Origin of Species Variorum

→ else. 1859 1860 1861 1866

else in the world. 1869 1872

→ OMIT 1861 1866 1869 1872

I do not doubt that 1859 1860

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

Hence more new places will be formed, and the competition to fill them will be more severe, on a large than on a small and isolated area.

→ owing to former oscillations of level, 1866 1869

owing to oscillations of level, 1859 1860 1861

OMIT 1872

→ have 1866 1869

have recently 1859 1860 1861

owing to former oscillations of level, have 1872

in our chapter on

geographical

Geographical

distribution;

Distribution;

yet of

the

these

species a very large proportion are endemic,— that is, have been produced there, and nowhere →else. Hence an oceanic island at first sight seems to have been highly favourable for the production of new species. But we may thus

~~greatly~~

greatly

deceive ourselves, for to ascertain whether a small isolated area, or a large open area like a continent, has been most favourable for the production of new organic forms, we ought to make the comparison within equal times; and this we are incapable of doing.

Although →OMIT isolation is of

great

considerable

importance in the production of new species, on the whole I am inclined to believe that largeness of area is

still

important,

importance,

....

especially

for

the production of

species

species,

which

shall

will

prove capable of enduring for a long period, and of spreading widely. Throughout a great and open area, not only will there be a better chance of favourable

variations,

variations

arising from the large number of individuals of the same species there supported, but the conditions of life are

infinitely

much more

complex from the large number of already existing species; and if some of these many species become modified and improved, others will have to be improved in a corresponding

degree

degree,

or they will be exterminated. Each new form, also, as soon as it has been much improved, will be able to spread over the open and continuous area, and will thus come into competition with many

other forms.

others.

↑

Moreover,

More-over,

great areas, though now continuous, →owing to former oscillations of level, will

often,

often

→have existed in a broken

condition;

condition,

so that the good effects of isolation will generally, to a certain extent, have concurred. Finally, I conclude that, although small isolated areas

~~probably~~

probably

have been in some respects highly favourable for the production of new species, yet that the course