Origin of Species Variorum

→ do not 1859 1860 1861 1866

are not 1869

are by no means sufficient to 1872

→ overthrow 1859 1860 1861 1866 1872

sufficient to overthrow 1869

→ with 1859 1869 1872

from a few created forms with subsequent 1860

from a few primordial forms with subsequent 1861 1866

→ variability. 1859 1860 1861 1866

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

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

→ by 1859 1860 1861 1866 1869

compensation, the increased 1872

→ and by the direct 1859 1860 1861 1866

and by the definite 1869

of parts, and the definite 1872

→ for 1859 1860 1861 1866

under domestication for a very long period; for 1869

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

doubt their weight. But it deserves especial notice that the more important objections relate to questions on which we are confessedly ignorant; nor do we know how ignorant we are. We do not know all the possible transitional gradations between the simplest and the most perfect organs; it cannot be pretended that we know all the varied means of Distribution during the long lapse of years, or that we know how imperfect

is the

the

Geological

Record.

Record

~~is.~~

is.

Serious

Grave

as these several

objections

difficulties

are, in my judgment they →do not →overthrow the theory of descent →with

subsequent modification.

modification.

Now let us turn to the other side of the argument. Under domestication we see much →variability. This seems to be

in part

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.

This variability

Variability

is governed by many complex laws,— by

correlation,

correlated

correlation

growth,

~~of growth,~~

of growth,

→by use and

disuse

disuse,

→and by the direct action of the

surrounding

physical

conditions.

conditions

~~life.~~

life.

There is much difficulty in ascertaining how

largely

much modification

our domestic productions have

been modified;

undergone;

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~~

wholly

cease

cease;

→for new varieties are still occasionally produced by our

oldest

most anciently

domesticated productions.

Variability is

Man does

not actually →produce variability; he only