PRODUCTION OF NEW FORMS 117 



number of the inhabitants will be small; and this will retard 

 the production of new species through natural selection, by 

 decreasing the chances of favourable variations arising. 



The mere lapse of time by itself does nothing, either for 

 or against natural selection. I state this because it has been 

 erroneously asserted that the element of time has been as- 

 sumed by me to play an all-important part in modifying 

 species, as if all the forms of life were necessarily undergo- 

 ing change through some innate law. Lapse of time is only 

 so far important, and its importance in this respect is great, 

 that it gives a better chance of beneficial variations arising 

 and of their being selected, accumulated, and fixed. It like- 

 wise tends to increase the direct action of the physical 

 conditions of life, in relation to the constitution of each 

 organism. 



If we turn to nature to test the truth of these remarks, and 

 look at any small isolated area, such as an oceanic island, al- 

 though the number of species inhabiting it is 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 in the world. 

 Hence an oceanic island at first sight seems to have been 

 highly favourable for the production of new species. But 

 we may thus 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 great importance in the production 

 of new species, on the whole I am inclined to believe that 

 largeness of area is still more important, especially for the 

 production of species which shall 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 indi- 

 viduals of the same species there supported, but the conditions 

 of life are much more complex from the large number of al- 

 ready existing species; and if some of these many species 

 become modified and improved, others will have to be im- 

 proved in a corresponding degree, or they will be extermi- 



