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BioKnowledgy C.2 Communities and ecosystems

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BioKnowledgy presentation on C.2 Communities and ecosystems

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BioKnowledgy C.2 Communities and ecosystems

  1. 1. C.2 Communities and Ecosystems Essential idea: Changes in community structure affect and are affected by organisms. Between the two coral heads is a crown of thorns sea star. These predators graze the corals. If too successful they will change the community structure of the reef so that it becomes dominated by algae rather than coral. This in turn forces the sea star to migrate to other reefs where coral dominates the community structure. By Chris Paine https://bioknowledgy.weebly.com/
  2. 2. Understandings Statement Guidance C.2.U1 Most species occupy different trophic levels in multiple food chains. C.2.U2 A food web shows all the possible food chains in a community. C.2.U3 The percentage of ingested energy converted to biomass is dependent on the respiration rate. C.2.U4 The type of stable ecosystem that will emerge in an area is predictable based on climate. C.2.U5 In closed ecosystems energy but not matter is exchanged with the surroundings. C.2.U6 Disturbance influences the structure and rate of change within ecosystems.
  3. 3. Applications and Skills Statement Guidance C.2.A1 Conversion ratio in sustainable food production practices. C.2.A2 Consideration of one example of how humans interfere with nutrient cycling. C.2.S1 Comparison of pyramids of energy from different ecosystems. C.2.S2 Analysis of a climograph showing the relationship between temperature, rainfall and the type of ecosystem. C.2.S3 Construction of Gersmehl diagrams to show the inter-relationships between nutrient stores and flows between taiga, desert and tropical rainforest. C.2.S4 Analysis of data showing primary succession. C.2.S5 Investigation into the effect of an environmental disturbance on an ecosystem. Examples of aspects to investigate in the ecosystem could be species diversity, nutrient cycling, water movement, erosion, leaf area index, among others.
  4. 4. C.2.U2 A food web shows all the possible food chains in a community. There can be more than one producer in a food web, and consumers can occupy multiple positions (trophic levels) A food web is a diagram that shows how food chains are linked together into more complex feeding relationships within a community http://ib.bioninja.com.au/_Media/food_web_med.jpeg
  5. 5. C.2.U1 Most species occupy different trophic levels in multiple food chains.
  6. 6. C.2.U1 Most species occupy different trophic levels in multiple food chains.
  7. 7. C.2.S3 Construction of Gersmehl diagrams to show the inter-relationships between nutrient stores and flows between taiga, desert and tropical rainforest. http://commons.wikimedia.org/wiki/File:Nutrient_cycle.svg Gersmehl diagrams were first developed in 1976, by P.F. Gersmehl, to show the differences in nutrient flow and storage between different ecosystems Sinks for nutrient storage: • Biomass (flora and fauna) • Litter • Soil
  8. 8. C.2.S3 Construction of Gersmehl diagrams to show the inter-relationships between nutrient stores and flows between taiga, desert and tropical rainforest. http://commons.wikimedia.org/wiki/File:Nutrient_cycle.svg Gersmehl diagrams were first developed in 1976, by P.F. Gersmehl, to show the differences in nutrient flow and storage between different ecosystems Nutrient inputs into the ecosystem: • Nutrients dissolved in raindrops • Nutrients from weathered rock Nutrient outputs (losses) from the ecosystem: • Nutrients lost through surface runoff • Nutrients lost through leaching
  9. 9. C.2.S3 Construction of Gersmehl diagrams to show the inter-relationships between nutrient stores and flows between taiga, desert and tropical rainforest. http://commons.wikimedia.org/wiki/File:Nutrient_cycle.svg When used to analyse a particular ecosystem: • Diameter of sinks are proportional to the mass of nutrients stored in each sink • the thickness of the arrows are proportional to the rate of nutrient flow Gersmehl diagrams were first developed in 1976, by P.F. Gersmehl, to show the differences in nutrient flow and storage between different ecosystems Flows between the sinks: • Littering (including withering, defoliation, excretion, unconsumed parts left over, dead bodies of animals, and so on) * • Decomposition of the litter into inorganic nutrients, which are then stored in the soil • Nutrient uptake by plants Human interactions are not considered – do not confuse littering with dropping trash *
  10. 10. C.2.S3 Construction of Gersmehl diagrams to show the inter-relationships between nutrient stores and flows between taiga, desert and tropical rainforest. • Litter (pine needles) is the main store • Slow rate of nutrient transfer between stores • Soil is the main store • Slow rate of nutrient transfer between stores (except for the transfer from biomass to litter) • Biomass is the main store (soil is nutrient poor) • Fast rate of nutrient transfer between stores tagia (temperate forest) desert tropical rainforest Image source: Allott, A. (2014). Biology: Course companion. S.l.: Oxford University Press.
