GENERAL BIOLOGY 



CHAPTER I 

 INTRODUCTION 



Biology is the science which treats of living things. 

 The number and diversity of organisms in the world is 

 so great as to be almost incredible. It is said that there 

 are more than a half million kinds or species of insects 

 alone already known and that there are undoubtedly a 

 great many as yet undiscovered. Of Diatoms, a sort of 

 one-celled plant, there have been named more than ten 

 thousand species. Altogether, it is well within the limit 

 to say that there are more than a million kinds of animals 

 and plants. 



Not only are organisms immensely numerous and 

 highly diversified but their activities are also extremely 

 numerous and complicated. Even apparently simple 

 processes frequently turn out to be complex and very 

 difficult to understand. This makes it necessary in order 

 to accomplish much in the way of new knowledge for 

 investigators to confine their attention not merely to a 

 few kinds of organisms but also to a single one or a few 

 of their activities. To add to the difficulty of the matter, 

 it is usual to have a great many different chemical re- 

 actions going on in one small bit of living matter so close 

 together that it is difficult to realize that they can pos- 

 sibly avoid interfering with one another. For this same 

 reason it is difficult to isolate a single activity for study. 



It is very obvious that no person could possibly become 

 famihar with all the different kinds of living beings. 

 It is necessary, therefore, to subdivide so vast a subject. 



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