Origin of Species Variorum

→ with 1859 1869 1872

from a few created forms with subsequent 1860

from a few primordial forms with subsequent 1861 1866

→ variability, caused, or at least excited, by changed conditions of life. 1869

variability. 1859 1860 1861 1866

variability, caused, or at least excited, by changed conditions of life; but often in so obscure a manner, that we are tempted to consider the variations as spontaneous. 1872

↑ 1 blocks not present in 1869 1872; present in 1859 1860 1861 1866

This seems to be mainly due to the reproductive system being eminently susceptible to changes in the conditions of life; so that this system, when not rendered impotent, fails to reproduce offspring exactly like the parent-form.

→ by 1859 1860 1861 1866 1869

compensation, the increased 1872

→ and by the definite 1869

and by the direct 1859 1860 1861 1866

of parts, and the definite 1872

→ under domestication for a very long period; for 1869

for 1859 1860 1861 1866

under domestication for a very long period; nor do we know that it ever ceases, for 1872

→ produce variability; 1859 1860 1861 1866 1869

caused by man; 1872

→ variability. 1859 1860 1861 1866 1869

it to vary. 1872

→ or pleasing to him 1869 1872

to him at the time, 1859 1860

to him at the time 1861

to him 1866

the theory of descent →with

modification.

subsequent modification.

Now let us turn to the other side of the argument. Under domestication we see much →variability, caused, or at least excited, by changed conditions of life. ↑

Variability

This variability

is governed by many complex laws,— by

correlation

correlated

correlation,

of growth,

growth,

....

→by use and

disuse

disuse,

→and by the definite action of the

physical

conditions

life.

There is much difficulty in ascertaining how

much modification

largely

our domestic productions have

undergone;

been modified;

but we may safely infer that the amount has been large, and that modifications can be inherited for long periods. As long as the conditions of life remain the same, we have reason to believe that a modification, which has already been inherited for many generations, may continue to be inherited for an almost infinite number of generations. On the other

hand

hand,

we have evidence that

variability

variability,

when it has once come into play, does not

wholly

....

cease;

cease

→under domestication for a very long period; for new varieties are still occasionally produced by our

most anciently

oldest

domesticated productions.

Variability is

Man does

not actually →produce variability; he only unintentionally exposes organic beings to new conditions of life, and then nature acts on the

organisation

organisation,

and causes →variability. But man can and does select the variations given to him by nature, and thus

accumulates

accumulate

them in any desired manner. He thus adapts animals and plants for his own benefit or pleasure. He may do this methodically, or he may do it unconsciously by preserving the individuals most useful →or pleasing to him without any

thought

intention

of altering the breed. It is certain that he can largely influence the character of a breed by selecting, in each successive generation, individual differences so slight as to be

quite

....