Primary producers 初级生产者Autotrophs 自营生物2nd - Primary .PPT

Impacts, IssuesBye-Bye, Blue Bayou Among many effects of global warming, coastal marshes in Louisiana are disappearing under rising water – along with habitat and revenues（歲入） Structure of Ecosystems生態系的結構 Trophic Levels 營養階層 1st - Primary producers 初級生產者 Autotrophs 自營生物 2nd - Primary consumers 初級消費者 Herbivores, Decomposers, Detritivores---異營生物 3rd - Secondary consumers 次級消費者 Primary carnivores 4th - Tertiary consumers 三級消費者 Secondary carnivores and parasites Tallgrass Prairie: A Food Chain and Trophic Levels 47.2 The Nature of Food Webs Food chain :以直線順序，來表示生態系中的生物食性關係。大魚吃小魚， 小魚吃蝦米 Food web : “ Network of crossing, interlinked food chains involving primary producers, consumers, and decomposers” 食物鏈為何無法太長?? Lindemann’s efficiency: in lake, no secondary consumer if the NPP 10g/ m2 year inhibition of evolution optimal foraging dynamic inhibition Model for a Food Web Major Pathways of Energy Flow Primary source Grazing food webs Photosynthetic organisms to herbivores Detrital food webs Photosynthetic organisms to detritivores and decomposers Food Webs 47.3 Energy flow  through ecosystems Primary productivity 初級生產力  Gross primary productivity (總生產力) :  Total energy trapped 光合作用  Net primary productivity(淨生產力): Total energy trapped – energy used  光合作用 – 呼吸作用 Ecological Pyramids Energy Flow at silver springs Energy loss with each trophic level Annual Energy Flow: Silver Springs 47.4 Biological magnification 生物放大作用 47.6 Hydrologic Cycle Rain and snow returns water to land Ocean currents and winds Evaporation “Watershed” Environmental Water Reservoirs Experimental Watershed Deforested area had greater calcium loss than undisturbed area A Global Water Crisis Plenty of saltwater, little freshwater Two-thirds of freshwater use sustains agriculture Salinization Buildup of mineral salts in soil Stunts crop plants and decreases yields Aquifers are becoming pol