Contents 



PART ONE: A DEFINITION OF EVOLUTION 1 



Chapter One: Evolution by Natural Selection: 



Darw/n's Conception 3 >^i\fk 



Darwinian Premises 3 /jSy^ 



The Prodigality of 'Nature 4 



Organic Variation 5 



Natural Selection 5 

 Biographical Sketch of Darwin 5 



The Voyage of the Beagle 7 



Darwin's Publications 7 



The Origin of Species 8 



Darwin's Mental Qualities 11 

 Alfred Russel Wallace— Co-Discoverer 12 

 References 13 



Chapter Two: Evidences of Evolution I: Biogeography 14 



Discontinuous Distribution 15 



Biogeographical Regions 18 



Ecological Zones in the Ocean 19 



Darwin's Explanation 21 



Distribution of Fresh-water Organisms 22 



Island Life 23 



References 26 



Chapter Three: Evidences of Evolution II: 



Taxonomy. Comparafive Anatomy, and Embryology 27 



Linnaeus and Biological Nomenclature 27 



The Species Concept 27 



Taxonomic Categories 28 

 Significance of the Taxonomic Hierarchy 29 



The Tree of Life 29 

 Evidence from Comparative Anatomy 31 



The Vertebral Column 31 



Serial Homology in the Crustacea 35 



Adaptive Radiation in the Forelimbs of Mammals 39 



Homology and Analogy Contrasted 39 



Vestigial Organs 42 

 Evidence from Embryology 45 



Examples Among Vertebrates 48 



Examples Among Plants 51 



Difficulties of the Biogenetic Law 51 



Von Baer's Principles 52 

 References 52 



Chapter Four: Evidences of Evolution III: 



Comparative Physiology and Biochemistry 54 *^fii'-'^'^ 



Comparative Physiology and Biochemistiy 54 4-»^n-i 



Enzymes and Hormones 55 



xt 



