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On the origin of species;The Origin of Species by means of Natural Selection, 6th Edition by Charles Darwin
page 52 of 685 (07%)
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
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