PROTOZOA 



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2. Economic importance, 



Food, scavengers, soil and rock formation. 

 Producing certain diseases. 

 Amoeba (a very simple protozoan). 



Where found. Appearance. 



Structure. 



Protoplasm, nucleus, lobes, vacuoles, food grains. 

 Paramcecium. (A more specialized protozoan.) 



Where found. Appearance. How distributed. 



Structure. 



Protoplasm, nucleus, cell wall, cilia, "mouth," vacuoles, food grains. 

 Points of advance over amoeba: 

 Fixed shape (cell wall). 

 Cilia for locomotion and food-getting. 

 Definite mouth region. 

 Two definite places for excretion. 

 Reproduction both by fission and conjugation. 



COMPARISON OF THE MEANS OF PERFORMING THE 



Comparison of Fission and Conjugation 

 Fission (increases numbers) Conjugation (increases vitality) 



1. Nucleus divides. 



2. Cell divides. 



3. Growth to adult size. 



1. Union of two individuals. 



2. Complicated nuclear division. 



3. Cross transfer of part of nucleus. 



4. Union of portions of nuclei. 



5. Separation of individuals. 



