Pronunciation key ( prō′tə-zō′ə ) |
Pro•to•zo•a
n.pl.
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[Mod.L., pl. of protozoon < Gr. prōtos, first + zōia, pl. of zōion an animal.]
- The phylum of protozoans.
- Phylum classified in the Kingdom Protozoa, which contains microscopic organisms composed of one cell and reproduce through binary fission. They are typically aquatic and include many parasitic forms.
Usually protozoans are microscopic, single-cell organisms, which may be colonial or solitary, free-living or parasitic. They are found in both fresh and salt water, damp soil and sometimes in the bodies of plants and animals. Classification is based on structural specialization for locomotion. In the mid 20th century there were about 15,000 known species.
Among these are the
- Ameboid Protozoa, (Class Rhizopoda) which move about by the extension of pseudopodia (false feet).
- Flagellate Protozoa, (Class Flagellata) locomotion by means of a whiplike extension of protoplasm.
- Spore-forming Protozoa, (Class Sporozoa) parasitic forms lacking organs for locomotion.
- Ciliate Protozoa, (Class Ciliata), locomotion by means of cilia.
—pro′to·zo′an, adj. & n.
—pro′to·zo′ic, adj.
—pro′to·zo′on, n.
| Taxonomic Hierarchy | |
| Kingdom | Protozoa |
| Phylum | Protozoa |
| Direct Children: | |
| Subphylum | Mycetozoa |
| Subphylum | Sarcodina |
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