The Foundations of the Origin of Species. Darwin Charles. Читать онлайн. Newlib. NEWLIB.NET

Автор: Darwin Charles
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are not immutable. The affinity of different groups, the unity of types of structure, the representative forms through which fœtus passes, the metamorphosis of organs, the abortion of others cease to be metaphorical expressions and become intelligible facts. We no longer look «an» on animal as a savage does at a ship179, or other great work of art, as a thing wholly beyond comprehension, but we feel far more interest in examining it. How interesting is every instinct, when we speculate on their origin as an hereditary or congenital habit or produced by the selection of individuals differing slightly from their parents. We must look at every complicated mechanism and instinct, as the summary of a long history, «as the summing up» of180 useful contrivances, much like a work of art. How interesting does the distribution of all animals become, as throwing light on ancient geography. [We see some seas bridged over.] Geology loses in its glory from the imperfection of its archives181, but how does it gain in the immensity of the periods of its formations and of the gaps separating these formations. There is much grandeur in looking at the existing animals either as the lineal descendants of the forms buried under thousand feet of matter, or as the coheirs of some still more ancient ancestor. It accords with what we know of the law impressed on matter by the Creator, that the creation and extinction of forms, like the birth and death of individuals should be the effect of secondary [laws] means182. It is derogatory that the Creator of countless systems of worlds should have created each of the myriads of creeping parasites and [slimy] worms which have swarmed each day of life on land and water «on» [this] one globe. We cease being astonished, however much we may deplore, that a group of animals should have been directly created to lay their eggs in bowels and flesh of other, – that some organisms should delight in cruelty, – that animals should be led away by false instincts, – that annually there should be an incalculable waste of eggs and pollen. From death, famine, rapine, and the concealed war of nature we can see that the highest good, which we can conceive, the creation of the higher animals has directly come. Doubtless it at first transcends our humble powers, to conceive laws capable of creating individual organisms, each characterised by the most exquisite workmanship and widely-extended adaptations. It accords better with [our modesty] the lowness of our faculties to suppose each must require the fiat of a creator, but in the same proportion the existence of such laws should exalt our notion of the power of the omniscient Creator183. There is a simple grandeur in the view of life with its powers of growth, assimilation and reproduction, being originally breathed into matter under one or a few forms, and that whilst this our planet has gone circling on according to fixed laws, and land and water, in a cycle of change, have gone on replacing each other, that from so simple an origin, through the process of gradual selection of infinitesimal changes, endless forms most beautiful and most wonderful have been evolved184.

      N.B. – There ought somewhere to be a discussion from Lyell to show that external conditions do vary, or a note to Lyell's works «work?».

      Besides other difficulties in ii. Part, non-acclimatisation of plants. Difficulty when asked how did white and negro become altered from common intermediate stock: no facts. We do NOT know that species are immutable, on the contrary. What arguments against this theory, except our not perceiving every step, like the erosion of valleys185.

       THE ESSAY OF 1844

      PART I

      CHAPTER I

      ON THE VARIATION OF ORGANIC BEINGS UNDER DOMESTICATION; AND ON THE PRINCIPLES OF SELECTION

      The most favourable conditions for variation seem to be when organic beings are bred for many generations under domestication186: one may infer this from the simple fact of the vast number of races and breeds of almost every plant and animal, which has long been domesticated. Under certain conditions organic beings even during their individual lives become slightly altered from their usual form, size, or other characters: and many of the peculiarities thus acquired are transmitted to their offspring. Thus in animals, the size and vigour of body, fatness, period of maturity, habits of body or consensual movements, habits of mind and temper, are modified or acquired during the life of the individual187, and become inherited. There is reason to believe that when long exercise has given to certain muscles great development, or disuse has lessened them, that such development is also inherited. Food and climate will occasionally produce changes in the colour and texture of the external coverings of animals; and certain unknown conditions affect the horns of cattle in parts of Abyssinia; but whether these peculiarities, thus acquired during individual lives, have been inherited, I do not know. It appears certain that malconformation and lameness in horses, produced by too much work on hard roads, – that affections of the eyes in this animal probably caused by bad ventilation, – that tendencies towards many diseases in man, such as gout, caused by the course of life and ultimately producing changes of structure, and that many other diseases produced by unknown agencies, such as goitre, and the idiotcy resulting from it, all become hereditary.

