INTRODUCTION 



You and Biology 



You have to learn biology, whether you like it or not. Everybody does. 



And why so? Because the curriculum requires it? Or because some 

 college entrance board says so? Not for these reasons. It is because we are 

 the kind of people that we are. Indeed, all of us have already learned a 

 great deal of biology — very largely without meaning to. It just cannot be 

 helped. 



Life Is Everywhere As far back in time as human beings first roamed 

 the earth, they were surrounded by many different kinds of plants and ani- 

 mals. All around were many kinds of birds, many kinds of tur-bearing 

 animals, both large and small, many kinds of creepy and crawly things, 

 bugs and worms and spiders, and fleas too. In the waters were many kinds 

 of fish and crabs and clams, as well as frogs and newts, which shifted be- 

 tween land and water. There were trees and shrubs and herbs, with 

 flowers and thorns and berries, and some with thick, fleshy roots. 



What We Need to Know Through all the ages it must have been 

 necessary for human beings to kjiow a great deal about many of these plants 

 and animals, and for two very good reasons. 



First, it was necessary to know which of these natural objects could be 

 used for food, or for clothing, shelter, tools, and weapons. Is that good to 

 eat? Is that kind of wood good for a bow or for a club? 



Second, it was necessary to know which of these different kinds of things 

 were injurious or dangerous. Is that snake poisonous? or that berry? Is 

 that animal one to run after, or one to run away from? 



It is important to know how difiFerent kinds of birds and fishes behave, 

 or we should have no luck killing or catching them. It is necessary to know 

 something of the habits of wild beasts if we are to act in a manner that 

 suits our needs. 



If you want to raise beans, you have to know something of the condi- 

 tions suitable to the growth of beans. If you want to get rid of poison ivy or 

 rats, you have to know what conditions destroy these forms of life. If you 

 care about your own well-being, you must know some things about the 

 workings of your own body: you must know what dangers to avoid, what 

 conditions favor health, what to do in an emergency. 



Human beings have, in fact, always known a great deal about plant life 

 and about animal life. Such knowledge is, as you can see, extremely prac- 

 tical — that is, it bears directly upon what people do. Two plants or two 



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