Ecosystems consists of all the organisms living in a community

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

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

7. Primary Productivity • The energy budget of an ecosystem depends on its primary productivity.

8. 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.

9. What is gross primary productivity? (GPP)

10. GPP represents energy available to consumers in an ecosystem. It is the amount of light energy converted to chemical energy by photosynthesis per unit time.

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

12. What is Net Primary Productivity? (NPP)

13. Net Primary Productivity • NPP = GPP - R • Why is NPP a more useful measurement than GPP?

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

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

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

17. 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?

18. 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

19. 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?

20. 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.

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

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

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

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

25. Chemical Cycling

26. 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. Review of Biogeochemical Cycles: http://www.bozemanscience.com/biogeochemical-cycling

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

28. Transpiration in Leaves

30. Open and Closed Stomata in a Spider Plant Leaf

31. 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.

32. 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 The Water Cycle from NSF: https://www.youtube.com/watch?v=al-do-HGuIk#action=share

34. 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?

35. 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).

36. 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

37. (conversion to organic forms)

38. 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.

39. 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.

40. 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

41. 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.

42. The Experimental Eutrophication of a Lake

43. 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?

44. For which macromolecules do organisms need phosphorus? Weathering of sedimentary rocks gradually adds phosphate to soil. Plants absorb phosphorus from the soil or from water. Phosphorus is returned to soil by the death of organisms or excretion.

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

47. What is going on in this picture?

48. We’ve Changed Our Tune

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

50. Chlorine from CFCs interacts with ozone (O3),forming chlorine monoxide (ClO) and oxygen (O2). 1 Chlorine atoms O2 Chlorine O3 ClO O2 Sunlight causes Cl2O2 to break down into O2and free chlorine atoms. The chlorine atoms can begin the cycle again. 3 ClO Cl2O2 Two ClO molecules react, forming chlorine peroxide (Cl2O2). 2 Sunlight Figure 54.27 • The destruction of atmospheric ozone • Probably results from chlorine-releasing pollutants produced by human activity