312 INTRODUCTION TO EVOLUTION 



that employed above for the dog. We see that the higher or more inclusive 

 categories are shared by large numbers of animals. Thus a dog and its 

 master both belong to Phylum Chordata, Subphylum Vertebrata, and Class 

 Mammalia (Fig. 14.1). The "parting of the ways" comes at the level of 

 orders. While the dog belongs to Order Carnivora, its master belongs to 

 Order Primates. Within the Order Primates, man is classified as belonging 



PHYLUM 

 SUBPHYLUM 

 CLASS 



ORDER 

 FAMILY 



GENUS 

 SPECIES 



CHORDATA 



VERTEBRATA 



MAMMALIA 



CARNIVORA 

 CAN I DAE 

 GANIS 

 FAMILIARIs' 



FIG. 14.2. Classification viewed as a series of steps. 



to Family Hominidae. Man's genus in this family is called Homo; his spe- 

 cies within the genus, sapiens. Hence Homo sapiens is his scientific name, 

 as mentioned previously. 



Classification Reflects Evolution 



Having reviewed the general principles followed in classifying animals, 

 we may next ask: what has this classification to do with evolution? As al- 

 ready noted, the system was designed by Linnaeus as a logical method of 

 classifying and cataloguing, a method to be adopted by biologists of all 

 countries, thereby eliminating the confusion which had existed up to that 

 time. The Linnaean system has served this purpose admirably. 



Linnaeus was not convinced of the truth of evolution. He believed that 

 the species he named had been created as he found them. This view of the 

 fixity of species was the one commonly held by biologists of his day, al- 

 though, as we saw in Chapter 1 , ideas of evolution had existed long before 

 the eighteenth century. Nevertheless, it was not until the nineteenth cen- 

 tury, bringing the writings of Darwin, that belief in evolution became really 

 common. It may be of interest to note in passing that before the end of his 

 life Linnaeus modified his views sufficiently to think it probable that some 

 new species might have arisen by crossing or hybridization of the species 

 originally created. 



As we have seen, the Linnaean system is based on similarity. Animals 



