What Do Protozoa Mean?

The word protozoa is defined as the lowest great division of the animal kingdom. Protozoa are animals that are composed of a gelatinous material. They scarcely show any trace of having distinct organs in the bodies. The Infusoria, the Foraminifera and sponges, along with some other forms of protozoa, belong to this division.

The name protozoa is derived from two words, the prefix proto- and the word zoon, which is the Greek word for animal. Protozoa is a subkingdom or a phylum which comprises the simplest organisms of the animal kingdom. All protozoa are unicellular organisms. They range in size from submicroscopic protozoa to macroscopic protozoa. Most protozoa are free living. However, there are also other species of protozoa which lead commensalistic, mutualistic or parasitic existences.

Protozoa do not have cell walls. They are eukaryotic microorganisms. They are larger in size and more complex than bacteria. Protozoa may cause disease.