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GENERAL BIOLOGY 



striking examples of adaptation. It must not be 

 forgotten, however, that all species, except, perhaps, 

 such as are in the process of extinction, are very 

 adequately adapted to the particular environment 

 in which they are found, else they would not be 

 existent at all. 



SOME TYPES OF ADAPTATION 

 Aquatic Organisms. All the animals that live in 

 the water show a certain general form and structure 



FIG. 88. Types of aquatic adaptation, showing convergence toward 

 a boat-like structure in diverse and unrelated groups of animals. The 

 outline opposite each figure is a diagrammatic cross-section : A, diving 

 beetle ; B, herring ; C, mud turtle ; D, killer whale (a warm-blooded 

 animal most nearly akin, perhaps, to the cud-chewing mammals or 

 perhaps to the ant-eaters). 



that enables them to go the more easily through the 

 resistant medium in which they live. If we examine 

 a diving beetle (fig. 88, a), a fish (fig. 88, b), a turtle 



