Protozoal

Protozoa are a diverse group of unicellular eukaryotic organisms, many of which are motile. Originally, protozoa had been defined as unicellular protists with animal-like behavior, such as predation and mobility. The term protozoa was coined in 1818 by zoologist Georg August Goldfuss, as the Greek equivalent of the German Urthiere, meaning "primitive, or original animals". Protozoa were regarded as the partner group of protists to protophyta, which have plant-like behaviour, such as photosynthesis.

Characteristics

Protozoa, as traditionally defined, range from 10 to 52 micrometers in size. They are eukaryotes, meaning they have a true nucleus that houses their DNA. Most protozoa are heterotrophic, obtaining food by eating other organisms. Some are autotrophic, producing their own food via photosynthesis. Protozoa reproduce asexually and some also have the ability to reproduce sexually.

Classification

Protozoa have traditionally been divided into several groups based on their mode of locomotion: the flagellates, the amoebae, the ciliates, and the sporozoans. However, modern molecular biological techniques have shown that these groups are not monophyletic. As a result, the higher taxonomic structure of the protozoa has been hotly debated.

Disease

Some protozoa are human parasites, causing diseases such as malaria (caused by Plasmodium), amoebiasis, giardiasis, toxoplasmosis, cryptosporidiosis, trichomoniasis, Chagas disease, leishmaniasis, African trypanosomiasis (sleeping sickness), Acanthamoeba keratitis, and primary amoebic meningoencephalitis (naegleriasis).

See also

• Amoeba
• Ciliate
• Flagellate
• Sporozoan
• Malaria
• Amoebiasis
• Giardiasis
• Toxoplasmosis
• Cryptosporidiosis
• Trichomoniasis
• Chagas disease
• Leishmaniasis
• African trypanosomiasis
• Acanthamoeba keratitis
• Primary amoebic meningoencephalitis

Protozoal Resources
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