Lecture 24, Ch. 54

Lecture 24, Ch. 54 - Energy Flow, II ✦ Ecological...

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Lecture #24 Date ________ Chapter 54 ~ Ecosystems
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Relationships, I Trophic structure / levels ~ feeding relationships in an ecosystem Primary producers ~ the trophic level that supports all others; autotrophs Primary consumers ~ herbivores Secondary and tertiary consumers ~ carnivores Detrivores/detritus ~ special consumers that derive nutrition from non-living organic matter Food chain ~ trophic level food pathway
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Relationships, II Food webs ~ interconnected feeding relationship in an ecosystem
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Energy Flow, I Primary productivity (amount of light energy converted to chemical energy by autotrophs) •Gross (GPP): total energy •Net (NPP): represents the storage of energy available to consumers •Rs: respiration NPP = GPP - Rs Biomass: primary productivity reflected as dry weight of organic material Secondary productivity : the rate at which an ecosystem's consumers convert chemical energy of the food they eat into their own new biomass
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Unformatted text preview: Energy Flow, II ✦ Ecological efficiency : % of E transferred from one trophic level to the next (5-20%) ✦ Pyramid of productivity : multiplicative loss of energy in trophic levels ✦ Biomass pyramid : trophic representation of biomass in ecosystems ✦ Pyramid of numbers : trophic representation of the number of organisms in an ecosystem Chemical Cycling ✦ Biogeochemical cycles: the various nutrient circuits, which involve both abiotic and biotic components of an ecosystem ✦ Water ✦ Carbon ✦ Nitrogen ✦ Phosphorus Human Impact ✦ Biological magnification : trophic process in which retained substances become more concentrated at higher levels ✦ Greenhouse effect : warming of planet due to atmospheric accumulation of carbon dioxide ✦ Ozone depletion : effect of chlorofluorocarbons (CFC’s) released into the atmosphere ✦ Rainforest destruction ✦ Cause: Overpopulation?...
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This note was uploaded on 09/22/2009 for the course BIOL BIOL 51 taught by Professor Janetkoprivnikar during the Spring '08 term at Pacific.

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Lecture 24, Ch. 54 - Energy Flow, II ✦ Ecological...

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