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Ecosystems consists of all the organisms living in a community

Ecosystems consists of all the organisms living in a community as well as all the abiotic factors with which they interact. What is missing from this food chain?. decomposers. Energy can be neither created nor destroyed. It can only be transformed to another form.

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Ecosystems consists of all the organisms living in a community

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  1. Ecosystems consists of all the organisms living in a community as well as all the abiotic factors with which they interact.

  2. What is missing from this food chain? decomposers

  3. Energy can be neither created nor destroyed. It can only be transformed to another form. This is called the law of conservation of energy.

  4. In what way is this food web more realistic than the food chain? The food web incorporates consumers that feed at multiple trophic levels

  5. Primary Producers • Who are the primary producers of most terrestrial ecosystems? • Plants • Who are the primary producers of most aquatic ecosystems? • Microscopic algae and bacteria (phytoplankton), and multicellular algae and aquatic plants.

  6. Consumers • Herbivores - primary consumers • Carnivores - secondary consumers • Omnivores - can feed at multiple trophic levels

  7. Decomposers • What organisms are decomposers in most ecosystems? • Fungi and Bacteria • What do the decomposers do?

  8. Primary Productivity • The energy budget of an ecosystem depends on its primary productivity. • What is gross primary productivity? (GPP)

  9. GPP represents energy available to consumers in an ecosystem.

  10. What is Net Primary Productivity? (NPP) • NPP = GPP - R

  11. Net Primary Productivity • Why is NPP a more useful measurement than GPP?

  12. How is it that the open ocean has low net productivity yet accounts for most of the Earth’s total productivity?

  13. Limiting Factors • What sort of factors will limit productivity? • Light intensity • Water • Inorganic nutrients such as nitrogen and phosphorus. • CO2

  14. Energy Partitioning Within the Food Chain Energy may also be expressed as kilocalories (kcal) What does this number represent?

  15. Energy Partitioning Within the Food Chain The energy available for the next trophic level. This is also called biomass

  16. Typically the amount of energy that is eaten by an organism is not all converted into waste, growth, and used for cellular respiration. What happens to the rest?

  17. Energy Partitioning Within the Food Chain Total Energy Output: Respiration Heat Loss Waste The energy available for the next trophic level. This is also called biomass

  18. Ecological Efficiency • How much of energy is actually available to the next trophic level? • Usually around 10% is available • Why is it that we don’t see 6th order consumers?

  19. An ecological pyramid is a diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web.

  20. Which has more energy, a quarter pound of salad or a quarter pound of beef ?

  21. How can the producers in the English Channel support the consumers in this ecosystem?

  22. Answer: The primary producers have a short life span and also reproduce rapidly

  23. How many individuals are supported at the top level of this ecosystem?

  24. Chemical Cycling

  25. Biogeochemical Cycles/Cycles of Matter – the way in which elements, chemical compounds, and other forms of matter are passed from one organism to another and throughout the biosphere.

  26. ** The numbers represent water flow in billion billion grams per year

  27. Transpiration in Leaves

  28. Open and Closed Stomata in a Spider Plant Leaf

  29. Humans Affect the Water Cycle by Changing Land Use: Reduced vegetation (deforestation, cultivation, etc.) reduces precipitation retained in soil and increases amount that runs off. Groundwater pumping depletes aquifers, brings water to surface where it evaporates. Climate warming will melt ice caps and glaciers and cause sea level rise and increased evaporation. Water vapor is a greenhouse gas.

  30. Review of the Water Cycle: http://studyjams.scholastic.com/studyjams/jams/science/ecosystems/water-cycle.htm http://www.epa.gov/ogwdw/kids/flash/flash_watercycle.html

  31. Carbon is a key ingredient in the tissues of living things. What are three large reservoirs where carbon is found around the earth? In what process do plants use carbon dioxide?

  32. Human Activities Affect the Global Carbon Cycle: Runoff brings carbon to aquatic ecosystems. Deforestation and fossil fuel burning increase atmospheric CO2. Atmospheric CH4 is increased through livestock production, rice cultivation, and water storage in reservoirs (microbes in water-logged soils produce CH4).

  33. Review of the Carbon Cycle: http://studyjams.scholastic.com/studyjams/jams/science/ecosystems/carbon-cycle.htm http://bcs.whfreeman.com/thelifewire/content/chp58/5802002.html

  34. (conversion to organic forms)

  35. Why do organisms require nitrogen? Nitrogen fixation occurs when soil bacteria convert N gas into ammonia at their roots. Denitrification releases N gas back into the atmosphere by a different type of bacteria.

  36. Human Activities Affect the Nitrogen Cycle: Burning fossil fuels, rice cultivation, and raising livestock releases oxides of nitrogen to the atmosphere. These oxides contribute to smog and acid rain. Humans fix nitrogen by an industrial process to manufacture fertilizer and explosives.

  37. Review of the Nitrogen Cycle: http://bcs.whfreeman.com/thelifewire/content/chp58/5802004.html http://www.biology.ualberta.ca/facilities/multimedia/uploads/ecology/ncycle.html http://studyjams.scholastic.com/studyjams/jams/science/ecosystems/nitrogen-cycle.htm

  38. Concept 46.3 Certain Biogeochemical CyclesAre Especially Critical for Ecosystems Topsoil and dissolved nitrates are lost from farm fields and deforested areas by wind and water runoff. The nitrates are deposited in aquatic ecosystems and result in eutrophication— increased primary productivity and rapid phytoplankton growth. Decomposition of the phytoplankton can deplete oxygen; other organisms cannot survive, and dead zones form offshore in summer.

  39. The Experimental Eutrophication of a Lake

  40. What does the loss of nitrates from the deforested ecosystem tell you about the water, and about how nitrates are normally maintained in the ecosystem?

  41. Review of the Phosphorus Cycle: http://nortonbooks.com/college/biology/animations/ch37a03.htm http://www.sumanasinc.com/webcontent/animations/content/phosphorouscycle.html

  42. For which macromolecules do organisms need phosphorus? Plants absorb phosphorus from the soil or from water.

  43. What is going on in this picture?

  44. We’ve Changed Our Tune

  45. Erosion of Earth’s Ozone Shield: The Ozone Hole Over the Antarctic

  46. Erosion of Earth’s ozone shield: Thickness of the ozone layer

  47. Biogeochemical Cycles Affect Global Climate Greenhouse Effect: Earth’s surface re-emits energy in longer, less energetic infrared wavelengths. Some of this infrared radiation is absorbed by gas molecules in the atmosphere (greenhouse gases). The molecules are warmed and radiate photons back to Earth’s surface, keeping the energy within the Earth system as heat.

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