48 THE ORIGIN AND EVOLUTION OF LIFE 



presence iii the sun and stars of the metallic elements. Before 

 passing to the properties of these and other life elements let us 

 consider how lifeless energy is transformed into living energy. 



Primordial Environment — Electric Energy and the 



Sun's Heat 



As remarked above, in the change from the lifeless to the 

 life world, the properties of the chemical life elements become 

 known as the fimctions of living matter. Stored energy becomes 

 known as nutriment or food. 



The earliest function of living matter appears to have been 

 to capture and transform the electric energy of those chemical 

 elements which throughout we designate as the '4ife elements." 

 This function appears to have developed only in the presence 

 of heat energy, derived either from the earth or from the sun 

 or from both; this is the first example in the life process of 

 the capture and utiKzation of energy wherever it may be found. 

 At a later stage of evolution life captured the light energy of 

 the sun through the agency of chlorophyll, the green coloring 

 matter of plants. In the final stage of evolution the intellect 

 of man is capturing and controlling physicochemical energy in 

 many of its forms. 



The primal dependence of the electric energy of life on the 

 original heat energy of the earth or on solar heat is demon- 

 strated by the universal behavior of the most primitive organ- 

 isms, because when the temperature of protoplasm is lowered to 

 o° C: the velocity of the chemical reactions becomes so small 

 that in most cases all manifestations of life are suspended, 

 that is, Hfe becomes latent. Some bacteria grow at or very 

 near the freezing-point of water (o° C.) and possibly primordial 

 bacteria-like organisms grew below that point. Even now the 



