CHAPTER 8 



BIOCHEMICAL STUDIES OF 

 PHYLOGENY 



The previous discussions concerning the phylogeny of animals 

 has been concerned with evidence based mainly on morphological 

 data. Within recent years, however, biochemical studies have 

 been used to help determine animal relationships and the results 

 so obtained have aroused considerable interest. Only two such 

 studies will be considered here: those concerned with the dis- 

 tribution of phosphagens and those concerned with the distribution 

 of sterols through the animal kingdom. 



Due mainly to the work of the Cambridge biochemists, con- 

 siderable interest has been focused on the phosphagens present 

 in the invertebrates and the work has led to the discovery of a 

 series of new and interesting chemical compounds. It is now 

 intended to discuss the " phosphagen story " in some detail. 



(1) Phosphagens 



In many of the textbooks on comparative biochemistry or 

 physiology such as those of Baldwin (1940) or Prosser (1952) one 

 will find the following table. 



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