The Descent of Man (Darwin)

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Descent of Man, and Selection in Relation to Sex  (1874) 
by Charles Darwin
The Descent of Man, and Selection in Relation to Sex is the second edition of a book on evolutionary theory by British naturalist Charles Darwin. The first edition was published in 1871, and the second, enlarged edition in 1874 (this Wikisource edition is based on an unchanged reprint of the second edition). It followed his 1859 work, The Origin of Species, and is concerned with outlining the application of Darwin's theory to human evolution, and detailing the theory of sexual selection. The book touches on a number of related issues, including evolutionary psychology, evolutionary ethics, differences between human races, differences between human sexes, and the relevance of evolutionary theory to society. — Excerpted from Descent of Man on Wikipedia, the free encyclopedia.


THE


DESCENT OF MAN,


AND


SELECTION IN RELATION TO SEX.


BY

CHARLES DARWIN, M.A.,

FELLOW OF THE ROYAL SOCIETY, ETC.


With Illustrations.


NEW EDITION, REVISED AND AUGMENTED.


COMPLETE IN ONE VOLUME.


NEW YORK

D. APPLETON AND COMPANY,

549 AND 551 BROADWAY.

1875.



CONTENTS.




Introduction Pages 1-4
PART I.
THE DESCENT OR ORIGIN OF MAN.



Chapter I.
The Evidence of the Descent of Man from some Lower Form.
Nature of the evidence bearing on the origin of man — Homologous structures in man and the lower animals — Miscellaneous points of correspondence — Development — Rudimentary structures, muscles, sense-organs, hair, bones, reproductive organs, &c. — The bearing of these three great classes of facts on the origin of man 5

Chapter II.
On the Manner of Development of Man from some Lower Form.
Variability of body and mind in man — Inheritance — Causes of variability — Laws of variation the same in man as in the lower animals — Direct action of the conditions of life — Effects of the increased use and disuse of parts — Arrested development — Reversion — Correlated variation — Rate of Increase — Checks to increase — Natural selection – Man the most dominant animal in the world — Importance of his corporeal structure — The causes which have led to his becoming erect — Consequent changes of structure — Decrease in size of the canine teeth — Increased size and altered shape of the skull — Nakedness — Absence of a tail – Defenceless condition of man 26

Chapter III.
Comparison of the Mental Powers of Man and the Lower Animals.
The difference in mental power between the highest ape and the lowest savage, immense — Certain instincts in common — The emotions — Curiosity — Imitation — Attention — Memory — Imagination — Reason — Progressive improvement – Tools and weapons used by animals — Abstraction, Self-consciousness — Language — Sense of beauty — Belief in God, spiritual agencies, superstitions 65

Chapter IV.
Comparison of the Mental Powers of Man and The Lower Animals — continued.
The moral sense — Fundamental proposition – The qualities of social animals — Origin of sociability — Struggle between opposed instincts — Man a social animal — The more enduring social instincts conquer other less persistent instincts — The social virtues alone regarded by savages — The self-regarding virtues acquired at a later stage of development — The importance of the judgment of the members of the same community on conduct — Transmission of moral tendencies — Summary 97

Chapter V.
On the Development of the Intellectual and Moral Faculties during Primeval and Civilised Times.
Advancement of the intellectual powers through natural selection — Importance of imitation — Social and moral faculties — Their development within the limits of the same tribe — Natural selection as affecting civilised nations — Evidence that civilised nations were once barbarous 127

Chapter VI.
On the Affinities and Genealogy of Man.
Position of man in the animal series — The natural system genealogical — Adaptive characters of slight value — Various small points of resemblance between man and the Quadrumana — Rank of man in the natural system — Birthplace and antiquity of man — Absence of fossil connecting-links — Lower stages in the genealogy of man, as inferred, firstly from his affinities and secondly from his structure — Early androgynous condition of the Vertebrata — Conclusion 146

Chapter VII.
On the Races of Man.
The nature and value of specific characters — Application to the races of man — Arguments in favour of, and opposed to, ranking the so-called races of man as distinct species — Sub-species — Monogenists and polygenists — Convergence of character — Numerous points of resemblance in body and mind between the most distinct races of man — The state of man when he first spread over the earth — Each race not descended from a single pair — The extinction of races — The formation of races — The effects of crossing — Slight influence of the direct action of the conditions of life — Slight or no influence of natural selection — Sexual selection 166
PART II.
SEXUAL SELECTION.



