INTEGRATION OF AGGREGATIONS 83 



den, and farm, affecting the food of grain- and fruit-eating birds and 

 mammals and of man himself. These are finally checked by the sub- 

 sequent increase in predaceous insects and birds that live on garden 

 and orchard pests, and the rough biotic balance characteristic of 

 animal and plant communities in nature thus tends to be restored. 



These instances are enough to illustrate the interdependence and 

 general type of organization of an animal community of which man 

 is a dominant element. The removal or introduction of animals, 

 whether by accident or by purposive action by man, may upset the 

 whole equilibrium, as has happened with the introduction of rabbits 

 into Australia. 



A similar organization has long been recognized to exist in animal 

 communities of which man is only a minor part, or perhaps no part 

 at all. This type of organization has been called by J. Arthur Thomp- 

 son the "web of life." Frequently the food relationships are the most 

 easily demonstrated in a group of this kind. A partial idea of the 

 complexity of such organization is given by a consideration of the 

 food relations of the black bass as summarized from Forbes' excel- 

 lent essay on "The Lake as a Microcosm." 



INTEGRATION OF THE BLACK-BASS COMMUNITY 



The organization of animal communities is more marked in the 

 case of inhabitants of small bodies of water than of equal bodies of 

 land, since conditions tend to isolate such aquatic animals and since, 

 through long evolution, they have become closely integrated and 

 highly independent of the newer societies of the land. The hfe in 

 such a body of water represents an islet of older, lower life in the 

 midst of the higher, more recent life of the surrounding region. It 

 forms a microcosm, a little world in itself. The play of Hfe is full, but 

 on a smaller scale and less confusing to observe. 



In such a community one can see fully illustrated the degree of 

 sensitivity characteristic of an organic complex, which has just been 

 demonstrated for a man-dominated community. Whatever affects 

 one species must have its influence on the whole assemblage. It thus 

 becomes apparent that it is impossible to study any one animal 

 completely if it be out of its relations to other animals and to plants. 



