CONTENTS 



CHAPTER I 

 INTRODUCTION 



PAGE 



Subject-matter The study of evolution Dependence 

 on other sciences The problem of the nature and 

 origin of species Linnaean species Jordan's species 

 The discontinuity of species Methods of study 

 Variation Different theories as to the origin of 

 species : Lamarck's theory ; Darwin's theory ; the 

 mutation theory Recent study of species ; Biometry ; 

 Mendelism - i 



CHAPTER II 

 EVOLUTION 



Definition Evolution of matter Evolution in geology 

 The age of the earth Organic evolution Evi- 

 dences of organic evolution The theory of 

 Lamarck - 2 1 



CHAPTER III 

 THE THEORY OF NATURAL SELECTION 



Historical Darwin's attitude to variation Artificial 

 selection Malthus and the geometrical rate of 

 increase of living things Natural selection Adapta- 

 tion Protective resemblance and mimicry Parallel 

 evolution Regeneration Sexual selection The 

 inheritance of acquired characters Herbert Spencer's 

 arguments Weismann and the purity of the germ 

 cells - 38 



xi 



