:' ;; I I . In i i ! i ! ! hi il i ! n I I < lM»(MM*f HJIt III 11 II A Ch fJKOHCK ■''*' niniiiiiiinn i-i '\ III ittiinnTnTn& U ti iiii-i S!»i Mi hi i^m! milt §, p, pU pkarg QH30S nrggTgiTC Lll.,«.l....L^. ..«...— .r^ LCATIOM '' •. •* A * ^» Date Due ^ ^^ - lull 9*32 t8Apr34 t»> W- Lb ' k I. ■■ L. - r-*- -^ K 4 .V^ 4 ^ rii^ .50^011."). ly :^ %0! 'i-'w i.U_3i- >tBI / SLA^ G-uU- L. B. Cat. No. 1 137 1T530 X / Compare the unfavorable artificial environment of a crowded city with the more favorable environment of the country. A CIVIC BIOLOGY Presented in Problems BY GEORGE WILLIAM HUNTER, Pii.D. HEAD OF THE DEPARTMENT OF BIOLOGY, DE WITT CLINTON HIGH SCHOOL, CITY OF NEW YORK. AUTHOR OF "elements OF BIOLOGY," "ESSENTIALS OF BIOLOGY," ETC. AMERICAN BOOK COMPANY NEW YORK CINCINNATI CHICAGO Copyright, 1914, by GEORGE WILLIAM HUNTER. Copyright, 1914, in Great Britain. HUNTER, CIVIC BIOLOGY. W. p. 12 DeMcateb TO MY FELLOW TEACHERS OF THE DEPARTMENT OF BIOLOGY IN THE DE WITT CLINTON HIGH SCHOOL WHOSE CAPABLE, EARNEST, UNSELFISH AND INSPIRING AID HAS MADE THIS BOOK POSSIBLE 17530 FOREWORD TO TEACHERS A COURSE in biology given to beginners in the secondary school should have certain aims. These aims must be determined to a degree, first, by the capabilities of the pupils, second, by their native interests, and, third, by the environment of the pupils. The boy or girl of average ability upon admission to the second- ary school is not a thinking individual. The training given up to this time, with but rare exceptions, has been in the forming of simple concepts. These concepts have been reached didactically and empirically. Drill and memory work have been the peda- gogic vehicles. Even the elementary science work given has resulted at the best in an interpretation of some of the common factors in the pupil's environment, and a widening of the mean- ing of some of his concepts. Therefore, the first science of the secondary school, elementary biology, should be primarily the vehicle by which the child is taught to solve problems and to think straight in so doing. No other subject is more capable of logical development. No subject is more vital because of its relation to the vital things in the life of the child. A series of experiments and demonstrations, discussed and applied as definite concrete problems which have arisen within the child's horizon, will develop power in thinking more surely than any other subject in the first year of the secondary school. But in our eagerness to develop the power of logical thinking we must not lose sight of the previous training of our pupil. Up to this time the method of induction, that handmaiden of logical thought, has been almost unknown. Concepts have been formed deductively by a series of comparisons. All concepts have been handed down by the authority of the teacher or the text; the inductive search for the unkno^\Ti is as yet a closed book. It is unwise, then, to directly introduce the pupil to the method of in- duction with a series of printed directions which, though definite in the naind of the teacher because of his wider horizon, mijan HOfERTY LIBURY 8 FOREWORD TO TEACHERS little or nothing as a definite problem to the pupil. The child must be brought to the appreciation of the problem through the deductive method, by a comparison of the future problem with some definite concrete experience within his own field of vision. Then by the inductive experiment, still led by a series of oral questions, he comes to the real end of the experiment, the conclu- sion, with the true spirit of the investigator. The result is tested in the light of past experiment and a generalization is formed which means something to the pupil. For the above reason the laboratory problems, which naturally precede the textbook work, should be separated from the subject matter of the text. A textbook in biology should serve to verify the student's observations made in the laboratory, it should round out his concept or generalization by adding such material as he cannot readily observe and it should give the student directly such information as he cannot be expected to gain directly or indirectly through his laboratory experience. For these reasons the .laboratory manual has been separated from the text. "The laboratory method was such an emancipation from the old-time bookish slavery of pre-laboratory days that we may have been inclined to overdo it and to subject ourselves to a new slavery. It should never be forgotten that the laboratory is simply a means to the end ; that the dominant thing should be a consistent chain of ideas which the laboratory may serve to elucidate. When, however, the laboratory assumes the first place and other phases of the course are made explanatory to it, we have taken, in my mind, an attitude fundamentally wrong. The question is, not what types may be taken up in the laboratory to be fitted into the general scheme afterwards, but what ideas are most worth while to be worked out and developed in the laboratory, if that happens to be the best way of doing it, or if not, some other way to be adopted with perfect freedom. Too often our course of study of an animal or plant takes the easiest rather than the most illuminating path. What is easier, for in- stance, particularly