DARWIN ON THE ORIGIN
OF SPECIES
Excerpts from the 1859 1st edition of Charles Darwin's
major work: The Origin of Species By Means of
Natural Selection, or the Preservation of Favored Races in the Struggle
for Existence. His contribution (along with Wallace) was,
of course, demonstration of the power of the idea that species may undergo
change due to "natural selection". Such selection was argued
to result (to quote from the "Introduction") from "the Struggle for Existence
amongst all organic beings throughout the world, which inevitably follows
from the high geometrical powers of increase.... This is the doctrine of
Malthus, applied to the whole animal and vegetable kingdoms."
From Chapter 4: Natural Selection
Summary of Chapter. If during the long course
of ages and under varying conditions of life, organic beings vary at all
in the several parts of their organization, and I think this cannot be
disputed; if there be, owing to the high geometrical powers of increase
of each species, at some age, season, or year, a severe struggle for life,
and this certainly cannot be disputed; then, considering the infinite complexity
of the relations of all organic beings to each other and to their conditions
of existence, causing an infinite diversity in structure, constitution,
and habits, to be advantageous to them, I think it would be a most extraordinary
fact if no variation ever occurred useful to each being's own welfare,
in the same way as so many variations have occurred useful to man.
But if variations useful to any organic being do occur, assuredly individuals
thus characterised will have the best chance of being preserved in the
struggle for life; and from the strong principle of inheritance they will
tend to produce offspring similarly characterised. This principle
of preservation, I have called, for the sake of brevity, Natural Selection.
Natural selection, on the principle of qualities being inherited at corresponding
ages, can modify the egg, seed, or young, as easily as the adult.
Amongst many animals, sexual selection will give its aid to ordinary
selection, by assuring to the most vigorous and best adapted males the
greatest number of offspring. Sexual selection will also give characters
useful to males alone, in their struggles with other males.
Whether natural selection has really thus acted
in nature, in modifying and adapting the various forms of life to their
several conditions and stations, must be judged of by the general tenour
and balance of evidence given in the following chapters. But we already
see how it entails extinction; and how largely extinction has acted in
the world's history, geology plainly declares. Natural selection,
also, leads to divergence of character; for more living beings can be supported
on the same area the more they diverge in structure, habits, and constitution,
of which we see proof by looking at the inhabitants of any small spot or
at naturalised productions. Therefore during the modification of the descendants
of any one species, and during the incessant struggle of all species to
increase in numbers, the more diversified these descendants become, the
better will be their chance of succeeding in the battle of life.
Thus the small differences distinguishing varieties of the same species,
will steadily tend to increase till they come to equal the greater differences
between species of the same genus, or even of distinct genera.
...On these principles, I believe, the nature of
the affinities of all organic beings may be explained. It is a truly
wonderful fact -- the wonder of which we are apt to overlook from familiarity
-- that all animals and all plants throughout all time and space should
be related to each other in group subordinate to group, in the manner which
we everywhere behold -- namely, varieties of the same species most closely
related together, species of the same genus less closely and unequally
related together, forming sections and sub-genera, species of distinct
genera much less closely related, and genera related in different degrees,
forming sub-families, families, orders, sub-classes, and classes.
The several subordinate groups in any class cannot be ranked in a single
file, but seem rather to be clustered round points, and these round other
points, and so on in almost endless cycles. On the view that each
species has been independently created, I can see no explanation of this
great fact in the classification of all organic beings; but, to the best
of my judgment, it is explained through inheritance and the complex action
of natural selection, entailing extinction and divergence of character....
From Chapter 3: Struggle for Existence
...Nothing is easier than to admit in words the
truth of the universal struggle for life, or more difficult -- at least
I have found it so -- than constantly to bear this conclusion in mind.
Yet unless it be thoroughly engrained in the mind, I am convinced that
the whole economy of nature, with every fact on distribution, rarity, abundance,
extinction, and variation, will be dimly seen or quite misunderstood.
We behold the face of nature bright with gladness, we often see superabundance
of food; we do not see, or we forget, that the birds which are idly singing
round us mostly live on insects or seeds, and are thus constantly destroying
life; or we forget how largely these songsters, or their eggs, or their
nestlings, are destroyed by birds and beasts of prey; we do not always
bear in mind, that though food may now be superabundant, it is not so at
all seasons of each recurring year.
I should premise that I use the term Struggle for
Existence in a large and metaphorical sense, including dependence of one
being on another, and including (which is more important) not only the
life of the individual, but success in leaving progeny....
From Chapter 14: Recapitulation and Conclusion
...During early periods of the earth's history,
when the forms of life were probably fewer and simpler, the rate of change
was probably slower; and at the first dawn of life, when very few forms
of the simplest structure existed, the rate of change may have been slow
in an extreme degree. The whole history of the world, as at present
known, although of a length quite incomprehensible by us, will hereafter
be recognised as a mere fragment of time, compared with the ages which
have elapsed since the first creature, the progenitor of innumerable extinct
and living descendants, was created.
In the distant future I see open fields for far
more important researches. Psychology will be based on a new foundation,
that of the necessary acquirement of each mental power and capacity by
gradation. Light will be thrown on the origin of man and his history.
Authors of the highest eminence seem to be fully
satisfied with the view that each species has been independently created.
To my mind it accords better with what we know of the laws impressed on
matter by the Creator, that the production and extinction of the past and
present inhabitants of the world should have been due to secondary causes,
like those determining the birth and death of the individual. When I view
all beings not as special creations, but as the lineal descendants of some
few beings which lived long before the first bed of the Silurian system
was deposited, they seem to me to be ennobled....As all the living forms
of life are the lineal descendants of those which lived long before the
Silurian epoch, we may feel certain that the ordinary succession by generation
has never once been broken, and that no cataclysm has desolated the whole
world. Hence we may look with some confidence to a secure future of equally
inappreciable length. And as natural selection works solely by and
for the good of each being, all corporeal and mental endowments will
tend to progress towards perfection.
It is interesting to contemplate an entangled bank,
clothed with many plants of many kinds, with birds singing on the bushes,
with various insects flitting about, and with worms crawling through the
damp earth, and to reflect that these elaborately constructed forms, so
different from each other, and dependent on each other in so complex a
manner, have all been produced by laws acting all around us. These
laws, taken in the largest sense, being Growth with Reproduction; Inheritance
which is almost implied by reproduction; Variability from the indirect
and direct action of the external conditions of life, and from use and
disuse; a Ratio of Increase so high as to lead to a Struggle for Life,
and as a consequence to Natural Selection, entailing Divergence of Character
and the Extinction of less improved forms. Thus, from the war of
nature, from famine and death, the
most exalted object which we are capable of conceiving, namely, the
production of the higher animals, directly follows. There is a grandeur
in this view of life, with its several powers, having been originally breathed
into a few forms or into one; and that, whilst this planet has gone cycling
on according to the fixed law of gravity, from so simple a beginning endless
forms most beautiful and most wonderful have been, and are being, evolved.
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