CHAPTER XXXIV 



RELATIONS BETWEEN PLANTS AND THEIR 

 SURROUNDINGS 



Think of all the different kinds of plants that you might 

 see in one short walk. Think of the microscopic plants 

 that grow in water as compared with the huge trees of the 

 forest. Think of the many forms of mushrooms, and of 

 the strange plants of the tropics. 



Evolution. We wonder why there is all this great 

 variety of forms that we see on every hand. This is one 

 of the great problems of natural science. Scientists for 

 many years have been at work upon it, but there is not 

 yet any complete answer. You know that we do not be- 

 lieve that all the many kinds of plants and animals were 

 separately created. We do believe that they have come 

 from common ancestors. This great process is called evolu- 

 tion, which means change. It means the production of 

 new things through the change of the old ones. It means 

 that in ancient times as well as to-day no two forms were 

 alike and that each new form was more or less different 

 from its parents. You can see that with this sort of thing 

 going on for some millions of years, there would surely 

 be a great increase in the number of kinds of plants and 

 animals. 



As you look over a field of corn you are quite sure to see 

 individuals that are different. Here is a fine plant, nearly 

 ten feet high, and bearing two good ears. Not far away we 

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