Anthony Roth, aged 12 , of Philadelphia, Penn, for his question:
Are there male and female bacteria?
Cats, dogs, rabbits, pigs and fishes all begin life with two parents. A baby turtle may never see either of his parents. Hut every little turtle had a mother and a father, nevertheless. A fish would never recognize his parents. Yet, like ourselves, he had two parents, four grandparents and sixteen great‑grandparents.
The world of microbes, however, does not follow these rules. One bacterium, all by itself, could produce enough bacteria to populate a cheese factory. This is a good place for certain bacteria to be. For, as you know, bacteria turn milk into cheese.
A bacterium is neither male nor female. It doesn’t even get to be a parent. It multiplies by dividing. Which is more than you can do with arithmetic. The minute creature may be no bigger than one twenty‑five‑thousandth part of an inch. But it knows just when to divide into two. The two new cells are exactly alike. They begin to eat and soon grow to be as big as the original cell.
In place of one bacterium, we now have a pair of identical twins. Each of the two bacterium starts life anew. Both are exactly the same age. There are no older parents left behind, no grandparents and no great‑grandparents. If there is plenty of food, air and the right temperature, each twin bacterium will divide and multiply into another pair of twins.
Some bacteria can multiply every fifteen minutes. Some need a whole day, even *hen things are right. Many of them divide and multiply every fifteen minutes when conditions are good. In ten hours, one bacterium could multiply into 1,000 bacteria. In ten more hours this batch could become a million bacteria. In thirty hours there may be a billion and in forty hours there may be a trillion bacteria. All came from the original bacterium.
Bacteria are the animals of the microbe kingdom. Yeasts are the plants of this kingdom of minute midgets. Yeasts do not divide and multiply as the bacteria do. But they do not grow from male and female parents, either. The little yeasts cell multiplies by budding.
The tiny one‑celled yeasts plant grows a still tinier bud. When half grown, the bud seals itself off and grows to full size on its own. It may remain attached to the original cell all its life. But the original cell is a generation older. The yeast cell gets to be a parent. You might call it both a mother and a father.
The newly budded yeast cell soon grows a bud of its own. Often the new generations stay attached to the older ones. A colony of yeast cells may contain many generations.