33^ 



BIOLOGY AND HUMAN LIFE 



WORMS AND OTHER CONTROLLABLE DISEASE AGENTS 



I. Meaning of term worms; general characteristics 

 Main groups 



Rotifers, or wheel 



animalcules 

 Ringed worms (not 

 disease agents) 



Flatworms 

 Liver fluke 

 Tapeworm 

 Bladder worm 



Roundworms 

 Trichina 

 Hookworm 

 Vinegar eel 



2. Life histories of some parasitic worms 



3. The hookworm (appearance, size, structure) 

 Importance (effects upon host) 



Exhaustion of nutrition ; (poisoning of system) 

 Reproduction 



Eggs and sperms ; embr>'o discharged with feces 

 Entrance to new host 



Through skin ; (contaminated food) 



