TABLE 2-1 Comparison of nichas of fhe 



Factor 



white-footed and deer 



both species of the genus P«iomyicu>. 



P. leucopus noveboracensis 



P. maniculatus bairdii 



Vegetation, substratum or 

 space occupied 



Microclimate 



Food 

 Enemies 



stratum where food found 

 Reproductive site; nesting 

 materials 



Dlel activity 

 Seasonal activity 



Deciduous forest; subterranean, 



terrestrial, arboreal; home 



range 0.12 hectare 

 Shade, rich humus, moderate 



moisture, medium temperature 

 Seeds, nuts. Insects 

 Owls, foxes, weasels, shrews 

 Surface of ground 

 Nests of leaves in burrows, 



logs, stumps, or tree 



cavities 

 Nocturnal 

 Active throughout year 



Sparse grassland; subterra- 

 nean and terrestrial only; 

 home range 0.24 hectare 



Sunlit habitat, low moisture, 

 temperature often extreme 



Seeds, grass, insects 



Owls, foxes, weasels, shrews 



Surface of ground 



Nests of dried grass in bur- 

 rows, crannies, or clumps of 

 grass 



Nocturnal 



Active throughout year 



and in its internal dynamics, succession, and distri- 

 bution. The analysis of the community responses and 

 interrelations of organisms is a major objective of 

 tiiis book. 



SUMMARY 



The environment, or specifically the habi- 

 tat, of an organism consists of the physical conditions 

 that surround it. In order to live in a particular habi- 

 tat, an organism must be morphologically adapted to 

 it. This may be accomplished to a certain extent dur- 

 ing growth, especially in sessile forms, but depends 



mainly on long evolutionary processes of variation 

 and natural selection. I"!<ach organism must also be 

 physiologically adjusted to the various factors of its 

 environment. Species vary in their limits of toler- 

 ance, and those factors in their surroundings that are 

 most immediately unfavorable limit their habitat dis- 

 tribution. In order for an organism to take advan- 

 tage of its morphological and physiological adjust- 

 ments, it must have the proper behavior responses. 

 These inherited and acquired action patterns involve 

 selective orientation in response to environmental 

 stimuli. Occurrence of different species in the same 

 habitat necessitates the establishment of compatible 

 community interrelations. 



The general nature of responses 1 7 



