INTRODUCTION 



27 



Intermedigte 

 decotDposltion 

 products 



Chlorophyll 

 Sunl'iqbt 



\ ^uniu 



qreen plants 



Respiration 



\ 



formaldehyde 



Livmq ^f Carbohydrates , 

 animals ^ p^ ^5^ (af^d proteins) 



/ 



Dead 

 orqanisms 



Pig, 3. — The carbon cycle as it occurs in living organisms. 



Bacterial 

 decomposition 



Jn-yj/z^Q^ronfa') 



(jropn/c i^aoc/ 



frc/-e^/on 



fi.n/mho/} (COi) 



F^M^/on dfecej)^ 



a An/ma/ 



>)/ ^^^.fs .f ex. , 



Fig. 4. — The metabolic processes of plants and animals as well as the foo^ 

 manufacturing process (photosynthesis). (Redrawn by permission from Wolcott. 

 Animal Biology, published by McGraw-Hill Book Company, Inc.) 



