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ENERGY FLOW PowerPoint Presentation
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ENERGY FLOW

ENERGY FLOW

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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