IN MEMORIAM : CHARLES DARWIN 



of any other tropical mainland, such as Africa 

 or India. One might indeed object that organ- 

 isms have been created in such wise as most 

 completely to harmonize with the physical con- 

 ditions by which they are surrounded, and that 

 it is to be presumed that the physical conditions 

 of the Galapagos Islands are more like those of 

 Ecuador and Peru than they are like those of 

 any other countries ; so that in this way the 

 general similarity between the floras and faunas 

 may be accounted for. But such an explanation 

 is very weak, for it rests upon an assumption 

 which has been proved to be untrue. It is not 

 always true that the organisms in any given part 

 of the world are such as harmonize best with the 

 physical conditions by which they are sur- 

 rounded. It is approximately true only where 

 the competition among organisms is practically 

 unlimited ; in protected areas it is not at all true. 

 In Australia and New Zealand, for example, 

 the plants and animals which have been intro- 

 duced by Europeans are exterminating and sup- 

 planting the native plants and animals quite as 

 rapidly as the Englishman is supplanting the 

 native human population of these countries. 

 And to state this fact is only to say, in other 

 words, that the plants and animals of Europe 

 are better adapted to the physical conditions 

 which prevail in Australia and New Zealand 

 than the plants and animals which are indige- 

 3'7 



