n8 



ZOOLOGY 



Effects of 

 environment 



Varieties, 



subspecies 



latter event, practically new constant forms 

 may arise, representing no new factors but the 

 old factors newly distributed. They are like 

 new words, formed out of the old letters of the 

 alphabet. It is probable that this process has 

 been a factor in evolution. 



d. Variations due to environmental conditions acting 

 on the body or mind, such as education, the 

 effects of starvation, cuts or wounds of any 

 kind, and so forth. These are not inherited. 

 Although this kind of variation has no direct 

 significance for evolution, it is not without its 

 importance. Except in the case of purely ex- 

 ternal injuries, the variation observed is only 

 in part due to environment. That is to say, it 

 represents the response of the organism to cer- 

 tain conditions, and the nature of this response 

 is determined by heredity. The ability to re- 

 spond, as in education, is part of the inherited 

 adaptability of the animal. Now this will often 

 be a prime factor in the struggle for existence, 

 enabling the creature to survive where others, 

 less ready to become modified, will perish. In 

 the case of man, especially, all his higher 

 achievements are conditioned by his extraordi- 

 nary tducability, and the educational process 

 has to be repeated in each generation. 

 When environmental conditions (e.g., alcohol) af- 

 fect the germ plasm, there may be results 

 appearing in the next generation, as we shall 

 see below. 



4. In zoological and botanical nomenclature, the 

 word "variety" is used very loosely. The student 

 usually has to deal with preserved specimens, and does 



