THE ABUNDANCE OF ANIMAL LIFE 5 



DEFINITIONS 



Biology is the branch of natural science which includes 

 all studies pertaining to living things. There are two great 

 subdivisions: Botany, which deals with plants; and Zool- 

 ogy, which is concerned with animals. Zoology, then, is 

 the body of facts and theories derived from the scientific 

 study of animals. Our science is founded on facts, and 

 over this superstructure there have been erected a number 

 of theories which are intended to blend zoology into a 

 harmonious whole. We must be scientific in our study. 

 This is the hardest task a zoologist has from day to day. 

 A scientist's aim is to discover the truth about phenomena. 

 A real scientist formulates his conclusions and general laws 

 from a study of the available facts, and he does this without 

 prejudice, or superstition, or thought of self interest. Let 

 us be scientific! This means accurate observation and 

 sound, thoughtful conclusions. 



On account of the amount of material which has been 

 accumulated from zoological studies, men's interests have 

 been divided and a number of subsciences established. 

 Chief among these are the following: 



Systematic Zoology deals with the description of species 

 and their classification according to accepted systems. 

 About 522,400 species have been described, and the mere 

 cataloguing of these requires considerable work by special- 

 ists. There are many branches of systematic zoology, 

 such as: entomology, relating to the classification of insects ; 

 ornithology, birds; conchology, molluscs, etc. 



Distributional Zoology has two aspects. Under Zoogeog- 

 raphy are included facts relating to the present arrange- 

 ment of animals on the earth. Five great realms which 

 possess characteristic animals are recognized (Holoarctic, 

 African, Indo-Malayan, Neotropical, Australian), and 

 these have each been subdivided into smaller parts. 

 Paleozoology deals with the distribution of animals during 



