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200M/06-99-991212



GENERAL BIOLOGY

A Book of Outlines and Practical Studies
for the General Student



By JAMES G. NEEDHAM, Ph.D.

ASSISTANT PROFESSOR OF LIMNOLOGY AND GENERAL BIOLOGY

IN CORNELL UNIVERSITY



WITH 64 PRACTICAL STUDIES
287 TEXT FIGURES, AND
9 PORTRAITS



ITHACA, N. Y.
THE COMSTOCK PUBLISHING CO.
1910



Copyright, 19 io

BY
COMSTOCK PUBI^ISHING Co.



TO THE MEMORY OF

JOHN GORE

MY TEACHER IN THE DISTRICT
SCHOOL, WHO FIRST TAUGHT ME
THE USE OF A PRINCIPLE AS A
TOOL OF THE MIND.



. 19705



PREFACE.

This book offers a series of practical studies of biological
phenomena for the guidance of the general student. It is
not a formal text, and not at all a treatise, but only a guide
intended to assist the student in acquiring for himself some
real knowledge of living nature. It differs chiefly from
other books intended for the use of college classes in the
wider range of studies it offers, some important phases of
biology having hitherto been dismissed with mere didactic
instruction. Morphology has dominated — often monopo-
lized — college work in biology in the past; doubtless, be-
cause it was first reduced to pedagogic form, and made
available for laboratory instruction. A more equable
treatment is here attempted, in the hope of leading the
student to a practical acquaintance with elementary
phenomena in the whole broad field.

The generation of biologists which began its studies with
Huxley and Martin's pioneer laboratory manual has wit-
nessed a marvelous expansion of biological knowledge.
Departments have sprung up, and teachers as well as prac-
titioners have specialized, and courses have multiplied
amazingly. Yet I am persuaded that the reasons given by
Huxley and Martin for offering a general course are as valid
today as they were in 1868. Indeed I am inclined to think
that some added reasons have grown out of the increasing
applications of biological knowledge to the practical affairs
of life. The conditions of our living make ever increasing
demands for knowledge of life phenomena, and some com-
prehension of biological principles is fast becoming a part of
the common intelligence.

V



vi GENERAL BIOLOGY

We are organisms; and out of that fact grow the funda-
mental relations that general biology bears to a whole wide
range of special sciences, the threshold of which may, I hope,
be reached by those who follow the course here outlined.
After Chapter I, which is introductory, the studies of chap-
ter II should lead up to physiology, algology, mycology,
bacteriology, protozoology, etc., those of chapter III, to
morphology, comparative anatomy, embryology, palaeon-
tology and special botany and zoology ; those of chapter IV,
to cytology and eugenics; those of chapter V, to ecology,
and limnology; those of chapter VI, to pathology, experi-
mental biology, etc.; those of chapter VII, to neurology,
psychology, sociology and ethnology. And in the broader
sense of these terms many more special sciences are included.
In the preparation of this course I have had in mind the
needs of the great majority of college students, who may
hardly spend more 'than a year in this subject. Certainly
no other subject touches their lives at so m.any important
points. What will best serve their needs ? has been the ques-
tion constantly before me; not. What has been taught
hitherto? Ecological and evolutionary phenomena are
just as available for practical studies as are morphological
types, and I have introduced them freely, although not
without pangs of regret for the good things of former courses
that had to be omitted to make room. I have reduced to
a minimum the directions for the laboratory study of
morphological types, for excellent outlines are everywhere
available for work of this sort; and I have given a larger
place to outlines for field work and experimental studies. I
have arranged the subject-matter to suit the seasons of the
college year. I have included more than a year's work in
order that selections might be made. For pedagogic
reasons, I have introduced at the first phenomena of some
familiarity, postponing more technical matters. Mere



PREFACE vii

technique has no part in this course. Facts are neither
better nor worse for educational purposes because of
technical difficulties that may or may not stand in the way
of their acquisition; and therefore, other things being equal
I have given preference to such observations as are most
likely to be continued after the work of the college course is
ended.

The purpose of the introduction given for each subject is
to orient the student for the work assigned — not to replace
the lecture or the recitation. I have tried to tell what he
should know in order to outline what he should do; and I
have tried so to shape the conclusion of his work as to invite
a little thinking. During the past seven years I have been
seeking methods that would facilitate the handling of bodies
of facts sufficiently large for satisfactory illustration of
general biological principles and phenomena. Many new
exercises have been tried by my classes in field and labora-
tory; the ones that have proved most serviceable are
included in the following pages. Herein are detailed the
methods I have found most available. The materials used
are of less consequence. I have used whatever lay nearest
at hand, only seeking to draw my materials from a wide
range of groups, in order to extend the acquaintance of the
student with the face of nature. In so far as it has been
necessary to touch upon theoretical questions, it has been
my purpose, not to advance any biological theories but to
bring the student into practical contact with the facts under-
lying all the theories.