      It is very doubtful whether the flowers and leaf-buds, annually produced from the same bulb, root, or tree, can properly be considered as parts of the same individual, though in some respects they certainly seem to be so. If they are parts of an individual, plants also are subject to considerable changes during their individual lives. Most florist-flowers if neglected degenerate, that is, they lose some of their characters; so common is this, that trueness is often stated, as greatly enhancing the value of a variety188: tulips break their colours only after some years’ culture; some plants become double and others single, by neglect or care: these characters can be transmitted by cuttings or grafts, and in some cases by true or seminal propagation. Occasionally a single bud on a plant assumes at once a new and widely different character: thus it is certain that nectarines have been produced on peach trees and moss roses on provence roses; white currants on red currant bushes; flowers of a different colour from that of the stock, in Chrysanthemums, Dahlias, sweet-williams, Azaleas, &c., &c.; variegated leaf-buds on many trees, and other similar cases. These new characters appearing in single buds, can, like those lesser changes affecting the whole plant, be multiplied not only by cuttings and such means, but often likewise by true seminal generation.

      The changes thus appearing during the lives of individual animals and plants are extremely rare compared with those which are congenital or which appear soon after birth. Slight differences thus arising are infinitely numerous: the proportions and form of every part of the frame, inside and outside, appear to vary in very slight degrees: anatomists dispute what is the “beau ideal” of the bones, the liver and kidneys, like painters do of the proportions of the face: the proverbial expression that no two animals or plants are born absolutely alike, is much truer when applied to those under domestication, than to those in a state of nature189. Besides these slight differences, single individuals are occasionally born considerably unlike in certain parts or in their whole structure to their parents: these are called by horticulturists and breeders “sports”; and are not uncommon except when very strongly marked. Such sports are known in some cases to have been parents of some of our domestic races; and such probably have been the parents of many other races, especially of those which in some senses may be called hereditary monsters; for instance where there is an additional limb, or where all the limbs are stunted (as in the Ancon sheep), or where a part is wanting, as in rumpless fowls and tailless dogs or cats190. The effects of external conditions on the size, colour and form, which can rarely and obscurely be detected during one individual life, become apparent after several generations: the slight differences, often hardly describable, which characterize the stock of different countries, and even of districts in the same country, seem to be due to such continued action.

      On the hereditary tendency

      A volume might be filled with facts showing


<p>179</p>

The simile of the savage and the ship occurs in the Origin, Ed. i. p. 485, vi. p. 665.

<p>180</p>

In the Origin, Ed. i. p. 486, vi. p. 665, the author speaks of the “summing up of many contrivances”: I have therefore introduced the above words which make the passage clearer. In the Origin the comparison is with “a great mechanical invention,” – not with a work of art.

<p>181</p>

See a similar passage in the Origin, Ed. i. p. 487, vi. p. 667.

<p>182</p>

See the Origin, Ed. i. p. 488, vi. p. 668.

<p>183</p>

The following discussion, together with some memoranda are on the last page of the MS. “The supposed creative spirit does not create either number or kind which «are» from analogy adapted to site (viz. New Zealand): it does not keep them all permanently adapted to any country, – it works on spots or areas of creation, – it is not persistent for great periods, – it creates forms of same groups in same regions, with no physical similarity, – it creates, on islands or mountain summits, species allied to the neighbouring ones, and not allied to alpine nature as shown in other mountain summits – even different on different island of similarly constituted archipelago, not created on two points: never mammifers created on small isolated island; nor number of organisms adapted to locality: its power seems influenced or related to the range of other species wholly distinct of the same genus, – it does not equally effect, in amount of difference, all the groups of the same class.”

<p>184</p>

This passage is the ancestor of the concluding words in the first edition of the Origin of Species which have remained substantially unchanged throughout subsequent editions, “There is 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.” In the 2nd edition “by the Creator” is introduced after “originally breathed.”

<p>185</p>

Compare the Origin, Ed. i. p. 481, vi. p. 659, “The difficulty is the same as that felt by so many geologists, when Lyell first insisted that long lines of inland cliffs had been formed, and great valleys excavated, by the slow action of the coast-waves.”

<p>186</p>

The cumulative effect of domestication is insisted on in the Origin, see e. g. Origin, Ed. i. p. 7, vi. p. 8.

<p>187</p>

This type of variation passes into what he describes as the direct effect of conditions. Since they are due to causes acting during the adult life of the organism they might be called individual variations, but he uses this term for congenital variations, e. g. the differences discoverable in plants raised from seeds of the same pod (Origin, Ed. i. p. 45, vi. p. 53).

<p>188</p>

«It is not clear where the following note is meant to come»: Case of Orchis, – most remarkable as not long cultivated by seminal propagation. Case of varieties which soon acquire, like Ægilops and Carrot (and Maize) a certain general character and then go on varying.

<p>189</p>

Here, as in the MS. of 1842, the author is inclined to minimise the variation occurring in nature.

<p>190</p>

This is more strongly stated than in the Origin, Ed. i. p. 30.