604 



TEXTBOOK OF BOTANY 



r'^ 



;s 





^/VX-, 



Algae 



Blue-greens 



Greens 



Desmids 



Diatoms 



/ etc 



Water fleasA, Larger /^>X ^.l^ZZ' 



/°"Mother water :>^^; 

 animals 



Fig. 273. Food relations of aquatic lite. No matter how long the chain 

 is from Algae to fish, the fundamental food organisms are the algae that 

 inorganic materials into foods. Courtesy of World Book Co. 



of animals 

 transform 



Fig. 274. A diagrammatic representation of the dependence of Esquimaux on 

 diatoms. Assume that each organism obtains only 10 per cent of the food consumed 

 by the preceding one in the chain, and compute the amount of diatoms necessary 

 for a gain in weight of 1 pound in an Esquimau boy. 



