16 DARWINISM AND HUMAN LIFE 



a family or of a species are not bom alike : some 

 have qualities wHch give them a httle advantage 

 both as to hunger and as to love ; others are 

 relatively handicapped. We may not understand 

 their origin, but we know that useful variations 

 occur. 



(2) A struggle for existence is also a fact of 

 life — a struggle for existence in an intricate 

 web of interrelations. It operates whenever there 

 is disturbance of equilibrium or clashing of inter- 

 ests, whenever the living creature makes effective 

 responses to the limitations closing in upon it. 



(3) In certain forms of the struggle for existence 

 the relatively less fit forms are ehminated, which 

 does not necessarily mean that they come at 

 once to a violent end, but often simply that they 

 die before the average time and are less successful 

 than their neighbours as regards their offspring. 

 The result is that the relatively more fit tend 

 to survive, and to become the majority. The fit- 

 ness may refer to the whole constitution, or to a 

 particular character. 



(4) As many variations are transmitted from 

 generation to generation, and may, through the 

 pairing of similar or suitable mates, be gradually 

 increased in amount, the eUminative or selective 

 process, if discriminate, consistent, and sustained, 

 will work towards the estabHshmont of new 

 adaptations and new species. Natural Selection is 

 Nature's process of singling and sifting for parent- 

 hood by the discriminate elimination of the relatively 

 less fit to the given conditions. 



Take, in the meantime, just one illustration. 

 In Dublin Bay there is a sandy island, about 

 120 years old. It is frequented by a light-coloured 



