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F380    Book:     Darwin, C. R. 1860. The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. New York: D. Appleton. New edition, revised and augmented.   Text   Image   PDF
facts can be explained, as follows, on the view of descent with modification. It is commonly assumed, perhaps from monstrosities often affecting the embryo at a very early period, that slight variations necessarily appear at an equally early period. But we have little evidence on this head indeed the evidence rather points the other way; for it is notorious that breeders of cattle, horses, and various fancy animals, cannot positively tell, until some time after the animal has been born, what its
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F380    Book:     Darwin, C. R. 1860. The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. New York: D. Appleton. New edition, revised and augmented.   Text   Image   PDF
these vestiges of nails have appeared, not from unknown laws of growth, but in order to excrete horny matter, as that the rudimentary nails on the fin of the manatee were formed for this purpose. On my view of descent with modification, the origin of rudimentary organs is simple. We have plenty of cases of rudimentary organs in our domestic productions, as the stump of a tail in tailless breeds, the vestige of an ear in earless breeds, the reappearance of minute dangling horns in hornless breeds
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F380    Book:     Darwin, C. R. 1860. The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. New York: D. Appleton. New edition, revised and augmented.   Text   Image   PDF
organisation, which has long existed, to be inherited we can understand, on the genealogical view of classification, bow it is that systematists have found rudimentary parts as useful as, or even sometimes more useful than, parts of high physiological importance. Rudimentary organs may be compared with the letters in a word, still retained in the spelling, but become useless in the pronunciation, but which serve as a clue in seeking for its derivation. On the view of descent with modification, we may
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F380    Book:     Darwin, C. R. 1860. The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. New York: D. Appleton. New edition, revised and augmented.   Text   Image   PDF
descent with modification are grave enough. All the individuals of the same species, and all the species of the same genus, or even higher group, must have descended from common parents; and therefore, in however distant and isolated parts of the world they are now found, they must in the course of successive generations have passed from some one part to the others. We are often wholly unable even to conjecture how this could have been effected. Yet, as we have reason to believe that some species
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F380    Book:     Darwin, C. R. 1860. The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. New York: D. Appleton. New edition, revised and augmented.   Text   Image   PDF
more important objections relate to questions on which we are confessedly ignorant; nor do we know how ignorant we are. We do not know all the possible transitional gradations between the simplest and the most perfect organs; it cannot be pretended that we know all the varied means of Distribution during the long lapse of years, or that we know how imperfect the Geological Record is. Grave as these several difficulties are, in my judgment they do not overthrow the theory of descent with
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F380    Book:     Darwin, C. R. 1860. The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. New York: D. Appleton. New edition, revised and augmented.   Text   Image   PDF
support the theory of descent with modification. New species have come on the stage slowly and at successive intervals; and the amount of change, after equal intervals of time, is widely different in different groups. The extinction of species and of whole groups of species, which has played so conspicuous a part in the history of the organic world, almost inevitably follows on the principle of natural selection; for old forms will be supplanted by new and improved forms. Neither single
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F380    Book:     Darwin, C. R. 1860. The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. New York: D. Appleton. New edition, revised and augmented.   Text   Image   PDF
there has been during the long course of ages much migration from one part of the world to another, owing to former climatal and geographical changes, and to the many occasional and unknown means of dispersal, then we can understand, on the theory of descent with modification, most of the great leading facts in Distribution. We can see why there should be so striking a parallelism in the distribution of organic beings throughout space, and in their geological succession throughout time; for in
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F380    Book:     Darwin, C. R. 1860. The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. New York: D. Appleton. New edition, revised and augmented.   Text   Image   PDF
should not inhabit oceanic islands; and why, on the other hand, new and peculiar species of bats, which can traverse the ocean, should so often be found on islands far distant from any continent. Such facts as the presence of peculiar species of bats, and the absence of all other mammals, on oceanic islands, are utterly inexplicable on the theory of independent acts of creation. The existence of closely allied or representative species in any two areas, implies, on the theory of descent with
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F380    Book:     Darwin, C. R. 1860. The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. New York: D. Appleton. New edition, revised and augmented.   Text   Image   PDF
