14 ANIMAL ECOLOGY 



A teacher will find certain important advantages in 

 this plan, and certain disadvantages. One of the most 

 important considerations in its favor is that such a 

 study results in a familiarity with the kinds of animals 

 one actually finds in natural groups, as when his 

 class is on an excursion. The natural history which 

 a farmer, a fisherman, a summer vacationist, or a 

 sportsman acquires is grouped in this same manner. 

 Thus to a large number of people this is the natural 

 method of approach, and is generally of most perma- 

 nent value, except possibly to some professional 

 teachers or zoologists. One of its greatest disadvan- 

 tages is that in most of the literature which one must 

 use, the animals are not grouped in this way, but 

 taxinomically. 



The individual, aggregate, and associational 

 methods of study are in themselves subject to diverse 

 angles of approach, and each has its particular ad- 

 vantages and disadvantages. Of the methods of 

 approach mention will be made of three only, the 

 descriptive, the comparative, and the genetic or 

 method of processes. The descriptive method must 

 develop to some degree before the genetic problems 

 can be adequately stated, and the mature develop- 

 ment of the genetic may, and generally does, lag 

 far behind that of the descriptive. The reason 

 for this is simple, for it is evident that it is much easier 

 to describe what we see than it is to explain how it 

 originated or its process of development. At present 

 biology as a science is mainly in the descriptive stage, 

 though it is slowly but surely becoming explanatory 



