FIRST FOUR DECADES OF THE TWENTIETH CENTURY 



43 



that: "Within the last few years the sub- 

 ject of ecology has come to find a place 

 of more or less importance wherever botany 

 is studied in its general aspects." Cowles 

 indirectly documents his point by his Uter- 

 ature citations for 1896 to 1900. 



The end of the nineteenth century is a 

 convenient, though not a logical, division 

 between the early history of ecology and 

 its more recent development. Unlike tlie 

 modern subject of genetics, which has de- 

 veloped mainly from the spectacular redis- 

 covery of Mendehan heredity in 1900, we 

 can now see that for ecology the years 

 connecting the centuries mark a time of 

 relatively smooth progress. Ecologists of the 

 early 1900's gave praise to Semper for his 

 recognition of the physiology of organisms 

 in relation to "natural conditions of exist- 

 ence," and researches in this field proceeded 

 steadily. Work on ecological aspects of ani- 

 mal behavior was active. Population studies 



were moving at an increasing rate. Evolu- 

 tionary thought was in gradual transition, 

 with the theory of natural selection, 

 known by some even then to be largely eco- 

 logical, still holding the attention of biol- 

 ogists. Ideas concerning natural coopera- 

 tion were growing. Natural history had 

 passed its peak of activity in university 

 circles, but was directly and broadly re- 

 lated to the preceding years. The same is 

 true for oceanography; the related subject 

 of Hmnology was in the midst of a notable 

 advance. In self-conscious ecology, the 

 community concept had been clearly ex- 

 pressed, and there was active research in 

 animal and particularly plant ecology. 

 Scientific attention in general was focussed 

 on nonecological phases of biology, and 

 the science of ecology, now well and firmly 

 rooted, could continue to develop outside 

 the distorting influences often accompany- 

 ing high popularity. 



3. FIRST FOUR DECADES OF THE TWENTIETH CENTURY 



INTRODUCTION 



At this point let us take stock of what 

 has already been said of the historical ante- 

 cedents and background of ecology. We 

 have covered in considerable detail some 

 2200 years of ecological history. From the 

 viewpoint of ecology, four general chron- 

 ological periods have been recognized: 

 (1) the contributions of the Greeks and 

 Romans; (2) the subsequent thousand or 

 so years of stagnation; (3) the develop- 

 ments of the sixteenth, seventeenth and 

 eighteenth centiu-ies that led into (4) the 

 nineteenth century studies. It has been sug- 

 gested that since the Renaissance the major 

 contributions to the growth of ecology oc- 

 curred along four channels: developmental 

 physiology, response physiology, relation 

 of species to their environment, and organic 

 evolution. 



Enough of a background has been pre- 

 sented to show that ecology had multiple 

 origins. It was descended neither from a 

 single idea nor from isolated facts. The task 

 now confronting us is that of showing how 

 "modern" or twentieth century animal ecol- 

 ogy has come into being and how it is 

 practiced today. There are many ways of 

 approaching this problem. For our purposes 



it seems best to adopt a chronological treat- 

 ment based roughly on the first four dec- 

 ades of the twentieth century. It will be 

 necessary, particularly in discussing the 

 later decades, to appreciate that even pres- 

 ent day ecology is not so clearly delimited 

 as are, for example, modern genetics or 

 many other biological disciplines. This 

 means that we are compelled to discuss and 

 consider certain borderfine fields. The point 

 is emphasized by examining the "Ecology" 

 section of a recent (1940) issue of Biolog- 

 ical Abstracts; the following subheadings 

 are listed: "General Animal Ecology;" 

 "General Plant Ecology;" "Hydiobiology" 

 (Oceanography, Limnology); "Ecology of 

 Wildhfe Management— Aquatic and Terres- 

 trial," and "BiocHmatology, Biometeorol- 



ogy-" 



It is advisable to discuss briefly certain 

 aspects of the history of plant ecology dur- 

 ing the twentieth century before attention 

 is focussed on animal ecology. Plant ecol- 

 ogy got off to a faster start at the turn of 

 the century. Thus, as will be shown later, 

 it had a great impact on the thinking and 

 research of certain pioneer animal ecolo- 

 gists. The development of plant ecology 

 has been reviewed by Conard (1939). 



Our responsibihty is not to linger on 



