Living Things Are Named mid Classified ioi 



PROBLEM 3, 



teristics in common are grouped into a 

 phylum; phvla are grouped into a king- 

 dom. There are only tw^o kingdoms: the 

 plant kingdom and the animal kingdom. 



All classification is the same in prin- 

 ciple. In describing the classification of 

 animals we began at the bottom with the 

 dog species and showed how similar 

 species may be grouped together to make 

 a larger grouping, a genus, and thus we 

 worked up to larger groupings and still 

 larger ones and finally to the animal 

 kingdom. In describing the classification 

 of coins we did the reverse. We began 

 at the top with the coin ^^k'mgdovi''' and 

 divided it into groups (corresponding to 

 phyla) and so on down until we reached 

 the final subdivisions into pennies coined 

 in a certain year. These would corre- 

 spond to species. Do you see that the sys- 

 tem is the same? Figure 136 will show 

 you how the animal kingdom is divided 

 first into phyla, phyla into classes, classes 

 into orders, orders into families, families 

 into genera, and genera into species. 

 Species are sometimes subdivided into 

 varieties or breeds. Thus you see how 

 the northern gray squirrel fits into the 

 animal kingdom. 



As in the case of the coin collection, 

 the first large groupings are few in num- 

 ber; but the smallest subdivisions are 

 very numerous. There are only two 

 kingdoms and only about eleven phyla 

 in the animal kingdom but the number 



of species runs to about 800,000. Further- 

 more, the larger the grouping the 

 smaller the number of characteristics 

 which the members have in common. 

 (See Fig. 126.) But when you arrive at 

 the smallest subdivision, the species or 

 perhaps the variety, the animals in such a 

 subdivision have a great many charac- 

 teristics in common. 



The classification of plants. The classi- 

 fication of plants is not quite as clear 

 and easy to follow as the classification of 

 animals, but the principles remain the 

 same and the double naming is also used. 

 All maples, for example, belong to the 

 genus Acer (a'sir). One species from 

 which we get maple sugar is Acer sac- 

 chanmi. The red maple is Acer ruhrimi. 

 Every oak is called Quercus (kwir'cuss). 

 Quercus virginimm is the live oak of the 

 southeastern states. Quercus alba is the 

 white oak of the northeastern and cen- 

 tral states; and Quercus agri folia is the 

 coast live oak of California. Sometimes 

 there are slight but regular differences 

 between members of a species so that 

 we can make a further subdivision into 

 varieties. There are two varieties of red 

 maple. Each has a different third name 

 added to Acer nibrum. 



A quick review of the summary tables 

 at the end of Problems i and 2 will help 

 you to remember the important facts 

 about animal and plant groups that have 

 been presented. 



Questions 



1. About how many different kinds of living things have been named? 



2. What is meant by classification? Of what advantage is classification? 



3. List the followinor characteristics in order of importance in grouping 

 coins: date, value, and country of coinage. Are the first groupings 

 or the last more numerous? In which grouping, first or last, are the 



