Jain Biology ► [01] Biology : Science Of Living Organisms ► 1. Phylum Protozoa:

Posted: 14.09.2009

The cell of these unicellular animals possesses contractile as Well as food vacuoles Digestion is intracellular, i.e.., within the cell. The locomotion is achieved either by temporary pseudopodic as in amoeba or by whiplike flagella as in Euglena, or by cilia (hair-like processes) as in paramoecium, reproduction is normally asexual by binary or multiple fission. Examples: Amoeba, found in the mud of ponds; no definite shape just a mass of protoplasm bounded by a thin membrane with a nucleus in the centre; contractile vacuole is excretory in function.

Paramoecium (slipper anmalcule) has an unchanging and definite slipper-like shape; there are two nuclei—a small one surrounded by a larger one; towards either end of the body there is a contractile vacuole surrounded by a few radiating canals; found in fresh water with decaying vegetation.

Euglena contain chlorophyll as in plant cells (botanists regard them as algae). Due to the lashing movements of the flagellum it moves in water.

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