F880.1    Book:     Darwin, C. R. 1875. The variation of animals and plants under domestication. London: John Murray. 2d ed. vol. 1.   Text   Image   PDF

several islands had descended from each other, undergoing modification in the course of their descent; and that all the inhabitants of the archipelago were descended from those of the nearest land, namely America, whence colonists would naturally have been derived. But it long remained to me an inexplicable problem how the necessary degree of modification could have been effected, and it would have thus remained for ever, had I not studied domestic productions, and thus acquired a just idea of

F880.2    Book:     Darwin, C. R. 1875. The variation of animals and plants under domestication. London: John Murray. 2d ed. vol. 2.   Text   Image   PDF

, becomes a larva, it has to be adapted to the surrounding conditions in its structure and instincts, independently of those of its parents; and the principle of inheritance at corresponding periods of life renders this possible. This principle is, indeed, in one way so obvious that it escapes attention. We possess a number of races of animals and plants, which, when compared with one another and with 29 I have given in my 'Descent of Man' (2nd edit. p. 223) sufficient evidence that male animals

F880.1    Book:     Darwin, C. R. 1875. The variation of animals and plants under domestication. London: John Murray. 2d ed. vol. 1.   Text   Image   PDF

must have been carried back to their native homes. On the view that all the races are the product of variation, we can understand why they have not become feral, for the great amount of modification which they have undergone shows how long and how thoroughly they have been domesticated; and this would unfit them for a wild life. Fourthly.—If it be assumed that the characteristic differences between the various domestic races are due to descent from several aboriginal species, we must conclude

F3473    Periodical contribution:     Darwin, C. R. 1875. [Letter on animal tails]. In Lawson Tait, The uses of tails in animals. Birmingham Daily Post (8 April): 6.   Text   Image   PDF

letter 13-15 March 1875 in response to a letter of 12 March [1875] by Lawson Tait [born Robert Lawson Tait] (1845-1899) Birmingham surgeon, gynaecologist and anti-vivisectionist. On 16 March [1875] Tait wrote to thank Darwin for his reply. See Correspondence vol. 23. Much further information on the connections between Lawson Tait and Darwin can be found by searching the texts in Darwin Online, here. See also the printed items in Darwin's papers by Lawson Tait here. 3 Belt 1874. In CUL-DAR88.94

F401    Book:     Darwin, C. R. 1876. 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. [First issue of final definitive text]   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

F401    Book:     Darwin, C. R. 1876. 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. [First issue of final definitive text]   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

F401    Book:     Darwin, C. R. 1876. 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. [First issue of final definitive text]   Text   Image   PDF

, within known geological periods, undergone much modification, should in the older formations make some slight approach to each other; so that the older members should differ less from each other in some of their characters than do the existing members of the same groups; and this by the concurrent evidence of our best 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

F401    Book:     Darwin, C. R. 1876. 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. [First issue of final definitive text]   Text   Image   PDF

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, most of the great facts in Morphology become intelligible, whether we look to the same pattern displayed by the different species of the same class in their homologous organs, to whatever purpose applied; or to the serial and lateral homologies in each individual animal and plant. On the principle

F401    Book:     Darwin, C. R. 1876. 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. [First issue of final definitive text]   Text   Image   PDF

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 areas, some identical species are still common to both. Wherever many closely allied yet distinct species occur, doubtful forms and varieties belonging to the same groups likewise occur. It is a rule of high generality that the inhabitants of each area are related to

F401    Book:     Darwin, C. R. 1876. 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. [First issue of final definitive text]   Text   Image   PDF

the genealogical view of classification, how it is that systematists, in placing organisms in their proper places in the natural system, have often 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 for its derivation. On the view of descent with modification, we may conclude

F401    Book:     Darwin, C. R. 1876. 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. [First issue of final definitive text]   Text   Image   PDF

CHAPTER VI. DIFFICULTIES OF THE THEORY. Difficulties of the theory of descent with modification 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 Natura non facit saltum Organs of small importance Organs not in all cases absolutely perfect The law of Unity of Type and of the Conditions of Existence

F401    Book:     Darwin, C. R. 1876. 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. [First issue of final definitive text]   Text   Image   PDF

with modification 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 Natura non facit saltum Organs of small importance Organs not in all cases absolutely perfect The law of Unity of Type and of the Conditions of Existence embraced by the theory of Natural Selection 133-167 [page] vi

F401    Book:     Darwin, C. R. 1876. 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. [First issue of final definitive text]   Text   Image   PDF

, who has drawn an important distinction between certain classes of cases which have all been equally ranked by naturalists as homologous. He proposes to call the structures which resemble each other in distinct animals, owing to their descent from a common progenitor with subsequent modification, homogenous; and the resemblances which cannot thus be accounted for, he proposes to call homoplastic. For instance, he believes that the hearts of birds and mammals are as a whole homogenous, that is

