Origin of Species Variorum

→ similar variations 1872

variations of a similar character 1861 1866 1869

→ In practice, a fancier is, for instance, 1861 1866 1869 1872

A fancier is 1859 1860

→ the sub-breeds of the tumbler-pigeon) 1861 1866 1869 1872

tumbler-pigeons) 1859 1860

→ of history, the men of one nation or district required 1872

one man preferred 1859 1860 1861 1866 1869

→ whilst those of another required 1872

another 1859 1860 1861 1866 1869

→ in the one case, 1872

by some breeders, 1859 1860 1861 1866 1869

→ Ultimately, after the lapse of centuries, these sub-breeds would become converted into two well-established and distinct breeds. As 1872

As 1859 1860 1861 1866 1869

→ used for breeding, 1872

neglected, 1859 1860 1861 1866 1869

→ (though it was a long time before I saw how), from 1861 1866 1869 1872

from 1859 1860

head from our domestic productions. We shall here find something analogous. It will be admitted that the production of races so different as short-horn and Hereford cattle, race and cart horses, the several breeds of pigeons, &c., could never have been effected by the mere chance accumulation of →similar variations during many successive generations. →In practice, a fancier is, for instance, struck by a pigeon having a slightly shorter beak; another fancier is struck by a pigeon having a rather longer beak; and on the acknowledged principle that "fanciers do not and will not admire a medium standard, but like extremes," they both go on (as has actually occurred with →the sub-breeds of the tumbler-pigeon) choosing and breeding from birds with longer and longer beaks, or with shorter and shorter beaks. Again, we may suppose that at an early period →of history, the men of one nation or district required swifter

horses;

horses,

→whilst those of another required stronger and

more bulky

bulkier

horses. The early differences would be very slight;

but, in

the course of time, from the continued selection of swifter horses →in the one case, and of stronger ones

in the

others,

other,

the differences would become greater, and would be noted as forming two

sub-breeds;

finally,

after

the

lapse

centuries,

centuries

the

sub-breeds

would

become

converted

into

two

well-established

and

distinct

breeds.

→Ultimately, after the lapse of centuries, these sub-breeds would become converted into two well-established and distinct breeds. As the differences

slowly

....

become

became

greater, the inferior animals with intermediate characters, being neither very swift nor very strong,

will

would

would not

have been →used for breeding, and will

have

thus have

~~tended to~~

tended to

disappeared.

disappear.

Here, then, we see in

mans

man's

productions the action of what may be called the principle of divergence, causing differences, at first barely appreciable, steadily to increase, and the breeds to diverge in

character

character,

both from each other and from their common parent.

But how, it may be asked, can any analogous principle apply in nature? I believe it can and does apply most

efficiently,

efficiently

→(though it was a long time before I saw how), from the simple circumstance that the more diversified the descendants from any one species become in structure, constitution, and habits, by so much will they be better enabled to seize on many and widely diversified places in the polity of nature, and so be enabled to increase in numbers.

We can clearly

see

discern

this in the case of animals with simple habits. Take the case of a carnivorous quadruped, of which the number that can be supported in any country has long ago arrived at its full average. If its natural

powers

power

of increase be allowed to act, it can succeed in increasing (the country not undergoing any change in

its

....

conditions) only by its varying descendants seizing on places at present occupied by other

animals:

animals;

some of them,