The Origin of Species by Means of Natural Selection: Or, the Preservation of Favoured Races in the Struggle for Life, 6th EditionDarwin, Charles
History
The Origin of Species by Means of Natural Selection: Or, the Preservation of Favoured Races in the Struggle for Life, 6th Edition
Darwin, Charles
Evolution (Biology); Natural selection
The same principles are followed by horticulturists; but the variations
are here often more abrupt. No one supposes that our choicest
productions have been produced by a single variation from the
aboriginal stock. We have proofs that this is not so in several cases
in which exact records have been kept; thus, to give a very trifling
instance, the steadily-increasing size of the common gooseberry may be
quoted. We see an astonishing improvement in many florists’ flowers,
when the flowers of the present day are compared with drawings made
only twenty or thirty years ago. When a race of plants is once pretty
well established, the seed-raisers do not pick out the best plants, but
merely go over their seed-beds, and pull up the “rogues,” as they call
the plants that deviate from the proper standard. With animals this
kind of selection is, in fact, likewise followed; for hardly any one is
so careless as to breed from his worst animals.
In regard to plants, there is another means of observing the
accumulated effects of selection—namely, by comparing the diversity of
flowers in the different varieties of the same species in the
flower-garden; the diversity of leaves, pods, or tubers, or whatever
part is valued, in the kitchen-garden, in comparison with the flowers
of the same varieties; and the diversity of fruit of the same species
in the orchard, in comparison with the leaves and flowers of the same
set of varieties. See how different the leaves of the cabbage are, and
how extremely alike the flowers; how unlike the flowers of the
heartsease are, and how alike the leaves; how much the fruit of the
different kinds of gooseberries differ in size, colour, shape, and
hairiness, and yet the flowers present very slight differences. It is
not that the varieties which differ largely in some one point do not
differ at all in other points; this is hardly ever—I speak after
careful observation—perhaps never, the case. The law of correlated
variation, the importance of which should never be overlooked, will
ensure some differences; but, as a general rule, it cannot be doubted
that the continued selection of slight variations, either in the
leaves, the flowers, or the fruit, will produce races differing from
each other chiefly in these characters.
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