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01 - Variations Under Domestication 01-07 - Origin of Domestic Varieties from one or more Species 50 Having kept nearly all the English breeds of the fowl alive, having bred and crossed them, and examined their skeletons, it appears to me almost certain that all are the descendants of the wild Indian fowl, Gallus bankiva; and this is the conclusion of Mr. Blyth, and of others who have studied this bird in India.
fowl
fowl

Edward Blyth
Edward Blyth

India
India


In regard to ducks and rabbits, some breeds of which differ much from each other, the evidence is clear that they are all descended from the common wild duck and rabbit.

ducks
ducks

rabbit
rabbit
01 - Variations Under Domestication 01-08 - Breeds of the Domestic Pigeons, their Differences and Origin 50 Some facts in regard to the colouring of pigeons well deserve consideration.

The rock-pigeon is of a slaty-blue, with white loins; but the Indian sub-species, C. intermedia of Strickland, has this part bluish. The tail has a terminal dark bar, with the outer feathers externally edged at the base with white. The wings have two black bars.

Some semi-domestic breeds, and some truly wild breeds, have, besides the two black bars, the wings chequered with black.

These several marks do not occur together in any other species of the whole family.

Now, in every one of the domestic breeds, taking thoroughly well-bred birds, all the above marks, even to the white edging of the outer tail-feathers, sometimes concur perfectly developed.

Moreover, when birds belonging to two or more distinct breeds are crossed, none of which are blue or have any of the above-specified marks, the mongrel offspring are very apt suddenly to acquire these characters.

To give one instance out of several which I have observed:- I crossed some white fantails, which breed very true, with some black barbs- and it so happens that blue varieties of barbs are so rare that I never heard of an instance in England; and the mongrels were black, brown, and mottled.

I also crossed a barb with a spot, which is a white bird with a red tail and red spot on the forehead, and which notoriously breeds very true; the mongrels were dusky and mottled.

I then crossed one of the mongrel barb-fantails with a mongrel barb-spot, and they produced a bird of as beautiful a blue colour, with the white loins, double black wing-bar, and barred and white-edged tail-feathers, as any wild-rock pigeon!

We can understand these facts, on the well-known principle of reversion to ancestral characters, if all the domestic breeds are descended from the rock-pigeon.

But if we deny this, we must make one of the two following highly improbable suppositions.

Either, first, that all the several imagined aboriginal stocks were coloured and marked like the rock-pigeon, although no other existing species is thuscoloured and marked, so that in each separate breed there might be a tendency to revert to the very same colours and markings.

Or, secondly, that each breed, even the purest, has within a dozen, or at most within a score, of generations, been crossed by the rock-pigeon: I say within dozen or twenty generations, for no instance is known of crossed descendants reverting to an ancestor of foreign blood, removed by a greater number of generations.

In a breed which has been crossed only once, the tendency to revert to any character derived from such a cross will naturally become less and less, as in each succeeding generation there will be less of the foreign blood; but when there has been no cross, and there is a tendency in the breed to revert to a character which was lost during some former generation, this tendency, for all that we can see to the contrary, may be transmitted undiminished for an indefinite number of generations.

These two distinct cases of reversion are often confounded
together by those who have written on inheritance.

Rock Pigeon
Rock Pigeon
01 - Variations Under Domestication 01-09 - Principles of Selection anciently followed, and their Effects 50 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.

leaf
leaf

pod
pod

tuber
tuber

orchard
orchard


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.

cabbage
cabbage

heartsease
heartsease

gooseberry
gooseberry


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.
01 - Variations Under Domestication 01-10 - Methodical and Unconscious Selection 50 In plants the same gradual process of improvement, through the occasional preservation of the best individuals, whether or not sufficiently distinct to be ranked at their first appearance, as distinct varieties, and whether or not two or more species or races have become blended together by crossing, may plainly be recognised in the increased size and beauty which we now see in the varieties of the heartsease, rose, pelargonium, dahlia, and other plants, when compared with the older varieties or with their parent-stocks.

No one would ever expect to get a first-rate heartsease or dahlia from the seed of a wild plant.

heartsease
heartsease

rose
rose

pelargonium
pelargonium

dahlia
dahlia



No one would expect to raise a first-rate melting pear from the seed of the wild pear, though he might succeed from a poor seedling growing wild, if it had come from a garden-stock.

The pear, though cultivated in classical times, appears, from Pliny's description, to have been a fruit of very inferior quality.

I have seen great surprise expressed in horticultural works at the wonderful skill of gardeners, in having produced such splendid results from such poor materials; but the art has been simple, and, as far as the final result is concerned, has been followed almost unconsciously.

pear
pear


It has consisted in always cultivating the best-known variety, sowing its seeds, and, when a slightly better variety chanced to appear, selecting it, and so onwards.

But the gardeners of the classical period who cultivated the best pears which they could procure, never thought what splendid fruit we should eat; though we owe our excellent fruit in some small degree, to their having naturally chosen and preserved the best varieties they could anywhere find.