2 THE BIOLOGY OF THE SEA-SHORE 



naturalists. In addition to defining the limits of the study 

 and its relation to other branches of zoology, ecologists are 

 chiefly concerned in unravelling and reducing to order the 

 multitudinous factors composing the environment, and in 

 estimating their relative importance. One of the chief 

 features of the progress of the study of ecology is the framing 

 of a special nomenclature ; but valuable as many of the 

 new terms are, we intend to employ them as little as possible, 

 more particularly as there is not yet complete agreement as 

 to their equivalence. 



According to Adams (19 13) the study of ecology may be 

 approached from three distinct points of view, which are 

 " superficially so distinct that students of one branch may 

 be almost unaware of the existence of the co-ordinate 

 branches and may not realise that each is part of the larger 

 unit." The first is that of individual ecology. In this case, 

 investigation is focussed upon a particular animal which is 

 studied in all its manifold relations to its environment, 

 animate and inanimate. Not a few such studies have 

 already been attempted ; they vary, of course, greatly in 

 degree of completeness (in many cases observations might 

 well extend over a lifetime and be still incomplete). As 

 an example we may quote Darwin's study of the habits of 

 earthworms, written before the term ecology had been 

 invented. Many of Fabre's studies come under this heading 

 also. The tendency of the present-day ecologist, as com- 

 pared with a naturalist such as Fabre, is to pay an increasing 

 amount of attention to the physical environment and to 

 analyse behaviour in terms of factors such as hght, pressure 

 and contact, temperature, water, gravity, etc. 



A second point of view is that of aggregate ecology. 

 Here, instead of attention being directed towards a particular 

 individual, the study centres upon a unit group or aggregate 

 composed of a number of animals either generically related 

 or living as a family group. In this way, says Adams, 

 it is possible to speak of the ecology of birds, dragon-flies, 

 the genus Bombus, a hive of bees, or a colony of ants. To 

 use Adams' phrase, it is " the hereditary or taxonomic unit 



