Paramecium Dividing

Paramecia are unicellular organisms usually less than 0.25mm in length and covered with minute hair-like projections called cilia. They are characterized by their cilia which are used in locomotion and during feeding. Paramecia feed on bacteria.


Kingdom – Protista
Phylum – Ciliophora
Order – Hymenostomatida
Family -- Paramecidae
Genus – Paramecium
Species – caudatum

Natural Habitat:

Fresh water

Why fresh water?
They take in water by osmosis from the hypotonic environment, bladder-like contractile vacuoles accumulate the excess water from radial canals and periodically expel it through the plasma membrane by contractions of the surrounding cytoplasm.

Interesting characteristics:
Paramecia have 2 nuclei, 1 macronucleus and 1 micronucleus. Some have up to 80 micronuclei!
The organism cannot survive without macronucleus and cannot reproduce without micronucleus.

Reproduction is either by asexual binary fission or occasionally by conjugation (sexual). During binary fission a fully grown organism divides into two daughter cells. Conjugation consists of the temporary union of 2 organisms and the exchange of micronuclear elements. Without the rejuvenating effects of conjugation a paramecium ages and dies. Only opposite mating types, or genetically compatible organisms, can unite in conjugation

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