82 



COz 



ECOLOGY 



Atmosphere 



Part II 



CO2 



CO2 



CO2 



f 



CO2 



Photosynthesis C O2 



Bacterial action 

 Decomposition 



Respiration 

 of plants 



\ 



Bacterial action 

 Decomposition 



/Respii 

 of an 



ration 

 imals 



CO2 



Air, water, 

 rocks, soil 



CARBON CYCLE 



Free nitrogen Ng is mode available 

 to plants and animals ifixed) by 

 certain bacteria. Also fixed by 

 lightning and washed to earth. 



N2 fixing 

 soil bacteria 



The processes from free nitrogen to protein 

 are carried on mainly in the ground 



NITROGEN CYCLE 