Chapter VIII.
Principles of Sexual Selection.
Secondary sexual characters — Sexual selection — Manner of action — Excess of males — Polygamy — The male alone generally modified through sexual selection — Eagerness of the male — Variability of the male — Choice exerted by the female — Sexual compared with natural selection — Inheritance at corresponding periods of life, at corresponding seasons of the year, and as limited by sex — Relations between the several forms of inheritance — Causes why one sex and the young are not modified through sexual selection — Supplement on the proportional numbers of the two sexes throughout the animal kingdom — The proportion of the sexes in relation to natural selection 207

Chapter IX.
Secondary Sexual Characters in the Lower Classes of the Animal Kindgom.
These characters absent in the lowest classes — Brilliant colours — Mollusca — Annelids — Crustacea, secondary sexual characters strongly developed; dimorphism; colour; characters not acquired before maturity — Spiders, sexual colours of stridulation by the males — Myriapoda 260

Chapter X.
Secondary Sexual Characters of Insects.
Diversified structures possessed by the males for seizing the females — Differences between the sexes, of which the meaning is not understood — Difference in size between the sexes — Thysanura — Diptera — Hemiptera — Homoptera, musical powers possessed by the males alone — Orthoptera, musical instruments of the males, much diversified in structure; pugnacity; colours — Neuroptera sexual differences in colour — Hymenoptera, pugnacity and colours — Coleoptera, colours; furnished with great horns, apparently as an ornament; battles; stridulating organs generally common to both sexes 274

Chapter XI.
Insects, continued. — Order Lepidoptera. (butterflies and moths.)
Courtship of butterflies — Battles — Ticking noise — Colours common to both sexes, or more brilliant in the males — Examples — Not due to the direct action of the conditions of life — Colours adapted for protection — Colours of moths — Display — Perceptive powers of the Lepidoptera — Variability — Causes of the difference in colour between the males and females — Mimicry, female butterflies more brilliantly coloured than the males — Bright colours of caterpillars — Summary and concluding remarks on the secondary sexual characters of insects — Birds and insects compared 307

Chapter XII.
Secondary Sexual Charactters of Fishes, Amphibians, and Reptiles.
Fishes: Courtship and battles of the males — Larger size of the females — Males, bright colours and ornamental appendages; other strange characters — Colours and appendages acquired by the males during the breeding-season alone — Fishes with both sexes brilliantly coloured — Protective colours — The less conspicuous colours of the female cannot be accounted for on the principle of protection — Male fishes building nests, and taking charge of the ova and young. Amphibians: Differences in structure and colour between the sexes — Vocal organs. Reptiles: Chelonians — Crocodiles — Snakes, colours in some cases protective — Lizards, battles of — Ornamental appendages — Strange differences in structure between the sexes — Colours — Sexual differences almost as great as with birds 330

Chapter XIII.
Secondary Sexual Characters of Birds.
Sexual differences — Law of battle — Special weapons — Vocal organs — Instrumental music — Love-antics and dances — Decorations, permanent and seasonal — Double and single annual moults — Display of ornaments by the males 358

Chapter XIV.
Birds — continued.
Choice exerted by the female — Length of courtship — Unpaired birds — Mental qualities and taste for the beautiful — Preference or antipathy shewn by the female for particular males — Variability of birds — Variations sometimes abrupt — Laws of variation — Formation of ocelli — Gradations of character — Case of Peacock, Argus pheasant, and Urosticte 404

Chapter XV.
Birds — continued.
Discussion as to why the males alone of some species, and both sexes of others are briglilly coloured — On sexually-limited inheritance, as applied to various structures and to brightly-coloured plumage — Nidification in relation to colour — Loss of nuptial plumage during the winter 444

Chapter XVI.
Birds — concluded.
The immature plumage in relation to the character of the plumage in both sexes when adult — Six classes of cases — Sexual differences between the males of closely-allied or representative species — The female assuming the characters of the male — Plumage of the young in relation to the summer and winter plumage of the adults — On the increase of beauty in the birds of the world — Protective colouring — Conspicuously-coloured birds — Novelty appreciated — Summary of the four chapters on birds 463

Chapter XVII.
Secondary Sexual Characters of Mammals.
The law of battle — Special weapons, contined to the males — Cause of absence of weapons in the female — Weapons common to both sexes, yet primarily acquired by the male — Other uses of such weapons – Their high importance — Greater size of the male — Means of defence — On the preference shewn by either sex in the pairing of quadrupeds 500

Chapter XVIII.
Secondary Sexual Characters of Mammals — continued.
Voice — Remarkable sexual peculiarities in seals — Odour — Development of the hair — Colour of the hair and skin — Anomalous case of the female being more ornamented than the male — Colour and ornaments due to sexual selection — Colour acquired for the sake of protection — Colour, though common to both sexes, often due to sexual selection — On the disappearance of spots and stripes in adult quadrupeds — On the colours and ornaments of the Quadrumana — Summary 525
PART III.
SEXUAL SELECTION IN RELATION TO MAN,
AND CONCLUSION.



