CHAPTER 



6 



Selection and Preparation of 

 Organisms 



The whole concept of experimentation in biology implies that animals 

 or plants are the subjects of these experiments. Biologists no longer ex- 

 periment on "just whatever is handy." Once, when biology was young, 

 hundreds of isolated observations, on as many kinds of organisms, all 

 contributed to the general store of information. As biology has become 

 a more mature science, concepts and principles have become more im- 

 portant. The notion of a research program suggests the existence of 

 problems or questions that need answering. Sometimes, "whatever is 

 handy" is exacdy the right organism to provide the experimental answers 

 to a problem. Most often, however, several kinds of plants or animals 

 would be available. The short time spent considering the desirable and 

 undesirable features of experimental organisms usually is time well 

 spent. 



More than once the success or failure of a program of experimental 

 research has been determined by the choice of experimental organism. 

 In some cases, the choice of animal or plant seems to have been a lucky 

 or unlucky accident. In other cases, an especially fortunate choice was 

 made by an astute, experienced scientist. Several examples of fortunate 

 choices of organisms are given, along with one unfortunate selection 

 that led to a notable failure, apparendy entirely as a result of the whims 

 of chance. 



T. H. Morgan was one of several individuals who helped found the 

 science of genetics. In the course of some of his first experimental at- 



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