CHAPTER LV 





NEW ORGANISMS 



338. Reproduction. One of the common facts about life is 

 that the life of every organism comes to an end sooner or 

 later. Yet the species, 

 or kind, may continue 

 to live for centuries. 

 This is explained, of 

 course, by the fact 

 that new individuals 

 are constantly being 

 produced. The proc- 

 ess by which organ- 

 isms give rise to new 

 individuals is called 

 reproduction. 



The term reproduc- 

 tion carries the idea 

 of a special portion of 



, The cells of this plant multiply by pushing out buds. 



Under certain conditions the protoplasm of a cell 

 divides into two and then four parts, which then can 

 remain inactive for an indefinite time. These resting 

 'cells are called spores 



FIG. 124. Yeast plant 



being separated and 

 developing into an in- 

 dividual. The simplest 



case of which we know is that of a cell division among one- 

 celled plants or animals. When such an organism (for example, 

 a Paramecium, or a Pleurococcus cell, or some bacterium) divides 

 into two, it at the same time reproduces. The number of indi- 

 viduals is thus multiplied by a process of division, or cell fission. 

 Cell division resulting in the multiplication of individuals occurs 

 among nearly all one-celled plants and animals. 



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