IV. THE FUNCTIONS AND COMPOSITION OF LIVING 



THINGS 



Problems. --To discover the function* of living matter. 



(a) In a living plant. 



(b) In a living animal. 



LABORATORY SUGGESTIONS 



Laboratory study of a living plant. --Any whole plant may be used; a 

 weed is preferable. 



Laboratory demonstration or home study.- -The functions of a living 

 animal. 



Demonstration. - The growth of pollen tubes. 



Laboratory exercise. - The growth of the mature ovary into the fruit, 

 e.g. bean or pea pod. 



A Living Plant and a Living Animal Compared. - - A walk into 

 the fields or any vacant lot on a day in the early fall will give us 

 first-hand acquaintance with many common plants which, be- 

 cause of their ability to grow under somewhat unfavorable condi- 

 tions, are called weeds. Such plants - - the dandelion, butter and 

 eggs, the shepherd's purse - - are particularly well fitted by na- 

 ture to produce many of their kind, and by this means drive out 

 other plants which cannot do this so well. On these or other 

 plants we find feeding several kinds of animals, usually insects. 



If we attempt to compare, for example, a grasshopper with the 

 plant on which it feeds, we see several points of likeness and dif- 

 ference at once. Both plant and insect are made up of parts, 

 each of which, as the stem of the plant or the leg of the insect, 

 appears to be distinct, but which is a part of the whole living plant 

 or animal. Each part of the living plant or animal which has a 

 separate work to do is called an organ. Thus plants and 

 animals are spoken of as living organisms. 



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