16 Contents 



CHAPTER 32 Page 



PHYLOGENETIC CONSIDERATIONS 644 



Origin of the Metazoa, 644; Origin of Bilaterality, 645; Relationships of 

 the Phyla, 645 ; Origin of the Vertebrates, 646 ; Haeckel's Biogenetic Law, 

 647. 



SECTION V 

 ECOLOGY 



CHAPTER 33 



THE ECOLOGY OF ANIMALS 648 



Physical and Biotic Factors of the Environment, 648; Heat, 648; Wind, 

 649; Water Currents, 649; Light, 650; Water, 650; Presence of Various 

 Salts, 650: Biotic Factors, 651; Biomes. 651: Northern Tundra, 651; 

 Northern Coniferous Forest, 653 ; Temperate Deciduous Forest, 653 ; The 

 Prairie, 654; Desert, 654; Tropical Rain Forest, 655; Biomes of a Smaller 

 Extent, 656 ; Community Succession, 657 ; Fresh-Water Communities, 660 ; 

 Standing-Water Communities, 660 Running-Water Communities, 663 ; 

 Oceanic Communities, 663 ; Eulittoral Zone, 664 ; Sublittoral Zone, 665 ; 

 Archibenthic Zone, 666 ; Abyssal-Benthic Zone, 666 ; Populations, 667 ; 

 Growth of Populations, 667 ; Fluctuations of Abundance, 668 ; Food Net- 

 works, 668 ; Conservation, 670 ; Interference With Food Networks, 670 ; 

 Introduction of New Forms, 67L 



GLOSSARY 672 



SUGGESTED READINGS 684 



