CHAPTER XL. 

 SOME PRINCIPLES OF PLANT EVOLUTION. 



640. Evolution means development and progress accord- 

 ing to natural laws. It is growth and progress from very 

 simple conditions or things, to a more or less high, complex and 

 perfect condition,* by more or less gradual changes -which take 

 place in a natural way. Looking at the whole period of de- 

 velopment we can see different steps in the progress which has 

 taken place. 



641. If we look at the progress made by man from the 

 savage state up to the present high state of civilization, we can 

 see that there has been a gradual change, a progression in his 

 relations to his neighbors, in the relations and dealings of com- 

 munities, tribes and nations with each other. In the various 

 arts, trades, and manufactures there were very crude beginnings, 

 with gradual change and progressive improvements to the present 

 time, as shown by the many inventions and the high state of 

 efficiency in the trades and manufactures at the present time. 

 All this has come about by evolution. It is evolution of social 

 man, of communities, of tribes, of nations; evolution of trade, 

 evolution of arts and manufactures. It would have been impos- 

 sible for savage man or for the early civilized men to invent 

 and build at once the many highly useful and efficient appli- 

 ances, the means for transportation and communication, etc., 

 which exist to-day. Very crude utensils, appliances and build- 

 To THE TEACHER. This chapter is intended chiefly for reading and 



reference. It can serve as the basis for informal talks by the teacher, or 

 portions can be assigned for reading at his discretion. There should not be 

 any attempt to commit it to memory. The teacher can select such portions 

 as he wishes for special assignment. 



* There are also evolutions downwards, degeneration or retrogression. 



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