How long does a paramecium live?
The paramecium is a one celled protozoan, so small we need a micro¬scope to recognize him. He is a sophisticated cousin of the blobby little amoeba and kind of king in the humble world of the protozoa. But in spite of his small size, in one r6spect the paramecium is superior to us. He has discovered, you might say, the Fountain of Youth, for, barring accidents, he is immortal
The sizeable animals multiply, handing on life to their children, and finally die. The bigger animals, such as the elephant, tend to have longer life spans than the smaller animals, such as the frog. The tiny paramecium, however, does not. have a life span. He perishes only when food runs out, when his stream dries up or when he meets acme other accident.
If all goes well this tiny animal can live a hundred, a thousand or even a million years. The secret of his immortality is in the way he multiplies. He does not produce children and grow old. He multi¬plies by dividing into a pair of youthful twins. The amoeba and other protozoa also multiply in this way and they, too, can be immortal.
The paramecium, alias, the slipper animalcule, is shaped like the sole of a shoe. A row of 300 paramecia, plural, measure about an inch. Like the amoeba, he is a one celled blob. of protoplasm. But unlike the amoeba, he is coated with a firm outer layer. This gives him a permanent shape. He cannot flow along, as the amoeba does, like a blob of jelly.
The outside of the paramecium is covered with stubby threads which give him a furry look. The threads are called cilia and by waving them he can swim quite briskly through the water. He has a fixed mouth opening and a gullet.
His food is digested in the granular protoplasm inside. The cell also contains two nuclei which carry on the life processes of the tiny creature.
When time comes to multiply, the nuclei stretch and break apart: The cell also lengthens and breaks apart, each half taking its share of the nuclei. The original paramecium is now a pair of identical twins of equal age. There are no parents left behind to grow old and die. Each twin will go off on his own to feed and grow. When he reaches a state of bursting health, he will multiply and he will do this by dividing into a pair of twins. Barring accidents, the paramecia can keep up this`multiplication by division until, as they say, the seas run dry.
Sometimes a pair of paramecia will link together for perhaps 36 hours. In the process, they will swap some of their nuclear material. When they separate, each paramecium will divide several times in a few hours. Instead of two, we get four, eight or sixteen paramecia all identical.