with large classes of restless pupils who apparently need-to be kept in a condition of uniform occupation, than to kill a supply of animals, preferably as near alike as possible, and set the pupils to work drawing the dead remains? This method is usually supplemented by a series of questions concerning the remains which are sure to keep the pupils busy a while longer, perhaps until the bell strikes, and which usu- ally are so planned as to anticipate any ideas that might naturally crop up in the pupil's mind during the drawing exercise. FOREWORD TO TEACHERS 9 " Such an abuse of the laboratory idea is all wrong and should be avoided. The ideal laboratory ought to be a retreat for rainy days ; a substitute for out of doors ; a clearing house of ideas brought in from the outside. Any course in biology which can be confined within four walls, even if these walls be of a modern, well-equipped laboratory, is in some measure a failure. Living things, to be appreciated and correctly interpreted, must be seen and studied in the open where they will be encountered throughout Hfe. The place where an animal or plant is found is just as important a characteristic as its shape or function. Impossible field excur- sions with large classes within school hours, which only bring confusion to inflexible school programs, are not necessary to accomphsh this result. Properly administered, it is without doubt one of our most efficient de- vices for developing biological ideas, but the laboratory should be kept in its proper relation to the other means at our disposal and never be allowed to degenerate either into a place for vacuous drawing exercises or a bio- logical morgue where dead remains are viewed." — Dr. H. E. Walter. For the sake of the pupil the number of technical and scientific terms has been reduced to a minimum. The language has been made as simple as possible and the problems made to hinge upon material already known, by hearsay at least, to the pupil. So far as consistent with a well-rounded course in the essentials of bio- logical science, the interests of the children have been kept in the foreground. In a recent questionnaire sent out by the author and answered by over three thousand children studying biology in the secondary schools of Connecticut, Massachusetts, New Jersey, and New York by far the greatest number gave as the most interesting topics those relating to the care and functions of the human body and the control and betterment of the environment. As would be expected, boys have different biological interests from girls, and children in rural schools wish to study different topics from those in congested districts in large communities. The time has come when we must frankly recognize these interests and adapt the content of our courses in biology to interpret the immediate world of the pupil. With this end in view the following pages have been Awitten. This book shows boys and girls living in an urban community how they may best live within their own environment and how they may cooperate with the civic authorities for the betterment of their environment. A logical course is built up around the 10 FOREWORD TO TEACHERS topics which appeal to the average normal boy or girl, topics given in a logical sequence so as to work out the solution of problems bearing on the ultimate problem of the entire course, that of prep- aration for citizenship in the largest sense. Seasonal use of materials has been kept in mind in outlining this course. Field trips, when properly organized and later used as a basis for discussion in the classroom, make a firm foundation on which to build the superstructure of a course in biology. The normal environment, its relation to the artificial environment of the city, the relations of mutual give and take existing between plants and animals, are better shown by means of field trips than in any other way. Field and museum trips are enjoyed by the pupils as well. These result in interest and in better work. The course is worked up around certain great biological principles ; hence insects may be studied when abundant in the fall in connec- tion with their relations to green plants and especially in their re- lation to flowers. In the winter months material available for the laboratory is used. Saprophytic and parasitic organisms, wild plants in the household, are studied in their relations to man- kind, both as destroyers of food, property and life and as man's invaluable friends. The economic phase of biology may well be taken up during the winter months, thus gaining variety in sub- ject matter and in method of treatment. The apparent emphasis placed upon economic material in the following pages is not real. It has been found that material so given makes for variety, as it may be assigned as a topical reading lesson or simply used as reference when needed. Cyclic work in the study of life phenom- ena and of the needs of organisms for oxygen, food, and reproduc- tion culminates, as it rightly should, in the study of life-processes of man and man's relation to his environment. In a course in biology the difficulty comes not so much in know- ing what to teach as in knowing what not to teach. The author believes that he has made a selection of the topics most vital in a