F401    Book:     Darwin, C. R. 1876. 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. [First issue of final definitive text]   Text   Image   PDF

CHAPTER XIV. 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

F401    Book:     Darwin, C. R. 1876. 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. [First issue of final definitive text]   Text   Image   PDF

difficulties, but it does not accord with all the facts in regard to the productions of islands. In the following remarks I shall not confine myself to the mere question of dispersal, but shall consider some other cases bearing 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 Wollaston for

F401    Book:     Darwin, C. R. 1876. 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. [First issue of final definitive text]   Text   Image   PDF

briefly recapitulated. That many and serious objections may be advanced against the theory of descent with modification through variation and 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 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

F401    Book:     Darwin, C. R. 1876. 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. [First issue of final definitive text]   Text   Image   PDF

(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 be 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

F401    Book:     Darwin, C. R. 1876. 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. [First issue of final definitive text]   Text   Image   PDF

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. If, however, the modified offspring of a species get into some distinct country, or become quickly adapted to some [page] 9

F401    Book:     Darwin, C. R. 1876. 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. [First issue of final definitive text]   Text   Image   PDF

formerly more closely allied, than it is at present, to the northern half. In a similar manner we know, from Falconer and Cautley's discoveries, that Northern India was formerly more closely related in its mammals to 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

F401    Book:     Darwin, C. R. 1876. 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. [First issue of final definitive text]   Text   Image   PDF

same time be able to give a definite answer to the question why two distinct species, when crossed, as well as their hybrid offspring, are generally rendered more or less sterile, whilst two domesticated varieties when crossed and their mongrel offspring are perfectly fertile. 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

F948    Book:     Darwin, C. R. 1877. The descent of man, and selection in relation to sex. Twelfth thousand, revised and augmented. (final text). London: John Murray.   Text   PDF

, apart from the co-descendants of any other form; but if the parent-forms are related, so will be their descendants, and the two groups together will form a larger group. The amount of difference between the several groups—that is the amount of modification which each has undergone—is expressed by such terms as genera, families, orders, and classes. As we have no record of the lines of descent, the pedigree can be discovered only by observing the degrees of resemblance between the beings which are

F948    Book:     Darwin, C. R. 1877. The descent of man, and selection in relation to sex. Twelfth thousand, revised and augmented. (final text). London: John Murray.   Text   PDF

unimportant points. The greater number of naturalists who have taken into consideration the whole structure of man, including his mental faculties, have followed Blumenbach and Cuvier, and have placed man in a separate Order, under the title of the Bimana, and therefore on an equality with the orders of the Quadrumana, Carnivora, c. Recently many of our best naturalists have recurred to the view first propounded by Linnæus, so remarkable for his sagacity, and have placed man in the same Order with the

F3396    Book contribution:     Darwin, C. R. 1884. [Letter extract from 1881 and recollection of Darwin's words]. In R. Meldola, The presidential address: Darwin and modern evolution. Transactions of the Essex Field Club 3: 64-93.   Text

based, as previously stated, upon certain indisputable facts, viz., the high rate of multiplication of living beings, the struggle for existence, change of environment, and the principle of heredity. Every species is, on this view, genetically descended from some previously existing species; and since the changes of external conditions take place on the whole with extreme slowness, the process of modification must have proceeded with corresponding slowness. It is of the utmost importance to

F1795    Periodical contribution:     Darwin, C. R. 1881. Inheritance. Nature. A Weekly Illustrated Journal of Science 24 (21 July): 257.   Text   Image   PDF

remarkable case of the transmitted effects on the brain from an injury to a nerve; but I do not feel at liberty to give this case, as Mr Dupuy intends to pursue his researches, and will, as I hope, publish the results. CHARLES DARWIN July 13 1 There are numerous references to 'inheritance at corresponding ages' in Origin, Variation and Descent. See the annotated letter in Correspondence vol. 29, pp. 312-14. 2 Origin p. 448 ff. 3 Irving Prescott Bishop (1849-1913), American school science

F955    Book:     Darwin, C. R. 1882. The descent of man, and selection in relation to sex. London: John Murray. 2d ed., fifteenth thousand.   Text   Image   PDF

, apart from the co-descendants of any other form; but if the parent-forms are related, so will be their descendants, and the two groups together will form a larger group. The amount of difference between the several groups—that is the amount of modification which each has undergone—is expressed by such terms as genera, families, orders, and classes. As we have no record of the lines of descent, the pedigree can be discovered only by observing the degrees of resemblance between the beings which are