| → variations 1859 1860 1861 |
| variations, 1866 1869 |
| individual differences and variations, 1872 |
|
| → injurious variations, I call 1859 1860 1861 1866 1869 |
| those which are injurious, I have called 1872 |
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| → Selection. 1859 1860 1861 1866 |
| Selection, or the Survival of the Fittest. 1869 1872 |
|
| → the species called polymorphic. 1859 1860 1861 1866 |
| certain polymorphic species, or would ultimately become fixed, owing to the nature of the organism and the nature of the conditions. 1869 1872 |
|
| ↑ 10 blocks not present in 1859 1860; present in 1861 1866 1869 1872 |
| Several writers have misapprehended or objected to the term Natural Selection.
Some have even imagined that natural selection induces variability, whereas it implies only the preservation of such variations as occur
and are beneficial to the being under its conditions of life.
No one objects to agriculturists speaking of the potent effects of man's
selection; and in this case the individual differences given by nature, which man for some object selects, must of necessity first occur.
Others have objected that the term selection implies conscious choice in the animals which become modified; and it has even been urged that
as plants have no volition, natural selection is not applicable to them!
In the literal sense of the word, no doubt, natural selection is a misnomer;
but who ever objected to chemists speaking of the elective affinities of the various elements?
— and yet an acid cannot strictly be said to elect the base with which it will
in preference combine.
It has been said that I speak of natural selection as an active power or Deity; but who objects to an author speaking of the attraction of gravity as ruling the movements of the planets?
Every one knows what is meant and is implied by such metaphorical expressions; and they are almost necessary for brevity.
So again it is difficult to avoid personifying the word Nature; but I mean by Nature, only the aggregate action and product of many natural laws, and by laws the sequence of events as ascertained by us.
With a little familiarity such superficial objections will be forgotten.
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that many more individuals are born than can possibly survive) that individuals having any advantage, however slight, over others, would have the best chance of surviving and of procreating their kind? On the other hand, we may feel sure that any variation in the least degree injurious would be rigidly destroyed. This preservation of favourable
→variations
and the
of
→injurious variations, I call
Natural
→Selection. Variations neither useful nor injurious would not be affected by natural selection, and would be left
fluctuating element, as perhaps we see in
→the species called polymorphic.
↑ |
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| We shall best understand the probable course of natural selection by taking the case of a country undergoing some
change, for instance, of climate. The proportional numbers of its inhabitants
almost immediately undergo a change, and some species
become extinct. We may conclude, from what we have seen of the intimate and complex manner in which the inhabitants of each country are bound together, that any change in the numerical proportions of
the inhabitants, independently of the change of climate itself, would
seriously affect
the others. If the country were open on its borders, new forms would certainly immigrate, and this
would
disturb the relations of some of the former inhabitants. Let it be remembered how powerful the influence of a single introduced tree or mammal has been shown to be. But in the case of an island, or of a country partly surrounded by barriers, into which new and better adapted forms could not freely enter, we should then have places in the economy of nature which would assuredly be better filled up, if some of the original inhabitants were in some manner modified; for, had the area been open to immigration, these same
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