ANIMAL CLASSIFICATION— TAXONOMY 77 



must be used. There are many small and little-known animals which 

 have no common names, and we must of necessity use scientific names if 

 we are to speak or write about them. 



Scientific names have further advantages — they are universal in 

 nature and do not change from one language to another, as do the com- 

 mon names. Books and articles written in German, French, Spanish, 

 English, or any other language all use the same scientific names. This is 

 important because the scientists in one country must be able to interpret 

 the discoveries made in other countries without the possibility of mistakes 

 through translations. Scientific names have Latin endings and form 

 their plurals in the same manner as Latin words. This sometimes is con- 

 fusing if you have not studied Latin, but you should soon learn that the 

 plural of Amoeba is Amoebae and the plural of phylum is phyla, to mention 

 two common examples. 



In the system of taxonomy which we use today, living things are 

 placed into one of two great kingdoms — the plant kingdom, Phyta, and the 

 animal kingdom, Animalia. (We should mention at this point that there 

 are a few very small forms of life, such as the viruses, that do not fall into 

 either of these groups.) Each kingdom is then subdivided into phyla. 

 Each phylum consists of a group of organisms which have some important 

 characteristics in common, but which are different from those in other 

 phyla. By studying a typical member of each phylum it is possible to 

 gain a comprehensive picture of the entire world of animal life in spite 

 of the tremendous number of species that exist. Each phylum is broken 

 down into classes, the classes are further divided into orders, the orders 

 into families, the families into genera, and the genera into species. Each 

 of these groups includes a smaller number of kinds of individuals than 

 the one preceding it, until the species includes just one kind of animal, 

 such as a dog, a horse, or a robin. Even species, however, may be sub- 

 divided into varieties, which may be called subspecies since we all know 

 that there are different breeds of dogs, horses, and robins. 



A better understanding of the system can be gained through a classi- 

 fication of some form of life with which you are familiar. Let us assume 

 that you have a cocker spaniel dog named Becky. Now let us see how this 

 animal would be classified. Of course we know that it would be in the 

 kingdom Animalia, because it definitely is not a plant. As we look over 

 the descriptions of the phyla of the animal kingdom we find that only one 

 contains animals with a backbone. A dog's backbone can easily be felt 

 through the skin of its back, so we know that it belongs in this phylum 

 which is known as the Chordata. This phylum contains many diverse 

 animals — frogs, fishes, snakes, birds, monkeys, and cows, to name a few, 

 in addition to dogs. As we search for the proper class in this phylum, 



