PUNBAMENTAL PRINCIPLE'S 43 



The direct result of the enormous number of spores and 

 seeds produced is a struggle for existence — for sufl&cient soil, 

 water, light, and food to insure a healthy, mature plant. 



34. Elimination of the Unfit. — ^As a result of variation 

 certain individuals will succeed better than others in the 

 struggle for existence. Those most poorly adapted to 

 their surroundings will perish, and only the more vigorous 

 ones — those best adjusted to their surroundings — will 

 persist. The result of this struggle for existence was 

 called by Herbert Spencer the "survival of the fittest." 

 What really takes place in nature is the elimination, by 

 death, of the unfit. Darwin called this natural selection, 

 implying that the result is similar to that when plant 

 breeders select out of a progeny the best individual for 

 further breeding. What really takes place in nature, 

 however, is not so much the selection of the fittest, but a 

 rejection of the unfit. Thus, among the 50,000,000 

 progeny of a single fern-plant, some are sure to have a 

 weaker constitution than others; to develop a weaker root- 

 system, less chlorophyll in their leaves, a less number 

 of sporophylls or spores, or to be inferior in other ways. 

 The result will be that, in the course of only a few years, 

 the descendants of the most vigorous or otherwise superior 

 plants will alone be left to perpetuate the race. 



35. Problems to Solve. — In the preceding paragraphs 

 we have called attention to a number of the problems 

 which arise from the study of a fern. Some of these have 

 been partially solved — ^probably none of them has been 

 completely solved. In fact, we may say that our igno- 

 rance of life-processes greatly exceeds our knowledge. 

 Very much more remains to be ascertained than has al- 

 ready been found out; for example, what is protoplasm? 



