| ↑ 1 blocks not present in 1859 1860 1861 1866 1869; present in 1872 |
| Unintentionally he exposes organic beings to new and changing conditions of life, and variability ensues; but similar changes of conditions might and do occur under nature.
|
|
| → variations, 1866 1869 |
| variations 1859 1860 1861 |
| individual differences and variations, 1872 |
|
| → injurious variations, I call 1859 1860 1861 1866 1869 |
| those which are injurious, I have called 1872 |
|
| → 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 |
|
|
↑
Let it
borne in mind how infinitely complex and
are the mutual relations of all organic beings to each other and to their physical conditions of
and consequently what infinitely varied diversities of structure
be of use to each being under changing conditions of life. Can it, then, be thought improbable, seeing that variations useful to man have undoubtedly occurred, that other variations useful in some way to each being in the great and complex battle of life, should
occur in the course of
generations? If such do occur, can we doubt
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.
|
|
| 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
and are beneficial to the being under its conditions of life. No one objects to agriculturists speaking of the potent effects of
selection; and in this case the individual differences given by nature, which man for some object selects, must of necessity first occur. Others
|
