54 



THE HISTORY OF ECOLOGY 



and his 2913 book, Guide to the Study of 

 Animal Ecology, frequently makes the 

 point by imphcation that this is ecology! 



A word is in order about Shelford's then 

 current studies (1911, 1911a, 1911b, 1912, 

 1912a), We shall return to some of these in 

 a professional sense later. Historically, they 

 had great influence on the growth of 

 ecology. They were cHmaxed, integrated, 

 and summarized in the 1913 book. Animal 

 Communities in Temperate America. From 

 the viewpoint of succession Shelford's 

 greatest contribution was his interpretation 

 of fish succession in streams as contrasted 

 with that in ponds. In the former he 

 showed that physiographic erosion was the 

 important factor. In the latter, the succes- 

 sion was conditioned largely by biotic 

 factors that gradually made over the habi- 

 tat so that new forms could move in. 



One of Shelford's more important theo- 

 retical discussions was his "Physiological 

 Animal Geography" (1911c). This paper 

 showed Shelford's reaction away from evo- 

 lution as an interpretative factor in ecology 

 and towards physiology and function. He 

 discusses briefly the point of view of the 

 historical or faunistic zoogeographers and 

 then proceeds to develop, with case exam- 

 ples, the alternative or physiological aspect. 

 Of the latter he says (p. 554) : 



"There are two distinct points of view for 

 biological investigation. One is that of evolu- 

 tion; the other, that of physiology, or the ex- 

 planation of the organism in terms of physics 

 and chemistry. One may make a physiological 

 explanation of the behavior or structure of an 

 organism and in no wise explain its evolution. 

 On the other hand, one may make an evolu- 

 tionary explanation of an organism without 

 making any contribution to its physiology. The 

 study of physiological animal geography may 

 be conducted independently of the problems of 

 evolution. It does not need to be concerned 

 with centers of origin, or paths of dispersal, or 

 with other problems of faunistic animal geog- 

 raphy. In this paper we are concerned with 

 the physiological relations of animals to natural 

 environments." 



It is only fair to state that in concluding 

 paragraphs Shelford does make the point 

 that biological science will be best served 

 by the wedding of these two viewpoints. 

 But the strong feature of his paper is its 

 synthesis of the ecological approach to 

 problems of dispersion. 



In present day ecology succession no 

 longer occupies so prominent a place. It is 



studied, but the emphasis is on the total 

 community, with succession essentially a 

 developmental phase of that total unit. 

 However, during the first two decades of 

 the twentieth century the concept was a 

 vital one in the historical sense; it stimu- 

 lated much work and provided a rational 

 approach for field analyses. 



In 1915 C. C. Adams pubhshed his ex- 

 tensive monograph on "The Variations and 

 Ecological Distribution of the Snails of the 

 Genus lo." This gastropod is a river fonn 

 and was studied primarily in the south- 

 eastern and southern states. Adams states 

 the centi-al theme of liis study by quoting, 

 with patent approval, W. K. Brooks, who 

 wrote (Adams, p. 7) : 



"Inheritance and variation are not two 

 things, but two imperfect views of a single 

 process, for the difference between tliem is 

 neither in fiving beings nor in any external 

 standard of extermination, but in the reciprocal 

 interaction between each living being and its 

 competitors and enemies and the sources of 

 food and the other conditions of life . . , You 

 will note that it is as great an error to locate 

 species in the external world as it is to locate 

 it in germ cells or in chromatin. It neither 

 exists in the organisms nor in the environment, 

 because it is in the reciprocal interaction be- 

 tween the two." 



In this historical survey Adams' paper 

 makes an important point. Here was an in- 

 vestigation by an ecologist, utihzing ecolog- 

 ical techniques, that made a sincere 

 attempt to coordinate and inteipret the 

 findings as they were related to heredity 

 and evolution. In short, we use Adams' 

 paper as evidence to show that, historically, 

 ecology was not divorced from evolution in 

 the minds of many workers in the field. 



Before closing this 1911 to 1920 survey, 

 we wish to draw attention to the point that 

 biometry was growing and its influence on 

 biologists and biology was gradually in- 

 creasing. The ecologist can not ignore the 

 importance of this fact. Much of modern 

 ecology is statistical and seems destined to 

 become more so. We have mentioned in our 

 review the names of Malthus, Quetelet, 

 Farr, Galton, Weldon, Pearson, Davenport, 

 Harris, and Pearl, names inextricably 

 woven into the history of ecology. Although 

 statistical methods per se did not contribute 

 greatly to ecology between 1911 and 1920, 

 they were available and were beginning to 

 be used. The then contemporary situation 



