生态学 水分关系.ppt

* * Soil moisture and root development * Water Conservation by Plants and Animals Another way to balance a water budget is by reducing water loss. One of the most obvious ways to cut down on water losses is by waterproofing to reduce evaporation Dissimilar Organisms with Similar Approaches to Desert Life * Water Conservation by Plants and Animals Many terrestrial organisms equipped with waterproof (不透水) outer covering. Concentrated urine / feces. Condensing water vapor in breath. Behavioral modifications to avoid stress times. Drop leaves in response to drought. Thick leaves Few stomata Periodic dormancy * * * Water and Salt Balance in Aquatic Environments Marine and freshwater organisms use complementary mechanisms for water and salt regulation. Aquatic organisms, like their terrestrial kin, regulate internal water, by balancing water gain against water loss Wi = Wd—Ws ± Wo Wo:an aquatic organism may either gain or lose water, depending on the organism and the environment * * Osmoregulation by Marine Organisms Marine Fish and Invertebrates Saltwater mosquitoes are hypoosmotic to the surroundings, they also make up water loss by drinking large amounts of water, then excrete a urine that is hyperosmotic to their body fluids, which reduces water loss through the urine * Osmoregulation by Marine Organisms * Osmoregulation by Freshwater Organisms Freshwater Fish and Invertebrates Hyper-osmotic organisms that excrete excess internal water via large amounts of dilute urine. Replace salts by absorbing sodium and chloride at base of gill filaments and by ingesting food. * Osmoregulation by Freshwater Organisms Thank you * Water Relations Chapter 5 Camels’s activity in the broilingdesert * * Marine Organisms * * * ?organism on the land * Water relations * * Outline Water Availability Water Content of Air Water Movement in Aquatic Environments Water Movement Between Soils and Plants Water Regulation on Land Water Acquisition by Animals and Plants Water Conservation by