Hillsborough Community College - Phylums Sarcodina/Rhizpodoa

The Protozoa are a large and diverse group of unicellular, eukaryotic organisms, some of which are parasites. Their classification or division into groups is based on the types of locomotion in the mature stage. A typical life cycle includes a vegetative trophozoite and a resting cyst stage.

The Phylum Sarcodina or Rhizopoda consists of amoeboid protozoans that use long cytoplasmic processes called pseudopodia (“false feet”). The motility results from the streaming of protoplasm that forms the processes.

Amoeba and Entamoeba are common examples of this group. They feed by taking nutrients into the cell by diffusion and packaging it into food vacuoles. Entamoeba causes amoebiasis or amoebic dysentery, a disease common in areas with poor sanitation. Cysts are ingested in contaminated food and water and develop into trophozoites, which invade the mucosa of the large intestines producing ulcers accompanied by dysentery. Trophozoites can be found in erythrocytes and feces of an infected person.