The Making of Species 



potent than the devastation caused by those 

 creatures which feed upon it. Let us, however, 

 first briefly set forth some of the checks on 

 the multiplication of organisms which Darwin 

 mentions in the Origin of Species. 



" Eggs, or very young animals," he says, 

 "seem generally to suffer the most, , but this is 

 not invariably the case." This is, as we have 

 already insisted, a most important point to be 

 borne in mind, especially when considering the 

 various current theories of animal colouration. 

 When once the average animal has become adult 

 its chances of survival are enormously increased. 



A second check mentioned by Darwin is the 

 limitation of food supply. <c The amount of food 

 for each species," he writes (p. 84), " of course 

 gives the extreme limit to which each can 

 increase ; but very frequently it is not the 

 obtaining food, but the serving as prey to other 

 animals, which determines the average numbers 

 of a species. Thus there seems to be little 

 doubt that the stock of partridges, grouse, and 

 hares on any large estate depends chiefly on 

 the destruction of vermin. . . . On the other 

 hand, in some cases, as with the elephant and 

 rhinoceros, none are destroyed by beasts of 

 prey." 



We are inclined to think that neither the food 

 limit nor the beasts of prey are a very important 

 check on the multiplication of organisms. The 



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