well-rounded course in elementary biology directed toward civic betterment. The physiological functions of plants and animals, the hygiene of the individual within the community, conservation and the betterment of existing plant and animal products, the FOREWORD TO TEACHERS 11 big underlying biological concepts on which society is built, have all been used to the end that the pupil will become a better, stronger and more unselfish citizen. The '' spiral " or cyclic method of treatment has been used throughout, the purpose being to ultimately build up a number of well-rounded concepts by constant repetition but with constantly varied viewpoint. The sincere thanks of the author is extended to all who have helped make this book possible, and especially to the members of the Department of Biology in the De Witt Clinton High School. Most of the men there have directly or indirectly contributed their time and ideas to help make this book worth more to teachers and pupils. The following have read the manuscript in its entirety and have offered much valuable constructive criticism : Dr. Herbert E. Walter, Professor of Zoology in Brown University ; Miss Elsie Kupfer, Head of the Department of Biology in Wadleigh High School; George C. Wood, of the Department of Biology in the Boys' High School, Brooklyn ; Edgar A. Bedford, Head of Depart- ment of Biology in the Stuyvesant High School ; George E. Hew- itt, George T. Hastings, John D. McCarthy, and Frank M. Wheat, all of the Department of Biology in the De Witt Clinton High School. Thanks are due, also, to Professor E. B. Wilson, Professor G.N. Calkins, Mr. WllHam C. Barbour, Dr. John A. Sampson, W. C. Stevens, and C. W. Beebe, Dr. Alvin Davison, and Dr. Frank Overton; to the United States Department of Agriculture; the New York Aquarium ; the Charity Organization Society ; and the American Museum of Natural History, for permission to copy and use certain photographs and cuts which have been found useful in teaching. Dr. Charles H. Morse and Dr. Lucius J. Mason, of the De Witt Clinton High School, prepared the hygiene outline in the appendix. Frank M. Wheat and my former pupil, John W. Teitz, now a teacher in the school, m.ade many of the fine dra^vings and took several of the photographs of experiments prepared for this book. To them especially I wish to express my thanks. At the end of each of the following chapters is a list of books which have proved their use either as reference reading for students or as aids to the teacher. Most of the books mentioned are within 12 FOREWORD TO TEACHERS the means of the small school. Two sets are expensive : one, The Natural History of Plants, by Kerner, translated by Oliver, pub- lished by Henry Holt and Company, in two volumes, at $11 ; the other. Plant Geography upon a Physiological Basis, by Schimper, pubHshed by the Clarendon Press, $12 ; but both works are inval- uable for reference. For a general introduction to physiological biology, Parker, Elementary Biology, The Macmillan Company ; Sedgwick and Wilson, General Biology, Henry Holt and Company; Verworn, General Physiology, The Macmillan Company ; and Needham, Gen- eral Biology, Comstock Publishing Company, are most useful and inspiring books. Two books stand out from the pedagogical standpoint as by far the most helpful of their kind on the market. No teacher of botany or zoology can afford to be without them. They are : Lloyd and Bigelow, The Teaching of Biology, Longmans, Green, and Company, and C. F. Hodge, Nature Study and Life, Ginn and Company. Other books of value from the teacher's standpoint are : Ganong, The Teaching Botanist, The Macmillan Company ; L. H. Bailey, The Nature Study Idea, Doubleday, Page, and Com- pany ; and McMurry's How to Study, Houghton Mifflin Company. CONTENTS CHAPTER PAGB Foreword to Teachers 7 15 19 '28 47 I. Some Reasons for the Study of Biology II. The Environment of Plants and Animals . III. The Interrelations of Plants and Animals IV. The Functions and Composition of Living Things V. Plant Growth and Nutrition — The Causes of Growth 58 VI. The Organs of Nutrition in Plants — The Soil and ITS Relation to Roots 71 VII. Plant Growth and Nutrition — Plants make Food . 84 VIII. Plant Growth and Nutrition — The Circulation and Final Uses of Food by Plants .... 97 IX. Our Forests, their Uses and the Necessity of their Protection 105 X. The Economic Relation of Green Plants to Man . 117 XI. Plants without Chlorophyll in their Relation to Man 180 XII. The Relations of Plants to Animals .... 159 XIII. Single-celled Animals considered as Organisms . 166 XIV. Division of Labor, the Various Forms of Plants and Animals 173 XV. The Economic Importance of Animals .... 197 XVI. An Introductory Study of Vertebrates . . . 232 XVII. Heredity, Variation, Plant and Animal Breeding . 249 XVIII. The Human Machine and its Needs .... 2(56 XIX. Foods and Dietaries 272 XX. Digestion and Absorption 296 18 14 CONTENTS CHAPTEB PA3E XXL The Blood and its Circulation 313 XXII. Respiration and Excretion 329 XXIII. Body Control and Habit Formation .... 348 XXIV. Man's Improvement of his Environment . . . 373 XXV. Some Great Names in Biology 398 APPENDIX 407 Suggested Course with Time Allotment and Sequence OP Topics for Course beginning in Fall . . 