WHY AND HOW WE STUDY BIOLOGY 



The study of biology. The word biology comes from two Greek 

 words, bios (life) and logos (word or study). Biology, then, is the 

 study of things that are alive, both plants and animals. Man lives 

 in a world filled with living things. Some are his friends and some 

 are his enemies. It is essential, if he is to be master of this world, 

 that he should understand the living things that are around him. 

 His mastery is due to his understanding of the processes of life in 

 nature. There are many ways in which this conquest is achieved. 



Biology in relation to health. It is most important that we 

 control the living things that harm our health. We live in a 

 world that is filled with tiny enemies — some in the water, some 

 in the ground, some enricH. 



living on plants, some soil 



living on animals. We r ~, r<M , >•.,»,..**» 



o cause "RAf v 'TFDtA cctixse, 



call them parasites cfec^xy - * -dm.w.ckia — *- c ci 5 - ease 



because they take * \ 



nourishment from a cSSe 



living Organism and Some of the work done by bacteria. Can you add any 

 ■ I. • i others not given in the diagram ? 



give nothing m return. 



The smallest and yet most widespread of these parasites are the 

 tiny bacteria or germs existing almost everywhere about us, in 

 water, soil, food, and air. They play a tremendous part in shaping 

 the destiny of man. They help him in that they act as scavengers, 

 causing things to decay; they give flavor to cheese and butter; 

 they assist the tanner ; and they are invaluable aids to the farmer. 

 But, on the other hand, they cause the decay of meat, fish, vege- 

 tables, and fruits; they sour milk and sometimes spoil canned 

 goods; more than this, they cause diseases such as diphtheria, 

 tuberculosis, and typhoid fever. 



Hundreds of scientists are devoting their lives to the study of 

 germs and their control, which makes up that subdivision of biol- 

 ogy known as bacteriology. A great bacteriologist, Louis Pasteur, 



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