Protozoa-General characters-Locomotion in Paramecium-IAS-IFoS-PCS-Zoology Mains Exam


Locomotion in Paramecium


🖊 Paramecium shows following two methods of locomotion.

Ciliary movement  and Body contortions

Ciliary movement:

🖊 Cilia are main locomotory organ in paramecium this are fine hair like protoplasmic
processes all over the body

🖊 These are inclined backward and their beating drives the body forward but they may be
directed forward and then their strokes push the body backward.

🖊 The cilia of longitudinal row beat one after the other in a metachronial succession or in a
metachronous rhythm.

🖊 The cilia of transverse row vibrate simultaneously.

🖊 The movement of cilia is controlled by the neuromotor system

🖊 Each oscillation of cilia consists of two stocks, one is effective stock and another is
recovery stock.

🖊 The cilia beat somewhat towards the right sight. as a result the body of paramecium
rotates spirally slightly toward s the left.

🖊 The cilia of oral groove strike more vigorously and obliquely

Body contortions

🖊 The body of Paramecium Caudatum possesses elasticity, it can squeeze itself through a passage narrower than its body, after which the body assumes its normal shape.

🖊 Metaboly is a temporary change in the body, which is brought about in Paramecium by the protoplasm.

General Characters of protozoa

• They are aquatic (fresh and salt water) free living parasitic, symbiotic or commensally.
Usually microscopic with oval, elongated, spherical or ever changing shape
• They show cellular level of organization, where all the activities of the body are
performed by a single cell.
• The protozoan cell body is either naked or surrounded by a non rigid pellicle. Cellulose is
absent in the pellicle.
• Some protozoans secrete shells of various inorganic compounds as external covers.
• They possess different types of locomotory organs.
• They may bear flagella (flagellates), cilia (ciliates) or pseudopodia (scorodines).
• Locomotory organs are absent in the parasitic forms.
• They are holozoic (animal-like) and feed largely on bacteria, microscopic algae and
minute animals such as rotifers or on other protozoan’s including members of their own
• Some are holophytic (plant-like); they contain chlorophyll and prepare their own food by
photosynthesis (Euglena).
• The parasitic protozoans devour on materials obtained from the hosts (Monocystis).
• Some are saprozoic (subsisting on dead organic matter) and saprophytic (feeding on
liquid food).
• The osmotic concentration of cell body (Osmoregulation) is maintained by one or more
contractile vacuoles and these contractile vacuoles are help in excretion.
• The excretory product is ammonia.
• Asexual reproduction takes place by binary fission or budding.
• Sexual reproduction is performed by the fusion of gametes or by conjugation.

• Free living- Euglena (Fig.1), Amoeba (Fig.2), Noctiluca (Fig.3), Paramecium (Fig.4),
Elphidium (Polystomella)

• Parasitic-Monocystis, Entamoeba, Giardia (Fig.5), Plasmodium (Fig.6), Trypanosome, etc




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