The Descent of Man
and Selection in Relation to Sex
Charles Darwin
(London: John Murray, 2nd rev. ed: 1877)
Introduction
Part I: The Descent or Origin of Man
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, etc.--The bearing of these three great
classes of facts on the origin of man
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
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--Progressve
Improvement--Tools and weapons used by animals--Abstraction, self-consciousness--Language--Sense of beauty--Belief in God, spiritual agencies, superstitions
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
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
civilized nations--Evidence that civilized nations were once barbarous
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, first, from his affinities, and,
secondly, from his structure--Early androgynous condition of the
Vertebrata--Conclusion
The nature and value of specific characters--Application to the races of
man--Arguments in favor 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
Part II: : 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
These characters absent in the lowest classes--Brilliant
colors--Mollusca--Annelids--Crustacea, secondary sexual characters strongly
developed; dimorphism; color; characters not acquired before maturity--Spiders,
sexual colors of; stridulation by the males--Myriapoda
Diversified structures possessed by the males for seizing the females-
Differences between the sexes, of which the meaning is not under
stood--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; colors--Xeuroptels, sexual differences In color--Hymenoptera, pugnacity and colors-Coleoptera, colors; furnished with great horns, apparently as an ornament; battles; stridulating organs generally
common to both sexes
Courtship of butterflies--Battles--Ticking noise--Colors common to both
sexes, or more brilliant in the males--Examples--Not due to the direct action
of the conditions of life--Colors adapted for protection--Colors of
moths--Display--Perceptive powers of the Lepidoptera--Variability--Causes of
the difference in color between the males and females--Mimicry, female
butterflies more brilliantly colored than the males--Bright colors of
caterpillars--Summary and concluding remarks on the secondary sexual characters
of insects--Birds and insects compared
FISHES: Courtship and battles of the males--Larger size of the
females--Males, bright colors and ornamental appendages; other strange
characters--Colors and appendages acquired by the males during the breeding
season alone--Fishes with both sexes brilliantly colored--Protective
colors--The less conspicuous colors 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 color between the
sexes--Vocal organs--REPTILES: Chelonians--Crocodiles--Snakes, colors in some
cases protective--Lizards, battles of--Ornamental appendages--Strange
differences in structure between the sexes--Colors--Sexual differences almost
as great as with 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
Choice exerted by the female--Length of courtship--Unpaired birds--Mental
qualities and taste for the beautiful--Preference or antipathy shown 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
Discussion as to why the males alone of some species, and both sexes of
others, are brightly colored--On sexually limited inheritance, as applied to
various structures and to brightly colored plumage--Nidification in relation to
color--Loss of nuptial plumage during the winter
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
coloring--Conspicuously colored birds--Novelty appreciated--Summary of the four
chapters on birds
The law of battle--Special weapons, confined 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 shown by either sex in the
pairing of quadrupeds
Voice--Remarkable sexual peculiarities in seals--Odor--Development of the
hair--Color of the hair and skin--Anomalous case of the female being more
ornamented than the male--Color and ornaments due to sexual selection--Color
acquired for the sake of protection--Color, though common to both sexes, often
due to sexual selection--On the disappearance of spots and stripes in adult
quadrupeds--On the colors and ornaments of the Quadrumana--Summary
Part III: : Sexual Selection in Relation to Man and Conclusion
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
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 civilized and savage nations--Conditions favorable 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--Color of
the skin--Summary
Main conclusion that man is descended from some lower form--Manner of
development--Genealogy of man--Intellectual and moral faculties--Sexual
selection--Concluding remarks