407 Suggested Syllabus for Course in Biology beginning in February and ending the Next January . 411 Hygiene Outline 415 Weights, Measures, and Tempp:ratures . . . 417 Suggestions for Laboratory Equipment . . . 418 INDEX c 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 in- creasingly 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. 15 16 SOME REASONS FOR STUDYING 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. Phmts furnish man with the greater part of his food in the form of grains and cereals, fruits and nuts, edible roots and h'aves ; they provide his domesticated animals with food ; they giv(» 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 cloth- ing and the thread with which it is sewed together come from fiber-producing plants. Most medicines, beverages, flavoring ex- tracts, and spices are plant products, while plants are made use of in hundreds of ways in the useful arts and trades, producing var- nishes, dyestuffs, rubber, and other products. Bacteria in their Relation to Man. — In still another way, cer- tain i^lants vitall}^ 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 ])utter ; they improve the soil for crop growing ; so the farmer can- not 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 dis- eases, 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 sub' division 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 disap- SOME REASONS FOR STUDYING BIOLOGY 17 pear 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. The Relation of Animals to Man. — Animals also play an im- portant part in the world in causing and carrying disease. Ani- mals that cause disease are usually tiny, and live in other animals as parasites ; that is, they get their living from their hosts on which they feed. Among the diseases caused by parasitic animals are malaria, yellow fever, the sleeping sickness, and the hookworm disease. Animals also carry disease, especially the flies and mosquitoes ; rats and olj^ier animals are also well known as spreaders of disease. From a money standpoint, animals called insects do much harm. It is estimated that in this country alone they are annually re- sponsible for $800,000,000 worth of damage by eating crops, forest trees, stored food, and other material wealth. The Uses of Animals to Man. — We all know the uses man has made of the domesticated animals for food and as beasts of burden. But many other uses are found for animal products, and materials made from animals. Wool, furs, leather, hides, feathers, and silk are examples. The arts make use of ivory, tor- toise shell, corals, and mother-of-pearl ; from animals come per- fumes and oils, glue, lard, and butter; animals produce honey, wax, milk, eggs, and various other commodities. The Conservation of our Natural Resources. — Still another reason why we should study biology is that we may work under- standingly for the conservation of our natural resources, especially of our forests. The forest, aside from its beauty and its health- giving properties, holds water in the earth. It keeps the water from drying out of the earth on hot days and from running off on rainy days. Thus a more even supply of water is given to our rivers, and thus freshets are prevented. Countries that have been deforested, such as China, Italy, and parts of France, are now sub- ject to floods,~^nd are in many places barren. On the forests depend our supply of timber, our future Avater power, and the future commercial importance of cities which, like New York, are located at the mouths of our navigable rivers. HUNTER. CIV. BI. — 2 18 SOME REASONS FOR STUDYING BIOLOGY Plants and Animals mutually Helpful. — Most plants and ani- mals stand in an attitude of mutual helpfulness to one another, plants providing food and shelter for animals ; animals giving off waste materials useful to plants in the making of food. We also learn that plants and animals need the same conditions in their surroundings in order to live : water, air, food, a favorable temper- ature, and usually light. The life processes of both plants and animals are essentially the same, and the living matter of a tree is as much alive as is the living matter in a fish, a dog, or a man. Biology in its Relation to Society. — Again, the study of biology should be part of the education of every boy and girl, because so- ciety itself is founded upon the principles which biology teaches. Plants and animals are living things, taking what they can from their surroundings ; they enter into competition with one another, and those which are the best fitted for life outstrip, the others. Animals and plants tend to vary each from its nearest relative in all details of structure. The strong may thus hand down to their offspring the characteristics which make them the winners. Health and strength of body and mind are factors which tell in winning. Man has made use of this message of nature, and has developed improved breeds of horses, cattle, and other domestic animals. Plant breeders have likewise selected the plants or seeds that have varied toward better plants, and thus have stocked the earth with hardier and more fruitful domesticated plants. Man's dominion over the living things of the earth is tremendous. This is due to his understanding the principles which underlie the science of biology. Finally the study of biology ought to make us better men and women by teaching- us that unselfishness exists in the natural world as well as among the highest members of society. Ani- mals, lowly and complex, sacrifice their comfort and their very lives for their young. In the insect communities the welfare of the individual is given up for the best interests of the community. The law of mutual give and take, of sacrifice for the common good, is seen everywhere. This should teach us, as we come to take our places in society, to be willing to give up our individual pleasure/ or selfish gain for the good of the community in which we livjB. Thus the application of biological principles will benefit society. 