Origin of Species Variorum

→ have admitted the existence of varieties, which they think 1859 1860

have admitted the existence of varieties, which they have considered 1861 1866

admit that varieties exist, which are considered 1869

admit that natural varieties exist, which are considered 1872

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

On separate continents, and on different parts of the same continent when divided by barriers of any kind, and on outlying islands, what a multitude of forms exist, which some experienced naturalists rank as varieties, others as geographical races or sub-species, and others as distinct, though closely allied species!

→ we have under nature variability and a powerful agent always ready to act and select, 1859 1860

we have variability as well as a powerful agent always ready to act, 1861

animals and plants do vary, let it be ever so slowly or so little, 1866

animals and plants do vary, let it be ever so little or so slowly, 1869

animals and plants do vary, let it be ever so slightly or slowly, 1872

→ we doubt that variations 1859 1860 1861 1866

we doubt that the variations or individual differences, which are 1869

not variations or individual differences, which are 1872

→ useful to beings, under their excessively complex relations of life, would 1859 1860 1861

useful to them under their extremely complex relations of life would 1866

beneficial would 1869

beneficial, 1872

→ be preserved, accumulated, and inherited? 1859 1860 1861

occasionally occur, and then be preserved and accumulated by natural selection? 1866

be preserved and accumulated through natural selection, or the survival of the fittest? 1869 1872

→ himself, should nature fail in selecting variations useful, 1859 1860 1861

himself, should nature fail in preserving or selecting variations useful, 1866

him, why, 1869 1872

→ conditions 1859 1860 1861 1866

and complex conditions 1869 1872

→ to her 1859 1860 1861 1866

should not variations useful to natures 1869

should not variations useful to nature's 1872

→ products? 1859 1860 1861 1866

products often arise, and be preserved or selected? 1869 1872

→ itself 1859 1860 1861 1866 1869

the highest degree 1872

~~nature.~~

nature.

But, besides such differences, all naturalists →have admitted the existence of varieties, which they think sufficiently distinct to be worthy of record in

their systematic

systematic

works. No one

has

can

drawn

draw

any clear distinction between individual differences and slight varieties; or between more plainly marked varieties and sub-species, and species. ↑ Let it be observed how naturalists differ in the rank which they assign to the many representative forms in Europe and North America.

then,

then

→we have under nature variability and a powerful agent always ready to act and select, why should →we doubt that variations in

some

any

way →useful to beings, under their excessively complex relations of life, would →be preserved, accumulated, and inherited?

Why, if

man can by patience select variations

~~most~~

most

useful to →himself, should nature fail in selecting variations useful, under changing →conditions of life, →to her living →products? What limit can be put to this power, acting during long ages and rigidly scrutinising the whole constitution, structure, and habits of each creature,— favouring the good and rejecting the bad? I can see no limit to this power, in slowly and beautifully adapting each form to the most complex relations of life. The theory of natural selection, even if we

look

looked

farther

further

than this, seems to

~~me to~~

me to

be in →itself probable. I have already recapitulated, as fairly as I could, the opposed difficulties and objections: now let us turn to the special facts and arguments in favour of the theory.

On the view that species are only strongly marked and permanent varieties, and that each species first existed as a variety, we can see why it is that no line of demarcation can be drawn between species, commonly supposed to have been produced by special acts of creation, and varieties which are acknowledged to have been produced by secondary laws. On this same