Energy Management Strategies - Lecture 1C

Bryant University Energy Management Strategies (Sci355) Course Lecture Notes CLASSROOM DISCUSSION TOPICS Site Map Week 1-2: Energy Systems: An Overview Energy in Nature Production/Consumption in Ecosystems Photosynthesis - plants/algae can capture sunlight, converting light to chemical energy Dependent on pigments like chlorophyll Production of carbohydrates Respiration - ability of living cells to convert carbohydrates to ATP units Production/Consumption in Ecosystems (continued) Formula for Photosysnthesis (chlorophyll & sunlight) CO₂ + H₂0 ----------> C₆H₁₂0₆ + 0₂ Formula for Respiration C₆H₁₂0₆ + 0₂----------> CO₂ + H₂0 + ATP World Energy Budget Annual Insolation (equivalent to 15,000 times the 1990 world energy supply) 30% reflected back to space (albedo) 50% Absorbed, converted to heat and reradiated 20% creates wind, powers water cycle and drives photosynthesis Trophic Dynamics Producers Ability to photosynthesize Algae and plants (some bacteria) Usually small in size; exist in large numbers Base of food chains Responsible for primary productivity Generate carbohydrates for respiration Primary Consumers (Herbivores) Organisms that consume plants or algae Usually small in size Examples: Zooplankton, snails, cows, horses, insects, zebras, ciliated protozoa Contribute to secondary productivity Secondary Consumers (Carnivores) Consume herbivores Usually larger in size Examples: wolves, lions, sharks, reptiles, hawks, shrews, spiders, amoebae Many layers of carnivores in an ecosystem Contribute to secondary productivity Omnivores May act as herbivores or carnivores Varied feeding habits (versatile consumers) Include humans, pigs and many insects Contributed to secondary productivity Decomposers Detrivores (consume decaying material) Very important to detrital food chains; recycle nutrients Found in large numbers in forest litter, marine and aquatic benthos Examples: fungi, some invertebrates, bacteria, protozoa Grazing vs. Detrital Food Chains Grazing food chains based on producers (photosynthesis) Detrital food chains based on detrivores (breaking down detritus and wastes) Grazing food chains important in marine and aquatic ecosystems Detrital chains important in forest litter Trophic Pyramid Show feeding patterns Smaller to larger size Many to fewer in numbers Levels vary from one ecosystem to another Ecosystem Energetics Top of Page

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Gaytha A. Langlois, Ph.D., 1999
Bryant University, Smithfield, RI, USA
E-mail: langlois@bryant.edu
Last Updated: August 2006