F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

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, and being inherited at a corresponding age RUDIMENTARY ORGANS; their origin explained Summary

F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

this element of descent, the one certainly known cause of similarity in organic beings, we shall understand what is meant by the Natural System: it is genealogical in its attempted arrangement, with the grades of acquired difference marked by the terms, varieties, species, genera, families, orders, and classes. On this same view of descent with modification, all the great facts in Morphology become intelligible, whether we look to the same pattern displayed by the different species of the same

F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

pal ontologists is frequently 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, are 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 [page] 40

F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

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 modification, that the same parent-forms formerly inhabited both areas; and we almost invariably find that wherever many closely allied species inhabit two [page] 56

F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

less and more improved states of a species, as well as the original parent-species itself, will generally tend to become extinct. So it probably will be with many whole collateral lines of descent, which will be conquered by later and improved lines of descent. If, however, the modified offspring of a species get into some distinct country, or become quickly adapted to some quite new station, in which offspring and progenitor do not come into competition, both may continue to exist. If, then

F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

covered having affinities directed towards very distinct groups. Yet if we compare the older Reptiles and Batrachians, the older Fish, the older Cephalopods, and the eocene Mammals, with the more recent members of the same classes, we must admit that there is 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 reader to turn to the diagram in the fourth chapter. We

F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

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, all true classification being genealogical; that community of descent is the hidden bond which naturalists have been unconsciously seeking, and not some unknown plan of creation, or the enunciation of general propositions, and the mere putting

F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

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 may now be found, they must in the course of successive generations have travelled from some one point to all the others. We are often wholly unable even to conjecture how this could have been effected. Yet

F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

presented a widely different aspect; and that the older continents, formed of formations older than any known to us, exist now only as remnants in a metamorphosed condition, or lie still buried under the ocean. Passing from these difficulties, the other great leading facts in pal ontology 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

F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

, because allied in blood and alike in some other respects. With species in a state of nature, every naturalist has in fact brought descent into his classification; for he includes in his lowest grade, that of the species, the two sexes; and how enormously these sometimes differ in the most important characters, is known to every naturalist: scarcely a single fact can be predicated in common of the adult males and hermaphrodites of certain cirripedes, and yet no one dreams of separating them. As

F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

growth False correlations Multiple, rudimentary, and lowly organised structures variable Parts developed in an unusual manner are highly variable: specific characters more variable than generic: secondary sexual characters variable Species of the same genus vary in an analogous manner Reversions to long-lost characters Summary .. .. .. .. Page 165-206 CHAPTER VI. DIFFICULTIES OF THE THEORY. Difficulties of the theory of descent with modification Transitions Absence or rarity of transitional

F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

physiology lends any countenance; their existence would seem to show that the amount of modification which living beings have undergone during geological time is but very small in relation to the whole series of changes which they have suffered. In December, 1859, Dr. Hooker published his 'Introduction to the Australian Flora.' In the first part of this great work he admits the truth of the descent and modification of species, and supports this doctrine by many original observations. The first edition of

F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

He who will go thus far, ought not to hesitate to go one step further, if he finds on finishing this volume that large bodies of facts, otherwise inexplicable, can be explained by the theory of descent with modification; he ought to admit that a structure even as perfect as an eagles eye might be formed by natural selection, although in this case he does not know the transitional states. It has been objected that in order to modify the eye and still preserve it as a perfect instrument, many

F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

something more is included in our classification than mere resemblance. I believe that something more is included, and that propinquity of descent the only known cause of the similarity of organic beings is the bond, hidden as it is by various degrees of modification, which is partially revealed to us by our classifications. Let us now consider the rules followed in classification, and the difficulties which are encountered, on the view that classification either gives some unknown plan of

F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

succession of the same types within the same areas Summary of preceding and present chapter. LET us now see whether the several facts and laws relating to the geological succession of organic beings, better accord with the common view of the immutability of species, or with that of their slow and gradual modification, through descent and natural selection. New species have appeared very slowly, one after another, both on the land and in the waters. Lyell has shown that it is hardly possible to resist

F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

Hence the six new species descended from (I), and the eight descended from (A), will have to be ranked as very 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 letters

F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

same purpose. On the 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 of sheep, the reappearance of minute dangling horns in hornless breeds of cattle, more especially, according to Youatt, in young animals, and the state of the whole flower in the cauliflower. We often see rudiments of various parts in monsters

F387    Book:     Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th ed. Tenth thousand.   Text   Image   PDF

opinion it has done excellent service in this country in calling 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 modification, than that they have been separately created: the author

F937.1    Book:     Darwin, C. R. 1871. The descent of man, and selection in relation to sex. London: John Murray. vol. 1.   Text   Image   PDF

how it is that resemblances in unimportant structures, in useless and rudimentary organs, and in parts not as yet fully developed or functionally active, are by far the most serviceable for classification; for they can hardly be due to adaptations within a late period; and thus they reveal the old lines of descent or of true affinity. We can further see why a great amount of modification in some one character ought not to lead us to separate widely any two organisms. A part which already differs

A576    Pamphlet:     Wright, Chauncey. 1871. Darwinism: Being an examination of Mr. St. George Mivart's 'Genesis of species,' [Reprinted from the 'North American Review,' July 1871, with additions]. London: John Murray. 46pp.   Text   Image

processes by which races of animals and plants have been derived by descent from different ancestral forms. What is no longer regarded with suspicion as secretly hostile to religious beliefs by many truly religious thinkers is that which is denoted in common by the various names transmutation, development, derivation, evolution, and descent with modification. These terms are synonymous in their primary and general signification, but refer secondarily to various hypotheses of the processes of

F2042    Periodical contribution:     Darwin, C. R. 1871. The descent of man. (from advance-sheets of Darwin's new work.) Appletons' Journal 5 (98) (11 February): 171-173.   Text   Image

some have retained the same form during an enormous lapse of time. From what we see going on under domestication, we learn that within the same period some of the co-descendants of the same species may be not at all changed, some a little, and some greatly changed. Thus it may have been with man, who has undergone a great amount of modification in certain characters in comparison with the higher apes. We have thus far endeavored rudely to trace the genealogy of the vertebrata by the aid of their

F391    Book:     Darwin, C. R. 1872. The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 6th ed.; with additions and corrections. Eleventh thousand.   Text   Image   PDF

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 both cases the beings have been

F391    Book:     Darwin, C. R. 1872. The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 6th ed.; with additions and corrections. Eleventh thousand.   Text   Image   PDF

species had been independently created and varieties had been produced through secondary laws. If we admit that the geological record is imperfect to an extreme degree, then the facts, which the record does give, strongly 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

F391    Book:     Darwin, C. R. 1872. The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 6th ed.; with additions and corrections. Eleventh thousand.   Text   Image   PDF

developed condition; and this in some cases implies an enormous amount of modification in the descendants. Throughout whole classes various structures are formed on the same pattern, and at a very early age the embryos closely resemble each other. Therefore I cannot doubt that the theory of descent with modification embraces all the members of the same great class or kingdom. I believe that animals are descended from at most only four or five progenitors, and plants from an equal or lesser number

F391    Book:     Darwin, C. R. 1872. The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 6th ed.; with additions and corrections. Eleventh thousand.   Text   Image   PDF

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, all true classification being genealogical;—that community of descent is the hidden bond which naturalists have been unconsciously seeking, and not some unknown plan of creation, or the enunciation of general propositions, and the mere putting together and