EVOLUTION. 5 



male possessing the most perfect form, the most 

 pleasing voice, or the most attractive colors, and 

 these advantages are perpetuated in their offspring. 

 An improvement in the song and beauty of male 

 birds arises from this selection. In savage races the 

 females select the strongest men best qualified to be 

 defenders ; but in civilized races the choice is more 

 influenced by intellectual and moral qualities, and in 

 each case the race shows an increasing variation in 

 the direction of these selections. 



The Unity of Animal Life, 



The proofs of the theory of Evolution extend over 

 the whole realm of nature. The most prominent of 

 these is the apparent connection of all forms of 

 animal life, such as would exist if each order of life 

 had grown out of the order below it. The students 

 of nature are continually finding intermediate forms, 

 or " missing links," between the established classes 

 of the animal kingdom. As a tree from a single 

 stem spreads out into numerous branches and twigs, 

 so life appears to manifest itself in a series of forms, 

 each closely allied to the other, or with such strong 

 resemblances that a relationship appears certain. 



The most marked distinction between animals is 

 the possession or non-possession of a backbone. 

 The theory of special creation was long supported 

 by triumphant appeals to the gap between the back- 

 boned (vertebrate) and the non-backboned (inverte- 



