Читать книгу The Foundations of the Origin of Species - Чарльз Дарвин, Darwin Charles - Страница 10
PART II 104
§ X. Recapitulation and conclusion
ОглавлениеLet us recapitulate the whole «?» «of» these latter sections by taking case of the three species of Rhinoceros, which inhabit Java, Sumatra, and mainland of Malacca or India. We find these three close neighbours, occupants of distinct but neighbouring districts, as a group having a different aspect from the Rhinoceros of Africa, though some of these latter inhabit very similar countries, but others most diverse stations. We find them intimately related [scarcely «?» differences more than some breeds of cattle] in structure to the Rhinoceros, which for immense periods have inhabited this one, out of three main zoological divisions of the world. Yet some of these ancient animals were fitted to very different stations: we find all three «illegible» of the generic character of the Rhinoceros, which form a [piece of net]174 set of links in the broken chain representing the Pachydermata, as the chain likewise forms a portion in other and longer chains. We see this wonderfully in dissecting the coarse leg of all three and finding nearly the same bones as in bat’s wings or man’s hand, but we see the clear mark in solid tibia of the fusion into it of the fibula. In all three we find their heads composed of three altered vertebræ, short neck, same bones as giraffe. In the upper jaws of all three we find small teeth like rabbit’s. In dissecting them in fœtal state we find at a not very early stage their form exactly alike the most different animals, and even with arteries running as in a fish: and this similarity holds when the young one is produced in womb, pond, egg or spawn. Now these three undoubted species scarcely differ more than breeds of cattle, are probably subject to many the same contagious diseases; if domesticated these forms would vary, and they might possibly breed together, and fuse into something175 different «from» their aboriginal forms; might be selected to serve different ends.
Now the Creationist believes these three Rhinoceroses were created176 with their deceptive appearance of true, not «illegible» relationship; as well can I believe the planets revolve in their present courses not from one law of gravity but from distinct volition of Creator.
If real species, sterile one with another, differently adapted, now inhabiting different countries, with different structures and instincts, are admitted to have common descent, we can only legitimately stop where our facts stop. Look how far in some case a chain of species will lead us. «This probably refers to the Crustacea, where the two ends of the series have “hardly a character in common.” Origin, Ed. i. p. 419.» May we not jump (considering how much extermination, and how imperfect geological records) from one sub-genus to another sub-genus. Can genera restrain us; many of the same arguments, which made us give up species, inexorably demand genera and families and orders to fall, and classes tottering. We ought to stop only when clear unity of type, independent of use and adaptation, ceases.
Be it remembered no naturalist pretends to give test from external characters of species; in many genera the distinction is quite arbitrary177. But there remains one other way of comparing species with races; it is to compare the effects of crossing them. Would it not be wonderful, if the union of two organisms, produced by two separate acts of Creation, blended their characters together when crossed according to the same rules, as two races which have undoubtedly descended from same parent stock; yet this can be shown to be the case. For sterility, though a usual «?», is not an invariable concomitant, it varies much in degree and has been shown to be probably dependent on causes closely analogous with those which make domesticated organisms sterile. Independent of sterility there is no difference between mongrels and hybrids, as can be shown in a long series of facts. It is strikingly seen in cases of instincts, when the minds of the two species or races become blended together178. In both cases if the half-breed be crossed with either parent for a few generations, all traces of the one parent form is lost (as Kölreuter in two tobacco species almost sterile together), so that the Creationist in the case of a species, must believe that one act of creation is absorbed into another!
Such are my reasons for believing that specific forms 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
174
The author doubtless meant that the complex relationships between organisms can be roughly represented by a net in which the knots stand for species.
175
Between the lines occurs: – “one «?» form be lost.”
176
The original sentence is here broken up by the insertion of: – “out of the dust of Java, Sumatra, these «?» allied to past and present age and «illegible», with the stamp of inutility in some of their organs and conversion in others.”
177
Between the lines occur the words: – “Species vary according to same general laws as varieties; they cross according to same laws.”
178
“A cross with a bull-dog has affected for many generations the courage and obstinacy of greyhounds,” Origin, Ed. i. p. 214, vi. p. 327.
179
The simile of the savage and the ship occurs in the Origin, Ed. i. p. 485, vi. p. 665.
180
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.
181
See a similar passage in the Origin, Ed. i. p. 487, vi. p. 667.
182
See the Origin, Ed. i. p. 488, vi. p. 668.
183
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.”
184
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.”
185
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.”