Protozoa
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A protozoan magnified 60x |
Although all are single-celled, that is about all they have in common: protozoa are an extremely diverse group. Protozoa are included in the animal kingdom because they can move on their own, and because of the wide range of foods that they eat.
Protozoa come in a multitude of shapes and sizes, and many have quite complex physical structures. As a family they are adapted to all sorts of environmental conditions, including those found on the Great Barrier Reef. Although most protozoa live on their own, many live in colonies.
Individual independent protozoa range in size from a species of plankton called Micromonas which is just a micrometer across, to some amoebas, dinoflagellates and ciliates that may be several millimetres in diameter - which is considered large for a single-celled animal.
Free-living protozoa are found wherever there is water:
- in the sea
- in all types of fresh water
- in soil
- many varieties live in colonies, and
- several are parasites.
