The Strangest Things in the World: A Book About Extraordinary Manifestations of Nature
9781465669193
213 pages
Library of Alexandria
Overview
There may be as many as twenty-five million invisible plants and animals in a gram of soil about the size of a grain of sand. It would take a thousand such grains to make a marble. The population of this microscopic jungle is composed chiefly of single-celled organisms—bacteria, molds, yeasts and protozoa. Total numbers vary enormously—from time to time and place to place—chiefly because of variations in the food supply. Although thousands of species have been identified, the greater part of soil life still remains unknown. This jungle is a place of the hunter and the hunted—of an incessant and merciless struggle for survival. Invisible plants eat invisible animals and invisible animals eat invisible plants. Plants devour other plants and animals devour other animals. Giants of this nether world—largely invisible, although the average size is more than a thousand times that of the bacteria—are thread-like white worms from a hundredth to a fifth of an inch long. Relatively they are not very plentiful—less than six million to a cubic foot of soil in most places. In both size and numbers in the earth population, they are like elephants compared to mice. Still they probably are numerically the most abundant of all animals which consist of more than a single cell. In the entire animal kingdom only the protozoa outnumber them. These creatures are the nematodes, or eel worms. About ten thousand kinds have been described; there are probably as many more unknown to zoologists. Less than a hundred of these varieties cost American farmers and gardeners more than half a billion dollars a year. The rest of those species living in the soil are, so far as known, harmless or even slightly beneficial. Seas and fresh waters are full of other kinds. Still others, some very much larger than the soil organisms, are among the most dangerous parasites of animals and men. The little soil worms, in the opinion of Dr. Geoffrey LaPage of Cambridge University, “must be considered one of the major menaces of our civilization.” Although always invisible, the activities of these countless billions of organisms underfoot can be measured in various ways. For example, carbon dioxide is constantly escaping from the surface of the ground. This comes from the breathing of the unseen animals and plants. Measurement of the gas outflow gives a rough estimate of how many are present. It shows that the numbers vary greatly from hour to hour. The soil organisms are relatively immune to heat and cold, flood and drought. Even when a grain of soil has been made absolutely dry in the laboratory and then crushed to a very fine powder, they still remain. If it is placed in a sterile container filled with some fermentable material, a seething mass of microörganisms will appear in a few hours.
