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Ecosystems and the Biosphere

Ecosystems and the Biosphere. Energy flow through an ecosystem Linear Sun to producer to consumer to decomposer Trophic relationship may be expressed as food chains or as food webs. Energy flow through an ecosystem. Energy Flow. Ecological pyramids

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Ecosystems and the Biosphere

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  1. Ecosystems and the Biosphere

  2. Energy flow through an ecosystem • Linear • Sun to producer to consumer to decomposer • Trophic relationship may be expressed as food chains or as food webs

  3. Energy flow through an ecosystem

  4. Energy Flow

  5. Ecological pyramids • Express the progressive reduction in numbers of organisms, biomass, and energy found in successive trophic levels

  6. Pyramids of biomass

  7. The 10% Rule in Energy Flow

  8. Gross primary productivity • Rate at which photosynthesis captures energy Net primary productivity • Energy that remains after plants and other producers carry out cellular respiration

  9. NPP for selected ecosystems

  10. Carbon cycle • Carbon dioxide is the most important gas • Carbon enters plants, etc., as CO2 • Cellular respiration, combustion, and erosion of limestone return CO2 to the environment

  11. Carbon cycle

  12. Nitrogen cycle • Five steps • Nitrogen fixation • Nitrification • Assimilation • Ammonification • Denitrification

  13. Nitrogen cycle

  14. Phosphorus cycle • Phosphorus erodes from rock as inorganic phosphate • Animals obtain it from their diet

  15. Phosphorus cycle

  16. Hydrologic cycle (Water cycle) • Renews the supply of water • Involves an exchange of water between the land, ocean, atmosphere, and organisms • Water enters the atmosphere by evaporation and transpiration • Water leaves the atmosphere as precipitation

  17. Hydrologic cycle

  18. Bottom-up processes • Availability of resources such as nutrient minerals controls the number of producers, which controls the number of herbivores, etc. • Top-down processes • An increase in top predators cascades down the food web

  19. Sunlight primary source of energy • Combination of Earth’s spherical shape and its axis tilt concentrate solar energy at the equator • Inclination of Earth’s axis primarily determines the seasons

  20. Seasonal changes in temperature

  21. Visible light and infrared radiation warm the surface and lower part of the atmosphere • Atmospheric heat produces air movement, which moderates the climate

  22. Atmospheric circulation

  23. Major surface ocean currents

  24. Coriolis effect • Tendency of moving air or water to be deflected • Right in the Northern Hemisphere • Left in the Southern Hemisphere

  25. Regional precipitation differences • Influenced by latitude, elevation, topography, vegetation, distance from large bodies of water, and location • Precipitation greatest where warm air passes over the ocean and then cools

  26. Rain shadow

  27. Effect of fire on certain ecosystems • Fire frees the nutrient minerals locked in organic matter, removes plant cover, and increases erosion • Many ecosystems, such as savanna, chaparral, grasslands, and certain forests, contain fire-adapted organisms

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