184 ECOLOGY 



readily seen, if we consider certain recently evolved, feeble endemic 

 species in connection with their nearest relatives, and also study the 

 history of their modification under the influences of time and ex- 

 ternal circumstances. As such species we may mention the glacier 

 willows of Nova Zembla and the twenty-three species of the genus 

 Hieracium, restricted to the Faroe Islands and described by Dahl- 

 stedt. The presence of such species gives a decided geographical 

 character to the region in which they occur. 



Under the title Geographic botanique exptrimentale, Bonnier en- 

 deavors to prove the direct effect of change of climate upon the 

 variability of specific forms, and G6neau de Lamarliere uses the 

 phrase physiologie specifique to express the idea of the degree of 

 adaptation accomplished. R. von Wettstein draws his conclusions 

 from different premises, since he considers that the species which 

 have been developed have been derived from related species and 

 from those closely restricted to the same location. Having made this 

 assumption, he then proceeds to search for the causes which have 

 been influential in the accomplishing this end. 



The ecological point of view includes those things concerning the 

 question of continuance in a given location, the power of obtaining 

 nourishment, and the certainty of establishing the succession, which 

 are not general and uniform, but which differ according to the vary- 

 ing factors of the environment. Ecology is the study of epharmony 

 in the organic world, and the possibility of variation possessed by 

 species, as well as the mere fact of their life together, is an ever- 

 present, dynamical factor in the determination of the external 

 appearance of our earth. But it is not enough simply to discover 

 and describe these various specific relations; we must press forward 

 and from the mass of accumulated data obtain an intimate compre- 

 hension of the organic form in its dependence upon Mother Earth! 



During the course of our historical sketch of the development of 

 the ecological idea, three special points of view have been made 

 manifest, namely: 



(1) The relation of the organization of ecological forms to the 

 morphology of plants and animals (morphological relation). 



(2) The relation of the ecological formation to the physiography 

 of the country (physiographical relation). 



(3) The relation of ecological epharmony to the phylogeny of 

 systematic groups in both animal and plant kingdoms (phylo- 

 genetic relation). 



If we wish ecology to rank as a special branch of biology, we must 

 undoubtedly consider these three points of view as inseparable, and 

 we may give our attention to either one or the other, just as, until 

 recently, most North American studies have been devoted to inves- 



