Question

Paramecium and Corticella are ciliates. Briefly explain how these two organisms differ in:

a) Swimming habits:

b) Body shape:

c) Body flexibility:

Thanks a lot

Answer 1

b) A paramecium is a small one celled (unicellular) living organism that can move, digest food, and reproduce. The paramecium is an oval, slipper shaped micro-organism, rounded at the front/top and pointed at the back/bottom. The pellicle, a stiff but elastic membrane that gives the paramecium a definite shape but allows some small changes. Covering the pellicle are many tiny hairs, called cilia. On the side beginning near the front end and continuing half way down is the oral groove. The rear opening is called the anal pore. The contractile vacuole and the radiating canals are also found on the outside of a paramecium. Inside the paramecium is cytoplasm, trichocysts, the gullet, food vacuoles, the macronucleus, and the micronucleus.

Vorticella Campanula is a microscopic stalked form with an inverted bell-shaped asymmetrical body. Due to the bell-shaped body it is often called bell-animalcule. The largest species is Vorticella campanula, the bell of which measures up to 157 microns in length and 99 microns in width and stalk varies from 53 to 4150 microns in length which is highly contractile.The colour of the animalcule is yellowish, greenish or bluish. The smallest species is V. micro-stoma, which measures about 55 microns in length and 35 microns in width.

a) Vorticella Campanula does not move freely because it is usually found fixed aborally by its long highly contractile stalk. However, with the help of stalk and myonemes, the bell sways to and fro in the surrounding water like a flower in a breeze. The individuals of a group move in their own way. The detached individuals swim freely by means of cilia and are referred to as telotrochs.

The paramecium swims by beating the cilia. The paramecium moves by spiraling through the water on an invisible axis. For the paramecium to move backward, the cilia simply beat forward on an angle.   If the paramecium runs into a solid object the cilia change direction and beat forward, causing the paramecium to go backward. The paramecium turns slightly and goes forward again. If it runs into the solid object again it will repeat this process until it can get past the object.

c) On the exterior lies a membrane that is called the pellicle. The pellicle is both stiff, to provide support and to maintain the shape of the organism, and is flexible, to allow some flexing of the surface. Also on the surface are hundreds of tiny hairs called cilia. The cilia wave back and forth, and act to sweep food particles (bacteria and smaller protozoa) towards the primitive mouth of the organism (the gullet)