  11. 11. C.2.U3 The percentage of ingested energy converted to biomass is dependent on the respiration rate.
  12. 12. C.2.U3 The percentage of ingested energy converted to biomass is dependent on the respiration rate.
  13. 13. C.2.U3 The percentage of ingested energy converted to biomass is dependent on the respiration rate.
  14. 14. C.2.U3 The percentage of ingested energy converted to biomass is dependent on the respiration rate.
  15. 15. C.2.U3 The percentage of ingested energy converted to biomass is dependent on the respiration rate.
  16. 16. C.2.A1 Conversion ratio in sustainable food production practices. In commercial (animal) food production, farmers measure the food conversion ratio (FCR). It is a measure of an animal's efficiency in converting feed mass into the desired output. For dairy cows, for example, the output is milk, whereas animals raised for meat, for example, pigs the output is the mass gained by the animal. It is calculated by: mass of the food eaten (g) (increase in) desired output (g) (per specified time period)FCR = http://en.wikipedia.org/wiki/Feed_conversion_ratio Animal FCR Beef Cattle 5 - 20 Pigs 3 - 3.2 Sheep 4 - 6 Poultry 1.4 - 2 Salmon 1.2 - 3 The lower the FCR the more efficient the method of food production.
  17. 17. C.2.A1 Conversion ratio in sustainable food production practices. http://en.wikipedia.org/wiki/Feed_conversion_ratio Animal FCR Beef Cattle 5 - 20 Pigs 3 - 3.2 Sheep 4 - 6 Poultry 1.4 - 2 Salmon 1.2 - 3 A good (low) FCR is obtained by minimising the losses of energy by respiration, for example: • Restricting animal movement • Slaughtering the animal at a young age (older animals have higher FCRs as they grow more slowly) • Optimising feed so it is efficiently digested How ethical are the practices that lead to a low FCR? What is more important, efficient food production or the ethical treatment of animals?
  18. 18. C.2.S1 Comparison of pyramids of energy from different ecosystems.
  19. 19. C.2.S1 Comparison of pyramids of energy from different ecosystems.
  20. 20. C.2.S1 Comparison of pyramids of energy from different ecosystems.
  21. 21. C.2.S1 Comparison of pyramids of energy from different ecosystems.
  22. 22. C.2.S1 Comparison of pyramids of energy from different ecosystems.
  23. 23. C.2.S1 Comparison of pyramids of energy from different ecosystems.
  24. 24. C.2.S1 Comparison of pyramids of energy from different ecosystems.
  25. 25. C.2.S1 Comparison of pyramids of energy from different ecosystems.
  26. 26. C.2.S1 Comparison of pyramids of energy from different ecosystems.
  27. 27. C.2.S1 Comparison of pyramids of energy from different ecosystems. source of data: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/N/NetProductivity.html To understand why analyse the energy pyramids of the different ecosystems. Net productivity of different ecosystems varies greatly
  28. 28. C.2.S1 Comparison of pyramids of energy from different ecosystems. 1. High primary productivity (by producers) means more energy is available to the ecosystem. 3. Higher the primary productivity and greater the effeciency of energy transfer mean that more energy is available at high trophic levels. This can support longer the food chains, hence and more trophic levels increasing net productivity. Ecosystems rarely have more than 4 or 5 trophic levels. 2. The higher the efficiency of energy transfer between trophic levels the higher the net productivity. Energy transfer is typically 10%. Reasons for high net productivity of an ecosystem (4 trophic levels) (5 trophic levels)
  29. 29. C.2.U4 The type of stable ecosystem that will emerge in an area is predictable based on climate. Biome is a geographical area that has a particular climate and sustains a specific community of plants and animals (i.e. a type of ecosystem) Biosphere is the total of all areas where living things are found (i.e. the totality of biomes) • The main factors affecting the distribution of biomes is temperature and rainfall • These factors will vary according to latitude and longitude, elevation and proximity to the sea • Temperature is influential because it affects the rate of metabolism – the phases in the life cycles of many organisms are temperature dependent • In the same way, the availability of fresh water (both in the soil and in rivers and lakes) is critical to the growth and nutrition of organisms • Rainfall and warmer temperatures are more common near the equator and less common at the poles http://ib.bioninja.com.au/options/option-g-ecology-and-conser/g2-ecosystems-and-biomes.html
  30. 30. C.2.U4 The type of stable ecosystem that will emerge in an area is predictable based on climate. The six major types of biome/ecosystem are outlined in the table below http://ib.bioninja.com.au/options/option-g-ecology-and-conser/g2-ecosystems-and-biomes.html
  31. 31. C.2.U4 The type of stable ecosystem that will emerge in an area is predictable based on climate. The six major types of biome/ecosystem are outlined in the table below http://ib.bioninja.com.au/options/option-g-ecology-and-conser/g2-ecosystems-and-biomes.html
  32. 32. C.2.S2 Analysis of a climograph showing the relationship between temperature, rainfall and the type of ecosystem. http://cispatm.pbworks.com/f/1209212862/biome_graph.jpg n.b. The biomes in regions within the dashed line are strongly influenced by other factors (e.g. seasonality of drought, fire, animal grazing). A climograph is a diagram which shows the relative combination of temperature and precipitation in an area. This modified climograph (first developed by Robert Whittaker) shows the stable ecosystems/biomes that arise as a result of the relative combination of temperature and precipitation. It is a graphical representation of the biome summary table (last slide).