intervals between existing orders. Organs in a rudimentary condition plainly show that an early progenitor had the organ in a fully developed state; and this in some instances necessarily implies an enormous amount of modification in the descendants. Throughout whole classes various structures are formed on the same pattern, and at an embryonic age the species closely resemble each other. Therefore I cannot doubt that the theory of descent with modification embraces all the members of the same
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A17    Review:     Carpenter, W. B. 1860. [Review of Origin and On the tendency to form varieties]. Darwin on the Origin of species. National Review, 10: 188-214.   Text   PDF
by years, but only moderately long as measured geologically, closely-allied forms, or, as some authors term them, representative species. Now as this is just what we do find, the theory of descent, with modification, is so far conformable [page] 21
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A2908    Periodical contribution:     Gray, Asa. 1860. Darwin on the Origin of species. Annals and Magazine of Natural History 3d ser. 6 373-86.   Text   PDF
to the remarkable book under consideration. The questions What will he do with it? and How far will he carry it? the author answers at the close of the volume: cannot doubt that the theory of descent with modification embraces all the members of the same class. Furthermore, I believe that all animals have descended from at most only four or five progenitors, and plants from an equal or lesser number. Seeing that analogy as strongly suggests a further step in the same direction, while he protests
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A50    Review:     [Gray, Asa]. 1860. Review of Darwin's theory on the origin of species by means of natural selection. American Journal of Science and Arts. (Ser. 2) 29 (March): 153-184. [Silliman's Journal]   Text   Image   PDF
classes, by natural selection. He does not doubt that the theory of descent with modification embraces all the members of the same class, and he concedes that analogy would press the conclusion still farther; while he admits that the more distinct the forms are, the more the arguments fall away in force. To command assent we naturally require decreasing probability to be overbalanced by an increased weight of evidence. An opponent might plausibly, and perhaps quite fairly, urge that the links in
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A46    Review:     Carpenter, W. B. 1860. The Theory of Development in Nature. British and Foreign Medico-Chirurgical Review 25 (April): 367-404   Text   Image   PDF
deposits or in the contents of the same caves. Now when due weight is given to these and other considerations of the like tendency, it obviously becomes very difficult to form any rational conception as to the introduction of new types of organic life in any other mode than by descent with modification from those previously existing. We know that physical changes of the same order with those which formerly modified the condition of the earth's surface, are still in progress; if new creations of
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A46    Review:     Carpenter, W. B. 1860. The Theory of Development in Nature. British and Foreign Medico-Chirurgical Review 25 (April): 367-404   Text   Image   PDF
found out that butterflies and beetles were caterpillars in the earlier stage of their existence, instead of coming out from the egg in the full possession of their insect attributes, was considered on that account less religious than his neighbours. Why, then, should it be regarded as impious to maintain that an analogous development went on during what may be called the life of the world; and that the existing forms of Plants and Animals have originated by genetic descent with modification
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A46    Review:     Carpenter, W. B. 1860. The Theory of Development in Nature. British and Foreign Medico-Chirurgical Review 25 (April): 367-404   Text   Image   PDF
thus comes, in Mr. Darwin's view, to be only one of time; and he holds that any amount of change of type is conceivable on the principle of natural selection, if an unlimited lapse of ages be allowed for its operation. On this principle he would trace back all the species of one genus as derived by direct descent with modification from a single prototype; all the genera of one family, in like manner, he regards as having had a common ancestor still more remote; and by parity of reasoning he would
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A46    Review:     Carpenter, W. B. 1860. The Theory of Development in Nature. British and Foreign Medico-Chirurgical Review 25 (April): 367-404   Text   Image   PDF
action. Many of the great leading facts in pal ontology certainly harmonize most remarkably with the doctrine of continuous descent with modification through natural selection. We can thus understand how it is that new species come in slowly and successively; how species of different classes do not necessarily change together, or at the same rate, or in the same degree; yet in the long run that all undergo modification to some extent. The extinction of old forms is the almost invariable
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A49    Review:     [Gray, Asa]. 1860. [Review of Origin]. Darwin on the origin of species. Atlantic Monthly 6 (July-August): 109-116, 229-239.   Text   Image   PDF
the acknowledged varieties of any one species are the descendants of that species. Furthermore, I am convinced that Natural Selection has been the main, but not exclusive means of modification. This is the kernel of the new theory, the Darwinian creed, as recited at the close of the introduction to the remarkable book under consideration. The questions, What will he do with it? and How far will he carry it? the author answers at the close of the volume: I cannot doubt that the theory of descent
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A509    Review:     [Dixon, Edmund Saul]. 1860. [Review of Origin]. Natural selection. All the Year Round 3: 63 (7 July): 293-299.   Text   Image   PDF
