WHAT IS PHYSICAL LIFE 



will survive which prove advantageous to 

 the organism in the struggle for existence 

 with either competing living forms or with 

 the conditions of its environment. All 

 changes, therefore, which finally lead to 

 distinct species come simply by the elim- 

 ination of the less adapted by the better 

 adapted to their surroundings. This lat- 

 ter proposition, or the survival of the fit- 

 test by Natural Selection, of course as- 

 sumes that an organism, once acquiring an 

 advantage, would transmit it to its de- 

 scendants. Natural Selection would be 

 of no avail in producing varieties, and 

 their species, unless inheritance comes in 

 to so establish a variation. The trans- 

 mission of advantageous characters, there- 

 fore, is one of the great original pillars of 

 the Darwinian edifice. 



But it should be noted here that biology, 

 or the science of life, is no simple thing by 

 any means. Instead its domain is so vast 

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