100 



BIOLOGY FOR BEGINNERS 



process is, however, a destructive one as far as food and tissue are 

 concerned and necessitates excretion in order* to remove the waste. 



/too t r/ CAT i ON of FUNCTION 



FIG. 27. Modification of Function in Plant Parts. 



The circles at the left represent the usual parts of the plant, those at the 

 right, the forms into which they may be modified, to perform the functions 

 named. 



The usual function is connected with its plant part by a heavy line; those 

 less frequent by lighter lines. Thus the roots' normal function is absorption, 

 but it may be modified to form tendrils, spines, leaf supports, or for storage, as 

 the lines show. 



This diagram is intended to show the wide range of adaptation of struc- 

 ture to function. 



SUMMARY 



1. Photosynthesis. 



The manufacture of starch from carbon dioxide and water. 



2. Digestion. 



Making the food soluble by means of plant enzymes, such as, 

 Diastase j acting on sugars an( j starches. 



Lipase, acting on fats. 

 Pepto-trypsin acting on proteids. 



