THE EVIDENCE FOR EVOLUTION 737 



Questions 



1. What methods are used for estimating the age of rocks? 



2. What is a geological revolution? What effects have such revolutions on the course of 

 evolution? 



3. Describe the life of the Cambrian period. What are the biggest differences between 

 the animal life of that time and the present? 



4. Discuss the thesis that the hierarchical scheme of animal classification is evidence for 

 organic evolution. 



5. How would you define a species? What difficulties might be encountered in trying to 

 decide whether two populations of animals are one or two species? 



6. Define: homologous organs, vestigial organs, Rassenkreis, petrifaction. 



7. Describe the method used to determine evolutionary relationship by the nature of 

 serum proteins. 



8. Discuss the implications of the phrase "Ontogeny recapitulates phylogeny." What 

 changes in Haeckel's theory have been made necessary by subsequent research? 



9. Discuss the genetic explanation for the phenomenon of recapitulation. 



10. What is Jordan's rule? 



11. Define the terms "range" and "center of origin." 



12. If, in tracing evolutionary relationships, anatomic evidence pointed one way and 

 biochemical evidence another, which do you think would be the more reliable? Why? 



Supplementary Reading 



The fossil evidence for evolution is summarized in Dodson's Textbook of Evolution. 

 R. S. Lull's Organic Evolution and W. K. Gregory's Evolution Emerging provide more 

 advanced discussions of paleontology. The more important fossil vertebrates are described 

 in A. S. Romer's Man and the Vertebrates, P. E. Raymond's Prehistoric Life, and Colbert's 

 Evolution of the Vertebrates. Two excellent recent books on the evolution of the inverte- 

 brates are Principles of Invertebrate Paleontology by Shrock and Twenhofel and Inverte- 

 brate Fossils by Moore, Lalicker and Fischer. 



An Introduction to Comparative Biochemistry, by Ernest Baldwin, provides an inter- 

 esting account of some of the biochemical similarities in different animals which point 

 to evolutionary relationships. A detailed but readable discussion of the biochemical facts 

 bearing on evolutionary theories is Marcel Florkin's Biochemical Evolution. A brief dis- 

 cussion of this topic is found in George Walds Biochemical Evolution, in Trends in 

 Physiology and Biochemistry, edited by E. S. G. Barron. 



