REPRODUCTION BY SPORE FORMATION 



253 



brecccl 

 moloL 



mold. 



dx-een. 

 molcL 



Different species of molds form different types of sporan- 

 gia. Compare the different sporangia in the picture. 



Amoebas and certain 

 other protozoans may go 

 into a resting stage simi- 

 lar to spore formation, 

 when conditions are un- 

 favorable. This resting 

 stage in a protozoan is 

 called encystment. 

 Spore formation is not, 

 necessarily, a method of 

 reproduction. It may 

 be a method of protec- 

 tion only. But since 

 such a cell can germi- 

 nate, when brought into 

 favorable conditions, it 

 is usually classed with 

 reproduction. Spallanzani, Pasteur, and Tyndall discovered in 

 their investigations of spontaneous generation that certain micro- 

 organisms were harder to kill than others. It was later found 

 that some are more resistant to a high temperature than others, 

 and that some are spore formers and can resist unusual condi- 

 tions, while others are incapable of forming spores. 



Each of the types of repro- 

 duction described, namely binary 

 fission, budding, and spore forma- 

 tion, is really a type of cell division. 

 Each of the new cells formed is 

 i produced by a single organism. 

 Therefore, it is called asexual 

 (without sex) reproduction, in 

 contrast to sexual reproduction 



Certain sponges reproduce by budding. I* 1 which tWO Organisms take part. 



