FOREWORD 



This volume of essays has been prepared as part of the recognition of the 

 Centennial of the California Academy of Sciences. In May, 1951, three mem- 

 bers of the Council were authorized by the Trustees of the Academy to make 

 plans for a volume of scientific papers appropriate to the occasion. After care- 

 ful consideration the committee decided that a most appropriate central theme 

 for the volume would be the historical treatment of biosystcmatics, using this 

 term in the literal sense, namely, the systematic treatment of living things and 

 with emphasis on developments since the founding of the Academy a cen- 

 tury ago. 



This theme appealed to the committee as especially appropriate since it 

 was during this period, from the middle of the nineteenth to the middle of the 

 twentieth century, that the basic principles underlying our present concepts 

 and aims in the classification and systematic treatment of organisms were clearly 

 enunciated and definitely accepted among biologists. The nineteenth century 

 brought to biology two all-important contributions, Darwin's and Wallace's con- 

 ception of organic evolution and Mendel's principles of heredity. Recognition 

 of the doctrine of organic evolution led directly to the working concepts of the 

 continuity of species and the transformation of old species into new ones. Recog- 

 nition of the basic laws of heredity has led, in the twentieth century, to very 

 great progress in the development of our concepts of the nature of the evolu- 

 tionary processes. 



It was inevitable that these tremendous forward steps should have a pro- 

 found impact on the thinking and practices of those systematists who recognize 

 the significance of the facts, not only of comparative morphology, but also of 

 variation and heredity and of the contributory disciplines of cytogenetics, physi- 

 ology, biochemistry, serology, biometry, ecology, and biogeography. Inevitable 

 too was the apathy shown toward these epoch-making advances by many taxono- 

 mists who were content to pile up new names of species and genera without 

 critical study of all available criteria of relationship, thus creating a maze of 

 names rather than systematics. Although some taxonomists are still littering 

 the waj^sides of biological literature with unnecessary names, there is a growing 

 tendency among systematists to bring to bear upon problems of classification 

 and nomenclature all of the various categories of evidence that are available in 

 order that the decisions reached shall represent as nearly as possible the true 

 state of nature. This modern viewpoint and aim is the culmination of many 

 experiments in the systematic treatment of organisms prior to and extending 

 throughout this ''Darwinian" century. 



It is only in recent decades, however, that the advantages of the many-sided 

 attack on problems of relationship and phylogeny have been realized. Many ob- 

 scure problems in the relationship of organisms have been cleared up by the 

 evidence from cytology, genetics, and biochemistry, not to mention other con- 

 tributor}^ disciplines; and, in many instances, such evidence has resulted in radi- 

 cal changes in older taxonomic treatments. At the same time, it has been clearly 



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