The field of biology is so vast that no one can claim expert
knowledge in any considerable portion of it. It is very
probable, therefore, that in covering so much ground in even
so elementary a manner, I have made some mistakes. I
can only hope that they may not be of such nature as to
seriously mislead or confuse the student and that I may



viii GENERAL BIOLOGY

have the further aid of generous colleagues toward their
early elimination. •

Many of my colleagues and former pupils have helped me
with valuable suggestions and I would be glad if there were
space to thank them all; and I cannot refrain from making
mention of the special help that has been given me by Pro-
fessors J. H. Comstock, W. A. Riley, G. F. Atkinson, B. M.
Duggar, B. F. Kingsbury, I. M. Bentley, A. Hunter, R. H.
McKee and Drs. A. H. Wright and W. A. Hilton on the
part of the proofs that they have seen. Others of my
colleagues have generously loaned me valuable portraits,
concurring in my belief, that it would be worth while to
introduce the faces of at least a few of the great pioneers
of biology unobtrusively into the students' intellectual
environment.

This book exists for the sake of the practical studies con-
tained in it. Mere attendance on a lecture course does not
amount to much; for in biology, as in other subjects, it is
only those who handle the raw materials and build up with
them, who can ever really comprehend the superstructure.

James G. Needham.



CONTENTS.

CHAPTER I.

THE INTERDEPEXDEXCE OF ORGANISMS.

I. The Relations Between Flowers and Insects, p. 7. i.
The adaptation of flowers to insect visitation, p. 1 1. 2. The
adaptation of insects to flower visitation, p. 17. How to
know the orders of flower insects, p. 24. 3. The relative fit-
ness of the different visitors to one kind of flower, p. 26. 4.
The relative fitness of the different flowers visited by one
kind of insect to profit by its visitation, p. 28. 5. Precise
adaptation between flowers and insects, leading to mutual
dependence, p. 29. 6. Specialization miscarried, p. 32.
II. Galls, p. 35. Animal galls, p. 38. The animals that produce
galls, p. 42, Key to the commoner insect larvae and mites
found in galls, p. 45.
III. The Relations Between Ants and Aphids, p. 47. The
chance feeding by ants on the honey dew offered by aphids,
p. 48; The habitual guarding of aphid colonies by ants, p. 49.
The domestication of aphids by ants, p. 50.

PRACTICAL EXERCISES.
Study I . Floivcrs adapted to insect visitation, p. 14.
Study 2. Insects adapted to visiting ftowers, p. 24.
Study J. The relative fitness of the different visitors to one kind of

flower, p. 26.
Study 4. An examination of all the flowers visited by some cotnmon

insect, p. 28.
Study 5. A case of precise adaptation , p. J2.
Study 6. A study of common galls, p. 46.
Study 7. Observations on ants and aphids, p. 54.

CHAPTER II.
THE SIMPLER ORGANISMS.

I. Some Typical Alg^, p. 56. The cell, p. 61. The form of the
plant body in common algae, p. 64:
II. Some typical protozoans, p. 68.

ix



X GENERAL BIOLOGY

in. The Life Process in Plant and Animal Cell, p. 82. Mat-
ter, p. 82. Energy, p. 83. Protoplasm, p. 88.

IV. Some Intermediate and Undifferentiated Forms, p. 91. i.
Plants that lack chlorophyl, p. 92. Molds and other fungi,
p. 95. Bacteria, p. 97. 2. The slime molds, p. loi. ^.
The flagellates, p. 104.

IV. Reproduction Among the Simpler Organisms, p. 109. Cell
division, p. 109. Sexual reproduction, p. 112.

PRACTICAL EXERCISES.

Study 8. The cell of Spirogyra and the protoplasm of Nitella, p. 60.
Study g. Observations on cell form and growth habit in algcB, p. Oj.
Study 10. The structure and activities of Paramceciiim, p'. 72.
Study II. The specialized cell bodies of*Stcntor and Vorticella, p. 76.
Study 12. Observations on cultures of yeast and molds, p. g6.
Study I J. A few observations on bacteria, p. 100.
Study 14. Observations on slime molds, p. loj.

Study 75. A comparative examination of common flagellates, p. 107.
Study 16. Observations on reproduction among the simpler organisms,
p. 11^.

CHAPTER III.
ORGANIC EVOLUTION.

