Origin of Species Variorum

→ the 1859 1860 1861

life, their action on the reproductive system, are so far the 1866

↑ 3 blocks not present in 1859 1860 1861 1866; present in 1869 1872

Changed conditions of life are of the highest importance in causing variability, both directly by acting on the organisation, and indirectly by affecting the reproductive system. It is not probable that variability is an inherent and necessary contingent, under all circumstances. The greater or less force of inheritance and reversion determine whether variations shall endure.

→ I do not believe 1859 1860

It is not probable 1861 1866

→ more especially by that of correlation of growth. 1859 1860 1861 1866

more especially by that of correlation. 1869

of which correlated growth is probably the most important. 1872

→ may 1859 1860 1861 1866 1869

but how much we do not know, may 1872

→ life. 1859 1860 1861 1866 1872

life, but how much we do not know. 1869

→ Something must 1859 1860 1861 1866 1869

Some, perhaps a great, effect may 1872

→ use and disuse. 1859 1860 1861 1866 1869

the increased use or disuse of parts. 1872

→ I do not doubt that 1859 1860

OMIT 1861 1866 1869 1872

→ species, aboriginally distinct, 1859 1860 1861 1866

aboriginally distinct species, 1869

aboriginally distinct 1872

→ has 1859 1860 1861 1866 1869

species appears to have 1872

→ in any country several domestic 1859 1860 1861 1866

several 1869 1872

→ established, 1859 1860 1861 1866

formed in any country, 1869 1872

→ the formation of 1859 1860 1861 1866 1872

forming 1869

→ of varieties has, I believe, been greatly 1859 1860

of varieties has been greatly 1861 1866

has been much 1869 1872

→ both of distinct species and of varieties 1859 1860 1861 1866

OMIT 1869 1872

→ the cases of 1859 1860 1861 1866

OMIT 1869 1872

→ I am convinced that 1859 1860 1861 1866

OMIT 1869 1872

→ is by far 1859 1860 1861 1866 1869

seems to have been 1872

To sum up on the origin of our

domestic

Domestic

races

Races

of animals and plants. I believe that the conditions of life, from their action on the reproductive system, are so far of →the highest importance as causing variability. ↑ →I do not believe that variability is an inherent and necessary contingency, under all circumstances, with all organic beings, as some authors have thought. The effects of variability are modified by various degrees of inheritance and of reversion. Variability is governed by many unknown laws, →more especially by that of correlation of growth.

Some- thing

Something,

Something

→may be attributed to the

definite

direct

action of the conditions of →life. →Something must be attributed to →use and disuse. The final result is thus rendered infinitely complex. In some

cases

cases,

→I do not doubt that the intercrossing of →species, aboriginally distinct, →has

probably played

played

an important part in the origin of our

domestic breeds.

breeds.

domestic productions.

When →in any country several domestic breeds have once been →established, their occasional intercrossing, with the aid of selection, has, no doubt, largely aided in →the formation of new sub-breeds; but the importance of

~~the~~

the

crossing →of varieties has, I believe, been greatly exaggerated, both in regard to animals and to those plants which are propagated by seed.

With

plants which are temporarily propagated by cuttings, buds, &c., the importance of

~~the~~

the

crossing →both of distinct species and of varieties is immense; for the cultivator

may here

here quite

disregard

disregards

the extreme variability both of hybrids and

of mongrels,

mongrels,

and the

~~frequent~~

frequent

sterility of hybrids; but →the cases of plants not propagated by seed are of little importance to us, for their endurance is only temporary. Over all these causes of

Change,

Change

→I am convinced that the accumulative action of Selection, whether applied methodically and

~~more~~

quickly, or unconsciously and

~~more~~

slowly

slowly,

but more efficiently, →is by far the predominant Power.