DARWIN AS ECOLOGIST. 



27 



DAEWIN AS ECOLOGIST. 



By Eev. Peofessoe G. Henslow, M.A., V.M.H. 



[Read April 16, 1912; Dr. A. B. Rendle, M.A., F.R.S., in the Chair.] 



Since the year 1859 the world has been accustomed to associate 

 Daewin's name with " Darwinism," or the " Theory of the Origin of 

 Species by Means of Natural Selection." Present-day Darwinians 

 still do so, apparently quite ignoring the fact that Dae win gave us an 

 alternative explanation of evolution; for he introduced it in his 

 "Variation of Animals and Plants under Domestication" (1868) and 

 abundantly in the sixth edition of "The Origin of Species" (1878), 

 which is stated to have embodied his corrections up to 1872. 



It is first desirable to explain what ecology means and all that it 

 embraces, for the ultimate result of it is the discovery of the true 

 Origin of Species. By saying that Dae win was our first ecologist, I 

 mean that he was the first to realize the immense importance of study- 

 ing the structure of plant-organs in relation to the plant's own require- 

 ments. E.g., all botanists knew of the short- and long-styled prim- 

 roses; but Dae WIN alone investigated their meaning, in reference to 

 external influences — in this case, their pollination by insects. 



Moreover, he came to realize the fact that allied species separated by 

 the ocean must have had a common origin and inferred that the 

 environment had somehow been the cause of their differences. In fact 

 he perceived that appreciation of the facts of evolution was the outcome 

 of the geographical study of living and extinct animals and plants. 



It is only the word " ecology " which is new now, but " evolution " 

 was new in the 'thirties. 



We must go back to 1820 to find the first really scientific treatment 

 of geographical botany. We must turn to M. A. P. de Gandolle's 

 " Geographie Botanique. "''' In this article he makes three generaliza- 

 tions. 



The first two are as follows: — 1. "The influences which the 

 exterior elements exercise upon plants and the modijications which 

 result for each species." This corresponds with Daew^in's " direct 

 action of changed conditions of life," giving rise to " definite results," 

 i.e. new variations. 2. " The consequences which result from the 

 study of stations, i.e. the special nature of the locality in which 

 each species has been accustomed to grow, such referring to the 

 climate and the soil of a given place." This corresponds to the 

 modern "Associations" as Xerophytic, Hygrophytic, &c. While 

 " study of stations " is exactly the same thing as " study of homes " 

 or ecology. Though De Gandolle did not realize it, Daewin clearly 



* Dictionnaire des Sciences Naturelles. Tom. xviii. p. 359 (1820). 



