56 Resemblances and Differences Among Living Things 

 Organization 



A statuette of an elephant may be said to have the gen- 

 eral " form " of a natural elephant. There are of course 

 important differences in the structure of the two and in the 

 chemical composition. Even, however, if we could make a 

 statuette consisting of the same chemical substances as are 

 found in a living elephant, there would be great differences 

 in the structure, since the living thing, whether plant or 

 animal, has the characteristic of structure which we call 

 organization. The many distinct parts of which it consists 

 have particular relationships to one another, and especially 

 to the workings of the being as a whole. It is for this reason 

 that individual plants and animals are sometimes spoken of as 

 organisvtSy that is, structures consisting of organs or instru- 

 mentalities. The thought is that each part performs some 

 activity or serves some function in relation to the totality. 



Human skill has constructed a great variety of mechan- 

 isms or machines in which the different parts serve special 

 purposes, and which might therefore be thought of as " or- 

 ganisms." There is, however, more to a living thing than 

 any artificial contrivance can duplicate. 



Growth 



All the living beings that have been observed have the 

 capacity to increase in size or grow. It is common to think 

 of growth as characteristic of life for this reason, although 

 certain non-living things are also capable of growth, in a 

 proper sense. For example, a crystal in suitable surround- 

 ings steadily increases in size while maintaining its char- 

 acteristic form. An icicle may grow when there is a certain 

 alternation of thawing and freezing. Sand dunes and tide 

 beaches may be said to grow by the accretion or piling up 

 of materials brought by wind or wave. 



The growth of a plant or of an animal appears neverthe- 

 less to be fundamentally a different kind of process from the 



