ENERGY FLOW BIOCHEMICAL CYCLES TROPHIC FEEDING LEVELS n

ENERGY FLOW & BIOCHEMICAL CYCLES

TROPHIC (FEEDING) LEVELS n producer - organism that is able to make its own food from inorganic substances n consumer - organisms that gets its energy either directly or indirectly from producers n primary: herbivores (& omnivores) n secondary & higher levels: carnivores (& omnivores) n decomposer - organism that breaks down & obtains energy from dead organic material n supply soil, water, & air with chemicals in inorganic forms 12/26/2021 ENERGY FLOW & NUTRIENT CYCLING 2

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ECOLOGICAL PYRAMIDS n ecological pyramid - diagram used to represent energy relationships among trophic levels of an ecosystem n energy always decreases, but biomass & #s can vary in certain circumstances 12/26/2021 ENERGY FLOW & NUTRIENT CYCLING 4

FEEDING RELATIONSHIPS n food chain – series of organisms through which food energy is passes in an ecosystem producer primary consumer 2 ndary consumer n food web – complex relationship formed by interconnecting and overlapping food chains 12/26/2021 ENERGY FLOW & NUTRIENT CYCLING 5

A MEADOW FOOD WEB This food web is greatly simplified compared to what actually happens in nature Many species aren’t included, & numerous links in web aren’t shown 12/26/2021 ENERGY FLOW & NUTRIENT CYCLING 6

THE FLOW OF ENERGY THROUGH ECOSYSTEMS 12/26/2021 ENERGY FLOW & NUTRIENT CYCLING 7

ENERGY FLOW n energy flow – passage of energy in one-way direction through an ecosystem n occurs in food chains trophic level - each level in a food chain n energy is NOT recycled once used by an organisms it is lost as heat & unavailable for other organisms 12/26/2021 ENERGY FLOW & NUTRIENT CYCLING 8

ENERGY FLOW n Sun producers consumers n only ~0. 1% of Sun’s energy that reaches Earth’s surface is used by living things n ½ of energy absorbed by plants (producers) is used immediately n rest is stored in plant tissues in form of energy -containing compounds (carbohydrates) n animals (consumers) that eat plants obtain this energy, use most of it, & store small amount of it 12/26/2021 ENERGY FLOW & NUTRIENT CYCLING 9

ENERGY FLOW THROUGH A FOOD CHAIN energy enters ecosystems from Sun, flows linearly through ecosystems, & exits as heat loss much of energy acquired by a given level of food chain is used & escapes into surrounding environment as heat this energy, as 2 nd Law of Thermodynamics stipulates, is unavailable to next level of food chain 12/26/2021 ENERGY FLOW & NUTRIENT CYCLING 10

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