11. THE ENVIRONMENT OF PLANTS AND ANIMALS Problem, — To discover some of tlie factors of the environ- ment of plants and animals. (a) Environment of a plant. ib) Environment of an animal. (c) Hojne environment of a girl or boy. Laboratory Suggestions Laboratory demonstrations. — Factors of the environment of a living plant or animal in the vivarium. Home exercise. — The study of the factors making up my own environ- ment and how I can aid in their control. Environment. — Each one of us, no matter where he Hves, comes in contact with certain surroundings. Air is everywhere around us ; light is necessary to us, so much so that we use artificial light at night. The city street, with its dirty and hard paving stones, has come to take the place of the soil of the village or farm. Water and food are a necessary part of our sur- roundings. Our clothing, useful to maintain a certain temperature, must also be included. All these things — air, light, heat, water, food — together make up our environment. All other animals, and all plants as well, are surrounded by and use prac- tically the same things from their en- vironment as we do. The potted plant in the window, the goldfish in the aquarium, your pet dog at home, all use, as we will later prove, the factors of their environ- 19 An unfavorable city environ- ment. 20 ENVIRONMENT OF PLANTS AND ANIMALS ment in the same manner. Air, water, light, a certain amount of heat, soil to live in or on, and food form parts of the surroundings of every living thing. The Same Elements found in Plants and Animals as in their Environment. — It has been found by chemists that the plants and animals as well as their environment may be reduced to about eighty very simple substances known as chemical elements. For example, the air is made up largely of two ele- ments, oxygen and nitrogen. Water, by means of an electric current, may be broken up into two elements, oxygen and hydrogen. The elements in water are combined to make a cheynical com- poimd. The oxygen and nitrogen of the air are not so united, but exist as separate gases. If we were to study 1 An experiment that shows the air contains about four fifths nitrogen. Apparatus for separating water by means of an electric current into the two elements, hydrogen and oxygen. the chemistry of the bodies of plants and animals and of their foods, we would find them to be made up of certain chemical elements combined in various complex compounds. These ele- ments are principally carbon, hydrogen, oxygen, nitrogen, and perhaps a dozen others in very minute proportions. But the same elements present in the living things might also be found ENVIRONMENT OF PLANTS AND ANIMALS 21 SULPHUR PHOSPHORU5I CALCIUM NITROGEN 3.7s Iks. 0.031U %,o% SiGXts. y-jir HYDROGEN I3.65\bs. 9.1^ CARBON 13.5^ OXYGEN I08.l5lb5. in the environment, for example, water, food, the air, and the soil. It is logical to believe that living things use the chemical elements in their surroundings and in some won- derful manner build up their own bodies from the materials found in their en- vironment. How this is done we will learn in later chapters. What Plants and Animals take from their Environment. Air. — It is a self- evident fact that animals need air. Even those living in the water use the air dissolved in the water. A fish placed in an air-tight jar will soon die. It will be proven later that plants also need air in order to live. Water. — We all know that water must form part of the environment of plants and animals. It is a matter of common knowledge that pets need water to drink; so do other animals. Every one knows we must water a potted plant if we expect it to grow. Water is of so much importance to man that from the time of the Caesars until now he has spent enormous sums of money to bring pure water to his cities. The United States government is spending millions of dollars at the present time to bring by irrigation the water needed to support life in the western desert lands. Light as Condition of the Environment. — Light is another im- portant factor of the environment. A study of the leaves on any green plant growing near a window will convince one that such plants grow toward the light. All green plants are thus influenced by the sun. Other plants which are not green seem either indif- ferent or are negatively influenced (move away from) the source of light. Animals may or may not be attracted by light. A moth, for example, will fly toward a flame, an earthworm will move away from light. Some animals prefer a moderate or