.March 1, 1887.] 



♦ KNOWLEDGE ♦ 



97 



Illustrated MAGAZINE ^ 



liENCE,lITERATURE.& ARA 



LONDON: MARCH 1, 1887. 



THE STORY OF CREATION. 



a plain account of evolution. 



By Edward Clodd. 



PAUT U. 



Chapter IA'.— THE ORIGIN" OF SPECIES. 



HE history of the slow but sure preparation 

 of the scientific world for the reception of a 

 theory displacing the old notions of the 

 1 ?^ "^^^ ^ fixity of species is briefly but vividly told 

 «4ffia v/Pls by Mr. (irant Allen in his monograph on 

 " Charles Darwin." * Commending the 

 study of that book, especially of the fifth 

 chapter, as superseding the need for repeating the story here, 

 we may pass at once to a rapid summary of the evidence as 

 to the modes of organic evolution. 



I. No two individuals of the same species are exaeth/ alike ; 

 each tends to varij. — Of this obvious fact every species, from 

 man downwards, supplies abundant illustration ; for how- 

 ever closely individuals resemble one another in essential 

 features, causing them to be grouped under the same species, 

 there are always diflferences between them, often veiy marked, 

 both in organ and function. Children of the same parents 

 vary in size, feature, complexion, character, and constitution, 

 often very obvionsl}', sometimes too obscurely for detection ; 

 and this law of general resemblance, with more or less 

 variation in detail, ajiplies to all animals and plants. The 

 tendency to vary, which, in our ignorance of its ultimate 

 causes, we say " inheres " in the organism, and of which 

 what are called " sports " are an example, is fostered by the 

 change of condition in which the animal or plant may be 

 placed, as shown in its more marked tendency to vary in 

 a domesticated than in a wild state. Throughout these 

 papers stress has been laid on the fact that the organ adapts 

 itself to the work which it has to do ; hence changes of 

 structure in a species are necessitated to fit it for an altered 

 state of things. This implies increased or lessened activity 

 on the part of certain organs, the use or disuse leading to 

 their development or suppression. 



II. Variations are transmitted , and therefore tend to be- 

 come permanent. — In other words, what is peculiar to the 

 parent plant or animal reappears in the offspring. This is 

 known as " descent with modification," the serious import 

 of which will be shown later on. 



III. Man> takes advantage of these transmitted unliTce- 

 nesses to produce nei'j varieties of Plants and Animals. — 

 He selects certain individuals possessing variations which he 

 wants to preserve, and allows only them to breed together, 

 by which means in the course of time he produces varieties 

 differing greatly from the parent form with which he 



* " English Wortliies " Series. Longmans. 



started. The stock example of this is the pigeon. All our 

 domestic pigeons, exceeding in number a hundred well- 

 marked races, are descended from the ordinary blue rock- 

 pigeon of the European coasts. Variations as marked as 

 the fim-tail, the tumbler, and the pouter, have been ]iroduccd 

 by the breeder selecting birds with certain peculiarities, 

 and choosing from each successive brood only those which 

 exhibited the same peculiarities in more marked form, the 

 result being, after a long time, the production of entirely 

 new varieties. The same method has given us diflerent 

 races of dogs, sheep, horses, and other domestic animals. 

 The fleetest horses are chosen to breed together ; then the 

 fleetest offspring of these in succession, until horses are pro- 

 duced whose swiftness far exceeds that of the originally 

 selected pairs. In the development of the cart-horse 

 strength, not speed, is the quality selected : while in the 

 marked xmlikenesses between dogs we see the result of 

 artificial selection in producing such varieties as the blood- 

 hound, the terrier, and the spaniel. What varieties in 

 flowers, vegetables, and fruits — as, for example, the develop- 

 ment of the numerous kinds of apples from the small, 

 sour, crab species — the like method has induced, are too 

 well known to need detailed reference here. When we see 

 how successfully this choice of slight variations has brought 

 about plants and animals best adapted to the service of 

 man, we may desire the approach of that future when arti- 

 ficial selection will be extended to the human species, so 

 that only the men and women who are of the highest type, 

 both physically and morally, shall reproduce their kind. 



Now the important work which Darwin did was to show 

 that what man does on a small scale within a limited range of 

 time. Nature does on a large scale during countless epochs ; 

 with the further difference that the action of Nature is not 

 purposive, as is the action of man, but involved in the 

 necessities of things. We may quote what Darwin himself 

 says on this matter : 



As man can produce, and certainly has produced, a great result 

 by his methodical and unconscious means of selection, what may 

 not natural selection effect ? Man can act only on external and 

 visible characters : Nature, it I may be allowed to personify the 

 natural preservation or survival of the fittest, cares nothing for 

 appearances, except in so far as they are useful to any being. She 

 can act on every internal organ, on every shade of constitutional 

 difference, on the whole machinery of life. Man selects only for 

 his own good : Nature only for that of tlie being which she tends. 

 Every selected character is fully exercised by her, as is implied by 

 the fact of their selection. Man keeps the natives of many climates 

 in the same country ; he seldom exercises each selected character 

 in some peculiar and fitting manner; he feeds a long and a short- 

 beaked pigeon on the same food ; he does not exercise a long-backed 

 or long-legged quadruped in any peculiar manner ; he exposes 

 sheep with long and short wool to tlie same climate. He does not 

 allow the most vigorous males to struggle for the females. He does 

 not rigidly destroy all inferior animals, but protects during each 

 varying season, as far as lies in his power, all his productions. He 

 often begins his selection by some half monstrous form; or at least 

 by some modification prominent enough to catch the eye or to be 

 plainly useful to liim. Under Nature the slightest differences of 

 structure or constitution may well turn the nicely-balanced scale in 

 the struggle for life, and so be preserved. How fleeting are the 

 wishes and efforts of man ! how short his time ! and, consequently, 

 how poor will be his results, compared with those accumulated by 

 Nature during whole geological periods 1 Can we wonder, then, 

 that Nature's productions should be far " truer " in character than 

 man's productions ; that they should be infinitely better adapted to 

 the most complex conditions of life, and should plainly bear the 

 stamp of far higher workmanship ? * 



IV. More organisms are horn than survive. — To quote 

 Darwin once more, " there is no exception to the rule that 

 every organic being natui'ally increases at so high a rate 

 that, if not destroyed, the earth would soon be covered by 

 the progeny of a single pair. Even slow-breeding man has 



* " Origin of Species," sixth ed., p. 05. 



