534 



Index 



Vital index, 334 

 Vitamin D, 231-233 



Warm-blooded animals, 148 

 Wasps, parasitic, 388-389 

 Water, abrasive action of, 55-58 



balance, 107 



in air, 112-117 



in soil, 111-112 



loss, 114-119 



natural, composition of, 91-95 



occurrence on land, 109-117 



passage through organism, 35-36 



physical-chemical properties of, 25- 

 27 



plants, see Hydrophytes 



problem, in amphibious situations, 

 99-107 

 in aquatic environment, 91-99 

 in terrestrial environment, 107-129 



transmission of light by , 191- 

 198 



transparency, changes in, 197-198 



transport by, 48 



see also Moisture 

 Weakfish, range extension of, 12 

 Whales, 474-480 



diving adaptations in, 31-32 

 Wheat, in relation to rainfall, 110 



photosynthesis of, 260 



rust, transportation of, 46 

 Willow, relation of roots to oxygen, 

 254 



Willow community, 419 



Wilting coefficient. 111 



Wind, effect, in aerating water, 246 



on vegetation, 54-55 



on water loss, 116 

 Winter egg, 49 

 Wolves, 310, 462 

 Wood as substratum, 64-65 

 Wood duck, 486 



Xerarch succession, 432 

 Xerophytes, 119 



Year-class analvsis, 454-456 

 Yield, 482-483', 490-493, 502 



per unit effort, 346, 491-492 

 Yucca, pollination of, 373 



Zonation, of communities, 406-407 



of continental vegetation, 123-126 



of marine environment, 30 



of plant communities with altitude, 

 175-179 



related to temperature, 172-181 



tidal, 103-107 



vertical, in algae, 235-237 

 in bromeliads, 235 

 Zones, life, 175-181 

 Zoochlorellae, 368 

 Zooplankton, 38, 476-479 

 Zooxanthellae, 368 



