12 



Table ]. — The Dynamic Relations of Animal Activities 



Processes of Activity 



This unstable internal 

 condition tends towards 

 change, resulting in — • 



(1) New conditions; 



(2) Movement; 



(3) The processes of 

 hehavior: trial, experi- 

 ment, investigation, etc. 



Froducts of 

 Activity 



New states. 



Movement. 



Response. 



Regulation. 



Adjustment. 



Relative equilib- 

 rium. 



Learning. 



Orientation. 



Data. 



Concepts. 



Explanation. 

 j Theory. 

 I Hypotheses. 

 I Ideals. 



The Animal as an Agent 

 (Activity of an Agent) 



The animal as an agent transfomia 

 energy and substance by its metal)- 

 olic processes. These are acc(un- 

 panied by physiological conditions 

 or states; they constitute a condi- 

 tion of unstable equill)rium. The 

 transformations take place as — 



(1) Continuous and irreversible 

 processes, as development, differen- 

 tiation, etc.; or arc — 



(2) Periodic or rhythmic proc 

 esses, as digestion sexual activity, 

 etc. 



Changes in the internal conditions 

 are produced also by external stim- 

 uli. 



The responses of animals to the conditions in which they live are 

 of a composite character. Certain responses, such as the chirping re- 

 sponse of a coot within the tgg, are inherited and are relatively auto- 

 matic in character ; others are greatly modified by experience, as when 

 an animal "learns," or forms a habit by repeated responses. 



The responses of animals to the conditions of existence are the 

 basis for any study of their relations, not only to other members of 

 their own species, but to all elements, living or otherwise, of their com- 

 plete environment. It is from this standpoint that animals must be 

 considered in estimating their place in the economy of nature; that is, 

 in estimating how they influence one another in an association of ani- 

 mals living together in the same habitat, and in judging of their rela- 

 tion to the succession of animal commimities, and even to man him- 

 self. 



6. THE INTERRElvATlONS OF ANIMALS 



"A group or association of animals or plants is like a single organ- 

 ism in the fact that it brings to bear upon the outer world only the 

 surplus of forces remaining after all conflicts interior to itself have 

 been adjusted. Wliatcver expenditure of energy is necessary to main- 

 tain the existing internal l)alance amounts to so much power locked 

 up, and rendered unavailable for external use." — S. A. Forbes. 



We have now seen the dependence of the animal upon its environ- 

 ment, as this forms the basis for an understanding of conditions in- 

 volved in the problem of uiaiutcnancc or the upkeep of the animal. 

 The optimum conditions for prolonged maintenance produce the vital 



