SUMMARY 



269 



hunters to explore the unknown regions of the country 

 and mark out the trails afterward followed by the pio- 

 neers, have almost en- 

 tirely disappeared. 

 Small animals, like the 

 fox, the prairie dog, the 

 skunk, the woodchuck, 

 still remain, the puny 

 survivors of a once 

 varied fauna. Plain and 

 valley, hill and moun- 

 tain are at present nearly PRAIRIE DOG. 

 devoid of their native 



inhabitants. The horse, the cow, the mule are the chief 

 members of the present fauna. 



Summary. Physical conditions have a great effect on 

 the distribution of life upon the earth. It is hard for liv- 

 ing things to cross high mountains, broad oceans or vast 

 deserts. When confined to certain climates and areas, 

 plants and animals naturally adjust themselves to these. 



Life in the sea is so simple that plants and animals 

 there are not forced to become as highly developed as are 

 those of the land. On land there are greater ranges of 

 climate and other physical conditions, so that plants and 

 animals have been forced to a high development in order 

 to survive. Probably the two greatest forces affecting 

 land life are climate and man. Man transplants and 

 transports animals and plants according to his desires. 

 The physical conditions decide whether or not they 

 shall live. 



By his treatment of forests man can also have a great 

 effect upon the wealth and beauty of the country, upon the 

 safety of its rivers and the reliability of its water power. 



