Origin of Species Variorum

slow modification from some innate law. Lapse of time is only so far highly important, as it gives a better chance of beneficial variations arising, being selected, accumulated, and fixed, in relation to the slowly changing organic and inorganic conditions of life. It likewise favours the direct action of new or changed physical conditions of life.

If we turn to nature to test the truth of these remarks, and look at any small isolated area, such as an oceanic island, although the total number of the species inhabiting it, will be found to be small, as we shall see in our chapter on Geographical Distribution; yet of 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 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 ... isolation is of considerable importance in the production of new species, on the whole I am inclined to believe that largeness of area is of more importance, .. especially in the production of species, which 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 arising from the large number of individuals of the same species there supported, but the conditions of life are infinitely 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