ENVIRONMENT OF PLANTS AND ANIMALS 25 



hand for this work we say it is adapted to its function of grasping 

 objects. Each part of a plant or animal is usually fitted for some 

 particular work. The root of a green plant, for example, is fitted 

 to take in water by having tiny absorbing organs growing from it, 

 the stems have pipes or tubes to convey liquids up and down and 

 are strong enough to support the leafy part of the plant. Each 

 part of a plant does work, and is fitted, by means of certain struc- 

 tures, to do that work. It is because of these adaptations that 

 living things are able to do their work within their particular en- 

 vironment. 



Plants and Animals and their Natural Environment. Those 

 of us who have tried to keep potted plants in the schoolroom 

 know how difficult it is to keep them healthy. Dust, foreign 

 gases in the air, lack of moisture, and other causes make the 

 artificial environment in which they are placed unsuitable for 

 them. 



A goldfish placed in a small glass jar with no food or no green 

 water plants soon seeks 

 the surface of the water, 

 and if the water is not. 

 changed frequently so as 

 to supply air the fish will 

 die. Again the artificial 

 environment lacks some- 

 thing that the fish needs. 

 Each plant and animal is 

 limited to a certain en- 

 vironment because of cer- 

 tain individual needs which 

 make the surroundings fit 

 for it to live in. 



Changes in Environ- 

 ment. - - Most plants and 

 animals do not change 

 their environment. Trees, 

 green plants of all kinds, A natural barrier on a stream No trout 



and SOme animals remain would be found above this fall. Why not ? 



