FIRST FOUR DECADES OF THE TWENTIETH CENTURY 



49 



The answer is that, during this period, the 

 growth of ecology and evolution were so 

 inextricably woven together that it seems 

 artificial to separate the two. Many of the 

 studies we have mentioned in foregoing 

 pages contain data, conclusions, or concepts 

 that bear on evolution or speciation. In 

 other words, certain ecologists of these 

 times had a lively interest in such matters. 

 This is as it should be, and it epitomizes the 

 viewpoint of this book and its authors." 



1911-1920 



As we survey the second decade of the 

 twentieth century from the viewpoint of 

 ecological history, these items impress us: 



1. There was no major readjustment of 

 focus between this decade and the first. 



2. Not much theoretical synthesis of the 

 material of ecology was attempted. 



3. More work was done in the sense that 

 there were more investigators. 



4. Technical advances in other fields- 

 physics, chemistry, physiography, climatol- 

 ogy, physiology, biometry, and so on— reflect 

 upon ecological research largely through 

 refinement of methods and mensuration. 



5. Some books (both text and reference) 

 of use to the ecologist were published. 



6. The British Ecological Society and The 

 Ecological Society of America were founded 

 in 1913 and 1916, respectively, to aid ecolo- 

 gists and their enterprises. 



In short, this seems to be primarily a dec- 

 ade of sure, gradual growth without much 

 reorientation. 



Since the literature of this decade is 

 more extensive than that of the 1900 to 

 1910 era, there is a temptation to devote 

 more space to it. This we cannot do. We 

 can only sample as before and trust that 

 our samples are sufficiently representative 

 to be meaningful. 



Some of the books that appeared should 

 be mentioned. Books are valuable in a his- 

 torical survey because they indicate what 

 was considered important at the time and 

 how the subject matter was studied. Two 

 physiological texts were published that 

 ecologists found useful: Piitter's Vergleich- 



• For the sake of accuracy, however, it 

 should be mentioned that certain ecologists 

 were veering away from an evolutionary view- 

 point in the first decade. A good example, 

 perhaps, was V. E. Shelford, who, during that 

 period, was crystallizing his ideas on "physio- 

 logical animal geography" in contradistinction 

 to historical or faunal animal geography. 



ende Physiologie (1911) and Bayhss 

 Principles of General Physiology (second 

 edition, 1918). In 1913 C. C. Adams pub- 

 Hshed his Guide to the Study of Animal 

 Ecology. This served the useful purpose of 

 classifying the diverse literature of ecology 

 and outhned a reading program for stu- 

 dents. Probably the most valuable book of 

 the decade was Shelford's Animal Com- 

 munities in Temperate America (1913). 

 Here was a summary of much original field 

 research organized around a number of 

 habitats within a restricted area (Chicago). 

 The author gave due weight to physi- 

 ography, the nonbiotic and the biotic envi- 

 ronment, and to the quantitative enumera- 

 tion of animals. Although it is out of date 

 in some respects, teachers and students to 

 this day turn to it for ecological guidance. 

 It was reprinted without essential alteration 

 in 1937. 



Several books on hydrobiology appeared 

 and served a real need. Murray and Hjort's 

 The Depths of the Ocean (1912) became 

 rapidly a standard treatise on oceanography, 

 and the compendium Fresh-Water Biology 

 (1918), edited by Ward and Whipple, fa- 

 cilitated the study of limnology, particularly 

 through its emphasis on taxonomy. In 1916 

 Needham and Lloyd published The Life of 

 Inland Waters, "an elementary textbook of 

 freshwater biology" that served a useful 

 purpose in field zoology and beginning ecol- 

 ogy courses. In 1913 L. J. Henderson 

 published The Fitness of the Environment. 

 While not an ecological study in the re- 

 stricted sense, this book was a provocative 

 statement on the relation of the environ- 

 ment to its organism. It forced ecologists to 

 think in new and somewhat theoretical 

 terms and thereby exerted a healthy influ- 

 ence both on them and on the development 

 of their subject. We shall return specifically 

 to this book in a later section (p. 76). 



In 1915 Jordan and Kellogg brought forth 

 their Evolution and Animal Life, which con- 

 tained many correlations between ecology 

 and evolution and thus deserves mention in 

 this place. In the preface the authors state: 

 "... the writers have tried to give a lu- 

 cid elementary account, in limited space, of 

 the processes of evolution as they are so far 

 understood." The chapters with particular 

 ecological flavor are "Natural Selection and 

 Struggle for Existence;" "Geographic Isola 

 tion and Species-Forming;" "Geographical 

 Distribution;" "Adaptations;" "Mutual Aid 

 and Communal Life among Animals;" and 



