15/5 ADAPTATION IN ITERATED AND SERIAL SYSTEMS 



• • 



B 



Figure 15/4/1. 



the two might be that shown in Figure 15/4/2. Such an arrange- 

 ment would be shown functionally by any organism that deals 

 with its environment by several independent reactions. Such a 

 whole will be said to consist of iterated systems. 



Environment. 



Animal 



Figure 15/4/2 : Diagrammatic representation of an animalof eight variables 

 interacting with its environment as five independent systems. 



S. 13/10 exemplified the argument applicable to such a ' whole \ 

 If i is the number of subsystems that are at a state of equilibrium 

 at any particular moment, then in an iterated set i cannot fall, 

 and will usually rise. As subsystem after subsystem reaches 

 equilibrium so will each stay there ; and thus the whole will change 

 cumulatively towards total equilibrium. 



15/5. Whether the feedbacks in Figure 15/4/2 are first order or 

 second (S. 7/5) is here irrelevant: the whole still moves to equili- 

 brium progressively. Thus, if each subsystem has essential 

 variables and step-mechanisms as in Figure 7/5/1, the stability 

 of the second order will develop as in S. 7/23; and thus the 

 adaptation of the whole to this environment will also develop 

 cumulatively and progressively. 



In this case, the processes of learning by trial and error will 

 go on in one subsystem independently of what is going on in the 

 others. That such independent, localised learning can occur 

 within one animal was shown by Parker in the following experi- 

 ment: 



4 If a sea-anemone is fed from one side of its mouth, it will 



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