CHAPTER V 

 INTEGRATION OF AGGREGATIONS 



THE COMMUNITY LEVEL OF INTEGRATION 



It is instructive to regard an animal as a physiological system of 

 physicochemical processes in dynamic equilibrium. When this is 

 understood, one is prepared for the definition of an "animal society" 

 or an "ecological animal community" as a system of organisms which 

 is in the process of dynamic equilibration. 



In the case of the animal considered as an organism, the different 

 parts are integrated more or less perfectly into a unit, which has 

 been receiving considerable attention in the last decade in studies on 

 the organism as a whole as contrasted with the study of different 

 parts of organisms. One can readily see that there are highly inte- 

 grated organisms under close control of the nervous system or of 

 hormones, the loss of any major part of which will strongly affect the 

 whole system and frequently will cause death; but, on the other 

 hand, there are the lower organisms much more loosely correlated, 

 where the loss of even a major part of the body causes only tempo- 

 rary inconvenience pending the regeneration of replacement tissues. 

 Many of these more loosely organized animals are so poorly inte- 

 grated that different parts may be in active opposition to each other. 

 Thus, when an ordinary starfish is placed on its back, part of the 

 arms may attempt to turn the animal in one direction, while others 

 work to turn it in the opposite way. With sponges, the pores ad- 

 mitting water to the canal system may be open and the flagella 

 engaged in pumping water into the canals, while the ostia remain 

 closed so that no water can be brought in (Parker, 191 9). On ac- 

 count of its loose integration, the sea anemone may move off and 

 leave a portion of its foot clinging tightly to a rock, so that the ani- 

 mal suffers serious rupture. 



It is to such relatively slack systems that an ecological animal 



81 



