XXVII. THE STRUGGLE FOR EXISTENCE 



The great number of animals born that never reach 

 maturity. - — Pools of water are often seen that are literally 

 black with tadpoles. Is it possible that all of them become 

 full grown? If so, the earth would become alive with toads, 

 because there are thousands upon thousands of pools con- 

 taining polliwogs. Many insects increase in an enormous 

 geometrical ratio and if all lived , no other animals could exist 

 on the earth. A female codfish deposits from two to six 

 millions of eggs in one season. If all these hatched and the 

 young cod grew to maturity, the ocean would soon be so 

 full that no other fish could find room to live. It is plain 

 then that myriads of animals are born that never reach 

 maturity. 



The struggle for existence and survival of the fittest. — 

 Ever since animals appeared on the earth they have been 

 constantly struggling with one another and with their 

 surrounding conditions to maintain their existence on the 

 earth. Some tadpoles are stronger than others from the 

 start. These stronger ones are able to swim more rapidly, 

 hence are able to catch their food before the weaker ones 

 can get to it. In this way the strong ones grow stronger, 

 and the weak ones weaker, and in the end, only a few of 

 the hardier tadpoles are left to reach maturity. It is much 

 the same with the insects. Some are better fitted to obtain 

 food than others, and some are better protected from their 

 enemies and escape being devoured, while others travel far 



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