On the Origin of Species by Means of Natural Selection: or the Preservation of Favoured Races in the Struggle for Life. (2nd edition)Darwin, Charles
Science
On the Origin of Species by Means of Natural Selection: or the Preservation of Favoured Races in the Struggle for Life. (2nd edition)
Darwin, Charles
Evolution (Biology); Natural selection
indeed, have been a strange fact, had attention not been paid to breeding,
for the inheritance of good and bad qualities is so obvious.
At the present time, eminent breeders try by methodical selection, with a
distinct object in view, to make a new strain or sub-breed, superior to
anything existing in the country. But, for our purpose, a kind of
Selection, which may be called Unconscious, and which results from every
one trying to possess and breed from the best individual animals, is more
important. Thus, a man who intends keeping pointers naturally tries to get
as good dogs as he can, and afterwards breeds from his own best dogs, but
he has no wish or expectation of permanently altering the breed.
Nevertheless I cannot doubt that this process, continued during centuries,
{35} would improve and modify any breed, in the same way as Bakewell,
Collins, &c., by this very same process, only carried on more methodically,
did greatly modify, even during their own lifetimes, the forms and
qualities of their cattle. Slow and insensible changes of this kind could
never be recognised unless actual measurements or careful drawings of the
breeds in question had been made long ago, which might serve for
comparison. In some cases, however, unchanged, or but little changed
individuals of the same breed may be found in less civilised districts,
where the breed has been less improved. There is reason to believe that
King Charles's spaniel has been unconsciously modified to a large extent
since the time of that monarch. Some highly competent authorities are
convinced that the setter is directly derived from the spaniel, and has
probably been slowly altered from it. It is known that the English pointer
has been greatly changed within the last century, and in this case the
change has, it is believed, been chiefly effected by crosses with the
fox-hound; but what concerns us is, that the change has been effected
unconsciously and gradually, and yet so effectually, that, though the old
Spanish pointer certainly came from Spain, Mr. Borrow has not seen, as I am
informed by him, any native dog in Spain like our pointer.
By a similar process of selection, and by careful training, the whole body
of English racehorses have come to surpass in fleetness and size the parent
Arab stock, so that the latter, by the regulations for the Goodwood Races,
are favoured in the weights they carry. Lord Spencer and others have shown
how the cattle of England have increased in weight and in early maturity,
compared with the stock formerly kept in this country. By comparing the
accounts given in old pigeon treatises of carriers and tumblers with these
breeds as now existing in Britain, {36} India, and Persia, we can, I think,
clearly trace the stages through which they have insensibly passed, and
come to differ so greatly from the rock-pigeon.
Public-domain text, read in full here on John Shaqi.
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