This one-celled organism is found in stagnant water into which dead vegetation has fallen, since it feeds on the bacteria which rot these plants. Paramecium are usually about 0.25 mm in size.
This organism has a fairly stiff outer covering called a pellicle, very like the cell wall of a plant cell.
Very fine hairs called cilia cover this surface and move continually, causing the Paramecium to spiral rapidly through the water. These hairs can even beat in the opposite direction so that the organism reverses to avoid obstacles.
There are also cilia lining the gullet. As these hairs move they suck in water and any food floating in the water. This food is surrounded by a food vacuole, enzymes are poured in and the food is digested.
Oxygen enters through the pellicle and carbon dioxide leaves the same way. Wastes leave out of the anal pore. As Paramecium live in fresh water, water tends to flood in and if not removed the organism would burst. To prevent this, two contractile vacuoles gather the water and squirt it to the outside.
Paramecium can reproduce by splitting in two, producing identical offspring. Two Paramecium can also fuse together and swap small nuclei to reproduce sexually.
Make a heading: One-Celled Organisms.
1. Draw a large, labelled diagram of Paramecium . Write its name alongside.
2. In one sentence explain each of these:-
A. How this organism moves
B. How this organism obtains food
C. Where it lives
D. What feeds on it
3. Is this organism more like a plant cell or an animal cell? Explain.