THE CREATION OF SPECIES 



world can attain maturity and propagate their kind. 

 A plant may produce a hundred thousand seeds. If 

 all came to maturity and reproduced their kind in 

 like measure, every square inch of the earth's surface 

 would be covered with the descendants of this single 

 plant in a very few years. Similarly a codfish may 

 lay a million eggs. If all hatched and the offspring 

 propagated normally, the mass of codfish produced 

 in a century would surround the earth in a solid body, 

 reaching out in every direction well toward the orbit 

 of the moon. The progeny of one fly in a single 

 summer, if it lived and propagated normally, would 

 amount to several million bushels of flies. The 

 progeny of a single human pair in the time since the 

 discovery of America might readily enough give us 

 our population of a hundred million individuals. 



So it is obvious that the actual rate of increase of 

 any given plant or animal or human family can be 

 but a very trifling fraction of the normal or nominal 

 increase; and the reason is simply that the conditions 

 of life are more or less unfavorable for every race, 

 chiefly owing to the competition of the members of 

 the same or of other races. This is what is meant 

 by the phrase "struggle for existence" as applied by 

 the evolutionist. The phrase applies equally well to 

 the lowest plant and to the highest animal. 



In the case of plant and animal alike the individual 

 that differs slightly from its fellows in some favorable 

 direction is obviously the one likely to be preserved. 

 Such an individual will tend to transmit its inherent 

 peculiarities, and its descendants will constitute a 

 favored race. 



i 79 



