viii Preface 



chemistry, genetics, geology, ecology, and many other bordering 

 fields. Presenting a general background in each of these contributing 

 fields is, of course, outside the objectives of this book, but in some 

 fields, such as genetics and ecology, an explanation is given for those 

 facets needed to understand the basic concepts pertinent to evolu- 

 tion. These brief explanations are included so that the non-specialist 

 in these fields may gain a grasp of this inter-disciplinary information 

 to achieve a cohesive philosophy of evolution. Such a philosophy 

 of evolution, embracing the entire scope of the evolutionary process, 

 starts with pre-stellar evolution and continues by logical steps to the 

 evolution of biomes. 



By combining new ideas from different disciplines, evolutionary 

 studies bring out new perspectives which in turn continuously gen- 

 erate new questions. Efforts to answer evolutionary questions lead 

 to new ways of framing inquiries in affected disciplines. The analysis 

 of whole communities, for example, has been considered by several 

 writers (Andrewartha and Birch, 1954) as too complex a problem 

 to be fathomed through the use of present ecological research 

 methods. Because existing biotic communities are the products of 

 past evolution, a knowledge of the principles of their evolutionary 

 history will undoubtedly lead to new conceptual foundations valu- 

 able in community analysis. As the physicist, astronomer, and his- 

 torian Rudolf Thiel has said, "Only knowledge of how a thing be- 

 came what it is gives us a feeling of really understanding it. We 

 are not satisfied with insight into the character of things; we must 

 fathom their origins before we feel that we have begun to reach 

 the ultimate truth about them." 



The examples have been chosen carefully with two thoughts in 

 mind. First has been the desire to choose those which would help 

 to explain ideas with the greatest clarity. Second has been the hope 

 that these examples would assist the reader in understanding how 

 data from his investigations might fit into and augment evolutionary 

 concepts. 



The literature about evolution is voluminous, and it has been im- 

 practical to do more than cite a minimum number of papers bearing 

 on the topics discussed. More extended bibliographies and treatment 

 of special phases are contained in references listed in the bibli- 

 ography. 