independently created is erroneous. He is fully convinced that species are not immutable;* but that those belonging to what are called the same genera are lineal descendants of some other and generally extinct species. The modifications which species have undergone are mainly, but not exclusively, he believes, the result of a process called Natural Selection. He cannot doubt that the theory of descent, with modification, embraces all the members of the same class. He believes that animals have
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F3506    Periodical contribution:     Darwin, C. R. 1877. [Letter to T. Davidson, 1861]. In T. Davidson, What is a Brachiopod? Part III. The Geological Magazine or Monthly Journal of Geology n.s., 4, no. 6 (June): 262-273, p. 269.   Text   Image
suspect that on the whole it would be favourable to the notion of descent with modification. I can hardly doubt that many curious points would occur to any one thoroughly instructed in the subject, who could consider a group of beings under the point of view of descent with modification. All those forms which have come down from an ancient period very slightly modified ought, I think, to be omitted; and those forms alone considered which have undergone considerable change at each successive
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
CHAPTER VI. DIFFICULTIES ON THEORY. Difficulties on the theory of descent with modification — Transitions — Absence or rarity of transitional varieties — Transitions in habits of life — Diversified habits in the same species — Species with habits widely different from those of their allies — Organs of extreme perfection — Means of transition — Cases of difficulty — Natura non facit saltum — Organs of small importance — Organs not in all cases absolutely perfect — The law of Unity of Type and
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
ORGANS. CLASSIFICATION, groups subordinate to groups — Natural system — Rules and difficulties in classification, explained on the theory of descent with modification — Classification of varieties — Descent always used in classification — Analogical or adaptive characters — Affinities, general, complex and radiating — Extinction separates and defines groups — MORPHOLOGY, between members of the same class, between parts of the same individual — EMBRYOLOGY, laws of, explained by variations not
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
inferences briefly recapitulated. That many and serious objections may be advanced against the theory of descent with modification through natural selection, I do not deny. I have endeavoured to give to them their full force. Nothing at first can appear more difficult to believe than that the more complex organs and instincts should have been perfected, not by means superior to, though analogous with, human reason, but by the accumulation of innumerable slight variations, each good for the
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
are produced by descent with modification, from two or more species of the same genus. And the two or more parent-species are supposed to have descended from some one species of an earlier genus. In our diagram, this is indicated by the broken lines, beneath the capital letters, converging in sub-branches downwards towards a single point; this point representing a single species, the supposed single parent of our several new sub-genera and genera. It is worth while to reflect for a moment on
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
different colours; how will it account for one species of plant having pointed and another species obtuse leaves? I can give no definite answer to such questions; but I might ask in return, were these differences, on the doctrine of independent creation, formed for no purpose? If of use, or if due to correlation of growth, they could assuredly be formed through the natural preservation of such useful or correlated variations. I believe in the doctrine of descent with modification
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
CHAPTER VI. DIFFICULTIES ON THEORY. Difficulties on the theory of descent with modification — Transitions — Absence or rarity of transitional varieties — Transitions in habits of life — Diversified habits in the same species — Species with habits widely different from those of their allies — Organs of extreme perfection — Means of transition — Cases of difficulty — Natura non facit saltum — Organs of small importance — Organs not in all cases absolutely perfect — The law of Unity of Type and
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
older Cephalopods, and the eocene Mammals, with the more recent members of the same classes, we must admit that there is some truth in the remark. Let us see how far these several facts and inferences accord with the theory of descent with modification. As the subject is somewhat complex, I must request the [page] 35
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
members of the same groups; and this by the concurrent evidence of our best palæontologists seems frequently to be the case. Thus, on the theory of descent with modification, the main facts with respect to the mutual affinities of the extinct forms of life to each other and to living forms, seem to me explained in a satisfactory manner. And they are wholly inexplicable on any other view. On this same theory, it is evident that the fauna of any great period in the earth's history will be
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
Africa than it is at the present time. Analogous facts could be given in relation to the distribution of marine animals. On the theory of descent with modification, the great law of the long enduring, but not immutable, succession of the same types within the same areas, is at once explained; for the inhabitants of each quarter of the world will obviously tend to leave in that quarter, during the next succeeding period of time, closely allied though in some degree modified descendants. If the
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
wholly different aspect; and that the older continents, formed of formations older than any known to us, may now all be in a metamorphosed condition, or may lie buried under the ocean. Passing from these difficulties, the other great leading facts in palæontology seem to me simply to follow on the theory of descent with modification through natural selection. We can thus understand how it is that new species come in slowly and successively; how species of different classes do not necessarily
