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ENERGY FLOW

ENERGY FLOW. September 17, 2013. The sun’s energy powers life. The sun releases radiation from the electromagnetic spectrum Some is visible light Solar energy drives weather and climate, and powers plant growth. Photosynthesis. Autotrophs ( producers )

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ENERGY FLOW

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  1. ENERGY FLOW September 17, 2013

  2. The sun’s energy powers life • The sun releases radiation from the electromagnetic spectrum • Some is visible light • Solar energy drives weather and climate, and powers plant growth

  3. Photosynthesis • Autotrophs(producers) • green plants, algae and cyanobacteria • produce their own food from the sun’s energy • Photosynthesis • the process of turning light energy from the sun into chemical energy

  4. Photosynthesis produces food • Chloroplasts = organelles where photosynthesis occurs • Contain chlorophyll = a light-absorbing pigment • Light reaction = splits water by using solar energy • Calvin cycle = links carbon atoms from carbon dioxide into sugar (glucose) 6CO2+ 6H20 C6H12O6+ 6O2 (sunlight)

  5. Cellular respiration releases chemical energy • Organisms use chemical energy from photosynthesis • Oxygen is used to convert glucose into water + carbon dioxide + energy • Heterotrophs = organisms that gain energy by feeding on others • Animals, fungi, microbes C6H12O6 + 6O26CO2+ 6H20 + energy

  6. Predation • Exploitation = one member exploits another for its own gain • Predation • Structures food webs • Influences community composition through number of predators and prey

  7. Effects of predation on populations • Increased prey populations increases predators • Predators survive and reproduce • Increased predator populations decrease prey • Decreased prey population causes starvation of predators • Decreased predator populations increases prey populations

  8. Effects of zebra mussels • Zebra mussels eat phytoplankton and zooplankton • Both populations decrease in lakes with zebra mussels • They don’t eat cyanobacteria • Population increases in lakes with zebra mussels • Zebra mussels are becoming prey for some North American predators: • Diving ducks, muskrats, crayfish, flounder, sturgeon, eels, carp, and freshwater drum

  9. Energy passes through trophic levels • One of the most important species interactions is who eats whom • Matter and energy move through the community • Trophic levels = rank in the feeding hierarchy • Producers • Consumers • Detritivores and Decomposers

  10. Energy, biomass, and numbers decrease up the trophic levels • Most energy organisms use is lost as waste heat through respiration • Less and less energy is available in each successive trophic level • Each level contains only 10% of the energy of the trophic level below it • There are far fewer organisms at the highest trophic levels, with less energy available CONCLUSION: A human vegetarian’s ecological footprint is smaller than a meat-eater’s footprint

  11. Species can change communities Trophic Cascade • predators at high trophic levels can indirectly affect populations of organisms at low trophic levels by keeping species at intermediate trophic levels in check • Extermination of wolves led to increased deer populations, which led to overgrazed vegetation and changed forest structure

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