ANIMAL STUDIES 



CHAPTER I 



CONDITIONS OF ANIMAL LIFE 



1. Divisions of the subject. Biology is the science which 

 treats of living things in all their relations. It is sub- 

 divided into Zoology, the science which deals with animals, 

 and Botany, which is concerned with plants. The field 

 covered by each of these branches is very extensive. 

 Within the scope of zoology are included all subjects bear- 

 ing on the form and structure of animals, on their develop- 

 ment, and on their activities, including the consideration 

 of their habits and the wider problems of their distribution 

 and their relations to one another. 



These various subjects are often conveniently grouped 

 under three heads : Morphology, which treats of the form 

 and structure or the anatomy of organisms ; Physiology, 

 which considers their activities; and Ecology, which in- 

 cludes their relations one to another and to their surround- 

 ings. All the phases of plant or animal existence may be 

 considered under one or another of these three divisions. 



2. Difference between animals and plants. It is easy to 

 distinguish between the animal and plant when a butterfly 

 is fluttering about a blossoming cherry tree or a cow feed- 

 ing in a field of clover. It is not so easy, if it is, indeed, 

 possible, to say which is plant and which is animal when 

 the simplest plants are compared with the simplest ani- 

 mals. It is almost impossible to so define animals as to 



1 



