Selection

How are domesticated races produced either from one or several allied species?

• Some little effect is from the direct action of the external conditions of life.
• Some are little to habit

But it would be bold to say that these are the causes of the differences between:

• a dray and race horse
• a greyhound and bloodhound
• a carrier and tumbler pigeon

Our domesticated races are adapted based on the design of man, not for the good of the animal or plant.

Some useful variations have probably arisen suddenly or gradually.

Many botanists, for instance, believe that the fuller’s teazle, with its hooks is only a variety of the wild Dipsacus.

• This amount of change may have suddenly arisen in a seedling.

So it has probably been with the turnspit dog; and this is known to have been the case with the ancon sheep.

But the adaptations of following are good for humans in very different ways:

• the dray-horse versus the race-horse
• the dromedary and camel
• the various breeds of sheep for cultivated land or mountain pasture
  • the wool of one breed good for one purpose, and that of another breed for another purpose
• the many breeds of dogs

We must look beyond mere variability when we compare:

• the game-cock with other less quarrelsome breeds
• the agricultural, culinary, orchard, and flower-garden races of plants

The key to breeding is man’s power of accumulative selection:

• Nature gives successive variations
• Humans add them up in certain directions useful to him.

Several of our eminent breeders have modified some breeds of cattle and sheep.

In order fully to realise what they have done, it is almost necessary to read several of the many treatises devoted to this subject, and to inspect the animals.

Breeders habitually speak of an animal’s organisation as something quite plastic, which they can model almost as they please.

Youatt says that the principle of selection enables the agriculturist to modify the character of his flock. It is the magician’s wand, by means of which he may summon into life whatever form and mould he pleases.'

The improvement of species is not due to the crossing of different breeds. The best breeders are strongly opposed to this practice, except sometimes amongst closely allied sub-breeds.

When a cross has been made, the closest selection is far more indispensable even than in ordinary cases.

Selection is not merely the separating of some very distinct variety and breeding from it.

It is the great effect produced by the accumulation in one direction for successive generations of differences absolutely inappreciable by an uneducated eye.

A skilled breeder:

• studies his subject for years
• devotes his lifetime to it

The same principles are followed by horticulturists but with more abrupt variations.

Our choicest productions are not produced by a single variation from the aboriginal stock.

When a race of plants is once pretty well established, the seed-raisers do not pick out the best plants. Instead, they merely go over their seed-beds and pull up the ‘rogues’ that deviate from the proper standard.

Breeders do not allow the worst animals to breed.

The accumulated effects of selection is seen in plants by comparing the diversity of flowers in the different varieties of the same species in the flower-garden.