Chapter 57

Chapter 57 - Ingrid Shih BIO 1306-04 28 February 2011...

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Ingrid Shih BIO 1306-04 28 February 2011 Chapter 57: Community Ecology 57.1 What are Ecological Communities? An eco community consists of all the species that coexist and interact in a defined area Characterized in: o Productivity Driven by solar radiation Primary: sunlight is the ulti source of energy for most of Earth’s communities Photosynthese makes energy avai to other organisms in edi form Pri prod Photosynthetic autotrohps get their energy directy from sunlight Chemoautotrophs (energy from inorganic molecules) Two ways to characterize productivity Gross primary productivity (GPP): o Rate at which primary producers turn solar energy into stored chem. Energy via photosynthesis The energy that is accumulate is called gross primary production o Net primary productivity (NPP): rate at which energy is incorporated into primary producers’ bodies through growth and reproduction Prim producers use some of the GPP for respiration and metabolism Net primary production is the amt of primary producer biomass available for consumption by heterotrophs NPP = GPP – R R: energy lost to respiration o Trophic interactions (food web) Communities can be organized by trophic levels, based on the source of energy for the organisms Primary producers start the chain Herbivore eat plants and constitute the primary consumer level Organisms that eat herbivore are secondary consumers Org that eat secondary consumers are tertiary consumer Omnivore get their food from more than one trohpic lvl Detritivores (decomposers)- consume dead bodies and waste products A food chain depicts the linear sequence of who eats whom in a community
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This note was uploaded on 03/23/2011 for the course BIO 1306 taught by Professor Adair,tamarah during the Spring '08 term at Baylor.

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Chapter 57 - Ingrid Shih BIO 1306-04 28 February 2011...

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