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Ecosystem Ecology. the movement of materials and energy through an ecosystem Section 22-1 Pages 415-419. Producers. Manufacture their own food Capture energy and use it to make organic molecules There are two types: Photosynthetic = use energy from light
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Ecosystem Ecology the movement of materials and energy through an ecosystem Section 22-1 Pages 415-419
Producers • Manufacture their own food • Capture energy and use it to make organic molecules • There are two types: • Photosynthetic = use energy from light • Chemosynthetic = use energy from inorganic chemicals • Examples = plants, protists, and bacteria
Gross Primary Productivity - is the rate at which producers in an ecosystem capture energy
Biomass - is the organic material in an ecosystem
Net Primary Productivity = gross primary productivity – rate of respiration in producers • is the rate at which biomass accumulates • is expressed as: energy/area/year (kcal/m2/y) mass/area/year (g/m2/y)
Consumers • obtain energy by ingesting or consuming organic molecules made by other organisms • grouped according to the food they eat • Herbivores = eat producers • Carnivores = eat consumers • Omnivores = eat both producers and consumers • Detritivores = eat garbage • Decomposers = break down dead tissues and waste into smaller molecules
Trophic Levels • an organism’s position in the sequence of energy transfers • most ecosystems contain only three or four trophic levels Producers = 1st level Herbivores = 2nd level Carnivores = 3rd level +
Food Chain • a pathway of feeding relationships
Note 10% energy transfer between trophic levels Pyramid of Net Production
Why is energy transfer so low? • Energy is reflected. • Energy is lost when some parts cannot be digested. • Energy is lost as waste. • Energy is lost in cellular respiration. • Energy is lost as heat. • Organisms die without being eaten.
Ecological Efficiency 100 * 6 / 67 = 9% 100 * 67 / 1478 = 4.5% 100 * 3,368 / 20,810 = 17%
Pyramid Shape • A diagram of trophic level relationships • Width of bar correlates with the number • Three primary types of diagrams • Energy • Biomass • Population numbers