214 Struggle for Existence and Rivalry 



(1) The competition for food, etc., that arises among 

 organic beings from the overproduction of individuals or 

 from a limited supply of food. This is called the * Malthu- 

 sian form ' of struggle for existence. 1 



(2) Competition in any form of active contest in which 

 individuals are pitted against one another. 



(3) Survival due to greater fitness for life in a given 

 environment, whether combined with direct competition 

 with other organisms or not. 



The second case (2) is that in which animals either 



(a) fight with, or (b) prey upon, one another ; only the for- 

 mer of these (a) having any analogy to the form of com- 

 petition due to the overproduction of individuals or to a 

 limited supply of food, etc., and then only in the case in 

 which the strife results from the circumstances of getting 

 a living - - not in the case very common in nature of mere 

 combativeness of temper, through which the stronger ani- 

 mal kills the weaker simply from aggressiveness. In case 



(b) one animal feeds upon members of another group as 

 his natural prey, as is seen in the eating of insects by 

 birds. This is also extremely widespread, and leads to 

 some of the most beautiful special adaptations for con- 

 cealment, warning, etc. in the species preyed upon. This 

 has nothing to do with the overproduction of individuals 

 in the sense given under (i), except in so far as the spe- 

 cies preyed upon overproduces in the way of compensation 

 for the constant drain upon it ; but this is a very different 

 thing. 



vidual society, struggle of the totality of humanity with its organic and 

 inorganic environment.' See Chapter XIX. 7, for a criticism of certain of 

 Professor Pearson's positions. 



1 From the fact that both Darwin and Wallace were indebted to Malthus' 

 work On Population (see below). 



