INTRODUCTION 3 



the accumulation of biochemical data, many of which are already seen 

 to be of phylogenetic importance, points to an obligatory integration 

 of these data in systematics. The systematist does not have the pre- 

 rogative of evaluating the purely chemical aspects of data, but he has 

 a responsibility to be alert to progress in biochemistry, particularly 

 when discoveries bear potentially upon phylogenetic considerations. 

 Biochemistry relates to phylogeny at several levels, only one of which 

 involves the taxonomic distribution of specific compounds. Certain 

 approaches discussed in Chapter 4 may seem to be remote or even 

 irrelevant, but the writers believe that no approach should be dis- 

 couraged provided it is theoretically sound though its practical value 

 may eventually prove to be slight. 



It is not the purpose of this book to develop a case for 

 the use of biochemical data in systematics but rather to establish a 

 better perspective concerning the place of biochemistry in systematics. 

 There is a need for an exploration of some theoretical and intellectual 

 aspects of the subject, the development of a basic rationale, an inte- 

 gration of certain chemical and biological aspects, an analysis of the 

 advantages and hmitations of the biochemical approach, a broad and 

 essentially critical analysis of existing work. We have attempted to 

 accomplish this series of objectives. 



We do not beheve that biochemistry represents a panacea for 

 all systematic problems. If anything, the writing of this book has 

 modulated our initial enthusiasm which even in the beginning did not 

 lead us to conceive of present biochemical data as providing more 

 than supplementary data for phylogenetic considerations. However, 

 profound and far-reaching new insight into phylogenetic relationships 

 is potentially available in biochemistry, ultimately, we predict, from 

 intensive study of the comparative chemistry of macromolecules. 



Nowadays, much is spoken and written about what is pop- 

 ularly known as molecular biology and its relationship to descriptive 

 or classical biology. It is possible that some individuals regard these 

 two categories as mutually exclusive. It is true that in this age one per- 

 son rarely acquires eminence in both areas. However, there are many 

 who can excel in performance in one area and be intellectually in con- 

 tact with the other. It is the purpose of this book to contribute to an 

 integration of these disciplines by providing the groundwork for a more 

 effective utilization of biochemical data in systematics than has 

 previously existed. 



