EVOLUTION OF DIVERGENT AND ANALOGOUS MODES OF RESPIRATION, MOTION. FEEDING. OFFENSE AND DEFENSE. 



AERIAL 



AER5 ARBORt 



ARBOREAL 

 ARB0R5TERR!= 



TERRESTRIAL 

 TERR2 FOSSORt 

 FOSSORIAL 



TERR5 AQUATIC 



AQUATIC, FLUVt-^ 



LITTORAL 



PELAGIC 



ABYSSAL 



uw of adaptive radiation 

 Fig. 28. The Twelve Chief Habitat Zones of Animal Life. 



These twelve zones compose the environment, aerial to abyssal, into which the Inver- 

 tebrata and Vertebrata have adaptively radiated in the course of geologic time. The 

 Invertebrates range from the abyssal to the aerial zones. The fishes, ranging only 

 from the terrestrio-aquatic to the abyssal habitat zones, nevertheless evolve body 

 forms and types of locomotion similar to those observed in the Amphibia, which range 

 from the littoral to the arboreal habitat zones. The reptiles, birds, and mammals, 

 ranging from the aerial to the pelagic habitat zones, independently evolve through 

 the law of adaptive radiation many convergent, parallel, or similar types of body 

 form, as well as similar modes of locomotion and of offense and defense. 



Fig. 29. Life Zones of Cambrian ant) Recent Invertebrates. 



Chart showing in shaded areas the limited habitat zones — Littoral, Pelagic, Abyssal — of 

 the known Cambrian forms (left) compared with the wide adaptive radiation (Abyssal 

 to Arboreal) of recent forms (right). By Roy W. Miner. 



131 