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
to genera exclusively confined to the south, at these and other distant points of the southern hemisphere, is, on my theory of descent with modification, a far more remarkable case of difficulty. For some of these species are so distinct, that we cannot T 2 [page] 41
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
remove many difficulties, but it would not explain all the facts in regard to insular productions. In the following remarks I shall not confine myself to the mere question of dispersal; but shall consider some other facts, which bear on the truth of the two theories of independent creation and of descent with modification. The species of all kinds which inhabit oceanic islands are few in number compared with those on equal continental areas: Alph. de Candolle admits this for plants, and
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
CHAPTER XIII. MUTUAL AFFINITIES OF ORGANIC BEINGS: MORPHOLOGY: EMBRYOLOGY: RUDIMENTARY ORGANS. CLASSIFICATION, groups subordinate to groups — Natural system — Rules and difficulties in classification, explained on the theory of descent with modification — Classification of varieties — Descent always used in classification — Analogical or adaptive characters — Affinities, general, complex and radiating — Extinction separates and defines groups — MORPHOLOGY, between members of the same class
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
with slightly different grades of difference, have been subsequently discovered. All the foregoing rules and aids and difficulties in classification are explained, if I do not greatly deceive myself, on the view that the natural system is founded on descent with modification; that the characters which naturalists consider as showing true affinity between any two or more species, are those which have been inherited from a common parent, and, in so far, all true classification is genealogical
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
which it is developed? I believe that all these facts can be explained, as follows, on the view of descent with modification. It is commonly assumed, perhaps from monstrosities often affecting the embryo at a very early period, that slight variations necessarily appear at an equally early period. But we have little evidence on this head—indeed the evidence rather points the other way; for it is notorious that breeders of cattle, horses, and various fancy animals, cannot positively tell, until some
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
of growth, but in order to excrete horny matter, as that the rudimentary nails on the fin of the manatee were formed for this purpose. On my view of descent with modification, the origin of rudimentary organs is simple. We have plenty of cases of rudimentary organs in our domestic productions,—as the stump of a tail in tailless breeds,—the vestige of an ear in earless breeds,—the reappearance of minute dangling horns in hornless breeds of cattle, more especially, according to Youatt, in young
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
physiological importance. Rudimentary organs may be compared with the letters in a word, still retained in the spelling, but become useless in the pronunciation, but which serve as a clue in seeking for its derivation. On the view of descent with modification, we may conclude that the existence of organs in a rudimentary, imperfect, and useless condition, or quite aborted, far [page] 48
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
, together with their modification through natural selection, with its contingencies of extinction and divergence of character. In considering this view of classification, it should be borne in mind that the element of descent has been universally used in ranking together the sexes, ages, and acknowledged varieties of the same species, however different they may be in structure. If we extend the use of this element of descent,—the only certainly known cause of similarity in organic beings,—we shall
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
fertility. Turning to geographical distribution, the difficulties encountered on the theory of descent with modification are serious enough. All the individuals of the same species, and all the species of the same genus, or even higher group, must have descended from common parents; and therefore, in however distant and isolated parts of the world they are now found, they must in the [page] 49
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
varieties have been produced by secondary laws. If we admit that the geological record is imperfect in an extreme degree, then such facts as the record gives support the theory of descent with modification. New species have come on the stage slowly and at successive intervals; and the amount of change, after equal [page] 50
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
descent. Looking to geographical distribution, if we admit that there has been during the long course of ages much migration from one part of the world to another, owing to former climatal and geographical changes and to the many occasional and unknown means of dispersal, then we can understand, on the theory of descent with modification, most of the great leading facts in Distribution. We can see why there should be so striking a parallelism in the distribution of organic beings throughout space
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
the two countries will have received colonists from some third source or from each other, at various periods and in different proportions, the course of modification in the two areas will inevitably have been different. On this view of migration, with subsequent modification, we can see why oceanic islands should be inhabited by few species, but of these, that many should be peculiar. We can clearly see why those animals which cannot cross wide spaces of ocean, as frogs and terrestrial mammals
