Ill 



KEPKODUCTION 



REPRODUCTION is one of the most charac- 

 teristic and fundamental activities of living 

 things. Almost every organism, plant or an- 

 imal, possesses this power during some period 

 in its life. In a few instances it is lacking, as, 

 for example, in the worker bee, a sterile fe- 

 male, but in the vast majority of plants and 

 animals it is characteristically present. Every 

 species must contain at least certain individu- 

 als concerned with this function, else the spe- 

 cies would become extinct. 



The methods by which reproduction is ac- 

 complished are extremely diverse. In the sim- 

 pler instances the fully grown body of one 

 individual divides into two and thus produces 

 material for two new individuals. Examples 

 of this kind occur among the unicellular an- 

 imals and the simpler multicellular forms 

 such as the corals, worms, and the like. The 

 more complex methods of reproduction are 

 accomplished by means of two kinds of cells, 