I. The Plant Series, p. 1 18. Bryophytes, p. 118. Alternation
of generations, p. 124. Pteridophytes, p. 128. Speramato-
ph^-tes, p. 142.

II. The Animal Series, p. 156. The hydra, p. 157. The earth
worm, p. 163. The salamander, p. 179. Development, p.
193. Types of nurture, p. 214. The life process, p. 217.
Common features of development in plants and animals, p.
218. Systemiatic classification, p. 221.

II. General Evolutionary Phenomena as Illustrated in
Briefer Series of Organisms, p. 222. i. Divergence and
convergence of development, p. 222. Homologies and analogies
p. 223. The veins in the wings of insects, p. 225. The serial
homology of the higher crustaceans, p. 230. Phylogeny, p.
236. Convergence, p. 243. 2. Progressive and regressive
development, p. 245. Palaeontology, p. 246. The persistence
of the unspecialized, p. 250. Regressive development, p.
251. 3. The correspondence between ontogeny and phylogeny,
p. 255. Why evolutionary series? p. 264.



CONTENTS xi

III. The Processes of Evolution; Attempted Explanations,
p. 266. Natural selection, p. 266. Variation, p. 267.
Mutation, p. 273. The struggle for existence, p. 276. Arti-
ficial selection, p. 279. Orthogenesis, p. 281. Segregation,
p, 283. The interaction of external and internal forces, p.
286.

PRACTICAL EXERCISES.

Study 17. An examination of bryophyte characters, p. 12'/.

Study 18. Fern development, p. 140.

Study ig. The general structure of the fern sporophyte, p. 141.

Study 20. A comparison of developmental features of other pterido-
phytes, p. 141.

Study 21. Spermatophyte structure, p. 154.

Study 22. Spermatophyte development, p. 1^4.

Study 2j. Observations on the structure of the hydra, p. 162.

Study 24. The general structure of the earth worm, p. lyS.

Study 25. The cellular structure of the earth worm, p. 179.

Study 26. The ijtternal organs of an amphibian, p. 206.

Study 2J. The structures of the body wall in an amphibian, p. 207.

Study 28. The cellular structure of an amphibian, pp. 208.

Study 2g. The early development of an amphibian, p. 2og.

Study JO. Determination of homologies in three series of closely
allied insects, p. 22g.

Study J J. Observations on plasticity of form and persistence of type
in Malacostraca, p. 2jj.

Study J2. An attempt at interpreting a possible phylogeny, p. 2j8.

Study jj. A comparison of convergent species, p. 24J.

Study J4. The ontogeny of organs in the frog or salamander, p. 261,

Study j^. Fluctuating numerical variations, p. 272.

Study j6. The struggle for existence among seedlings, p. 278,

CHAPTER IV.
INHERITANCE.

I. The Visible Mechanism of Heredity, p. 289. The history
of the germ cells, p. 296. Fertilization and maturation, p.
299. Parthenogenesis, p. 204.
II. The Observable Results of Inheritance. Types of in-
heritance, p. 308. Alternative inheritance, p. 310.
III. Nature and Nurture, p. 318. Inheritance of acquired
characters, p. 318. The meaning of nurture, p. 321.



xii GENERAL BIOLOGY

PRACTICAL EXERCISES.
Study 27 • Observations on cell divisions and on maturation of sex cells,

P- 305-
Study j8. Observations on parthenogenesis, p. jo6.

Study JQ. Observations on the relation between fecundity and nurture,

P- 325-

CHAPTER V.

THE LIFE CYCLE.
I. Alternation of Generations, p. 330.
II. Special Methods of Asexual Reproduction, p. 331.

III. Change of Form With Alternation of Hosts, p. 340.

IV. Metamorphosis, p, 342. The transformations of insects, p.

343. Internal metamorphosis, p. 347.
V. Artificial Division and Combination of Organisms, p. 353.
Regeneration, p. 353. Grafting, p. 360.

PRACTICAL EXERCISES.

Study 40. Observations on asexual reproductive methods, p. JJ7.

Study 41. External metamorphosis in insects, p. J46.

Study 42. Observations on internal metamorphosis , p. 35/.

Study 4J. Experiments with regeneration in planarians, p. j6o.

Study 44. Grafting practice with plants, p. j6j.

CHAPTER VL

THE ADJUSTMENT OF ORGANISMS TO ENVIRONMENT.

I. Adjustment in Place and Time, p. 369. i. Local distribu-
tion of green plants 2. Hibernation and aestivation, p. 376..
3. Local distribution of animals, p. 378. 4. Pond life, p.

385-
II. Adjustment in Manner of Life, p. 390. i. Symbiosis, p.