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
that innumerable beings within each great class have been created with plain, but deceptive, marks of descent from a single parent. It may be asked how far I extend the doctrine of the modification of species. The question is difficult to answer, because the more distinct the forms are which we may consider, by so much the arguments fall away in force. But some arguments of the greatest weight extend very far. All the members of whole classes can be connected together by chains of affinities
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A567    Pamphlet:     Gray, Asa. 1861. Natural Selection not inconsistent with Natural Theology. A free examination of Darwin's treatise on the Origin of Species, and of its American reviewers. Reprinted from the Atlantic monthly for July, August, and October, 1860. London: Trübner & Co., Boston: Ticknor and Fields.   Text   Image   PDF
varieties of any one species are the descendants of that species. Furthermore, I am convinced that Natural Selection has been the main, but not exclusive, means of modification. This is the kernel of the new theory, the Darwinian creed, as recited at the close of the introduction to the remarkable book under consideration. The questions, What will he do with it? and How far will he carry it? the author answers at the close of the volume: I cannot doubt that the theory of descent with modification
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F381    Book:     Darwin, C. R. 1861. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 3d ed. Seventh thousand.   Text   Image   PDF
scientific caution, immediately had a very wide circulation. In my opinion it has done excellent service in calling in this country attention to the subject, in removing prejudice, and in thus preparing the ground for the reception of analogous views. In 1846 the veteran geologist M. J. d'Omalius d'Halloy published in an excellent, though short paper ('Bulletins de l'Acad. Roy. Bruxelles,' tom. xiii. p. 581), his opinion that it is more probable that new species have been produced by descent with
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F385    Book:     Darwin, C. R. 1866. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 4th ed. 8th thousand.   Text   Image   PDF
CHAPTER VI. DIFFICULTIES ON THEORY. Difficulties on the theory of descent with modification Transitions Absence or rarity of transitional varieties Transitions in habits of life Diversified habits in the same species Species with habits widely different from those of their allies Organs of extreme perfection Modes of transition Cases of difficulty Nature non facit saltum Organs of small inportance Organs not in all cases absolutely perfect The law of Unity of Type and of the Conditions of
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F385    Book:     Darwin, C. R. 1866. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 4th ed. 8th thousand.   Text   Image   PDF
. CLASSIFICATION, groups subordinate to groups Natural system Rules and difficulties in classification, explained on the theory of descent with modification Classification of varieties Descent always used in classification Analogical or adaptive characters Affinities, general, complex, and radiating Extinction separates and defines groups MORPHOLOGY, between members of the same class, between parts of the same individual EMBRYOLOGY, laws of, explained by variations not supervening at an early age
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F385    Book:     Darwin, C. R. 1866. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 4th ed. 8th thousand.   Text   Image   PDF
CHAPTER XIII. MUTUAL AFFINITIES OF ORGANIC BEINGS: MORPHOLOGY: EMBRYOLOGY: RUDIMENTARY ORGANS. CLASSIFICATION, groups subordinate to groups Natural system Rules and difficulties in classification, explained on the theory of descent with modification Classification of varieties Descent always used in classification Analogical or adaptive characters Affinities, general, complex, and radiating Extinction separates and defines groups MORPHOLOGY, between members of the same class, between parts of
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F385    Book:     Darwin, C. R. 1866. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 4th ed. 8th thousand.   Text   Image   PDF
briefly recapitulated. That many and serious objections may be advanced against the theory of descent with modification through natural selection, I do not deny. I have endeavoured to give to them their full force. Nothing at first can appear more difficult to believe than that the more complex organs and instincts should have been perfected, not by means superior to, though analogous with, human reason, but by the accumulation of innumerable slight variations, each good for the individual
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F385    Book:     Darwin, C. R. 1866. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 4th ed. 8th thousand.   Text   Image   PDF
distinct genera, or even as distinct sub-families. Thus it is, as I believe, that two or more genera are produced by descent with modification, from two or more species of the same genus. And the two or more parent-species are supposed to have descended from some one species of an earlier genus. In our diagram, this is indicated by the broken lines, beneath the capital [page] 13
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F385    Book:     Darwin, C. R. 1866. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 4th ed. 8th thousand.   Text   Image   PDF
for one species of plant having pointed and another species blunt leaves? I can give no definite answer to such questions; but I might ask in return, were these differences, on the doctrine of independent creation, formed for no purpose? If of use, or if due to correlation of growth, they could assuredly be formed through the natural preservation of such useful or correlated variations. I believe in the doctrine of descent with modification, notwithstanding that this or that particular change of
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