THE MOST PRIMITIVE FORMS OF LIFE 



could it have been possible for some of that living mat- 

 ter to draw on its living surroundings for material 

 with which to build its structure. Plant life is remark- 

 able for the further development of the originally 

 necessary property of living matter to synthesize its 

 structure from relatively simple compounds. Many 

 plants even now do not depend upon compounds of 

 intermediate complexity to build their substance, but 

 are able to do so from very simple starting materials. 

 In plants extropy is consequently locally increased at 

 the expense of energy absorption from sunlight. The 

 over-all effect is consequently in accord with the Sec- 

 ond Law of Thermodynamics. 



Animal life however depends upon the availability 

 of comparatively complex substances, which being of a 

 high extropy level cannot persist for long unless con- 

 stantly replenished by synthesis from simpler sub- 

 stances. Plant life is consequently an indispensable 

 prerequisite for the existence of animal life of the type 

 familiar to us. This basic dependence of animal life 

 upon the flourishing of plant life is ultimately predi- 

 cated upon its inability to utilize simple compounds to 

 build its own structure. This consideration is of greater 

 fundamental significance than the well-recognized and 

 more frequently discussed metabolic interchange that 

 exists between the two branches of living matter. 



The breaking down and utilization of complex ma- 

 terials for the building of biological structures makes a 



23 



