Behavior Pattern{s) (Couthiiicd) 

 exhibited by lake organisms to 

 decrease specific gravity of 

 body, 60 

 exogenous, periodic activity as: 

 inheritance of through chromo- 

 somal clues, possibility of, 251 

 inherited, as factor in responses 



to environment, 13, 15 

 in orientation to changes in envir- 

 onment, 12-13 

 in response to stimuli, 13, 14 

 motility as consideration in changes 



in, 7 

 new, acquiring of as factor in 



dispersal to new habitats, 150 

 of poikilotherms in maintaining 



constant conditions, 98 

 of stream animals; 

 in orientation to environment, 50, 



53 

 in respiration, 51-52 

 in response to bottom of stream, 



50-51 

 in response to stream size, 52 

 preadaptation to niche as advantage 



in competition, 250-251 

 transmission of by tradition rather 



than genetics, 251 

 trial and error in dispersal and 

 establishment of, 148 

 Benthos (see Biocies; Biocies, Lake; 

 Biocies, Pond- Marsh; Lakes; 

 Sea) 

 Bergmann's Rule, 9 

 Biocenose (see Communities) 

 Biociation(s) (see also Deserts; 



Forest(s); Grassland, Tropical 

 Biomes; Tundra): 

 as subdivision of biome, 276-279 

 concept of as disregarding plant 

 dominants in establishing 

 divisions of biome for animals, 

 276-279 

 coniferous forest{s): 

 evolution of separate North 



American and Asian, 307-308 

 location and number of, 302-303 

 North American boreal, 303-306 

 North American montane, 307 

 North American, species in, 302- 

 303 

 deciduous forest(s): 

 Asiatic, 299 

 European, 298-299 

 North American, 295-297 

 defined, 29-30, 30 

 differences of from biotic provin- 

 ces, 279 

 in alpme tundra, 321-323 

 in arctic tundra, 318-321 

 in chaparral, 312-313 



406 Index 



Biociation(s) (Continued) 

 in deserts other than North 



American, 337-338 

 in North American Basin 



sagebrush, 336-337 

 in North American deciduous 



forest- edge, 297-298 

 in North American desert scrub, 



335-336 

 in southeastern North American 



forest, 298 

 in tropical forest biomes, 344 

 in woodland, 311-312 

 Biocies (see also Deserts; Forests; 

 Grassland; Tundra): 

 defined. 29-30, 30, 276-279 

 forest- edge, 129 

 Biocies, Lake (see also Lakes): 

 benthos: 

 described, 66 

 distribution of in littoral zone, 



70-71 

 distribution of in profundal zone, 

 71-73 

 divisions of, 66 

 fish in, anatomical adaptations 



of, 74-75 

 nekton: 

 described. 66 

 position of limnetic species in 



lake, 74 

 segregation of littoral zone 



species, 74 

 shrimp as part of, 73-74 

 neuston, described. 66 

 plankton: 

 composition of, 66-67 

 diel movements of, 67-68 

 effect of annual overturns on 



distribution of, 69 

 effect of rainfall on distribution 



of, 69 

 in small and medium- sized lakes, 



67 

 irregularity of horizontal distri- 

 bution of, 67 

 irregularity of vertical distribu- 

 tion of, 67 

 pulses of distribution of, 69 

 role of in food- cycle of lakes, 74 

 times of maximum distribution 



of, 68-69, 69 

 times of minimum distribution 

 of, 68-69 

 seston, defined. 66 

 Biocies, Pond-Marsh (see also 

 Marsh; Pond(s)): 

 amphibians in, 85-86 

 benthos in: 

 dwellings of, 82 

 factors affecting changes in 

 species of, 82-83 



Biocies, Pond-Marsh (Continued) 

 relation of biomass of to biomass 

 of vegetation, 82 

 birds in, 86 



infraneuston in, composition of, 81 

 insects in: 

 air breathing aquatic, respiration 



of, 84-85 

 terrestrial, 83-84 

 mammals in: 

 beaver, 87 

 mice, 87 

 mink, 86-87 

 muskrat: 

 rice rat, 87 

 shrews, 87 

 plankton in: 

 distribution of, 82 

 species of, 81 

 reptiles in, 86 



supraneuston in composition of, 81 

 terrestrial invertebrates in, 85 

 use of surface film by, 81 

 Biocies, Stream (see also Fish; 

 Streams): 

 lack of indigenous species of in 



sand-bottom pools. 43 

 most characteristic forms of, 

 overwintering of in sand-bottom 



pools, 43 

 plankton in, 43-44 

 plants in, 43 

 pond animals in, 43 

 Biomass (see also Measurement of 

 Populations; Populations): 

 accurate computation of, 85 

 and net production of a generation 



of animal species, 204 

 and productivity values, 206 

 and reproduction of protozoa and 



bacteria, 177 

 as index to trophic levels, 198- 



199 

 as unaccumulated in balanced 



trophic levels, 206-207 

 determining of to measure popula- 

 tions, 31 

 increase in with growth of indi- 

 viduals, 202 

 in lakes: 

 and productivity of benthos, 76 

 and productivity of plankton, 76 

 of benthos, 75, 75-76 

 of plankton, 75, 75-76 

 in ponds: 

 as affected by food habits of fish 

 species, 91 

 as varying with fertility of pond, 



90-01 

 harvest of as key to productivity 



of fish, 91 

 of benthos and vegetation, 82 



