146 ^^^ ANIMAL KINGDOM 



Weimar, Georges Cuvier was court biologist in France, surviving both 

 the French Rcvohition and Napoleon. Cuvier extended classification 

 into the more complex area ol comparative anatomy, a field which he 

 established almost single-handed. He showed that reconstructions could 

 be made Irom lossil bones, and that they often represented animals no 

 longer living. He began to give names to these extinct species, of which 

 almost 100,000 have been identified since his time. 



During this period the diversity among the lower animals was dis- 

 covered, and the taxonomic system was expanded to provide for more 

 and more phyla of invertebrates, while the several classes of vertebrates 

 were joined together in a single phylum. 



By 1830, however, the museums and laboratories of the world sagged 

 under their collections, and the task of naming all the species appeared 

 less complete than ever. Furthermore, many of the known species were 

 discovered to vary in their characteristics from one region to another 

 and species formerly considered distinct were found to have intergrades. 

 Since the concept of evolution was not yet popular, and was denied 

 vigorously by such authorities as Cuvier, all species were believed to 

 have been created just as they were. The growing confusion over the 

 boundaries between species and the apparent endlessness of the job of 

 naming were discouraging indeed. Both Goethe and Cuvier died in 1832, 

 at which time interest in taxonomy began to decline. The original goals 

 set by Linnaeus have not yet been realized. 



It was partly because taxonomy was already in difficulty that evolu- 

 tion was accepted so readily when Darwin presented his arguments in 

 1858. From that moment on, taxonomy was no longer an end in itself, 

 and the taxonomic system was adjusted to serve the interest in evolution. 

 The races and intergrades of species that had been taxonomic obstacles 

 became interesting problems, evidence of evolution in action. Relation- 

 ships among species became more important than ever, and a new ques- 

 tion, the "why" of a species, could be asked. Finally, the definition of a 

 species became more complete, establishing the species as an evolution- 

 ary unit as well as a taxonomic category. 



A student of zoology in the time of Linnaeus had only the following 

 groups of animals to learn: mammals, birds, reptiles, amphibians, fishes, 

 insects and worms. Today, however, the beginning student is bewildered 

 and perhaps dismayed to discover that Linnaeus' category, "worms," 

 includes most of the phyla (21 out of 23 in this text). To facilitate mat- 

 ters the 23 phyla have been divided into 10 major and 13 minor phyla. 

 The major phyla, ones containing many species, are described in 10 

 separate chapters and accoimt for most of the material to be learned. 

 The minor phyla are to some extent interspersed among the major 

 groups, if it is especially convenient to do so, but most of them are con- 

 sidered together in Chapter 18. 



The insistence that all animals, including the "lower" animals, 

 should be studied was first expressed by Aristotle. In his treatise. Of the 

 Parts of Animals, as he begins an analysis of animal structures he argues 

 (from the translation by A. L. Peck): 



