THE DOGMA OF EVOLUTION 



brilliant school of Russians, hold that mutual aid is 

 as prevalent and as important as destruction ; others 

 believe that the struggle against the environment is 

 much more severe than that against other organisms ; 

 Kellogg does not believe in severe competition be- 

 tween adult insects. Kropotkin opposes the whole 

 idea that severe competition is beneficial as he finds it 

 not only kills off the weak but jeopardizes the health 

 and vigour of the strong; others, following his lead, 

 state that variations occur most frequently in periods 

 of peace and plenty and that harsh conditions pre- 

 vent variation. 



As it is obvious that many of the habits of ani- 

 mals, especially those connected with mating and 

 breeding, show the characteristics of choice, Darwin 

 assumed that traits, such as ornamentation, were fixed 

 by choice during the breeding season. Sexual selec- 

 tion, as he termed it, is due to the increased likelihood 

 of leaving progeny by those individuals which are 

 the bravest, the most prolific, and have characters 

 which are pleasing to the opposite sex. This theory is, 

 at the present time, harshly criticised and even aban- 

 doned by most naturalists. The objections to it may 

 be classed under the following heads. The theory re- 

 quires a great preponderance in numbers of one sex 

 over the other or else the poorest members of the sex 

 are likely to secure mates, and statistics do not show 

 such to be a general law. If the most ornamented in- 

 dividuals are also the strongest and most prolific, as 



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