EVOLUTION AS A NATURAL PROCESS 125 



than it can support, every animal is involved in many- 

 sided battles with countless foes, and the victory is 

 sometimes with one and sometimes with another par- 

 ticipant in the conflict. A survivor turns from one 

 vanquished enemy only to find itself engapjed in mortal 

 combat w^ith other attacking forces. Wherever we 

 look, we find evidence of an unceasing struggle for 

 life, and an apparently peaceful meadow or pond is 

 often the scene of fierce battles and tragic death that 

 escape our notice only because the contending armies 

 are dumb. 



A community of ants, often comprising more in- 

 dividuals than an entire European state, depends 

 for its national existence upon its ability to prevail 

 over other communities with which it may engage in 

 sanguinary wars where the losses of a single l)attle 

 may exceed those of Gettysburg. The developing 

 conger-eels find a host of enemies which greatly de- 

 plete their numbers before they can grow even into 

 infancy. An annual plant does not produce a million 

 living offspring in twenty years because seeds do not 

 always fall upon favorable soil, nor do they always 

 receive the proper amount of sunlight and moisture, 

 or escape the eye of birds and other seed-eating animals. 

 These three illustrations bring out the fact that there 

 are three classes of natural conditions which must 

 be met by every living creature if it is to succeed in 

 life. In detail, the struggle for existence is intra- 

 specific, involving some form of competition or rivalry 

 among the members of a single species; it is inter- 

 specific, as a conflict is waged by every species with 

 other kinds of hving things; and finally it involves 



