32 ANIMAL LIFE AND SOCIAL GROWTH 



grasses. There are more species in the Chicago 

 area in the four limited groups just mentioned 

 than there are individuals on the University of 

 Chicago quadrangles but their components scarcely 

 make a good beginning in a species census of the 

 region. 



The oldest and crudest type of community 

 study is to collect, identify and list the names of 

 the different species found living in a given habi- 

 tat. This is not an easy task yet it yields about 

 the same amount of information to the average 

 student that a list of the names of people in a 

 University would give to an outsider. When 

 the species present in an animal community are 

 numerous and diverse, the collections in the field 

 must of necessity be carried on by field workers 

 who would recognize at sight few, if any, of the 

 species concerned. These collectors conscienti- 

 ously select habitats that seem to them to be 

 typical and make more or less complete, drag- 

 net collections which are sorted and sent off to 

 specialists in the various groups who are able to 

 name the different specimens submitted to them. 



The field worker then assembles these identi- 

 fications and matches them with his field notes 

 where each specimen is represented by a number 

 in place of a name and so acquires named lists 

 of the animals that were taken from the different 



