64 Resemblances and Differences Among Living Things 



mon ancestors — in other words that there has been descent 

 of one Hving form out of a different Uving form, or evolu- 

 tion from simple forms to more complex forms. It is con- 

 ceivable, for example, that each particular kind of living 

 being came into existence through a separate act of creation, 

 and that there is no other connection or relationship between 

 one species and another except the simple fact that they 

 are all made up of living things. 



The difficulty of this supposition of separate origins ap- 

 pears when we try to describe any species of plants or animals. 



It was long ago recognized that the common names given 

 to various kinds of familiar plants and animals were not satis- 

 factory. First of all, common names are not very definite 

 and may mean one group in one region and something quite 

 different in another region. In the next place, as we have al- 

 ready noted in the name violet, each common name often in- 

 cludes several distinguishable groups of individuals. Such a 

 group is commonly called a genus. According to the system 

 of naming plants and animals developed by the Swedish scien- 

 tist Linnasus, each name consists of two parts, the genus and 

 the species names, as we should say red maple, sugar maple, 

 silver maple. Maple is the genus and the qualifying word 

 red, silver, etc., represents the species. The use of two names 

 for identifying individuals, the family name and the per- 

 sonal name, illustrates the same principle. In defining a 

 word it is also standard practice to give the genus and the 

 species. We say, for example, a keg is a small (species) bar- 

 rel (genus) ; and that a tun is a large (species) barrel (genus) . 

 We say that a barrel is a container or vessel (genus) made- 

 with-staves-and-hoops (species) . 



While we understand then what we mean in principle 

 by genus and species, we are nevertheless exposed to con- 

 fusion when we attempt to speak of the actual plants and 

 animals with precise definition of " kind." The word " corn " 

 for example means what we call *' rye " in some places and 

 any kind of " grain " in other places. Moreover, in this 

 country where we can fit the word as a rule to the ** Indian 



