A Civic Biology, Presented in Problems. George W. Hunter
to find living there the hardy stunted plants of the arctic region. Nor would we expect to find the same kinds of animal life in warm regions as in cold. The surroundings determine the kind of living things there. Plants or animals fitted to live in a given locality will probably be found there if they have had an opportunity to reach that locality. If, for example, temperate forms of life were introduced by man into the tropics, they would either die or they would gradually change so as to become fitted to live in their new environment. Sheep with long wool fitted to live in England, when removed to Cuba, where conditions of greater heat exist, soon died because they were not fitted or adapted to live in their changed environment.
Plant life in a moist tropical forest. Notice the air plants to the left and the resurrection ferns on the tree trunk.
Adaptations.—Plants and animals are not only fitted to live under certain conditions, but each part of the body may be fitted to do certain work. I notice that as I write these words the fingers of my right hand grasp the pen firmly and the hand and arm execute some very complicated movements. This they are able to do because of the free movement given through the arrangement of the delicate bones of the wrist and fingers, their attachment to the bones of the arm, a wonderful complex of muscles which move the bones, and a directing nervous system which plans the work. Because of the peculiar fitness in the structure of the hand for this work we say it is adapted to its function of grasping objects. Each part of a plant or animal is usually fitted for some particular work. The root of a green plant, for example, is fitted to take in water by having tiny absorbing organs growing from it, the stems have pipes or tubes to convey liquids up and down and are strong enough to support the leafy part of the plant. Each part of a plant does work, and is fitted, by means of certain structures, to do that work. It is because of these adaptations that living things are able to do their work within their particular environment.
Plants and Animals and their Natural Environment.—Those of us who have tried to keep potted plants in the schoolroom know how difficult it is to keep them healthy. Dust, foreign gases in the air, lack of moisture, and other causes make the artificial environment in which they are placed unsuitable for them.
A natural barrier on a stream. No trout would be found above this fall. Why not?
A goldfish placed in a small glass jar with no food or no green water plants soon seeks the surface of the water, and if the water is not changed frequently so as to supply air the fish will die. Again the artificial environment lacks something that the fish needs. Each plant and animal is limited to a certain environment because of certain individual needs which make the surroundings fit for it to live in.
Changes in Environment.—Most plants and animals do not change their environment. Trees, green plants of all kinds, and some animals remain fixed in one spot practically all their lives. Certain tiny plants and most animals move from place to place, either in air, water, on the earth or in the earth, but they maintain relatively the same conditions in environment. Birds are perhaps the most striking exception, for some may fly thousands of miles from their summer homes to winter in the south. Other animals, too, migrate from place to place, but not usually where there are great changes in the surroundings. A high mountain chain with intense cold at the upper altitudes would be a barrier over which, for example, a bear, a deer, or a snail could not travel. Fish like trout will migrate up a stream until they come to a fall too high for them to jump. There they must stop because their environment limits them.
A new apartment house, with out-of-door sleeping porch.
Man in his Environment.—Man, while he is like other animals in requiring heat, light, water, and food, differs from them in that he has come to live in a more or less artificial environment. Men who lived on the earth thousands of year ago did not wear clothes or have elaborate homes of wood or brick or stone. They did not use fire, nor did they eat cooked foods. In short, by slow degrees, civilized man has come to live in a changed environment from that of other animals. The living together of men in communities has caused certain needs to develop. Many things can be supplied in common, as water, milk, foods. Wastes of all kinds have to be disposed of in a town or city. Houses have come to be placed close together, or piled on top of each other, as in the modern apartment. Fields and trees, all outdoor life, has practically disappeared. Man has come to live in an artificial environment.
Care and Improvement of One's Environment.—Man can modify or change his surroundings by making this artificial environment favorable to live in. He may heat his dwellings in winter and cool them in summer so as to maintain a moderate and nearly constant temperature. He may see that his dwellings have windows so as to let light and air pass in and out. He may have light at night and shade by day from intense light. He may have a system of pure water supply and may see that drains or sewers carry away his wastes. He may see to it that people ill with "catching" or infectious diseases are isolated or quarantined from others. This care of the artificial environment is known as sanitation, while the care of the individual for himself within the environment is known as hygiene. It will be the chief end of this book to show girls and boys how they may become good citizens through the proper control of personal hygiene and sanitation.
Reference Books
elementary
Hunter, Laboratory Problems in Civic Biology. American Book Company.
Hough and Sedgwick, Elements of Hygiene and Sanitation. Ginn and Company.
Jordan and Kellogg, Animal Life. Appleton.
Sharpe, A Laboratory Manual for the Solution of Problems in Biology, p. 95. American Book Company.
Tolman, Hygiene for the Worker. American Book Company.
advanced
Allen, Civics and Health. Ginn and Company.
III. THE INTERRELATIONS OF PLANTS AND ANIMALS
Problem.—To discover the general interrelations of green plants and animals.
(a) Plants as homes for insects.
(b) Plants as food for insects.
(c) Insects as pollinating agents.
Laboratory Suggestions
A field trip:—Object: to collect common insects and study their general characteristics; to study the food and shelter relation of plant and insects. The pollination of flowers should also be carefully studied so as to give the pupil a general viewpoint as an introduction to the study of biology.
Laboratory exercise.—Examination of simple insect, identification of parts—drawing. Examination and identification of some orders of insects.
Laboratory demonstration.—Life history of monarch and some other butterflies or moths.
Laboratory exercise.—Study of simple flower—emphasis on work of essential organs, drawing.
Laboratory exercise.—Study of mutual adaptations in a given insect and a given flower, e.g. butter and eggs and bumble bee.
Demonstration of examples of insect pollination.
The Object of a Field Trip.—Many of us live in the city, where the crowded streets, the closely packed apartments, and the city playgrounds form our environment. It is very artificial at best. To understand better the normal environment of plants or animals we should go into the country. Failing in this,