390. 2. Parasitism, p. 396. 3. Pollen distribution, p. 400.
III. Adjustment in Form and Appearance, p. 404. i. The re-
adaptation of insects to aquatic life, p. 407. 2. Phylogenetic
adaptation in diving beetles, p. 415. 3. Animal coloration,
p. 422.

PRACTICAL EXERCISES.
Study 45. Woodland plant society, p. 373.

Study 46. Observations on the dessication and resuscitation of rotifers,
P- 378.



CONTENTS xiii

Study 47. The local resident terrestrial vertebrate fauna, p. j8j.
Study 48. A laboratory examination of typical pond animals, p. j86.
Study 4g. A field study of pond animals, p. j88.
Study §0. The relations of fungus and alga in the lichen, p. JQ4.
Study §1. A comparative examination of a series of adult parasites, of

a single order, p. 400.
Study §2. Pollen production as affected by its jnode of distribution, p.

402.
Study ^j. The principal types of gills found in aquatic insects, p. 410.
Study §4. The cornparative development of respiratory apparatus in

aquatic inesct larvae, p. 41 j.
Study ^^. A comparison of the structure of ground beetle and diving

beetle, p. 417.
Study §6. A comparative study of the size and activities of diving

beetles, p. 418.
Study §1. Field observations on diving beetles,. p. 420.
Study §8. The adaptive structures of diving beetles, p. 421.
Study 5p. Examples from the local fauna of the principal types of

animal coloration, p. 432.

CHAPTER VII.
THE RESPONSIVE LIFE OF ORGANISMS.

Introduction, p. 434.
I. Animal Activities, p. 437. i. Some typical sensory phe-
nomena of the Protozoza, p. 437. Organs of out-reach, p.
438. Some reactions of Paramoecium, p. 439. 2. Some
general features of the sensory mechanism in the Metazoa, p.
441. Intercommunication without nerves, p. 442. Sense
organs p. 444. Nerve and muscle, p. 448. The reflex
arc, p. 450. Control circuits, p. 453. Cephalisation, p. 455.
A mechanism for adaptation of the individual, p. 457. Re-
lations between parts and functions in the vertebrates p.
460. 3. Some typical sensory phenomena of the Metazoa,
p. 469. Automatic unvarying activities, p. 469. Respon-
ses automatically varying, p. 469. Sequences of automatic
activities, p. 473. Learning by experience, p. 479.
II. The Responsive Life of Man, p. 485. i. The natural
history of man, -p. 48^. Distinguishing human character-
istics, p. 486. Language, p. 489. Tool using, p. 490. Use
of fire, p. 491. 2. Unwritten human history, p. 492. Ar-



xiv GENERAL BIOLOGY

chaeology, p. 498. Ethnology, p. 494. Ontogeny, p. 498.
3. The social organism, p. 500. Animism, p. 502. Social
integration, p. 507. Social conduct, p. 509.

PRACTICAL EXERCISES.

Study 60. Demonstration of functions of sonic of the principal parts
of the nervous system in the frog, p. 456.

Study 61. Observations on certain activities of caterpillars, p. 472.

Study 62. The case-building instincts of caddis worms, p. 477.

Study 6 J. Experiments with trial and error in chicks, p. 481.

Study 64. Survivals of animism in our own titnes, p. 504.

APPENDIX.

Preliminary outline and instructions, p. 513. Lenses, lighting,
etc., p. 513. Stage mounts, p. 518. Dissecting, p. 519. Draw-
ings, p. 520. 2. Materials for the practical exercises, p. 520. 3.
Key to the genera of Dytiscidce . p. 526.

INDEX.

Pages 531—542.



PORTRAITS: Schultze, p. 8g; Pasteur, p. gT,; Von Baer, p. i'j4;
Linnaeus, p. 220; Agassiz, p. 224; Darwin, p. 277; Leeuwenhoek, p.
298; Mendel, p. 309; Aristotle, p. 470.



ru



GENERAL BIOLOGY

CHAPTER I.
INTERDEPENDENCE OF ORGANISMS

The primary demand of individual livelihood is for food.
Getting a living is the first business of life, and food is the
basis of a living; for the body derives both its substance
and its energy from its food.

The gathering of the food for the living world is mainly
the work of green plants. These derive carbon from the
air and mineral matters from the soil, and build them up
into living substance, clothing the earth with verdure and
storing up food materials that make animal life possible.
Green plants constitute in themselves by far the greater
part of the living substance that is in the earth, and support
other forms of life out of the excess of their product over
what is necessary to maintain their own growth and
reproduction.

