Origin of Species Variorum

→ by an educated 1869 1872

uneducated 1859 1860 1861 1866

→ rapid increase of many animals and plants during 1860 1861 1866 1869 1872

effects of 1859

→ and when naturalised in a new country. 1869

and by the results of naturalisation, as explained in the third chapter. 1859

or when naturalised in a new country. 1860 1861 1866

and when naturalised in new countries. 1872

→ other hand the struggle 1869 1872

struggle 1859 1860 1861 1866

→ balance. 1859 1860 1861 1866 1869

long run, turn the balance. 1872

inappreciable

by an

except

→by an educated eye. This

unconscious process

process

of selection has been the great agency in the

production

formation

of the most distinct and useful domestic breeds. That many

of the

....

breeds produced by man have to a large extent the character of natural species, is shown by the inextricable doubts whether

very

....

many of them are varieties or

aboriginal

aboriginally

species.

distinct species.

There is no

~~obvious~~

obvious

reason why the principles which have acted so efficiently under domestication should not

have acted

act

under nature. In the

preservation

survival

of favoured individuals and races, during the constantly-recurrent Struggle for Existence, we see

the most

powerful and ever-acting

means

form

selection.

Selection.

The struggle for existence inevitably follows from the high geometrical ratio of increase which is common to all organic beings. This high rate of increase is proved by

calculation,

calculation,—

by the →rapid increase of many animals and plants during a succession of peculiar seasons, →and when naturalised in a new country. More individuals are born than can possibly survive. A grain in the balance

will

may

determine which

individual

individuals

shall live and which shall die,— which variety or species shall increase in number, and which shall decrease, or finally become extinct. As the

indi- viduals

individuals

of the same species come in all respects into the closest competition with each other, the struggle will generally be most severe between them; it will be almost equally severe between the varieties of the same species, and next in severity between the species of the same genus.

But