Paramecium caudatum - your first friend from the microworld
Paramecium caudatum is perhaps one of the first protozoans that a young naturalist would explore. These organisms live in fresh standing water. They can also be found in an aquarium, especially if it hasn’t been cleaned for a long time. My ciliate-shoes were taken from the aquarium. Of course, there are only a few ciliate-shoes in aquarium water – the possibility of finding one of them in your microscope’s eyepiece is extremely low. Therefore, we need to increase their concentration. To do so, take a jar (about 17 fluid ounces or 0.5 liters), fill it with aquarium water, put a small spoiled onion and banana peel inside. Put the jar in a warm dark place for 5 to 7 days (don’t close it with a lid).
Paramecium caudatum. Animation. Magnification: 64x.
The average size of Paramecium caudatum is 0.02 inches (0.5 mm). For locomotion Paramecium caudatum uses its cilia (about 15 thousand cilia cover its little body!). Moreover, it has two nuclei (a large macronucleus is responsible for nutrition, respiration, metabolism, etc.; and a small micronucleus – for reproduction). Paramecium caudatum feeds on bacteria or algae. The food is caught by an oral groove covered in cilia and then goes to the cell mouth. It is then digested in the digestive vacuole (gullet). Undigested leftovers are ‘thrown out in the open’ through an anal pore (cytoproct). To remove all excess water, our heroine has two contractile vacuoles. They work like pumps on a boat, pumping excess water out of its body. Paramecium caudatum maintains its slipper-like shape thanks to a special membrane (pellicle).