486 THE CHANGING WORLD 



ADAPTATIONS 

 Making the Best of It 



Adaptations are biological charigcs that organisms make in adjusting 

 themselves to physical changes which constantly occur in the environ- 

 ment. Here are two variables to analyze and consider, namely, 

 changes made by the organism, and those that come to pass in the 

 environment of the organism. How do they interact? 



Organic adaptations vary widely in the degree of perfection. They 

 may be incipient, partial, and ineffective, or, at the other extreme, 

 they may have gone so far as to result in overspecialization. This 

 latter condition is frequently dangerous to its possessor, since the 

 specialist, having all his eggs in one basket, cannot help sacrificing 

 some of the saving adaptability necessary to meet a changing turn 

 of the environmental wheel. This is particularly true in human 

 affairs. The hobo who is limited to snow-shoveling is unemployable 

 in the summer season. 



Many instances of adaptation are entirely obvious. Others are 

 obscure and speculative, but in any case the extensive gallery of 

 common adaptations furnishes abundant and intriguing material for 

 the biologist. "Maeterlinck's essay on the adaptations of the bee," 

 says Henshaw Ward, "makes the Arabian Nights seem flat." 



Kinds of Organic Adaptations 



The classification which follows is entirely arbitrary and by no 

 means complete. It is simply an attempt to arrange certain cate- 

 gories of adaptation temporarily for purposes of description. There 

 is such a wealth of illustrative material that it is almost hopeless 

 to attempt to pick and choose. Consequently, resort will be made 

 more to suggestion than to detailed elaboration of particular cases. 

 Here is an excellent opportunity for the reader to fill in omissions 

 with supplementary material of his own. 



Structural Adaptations 



The elaborate mouth-parts of insects are all designed apparently 

 on the same fundamental plan, but this plan is carried out quite 

 differently in the "tobacco-chewing grasshopper," which feeds on 

 \'egetation, and in the prodding mosquito, that sucks blood out of 

 protesting humans. 



