A. THE ECOLOGICAL FOUNDATIONS OF 

 ZOOGEOGRAPHY 



CHAPTER I 



THE PROBLEMS AND RELATIONS OF ECOLOGICAL 



ANIMAL GEOGRAPHY 



Zoogeography is the scientific study of animal life with reference 

 to the distribution of animals on the earth and the mutual influence 

 of environment and animals upon each other. This branch of science, 

 therefore, forms a department of both zoology and geography. 

 Zoogeography corresponds to phytogeography, and with it forms the 

 single science of biogeography. These divisions of biogeography are 

 very unequally developed. Phytogeography, in general, has dealt 

 mainly with the distribution of the vascular plants, and zoogeography, 

 in this respect, rests upon a broader basis, since all groups of animals, 

 from protozoans and coelenterates to vertebrates, have been included 

 in zoogeographic studies, though very unequally. On the other hand, 

 phytogeography has been the subject of active research for a much 

 longer period, and has accordingly been much more intensively studied 

 in special fields. 



Among plants, the relations with the total environment are much 

 more direct and obvious than among animals. The capacity for motion 

 from place to place makes animals to a degree independent of their 

 environment; the majority of them are at least able to move towards 

 water, food, or warmth in new localities, and thus they become exposed 

 to new conditions. The formation of spores or seeds, effectively pro- 

 tected from unfavorable influences and easily distributed passively, 

 favors the wide distribution of plants, enabling them to cross barriers 

 more generally, so that among plants limitations of their distribution 

 in accordance with their ancestral history are very much less evident 

 than among animals. Many physiological problems were thus more 

 clearly defined for the plant geographer, and their solutions more 

 easily attained. Zoogeographers have been compelled to examine many 

 phases of animal distribution in the light of previous phytogeographic 

 studies. Zoogeography is made difficult by the great complexity of the 



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