PART VI 



MAN AND OTHER ORGANISMS 



CHAPTER LXXXV 

 THE CLASSIFICATION OF ORGANISMS 



499. Scientific classification. Apart from the fact that many 

 people derive satisfaction from collecting and sorting various 

 classes of objects, classification is of value because it facilitates 

 the work of reference. Just as the classification of the books 

 in the library makes it possible to find a particular book, or a 

 particular kind of book with the least effort, so classifying 

 plants and animals furnishes a convenient scheme for placing 

 each specimen where it belongs. 



In recent times the study of classification has acquired new mean- 

 ing because of the light it throws on problems of evolution and 

 because of its aid to the study of heredity. 



Every scheme for sorting things must provide a way of bring- 

 ing together plants or animals that are truly related to each 

 other, and it must at the same time avoid bringing together, 

 because of superficial resemblances, plants and animals that 

 are not related. 



500. The basis of classification. If we should sort our books 

 according to size or color of binding, we should often bring two 

 books on Mexican history together ; but we should be just as likely 

 to bring together a book on Mexican history and one on astronomy, 

 and we should be sure to separate books that really belong together. 

 In the sorting of plants and animals it is necessary to find a basis 

 that will secure the desired results. 



475 



