Origin of Species Variorum

→ to Natural Selection. — 1860 1861

to Natural Selection .— 1859

to Natural Selection. 1866

for the production of new forms through Natural Selection. 1869

for the production of new forms through Natural Selection. 1872

→ variability will evidently be favourable for the work of natural selection, but mere 1861 1866

inheritable and diversified variability is favourable, but I believe mere 1859 1860

variability, under which term 1869 1872

→ probably suffice. 1861 1866

suffice for the work. 1859 1860

are always included, will evidently be favourable. 1869 1872

→ for the appearance within any given period of profitable variations, 1859 1860 1861 1866

for the appearance of profitable variations within any given period, 1869

within any given period for the appearance of profitable variations, 1872

→ OMIT 1861 1866 1869 1872

it may be said, 1859 1860

→ selection. 1861 1866 1869

selection. The tendency to reversion may often check or prevent the work; but as this tendency has not prevented man from forming by selection numerous domestic races, why should it prevail against natural selection? 1872

→ has 1861 1866

may often check or prevent the work; but as this tendency has 1869

→ creating innumerable hereditary races in the animal and vegetable kingdoms, 1861 1866

forming by selection numerous domestic races, 1869

→ have stopped the process of 1861 1866

prevail against 1869

→ man's 1859 1860 1861 1866

the case of 1869 1872

investigate. Finally then, we may conclude that in many organic beings, a cross between two individuals is an obvious necessity for each birth; in many others it occurs perhaps only at long intervals; but in none, as I suspect, can self-fertilisation go on for perpetuity.

Circumstances

favourable

→ to Natural Selection. —

This is an extremely intricate subject. A

great

large

amount of →variability will evidently be favourable for the work of natural selection, but mere individual differences →probably suffice. A large number of individuals, by giving a better chance →for the appearance within any given period of profitable variations, will compensate for a lesser amount of variability in each individual, and is, I believe,

a highly

an extremely

important element of success. Though

nature

Nature

grants

long

vast

periods of time for the work of natural selection, she does not grant an indefinite period; for as all organic beings are

striving,

striving

→OMIT to seize on each place in the economy of nature, if any one species does not become modified and improved in a corresponding degree with its competitors, it will

~~soon~~

soon

be exterminated. Unless favourable variations be inherited by some at least of the offspring, nothing can be effected by natural →selection. Non-inheritance of any new character is, in fact, the same thing as reversion to the character of the grandparents or more remote ancestors; and no doubt the tendency to reversion may often have checked or prevented the action of natural selection; but its importance has been greatly exaggerated by some writers.

The

If the

tendency to reversion →has not prevented man from →creating innumerable hereditary races in the animal and vegetable kingdoms, why should it →have stopped the process of natural selection?

In →man's methodical selection, a breeder selects for