CH. XIV] GENERAL DISCUSSION 177 



Longley (26) thinks that it will be found that adaptation comes 

 automatically. 



Though natural selection comes more and more into play as 

 the species in a given region become more numerous, or as a 

 human society becomes more complex, its action is always 

 primarily individual. There is little or no competition between 

 entire species, varieties, or races (cf. pp. 107, 142, 144). 



The conclusion to be drawn, therefore, is that natural selection 

 has not been the driving force under whose influence evolution 

 has been carried on, though it has been the selecting force by 

 whose action the individuals best suited to the conditions of any 

 time and place have been continually picked out. In this way a 

 continual adaptation has gone on, and except in casual and im- 

 permanent cases, has ensured that the plants that occur under 

 natural conditions are very closely indeed adapted to those con- 

 ditions. This adaptation is not structural, but functional, as is 

 illustrated, to take one example only, by the structural resem- 

 blance of the members of a large family growing in a great variety 

 of conditions, and the great structural differences of a large 

 ecological "association " of plants growing in very uniform condi- 

 tions (p. 53). The work of Hutchinson and other agricultural 

 geneticists shows that natural selection picks out a mixture of the 

 most suitable individuals, not a type, as indeed may be seen every 

 day in ordinary life by any observant person, and as is shown by 

 the composition of any of the larger nations at the present time. 



There are a great many difficulties which to a logical mind are 

 fatal to the supposition that natural selection was responsible for 

 the great evolution of living forms that has gone on. Take for 

 example the facts of economic botany, always dismissed as 

 unimportant since they do not agree with the theory of natural 

 selection. The definite similarities and relationships that exist 

 among the various products belonging to the same family show 

 that whatever was responsible for the production of the family 

 must also be responsible for the economic products, while at the 

 same time the discontinuity in structure of the latter, and the 

 impossibility of gradual transitions between them, shows that 

 their evolution must have been by large mutations. The difference 

 between the distribution of a family and that of an association as 

 given in the last paragraph is another very strong argument in 

 the same direction. 



In the second place, natural selection would make the whole 

 great process of evolution, including man, the result of chance 



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