Animal-like protists can be categorized into four major phyla, which are characterized by how the organisms move. Zooflagellates move by wiggling their flagella (tiny extensions). Sarcodines move with their extensions of cytoplasm, much like a fish. Ciliates move by beating their cilia. Sporozoans cannot move.

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Since they destroy living cells of organisms, some **animal-like protists** can cause many nasty diseases. *Plasmodium* species, transmitted mainly by mosquitoes, can cause infections such as malaria; *Trypanosoma,* transmitted by flea, causes African or American sleeping sickness; *Entamoeba* causes severe dysentery; *Giardia* causes digestive problems.

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The **macronucleus** contains many replicas of genes that are used by the cell for its everyday processes– like a *working library* of genes. Micronucleus, on the other hand, contains only one copy of entire genetic information that is used as a *reserved copy* of the cell.

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Some phyla of animal-like protists live peacefully with other organisms. They are said to live symbiotically, meaning the organisms both benefit from living together. Animal-like protists play an important role in the environment by decomposing dead organic matter, helping other organisms to feed, and being a primary food source for other small organisms.

Zooflagellates move by wiggling their flagella. Ciliates move by beating their cilia. Most zooflagellates live inside other organisms while ciliates are free-living organisms.

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*Plasmodium* species cause a disease called **malaria**. Malarial infection can be transmitted from one person to another through a female mosquito vector. The infected female mosquito will continue to feed on any available individual thus causing a number of infections in certain areas or populations.

When the infected mosquito bites, the spores enter the bloodstream of the host, where *Plasmodium* species multiplies, causing severe fever and red blood cells to burst, if left untreated– this can cause death.

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