38 Dynamic Evolution 



few of the things which are special to living 

 organisms and which consequently influence 

 the application of the principles. 



In animals generally, and in the higher 

 animals particularly, we have what are known 

 as secondary sexual characters. These are 

 those characters by which the sexes are dis- 

 tinguished from each other, and which are 

 not directly involved in the reproductive 

 process. They include such things as size, 

 shape, extra appendages, color, voice, and 

 habits. The general facts in regard to these 

 characters is that they first appear after 

 sexual maturity and are confined to individ- 

 uals of one sex. It is highly probable that 

 this statement may be broadened into the 

 statement that any character or quality 

 which is developed in an individual after 

 sexual maturity is a secondary sexual charac- 

 ter, and is primarily transmitted only to 

 offspring of the same sex as that in which it 

 was first developed. 



The beard on the face of man is one of the 

 best known of secondary sexual characters. 