The primary food of animals is plants and plant products.
Animals consume a small part of living plants, a much
larger part of plant products (fruits, tubers, wood, etc.)
and nearly the whole of plant remains. They use this
plant material for building their own bodies and supplying
their energy, and excrete it again as simple mineral com-
pounds. Thus they rapidly restore to the soil plant food
materials which might otherwise remain long locked up in
the bodies of dead plants. Thus the world's available
supply of food material is kept in circulation; and thus, green
plants and animals are complemental, each preparing food
for the other.

That so large a part of living vegetation escapes being
eaten is due to the fact ^nat animals, primarily herbivorous,



4 GENERAL BIOLOGY

have become carnivorous, and have taken to eating each
other. The carnivores prevent overproduction of herbivores,
and are themselves held in check by parasites within their
own ranks. Herbivores and carnivores, parasites and
scavengers are everywhere; for they fulfill permanent
functions of animal society.

The need of shelter is another large factor in determining
the habits of animals, for few can afford to live in the open,
and most are so limited that they must find food and
shelter in the same haunts. For both food and shelter
animals are dependent primarily upon plants and secondarily
upon each other, and the relations that have come to exist
between them are so intricate they may fairly be compared
to a web with its threads all interwoven.

Interdependence. — The weak are dependent on a few,
the strong upon many. The sturdy oak in the woods
seems very independent in comparison with the vine that
hangs upon its branches or the green mould lodged in a
crevice of its bark. But from leaf to root it is beset by
enemies and aided by friends.- There are caterpillars
feeding upon and within its leaves. On its twigs are aphids
sucking the sap out, and within them are beetles boring.
Other beetles and caterpillars li\'e in bark and sapwood and
heartwood of its trunk, and other aphids attack its roots.

But about its roots there are friendly earthworms work-
ing in the soil, mixing it and making it porous; and moulds,
assisting in the preparation of its food. Neighboring
trees shade its trunk from the scorching rays of the summer
sun, and woodpeckers, nuthatches and warblers search its
bark and leaves for hidden insect enemies. There are
hosts of parasites also, individually insignificant, but
collectively, its greatest safeguards, that work wholesale



*In Packard's Forest Insects there are listed 442 species of
insects affecting American oaks, and 20 additional that are found
in their dead stumps.



INTERDEPEXDEXCE OF ORGANISMS 5

destruction upon any of its enemies that may become
excessively abundant ; and even the squirrels that greedily
gather its acorns to eat, distribute some of them in just the
way to insure another generation of oaks.

Moreover, this complex relation began at its birth, and
will continue until it is "resolved to earth again." Weevils
devour its acorns; cutworms and lusty smothering weeds
imperil its infancy; and the trampling and browsing of
quadrupeds are a great menace to its early youth. The
storm that scars it, or the disease that weakens it m.akes
the opportunity for attack by beetles or molds that are
harmless in its health. When it is dead, its corpse is
riddled by borers and softened by molds and speedily
reduced to dust.

And of the host of friends and enemies with which it has
come in contact, each has its own friends and enemies,
ready to help or to devour. There is no living thing that
either lives or dies unto itself alone.

Let anyone who would see for himself the complexity
of the web of life, study some common plant or animal,
observing all the other plants and animals affect irg it,
and their inter-relationships ; or, let him examme the home
of some social animal, and find all the inmates of different
species, and learn how ' they manage to live together.
There is no plant or animal, no flower or fruit, no nest or
burrow, no carcass or log, no product whatsoever of living
nature, that will not show a community of life with re-
lations infinitely varied and complex. To see how much
we ourselves are continually dependent on the organic life
of the world, we need only examine the food on our table,
the furnishings of our house or the materials of our ward-
robe; however simple these departments of our living may I
be, each will attest that many kinds of plants and animals "
from many parts of the earth are tributary to it.



GENERAL BIOLOGY



Balance in Nature. — To the careful observer the face of
nature changes little from, decade to decade. There are
giants and weaklings in every natural community, but
every species is strong enough to keep on living. There
are shifts of place, but rarely is one lost in the shifting.
Casualties may devastate a valley or a hill slope, but, left
to itself, it is soon repopulated.

And there is order and progress in the shifting. The

fungi growing
on this stump
(fig. i) and the
beetles boring in-
side it, are not
the same species
that will feed
there when it is
half rotted; nor
is any one of
these the same
thatw^ll mix its
disintegrating
fragments with
the soil. There
will be other
stumps with sound wood in them waiting for the descend-
ents of those now at work on this one. The conditions for
the life of all are fairly constant, and all are capable of
making such shifts as these conditions demand. The
balance is maintained by limitations of food and shelter
and increase of enemies, serving to prevent the undue
multiplication of any species.

Man is the only disturber of the natural balance of any