1. Energy from the sun enters ecosystems through photosynthesis by producers and flows through food chains and webs to consumers, with only about 10% being transferred between trophic levels as heat and inefficiencies. 2. Nutrients cycle through ecosystems, moving between living and nonliving matter through various biogeochemical cycles like carbon, nitrogen, phosphorus, and water cycles, which are essential for life. 3. Human activities like burning fossil fuels are releasing excess carbon dioxide and other greenhouse gases, interfering with nutrient cycles and causing global warming through the enhanced greenhouse effect.

1. How Do Ecosystems Work?

19. Energy Transfer and Loss Heat Heat Producer Primary Consumer Secondary Consumer Detritus Feeders Heat Chemicals

21. An Energy Pyramid for a Prairie Ecosystem: The 10% Law

22. The Carbon Cycle Reservoirs Processes/ Locations Trophic Levels/ Organisms CO 2 in atmosphere (reservoir) Producers Consumers Wastes, Dead bodies Soil bacteria & detritus feeders CO 2 in atmosphere (reservoir) Consumers Wastes, Dead bodies Soil bacteria & detritus feeders CO 2 in atmosphere (reservoir) Wastes, Dead bodies Soil bacteria & detritus feeders CO 2 in atmosphere (reservoir) Respitation CO 2 in atmosphere (reservoir) Burning of fossil fuels CO 2 in atmosphere (reservoir) Fire CO 2 in atmosphere (reservoir) CO 2 dissolved in ocean (reservoir) CO 2 in atmosphere (reservoir)

27. The Nitrogen Cycle Nitrogen in Atmosphere Reservoir Nitrogen in Atmosphere Reservoir Electrical storms produce nitrate Ammonia & nitrate Nitrogen-fixing bacteria in legume roots and soil Ammonia & nitrate Uptake by plants Producers Consumers Wastes, Dead bodies Soil bacteria and detritus feeders Ammonia & nitrate Dentitrifying bacteria Nitrogen in Atmosphere Reservoir Reservoirs Processes/ Locations Trophic Levels/ Organisms

31. The Hydrologic Cycle Evaporation from land & transpiration from plants Precipitation over land Water vapor in atmosphere Water in ocean (reservoir) Evaporation from ocean Water vapor in atmosphere Water in ocean (reservoir) Groundwater seepage Surface runoff Water in ocean (reservoir) Precipitation over ocean Reservoirs Processes/ Locations

39. Greenhouse Gases Contribute to Global Warming

40. Global Warming Parallels CO 2 Increases

46. The End