8 



INTRODUCTION 



tradition among nonhuman animals. How 

 much learning, if any, is involved? To what 

 extent, if at all, are animals conscious of 

 their actions or surroundings? 



These are troublesome questions con- 

 cerning which it is difficult to collect exact 

 and pertinent information, whether from 

 existing literature, directly from outdoor 

 nature, or by means of planned experi- 

 ments. Elton (1933) recognized the exist- 

 ence of such problems and suggested some 

 conclusions that depart from current trends 

 of thought in scientific circles. Apparently 

 speaking primarily of birds and mammals, 

 he says (p. 46) : 



"Changes in habitat are frequent, and we 

 do not yet know precisely what relative im- 

 portance to attach to psychological factors 

 (new ideas, or broken traditions or accumula- 

 tive fatigue with old habits) and how much to 

 organic changes in the form of mutations af- 

 fecting behaviour. Finally it is of great interest 

 to inquire whether animals are actually con- 

 scious of their actions, and whether in this 

 consciousness there is any element which is at 

 variance with the usual concepts of animal be- 

 haviour current among physiologists and also 

 many ecologists. There is definite evidence that 

 animals often migrate in response to stimuli 

 which cannot be called danger signals but 

 which appear to be unpleasant to them (Elton, 

 1930). Whether in this behaviour we can dis- 

 cern feelings akin to aesthetic feelings or 

 whether they are to be looked upon as me- 

 chanical aspects of mental balance, cannot be 

 decided. The whole question of animal be- 

 haviour in relation to the choice of habitats and 

 habits in general is of profound importance 

 both in theoretical science and in practical 

 economic biology." 



These are matters that we cannot yet 

 solve, but it is important that we should 

 not continue to ignore their existence. A 

 major difficulty lies in the absence of an 

 objective terminology. The use of vaguely 

 defined terms is associated with the un- 

 critical humanizing tendencies of many 

 naturahsts, who in turn give strong avoid- 

 ing reactions to the carefully objective and 

 perhaps overcorrected point of view of 

 critical modem students. 



Recognition of community of interests be- 

 tween the general and comparative phases 

 of psychology and of ecology calls for com- 

 mendation of the modem tendency toward 

 objective terminology in both subjects, as 

 well as in general biology and other phases 

 of science. General anthropomorphic con- 



cepts and language are to be avoided, ad- 

 mitting that other considerations such as 

 clarity and brevity or entrenched usage may 

 sometimes require exception. It is unfortu- 

 nate to have to use a Greek or Latin root 

 meaning "loving," for example, to denote an 

 ecological relation, when the EngUsh forai 

 would be objectionable or ridiculous. This 

 is a language ideal that is frequently diffi- 

 cult to apply even with conscious and 

 conscientious eJBEort. There is a severe strain 

 when one is convinced (a) that the Carte- 

 sian doctrine is essentially unsound, (b^ 

 that scientific writing should be simple, 

 clear, and direct, and (c) that even the 

 words used should not carry partially hid- 

 den suggestions unsupported by direct 

 evidence. 



A binding principle in ecology, as in 

 many other phases of biology, deals wdth 

 the integration of individual units into 

 larger wholes. Cells of more complex ani- 

 mals combine into tissues, organs, and sys- 

 tems, and yet all this complexity develops 

 from a single cell. Even at the cell level, 

 certain cells living in close association with 

 each other— as in lichens, for example— may 

 not be germinally related. All ecological 

 communities lack the germinal continuity 

 characteristic of populations of single spe- 

 cies and particularly characteristic of co- 

 lonial animals like sponges or many hy- 

 droids, or the typical societal colonies of 

 social bees, wasps, or ants. Interspecific 

 populations also obviously lack germinal 

 continuity. Their evolution is traced to a 

 combination of ecology and genetics that 

 will be outlined in the section on Evolution. 



The relationships between these ecologi- 

 cal categories may be traced either by the 

 type method or by the principles treatment 

 attempted in the present book. Neither ap- 

 proach is automatically preferable. The 

 cataloguing of one category after another 

 gives a readily indexed treatment that 

 orders the details in a workable manner, 

 but may conceal the underlying principles. 

 The approach through principles may con- 

 fuse the issue so far as facts are concerned 

 and may be unsatisfactory for those inter- 

 ested primarily in a catalog of existing data. 



The type treatment deals directly with 

 the ecology of the oceans, one after another, 

 of bays and gulfs, of the fresh water, and 

 of the land. The principles treatment draws 

 evidence now from one and now from an- 

 other type of habitat, and then passes on 



