Community Structure - Energy Flow - Presentation PDF

Community Structure – Energy Flow Copyright © 2021 W. H. Freeman and Company. All rights reserved. Communities are organized into food webs. Food Chain vs. Food Web Trophic Levels Tertiary consumer Secondary consumer Primary consumer Producer Primary productivity provi...

Community Structure – Energy Flow Copyright © 2021 W. H. Freeman and Company. All rights reserved. Communities are organized into food webs. Food Chain vs. Food Web Trophic Levels Tertiary consumer Secondary consumer Primary consumer Producer Primary productivity provides energy to the ecosystem. Gross vs Net Primary Production Let’s Add %’s to NPP & GPP Harvesting Primary Productivity Global Patterns of Net Primary Productivity Net Primary Productivity Among Ecosystems of the World Effects of Climate on the Net Primary Productivity of Terrestrial Ecosystems Increased leaching (washed away) & reduced decomposition (water-logged soils) The movement of energy depends on the efficiency of energy flow.  Energy Pyramid of Cedar Bog Lake 10% Rule Pyramids of Energy and Biomass Energy Flow vs Nutrient Cycling What happens when a food web is disturbed?  Types of Effects Direct effect – interaction between 2 species only Indirect effect – interaction between 2 species that involves 1 or more intermediate species Trophic cascade – indirect initiated predators (thus, top-down control) Top-down and Bottom-up Control  Bottom-up Control Example Increase flycatcher abundance Increase insect abundance Willow flycatcher Increase growth of willow trees Reintroduce beaver (create wetland) Effects of an Insecticide on an Aquatic Community Light reaches bottom of pond Light reduced at bottom of pond Direct & Indirect Effects Trait-Mediated Indirect Effects Nonlethal spider = glued mouthparts  grasshoppers spent less time feeding Biomagnification