30 



LIFE DEPENDS ON ADAPTATIONS 



ones are fed by the mother until they are able "to go on 

 their own," and we see that in very many ways the robin 



is fitted or adapted to 

 meet these big problems 

 of living. 



How a Green Plant 

 Meets the Problems of 

 Living. It is not so easy 

 for us to understand how 

 a green plant meets its 

 problems of life, for at 

 first they seem so differ- 

 ent from those of an 

 animal. But are they 

 very different? An ani- 

 mal has to have food in 

 order to live ; so does a 

 green plant, only a green 

 plant makes its food out 

 of substances from the 

 air and soil and the water 

 it takes in. We must 

 remember that both plants and animals have to breathe. 

 They therefore need oxygen from the air. They both 

 need a certain amount of heat and light, some more, some 

 less. They must be protected* and they must produce 

 offspring if they are to be successful. The cactus is an 

 example of a plant that has been successful in spite of 

 unfavorable conditions. What special fitnesses or adap- 

 tations do we find which help it solve its problems of life ? 

 In the first place, instead of green leaves, we find spines. 

 Leaves would wilt in the hot desert air, because they 

 have large surfaces which allow water to evaporate from 

 the plant. The cactus conserves its water by having a 

 soft pithy stem which holds water and by having this 



Wright Pierce 

 What kind of food does this bird eat ? 



