BIOLOGICAL DEATH AND REPRODUCTION 



However during the process of synthesis errors will 

 occasionally take place. Such errors must be expected 

 to occur at random intervals. They are events caused 

 by the occasional energetic particles which, in accord- 

 ance with probability considerations, will at times 

 appear at the prevailing temperature level. Errors will 

 also result from such causes as incident radiation of 

 sufficient quantum energy and from external chemical 

 and physical agents. These "errors" generally lead to 

 structures which either are unable to function, or are 

 at least less effective than the original. These "error 

 products" will consequently in time succumb to the 

 action of the Second Law. Yet at times some of these 

 "errors" can produce biological material of such a type 

 of organization as can maintain and re-synthesize itself 

 in a given environment more effectively than the orig- 

 inal. Such an "error product" then becomes the ances- 

 tor of a new strain of living material. In organisms, 

 such an error of synthesis is called by the biologist, a 

 mutation. 



Now this process is sufficiently effective in the virus, 

 which is essentially only a single molecule, where a 

 change in structure anywhere is a change in the nature 

 of the entire individual. But in a cell one deals with a 

 multitude of molecules. Any one of these is subject to 

 random change by the very same agents that have been 

 enumerated. Now one can see that here such a random 

 change does not as much affect the nature of the entire 



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