Chapter XIX.
Secondary Sexual Characters of Man.
Differences between man and woman — Causes of such differences, and of certain characters common to both sexes — Law of battle — Differences in mental powers, and voice — On the influence of beauty in determining the marriages of mankind — Attention paid by savages to ornaments — Their ideas of beauty in woman — The tendency to exaggerate each natural peculiarity 556

Chapter XX.
Secondary Sexual Characters of Man — continued.
On the effects of the continued selection of women according to a different standard of beauty in each race — On the causes which interfere with sexual selection in civilised and savage nations — Conditions favourable to sexual selection during primeval times — On the manner of action of sexual selection with mankind — On the women in savage tribes having some power to choose their husbands — Absence of hair on the body, and development of the beard — Colour of the skin — Summary 585

Chapter XXI.
General Summary and Conclusion.
Main conclusion that man is descended from some lower form — Manner of development — Genealogy of man — Intellectual and moral faculties — Sexual selection — Concluding remarks 603

Index 630

PREFACE TO THE SECOND EDITION.




During the successive reprints of the first edition of this work, published in 1871, I was able to introduce several important corrections; and now that more time has elapsed, I have endeavoured to profit by the fiery ordeal through which the book has passed, and have taken advantage of all the criticisms which seem to me sound. I am also greatly indebted to a large number of correspondents for the communication of a surprising number of new facts and remarks. These have been so numerous, that I have been able to use only the more important ones; and of these, as well as of the more important corrections, I will append a list. Some new illustrations have been introduced, and four of the old drawings have been replaced by better ones, done from life by Mr. T. W. Wood. I must especially call attention to some observations which I owe to the kindness of Prof. Huxley (given as a supplement at the end of Part I.), on the nature of the differences between the brains of man and the higher apes. I have been particularly glad to give these observations, because during the last few years several memoirs on the subject have appeared on the Continent, and their importance has been, in some cases, greatly exaggerated by popular writers.

I may take this opportunity of remarking that my critics frequently assume that I attribute all changes of corporeal structure and mental power exclusively to the natural selection of such variations as are often called spontaneous; whereas, even in the first edition of the 'Origin of Species,' I distinctly stated that great weight must be attributed to the inherited effects of use and disuse, with respect both to the body and mind. I also attributed some amount of modification to the direct and prolonged action of changed conditions of life. Some allowance. too, must be made for occasional reversions of structure; nor must we forget what I have called “correlated” growth, meaning, thereby, that various parts of the organisation are in some unknown manner so connected, that when one part varies, so do others; and if variations in the one are accumulated by selection, other parts will be modified. Again, it has been said by several critics, that when I found that many details of structure in man could not be explained through natural selection, I invented sexual selection; I gave, however, a tolerably clear sketch of this principle in the first edition of the 'Origin of Species,' and I there stated that it was applicable to man. This subject of sexual selection has been treated at full length in the present work, simply because an opportunity was here first afforded me. I have been struck with the likeness of many of the half-favourable criticisms on sexual selection, with those which appeared at first on natural selection; such as, that it would explain some few details, but certainly was not applicable to the extent to which I have employed it. My conviction of the power of sexual selection remains unshaken; but it is probable, or almost certain, that several of my conclusions will hereafter be found erroneous; this can hardly fail to be the case in the first treatment of a subject. When naturalists have become familiar with the idea of sexual selection, it will, as I believe, be much more largely accepted; and it has already been fully and favourably received by several capable judges.


Down, Beckenham, Kent,

September 1874.

TABLE

OF THE

PRINCIPAL ADDITIONS AND CORRECTIONS TO THE PRESENT EDITION.

First
Edition
Vol. I.
Present
Edition.

Page

22

26
27, note.
29
32, note.


40
42
44

47
50
53
58

64

78
79
81
90, note.
91

94
97
112
122
124, note.
125, note.
128-9

146

Page

15-17

19
20, note.
23
24, note,


70
71
72-3

75
80
83
88-9

92

104
104
105-6
112-113, note.
114

117, note.
120, note.
28
35-6
39, note.
36-8, note.
41-2

55, note.


