60 THEORY OF EVOLUTION 



off from the original characters, and whether 

 the differences are great or whether they are 

 small they are transmitted alike according to 

 Mendel's law. 



Many of the characteristics of our domesti- 

 cated animals and cultivated plants originated 

 long ago, and only here and there have the 

 records of their first appearance been pre- 

 served. In only a few instances are these rec- 

 ords clear and definite, while the complete 

 history of any large group of our domesticated 

 products is unknown to us. 



Within the last five or six years, however, 

 from a common wild species of fly, the fruit 

 fly, Drosophila ampelophila, which we have 

 brought into the laboratory, have arisen over a 

 hundred and twenty-five new types whose 

 origin is completely known. Let me call at- 

 tention to a few of the more interesting of 

 these types and their modes of inheritance, 

 comparing them with wild types in order to 

 show that the kinds of inheritance found in do- 

 mesticated races occur also in wild types. The 

 results will show beyond dispute that the char- 

 acters of wild types are inherited in precisely 



