207-203 



symmetry in rate of growth of 

 populations in, 160 



temporary nature of with migrant 

 species, 159 

 Ecological Classification: 



basis for: 

 characteristic species as, 20 

 cyclic species as, 20 



414 Index 