Discussion on the rudimentary points in the

 human ear revised.
Cases of men born with hairy bodies.
Muntegazza on the last molar tooth in man.
The rudiments of a tail in man.
Bianconi on homologous structures, as ex-
 plained by adaptation on mechanical
 principles.
Intelligence in a baboon.
Sense of humour in dogs.
Further facts on imitation in man and
 animals.
Reasoning power in the lower animals.
Acquisition of experience by animals.
Power of abstraction in animals.
Power of forming concepts in relation to
 language.
Pleasure from certain sounds, colours, and
 forms.
Fidelity in (he elephant.
Galton on gregariousness of cattle.
Parental affection.
Persistence of enmity and hatred.
Nature and strength of shame, regret, and
 remorse.
Suicide amongst savages.
The motives of conduct.
Selection, as applied to primeval man.
Resemblances between idiots and animals.
Division of the malar bone.
Supernumerary mammæ and digits.
Further cases of muscles proper to animals
 appearing in man.
Broca: average capacity of skull diminished
 by the preservation of the inferior members
 of society.

First
Edition
Vol. I.
Present
Edition.

Page

149

150

169

180

193

208. note.
209
239

245

250

256

275-6


290


301
314
315

327
338
339
345
349
350
351
354
359
366

387
397
401

412

117

Page

57

58-9

134-5

143

151

161, note.
163
188-190

195-6

199-206

209-210

224-5


235


243-4
254
255-6

264
272
273
277
280
281
282
284-5
288, note
292-3

308
315
319

324-5

326


Belt on advantages to man from his hair-

 lessness.
Disappearance of the tail in man and certain
 monkeys.
Injurious forms of selection in civilised
 nations.
Indolence of man, when free from a struggle
 for existence,
Gorilla protecting himself from rain with his
 hands.
Hermaphroditism in fish.
Rudimentary mammæ in male mammals.
Changed conditions lessen fertility and cause
 ill-health amongst savages.
Darkness of skin a protection against the
 sun.
Note by Professor Huxley on the develop-
 ment of the brain in man and apes.
Special organs of male parasitic worms for
 holding the female.
Greater variability of male than female;
 direct action of the environment in causing
 differences between the sexes.
Period of development of protuberances
 on birds' heads determines their trans-
 mission to one or both sexes.
Causes of excess of male births.
Proportion of the sexes in the bee family.
Excess of males perhaps sometimes deter-
 mined by selection.
Bright colours of lowly organised animals.
Sexual selection amongst spiders.
Cause of smallness of male spiders.
Use of phosphorescence of the glow-worm.
The humming noises of flies.
Use of bright colours to Hemiptera (bugs).
Musical apparatus of Homoptera.
Development of stridulating apparatus in
 Orthoptera.
Hermann Müller on sexual differences of
 bees.
Sounds produced by moths.
Display of beauty by butterflies.
Female butterflies, taking the more active
 part in courtship, brighter than their males.
Further cases of mimicry in butterflies and
 moths.
Cause of bright and diversified colours of
 caterpillars.

First
Edition
Vol. II.
Present
Edition.

Page

2
14

23
26
30
32
36
72
91

108
118
120

124
147-150

152
157

232


247

248
256
260

266
286
299
316

337
356

359 et seq.

373

380

Page

331
341

347
349
352
353
357
383
398

411
417
419

423
438-441

443
446

495-6


505

506
513-514
516

521
534
542-3
556

572
586

588 et seq.

59S-9

603


Brush-like scales of male Mallotus.

Further facts on courtship of fishes, and the
 spawning of Macropus.
Dufossé on the sounds made by fishes.
Belt on a frog protected by bright colouring.
Further facts on mental powers of snakes.
Sounds produced by snakes; the rattlesnake.
Combats of Chameleons.
Marshall on protuberances on birds' heads.
Further facts on display by the Argus
 pheasant.
Attachment between paired birds.
Female pigeon rejecting certain males.
Albino birds not finding partners, in a state
 of nature.
Direct action of climate on birds' colours.
Further facts on the ocelli in the Argus
 pheasant.
Display by humming-birds in courtship.
Cases with pigeons of colour transmitted to
 one sex alone.
Taste for the beautiful permament enough
 to allow of sexual selection with the lower
 animals.
Horns of sheep originally a masculine
 character.
Castration affecting horns of animals.
Prong-horned variety of Cervus virginianus.
Relative sizes of male and female whales and
 seals.
Absence of tusks in male miocene pigs.
Dobson on sexual differences of bats.
Recks on advantage from peculiar colouring.
Difference of complexion in men and women
 of an African tribe.
Speech subsequent to singing,
Schopenhauer on importance of courtship to
 mankind.
Revision of discussion on communal marriages
 and promiscuity.
Power of choice of woman in marriage,
 amongst savages.
Long-continued habit of plucking out hairs
 may produce an inherited effect.


This work was published before January 1, 1923, and is in the public domain worldwide because the author died at least 100 years ago.