CONTENTS
| chapter | page | |
|---|---|---|
| Foreword to Teachers | [7] | |
| I. | Some Reasons for the Study ofBiology | [15] |
| II. | The Environment of Plants andAnimals | [19] |
| III. | The Interrelations of Plants andAnimals | [28] |
| IV. | The Functions and Composition ofLiving Things | [47] |
| V. | Plant Growth and Nutrition—TheCauses of Growth | [58] |
| VI. | The Organs of Nutrition inPlants—The Soil and its Relation to Roots | [71] |
| VII. | Plant Growth andNutrition—Plants make Food | [84] |
| VIII. | Plant Growth and Nutrition—TheCirculation and Final Uses of Food by Plants | [97] |
| IX. | Our Forests, their Uses and theNecessity of their Protection | [105] |
| X. | The Economic Relation of Green Plantsto Man | [117] |
| XI. | Plants without Chlorophyll in theirRelation to Man | [130] |
| XII. | The Relations of Plants toAnimals | [159] |
| XIII. | Single-Celled Animals considered asOrganisms | [166] |
| XIV. | Division of Labor, the Various Formsof Plants and Animals | [173] |
| XV. | The Economic Importance ofAnimals | [197] |
| XVI. | An Introductory Study ofVertebrates | [232] |
| XVII. | Heredity, Variation, Plant and AnimalBreeding | [249] |
| XVIII. | The Human Machine and itsNeeds | [266] |
| XIX. | Foods and Dietaries | [272] |
| XX. | Digestion and Absorption | [296] |
| XXI. | The Blood and itsCirculation | [313] |
| XXII. | Respiration and Excretion | [329] |
| XXIII. | Body Control and HabitFormation | [348] |
| XXIV. | Man's Improvement of hisEnvironment | [373] |
| XXV. | Some Great Names inBiology | [398] |
| APPENDIX | [407] | |
| Suggested Course with Time Allotmentand Sequence of Topics for Course beginning in Fall | [407] | |
| Suggested Syllabus for Course inBiology beginning in February and ending the Next January | [411] | |
| Hygiene Outline | [415] | |
| Weights, Measures, andTemperatures | [417] | |
| Suggestions for LaboratoryEquipment | [418] | |
| INDEX | [419] | |
A CIVIC BIOLOGY
I. THE GENERAL PROBLEM—SOME REASONS FOR THE STUDY OF BIOLOGY
What is Biology?—Biology is the study of living beings, both plant and animal. Inasmuch as man is an animal, the study of biology includes the study of man in his relations to the plants and the animals which surround him. Most important of all is that branch of biology which treats of the mechanism we call the human body,—of its parts and their uses, and its repair. This subject we call human physiology.
Why study Biology?—Although biology is a very modern science, it has found its way into most high schools; and an increasingly large number of girls and boys are yearly engaged in its study. These questions might well be asked by any of the students: Why do I take up the study of biology? Of what practical value is it to me? Besides the discipline it gives me, is there anything that I can take away which will help me in my future life?
Human Physiology.—The answer to this question is plain. If the study of biology will give us a better understanding of our own bodies and their care, then it certainly is of use to us. That phase of biology known as physiology deals with the uses of the parts of a plant or animal; human physiology and hygiene deal with the uses and care of the parts of the human animal. The prevention of sickness is due in a large part to the study of hygiene. It is estimated that over twenty-five per cent of the deaths that occur yearly in this country could be averted if all people lived in a hygienic manner. In its application to the lives of each of us, as a member of our family, as a member of the school we attend, and as a future citizen, a knowledge of hygiene is of the greatest importance.
Relations of Plants to Animals.—But there are other reasons why an educated person should know something about biology. We do not always realize that if it were not for the green plants, there would be no animals on the earth. Green plants furnish food to animals. Even the meat-eating animals feed upon those that feed upon plants. How the plants manufacture this food and the relation they bear to animals will be discussed in later chapters. Plants furnish man with the greater part of his food in the form of grains and cereals, fruits and nuts, edible roots and leaves; they provide his domesticated animals with food; they give him timber for his houses and wood and coal for his fires; they provide him with pulp wood, from which he makes his paper, and oak galls, from which he may make ink. Much of man's clothing and the thread with which it is sewed together come from fiber-producing plants. Most medicines, beverages, flavoring extracts, and spices are plant products, while plants are made use of in hundreds of ways in the useful arts and trades, producing varnishes, dyestuffs, rubber, and other products.
Bacteria in their Relation to Man.—In still another way, certain plants vitally affect mankind. Tiny plants, called bacteria, so small that millions can exist in a single drop of fluid, exist almost everywhere about us,—in water, soil, food, and the air. They play a tremendous part in shaping the destiny of man on the earth. They help him in that they act as scavengers, causing things to decay; thus they remove the dead bodies of plants and animals from the surface of the earth, and turn this material back to the ground; they assist the tanner; they help make cheese and butter; they improve the soil for crop growing; so the farmer cannot do without them. But they likewise sometimes spoil our meat and fish, and our vegetables and fruits; they sour our milk, and may make our canned goods spoil. Worst of all, they cause diseases, among others tuberculosis, a disease so harmful as to be called the "white plague." Fully one half of all yearly deaths are caused by these plants. So important are the bacteria that a subdivision of biology, called bacteriology, has been named after them, and hundreds of scientists are devoting their lives to the study of bacteria and their control. The greatest of all bacteriologists, Louis Pasteur, once said, "It is within the power of man to cause all parasitic diseases (diseases mostly caused by bacteria) to disappear from the world." His prophecy is gradually being fulfilled, and it may be the lot of some boys or girls who read this book to do their share in helping to bring this condition of affairs about.