Adapting Material for the Needs of Different Readers
Note how Professor Brown has adjusted word choice, sentence length, approach, and tone to present the same basic concept to different readers with different knowledge and interest levels toward the subject.
I
Recent studies have provided reasons to postulate that the primary timer for long-cycle biological rhythms are closely similar in period to the natural geophysical ones and that persist in so-called constant conditions is, in fact, one of organismic response to subtle geophysical fluctuations which pervade ordinary constant conditions in the laboratory. In such constant laboratory conditions, a wide variety or organisms have been demonstrated to display, nearly equally conspicuously, metabolic periodicities of both solar-day and lunar-day frequencies, with their interference derivative, the 29.5 synodic month, and in some instances even the year. These metabolic cycles exhibit day-by-day irregularities and distortions which have been established to be highly significantly correlated with aperiodic meteorological and other geophysical changes.
Emma D. Terracini and Frank A. Brown, Jr., “Periodisms in Mouse Spontaneous Activity Synchronized with Major Geophysical Cycles,” Physiological Zoology, XXV (January, 1962), 27-37.
II
The question of whether living things are sensitive to terrestrial magnetism has undoubtedly fleeted through the minds of innumerable persons since this geophysical factor first became known. But neither the naturalist, observing the behavior of organisms in the field during their continuing responses to the myriads of more obvious physical factors, nor the experimental biologist, casually testing the response of living things to artificial magnetic fields, even very strong ones, found any consistent evidence that living creatures perceived this weak terrestrial force. It is a common observation that animals in nature may come to bear at any given moment apparently all possible compass relations in their bodily orientation; orientation of the normal resting or foraging animal to the horizontal component of the magnetic field would be expected generally to be of no adaptive significance.
Frank A. Brown, Jr., “Responses of the Planarian, Dugesia, and the Protozoan, Paramecium, to Very Weak Horizontal Magnetic Fields,” Biological Bulletin, 123 (October, 1962), 246-281.
III
Familiar to all are the rhythmic changes in innumerable processes of animals and plants in nature. Examples of phenomena geared to the 24-hour solar day produced by rotation of the earth relative to the sun are sleep movements of plant leaves and petals, spontaneous activity in numerous animals, emergence of flies from their pupal cases, color changes of the skin in crabs, and wakefulness in man.
Sample patterns of daily fluctuations, each interpretable as adaptive for the species are illustrated in the figure. Rhythmic phenomena linked to the 24-hour and 50-minute lunar-day period of rotation of the earth relative to the moon are most conspicuous among intertidal organisms whose lives are dominated by the ebb and flow of the ocean tides.
Frank A. Brown, Jr., “Living Clocks,” Science, 130 (December 4, 1959), 1535-1544.
IV
Everyone knows that there are individuals who are able to awaken morning after morning at the same time within a few minutes. Are they awakened by sensory cues received unconsciously, or is there some “biological clock” that keeps accurate account of the passage of time? Students of the behavior or animals in relation to their environment have long been interested in the biological question.
Most animals show a rhythmic behavior pattern of one sort or another. For instance, many animals that live along the ocean shores have behavior cycles which are repeated with the ebb and flow of the tides, each cycle averaging about 12 ½ hours in length.
Frank A. Brown, Jr., “Biological Clocks and the Fiddler Crab,” Scientific American, 190 (April, 1954), 34-37.
V
One of the greatest riddles of the universe is the uncanny ability of living things to carry out their normal activities with clocklike precision at a particular time of the day, month, and year. Why do oysters plucked from a Connecticut bay and shipped to a Midwest laboratory continue to time their lives to ocean tides 800 miles away? How do potatoes in hermetically sealed containers predict astmospheric pressure trends two days in advance? What effects do the lunar and solar rhythms have on the life habits of man? Living things clearly possess powerful adaptive capacities—but the explanation of whatever strange and permeative forces are concerned continues to challenge science.
Frank A. Brown, Jr., “Life’s Mysterious Clocks,” Saturday Evening Post, (December 24, 1960), 18-19.