  33. 33. C.2.S2 Analysis of a climograph showing the relationship between temperature, rainfall and the type of ecosystem. http://cispatm.pbworks.com/f/1209212862/biome_graph.jpg n.b. The biomes in regions within the dashed line are strongly influenced by other factors (e.g. seasonality of drought, fire, animal grazing). A climograph is a diagram which shows the relative combination of temperature and precipitation in an area. This modified climograph (first developed by Robert Whittaker) shows the stable ecosystems/biomes that arise as a result of the relative combination of temperature and precipitation. It is a graphical representation of the biome summary table (last slide).
  34. 34. C.2.S4 Analysis of data showing primary succession.
  35. 35. C.2.S4 Analysis of data showing primary succession. http://bcs.whfreeman.com/thelifewire/content/chp55/55020.html
  36. 36. C.2.S4 Analysis of data showing primary succession.
  37. 37. C.2.S4 Analysis of data showing primary succession. Changes over time in total plant species richness over time at select sites on Mount Saint Helens, WA http://www.nature.com/scitable/knowledge /library/succession-a-closer-look-13256638 Use the examples to analyse data showing primary succession http://wps.pearsoncustom.com/ wps/media/objects/2128/21794 41/28_03.html
  38. 38. C.2.U6 Disturbance influences the structure and rate of change within ecosystems. http://www.nature.com/scitable/knowledge/library/succession-a-closer-look-13256638 1. A stable deciduous forest community 2. A disturbance, such as a wild fire, destroys the forest 3. The fire burns the forest to the ground 4. The fire leaves behind empty, but not destroyed, soil. 5. Grasses and other herbaceous plants grow back first. 6. Small bushes and trees begin to colonize the area 7. Fast growing evergreen trees develop to their fullest, while shade-tolerant trees develop in the understory. 8. The short-lived and shade intolerant evergreen trees die as the larger deciduous trees overtop them. The ecosystem is now back to a similar state to where it began. http://en.wikipedia.org/wiki/File:Secondary_Succession.png Examples of secondary succession caused by disturbance to ecosystems Disturbance can be natural or caused by human activity
  39. 39. C.2.S5 Investigation into the effect of an environmental disturbance on an ecosystem. Your investigation should compare a site undergoing secondary succession with a primary ecosystem. This can be extended to look at the various stages of secondary succession if local sites allow. Possible opportunities include: • Abandoned settlements/fields • Fields recovering after fire damage • Fire breaks in woodland Ways of measuring the affect of succession include: • Species diversity • Stem/Seedling density • Biomass • Canopy coverage / light intensity at the surface • Depth/Volume of leaf litter • Soil nutrient levels http://en.wikipedia.org/wiki/File:NASAburningbrazil.jpg
  40. 40. C.2.U5 In closed ecosystems energy but not matter is exchanged with the surroundings. http://cdn.pickchur.com/wp-content/uploads/2013/02/bottle_ecosystem.jpg Most natural ecosystems are ‘open ecosystems’. They can exchange energy and matter with adjacent ecosystems or environments. Examples of matter exchange are: • migration of animals • harvesting of crops • the flow of water or gases Closed ecosystems, such as mesocosms (4.1.S2) and the Biosphere 2 project are closed ecosystems. Although energy can be exchanged (most commonly through the entry of light and the loss of heat), matter remains in the system. Water and nutrients are cycled within the ecosystem. Closed ecosystems are of interest to Scientists as they provide insight in how extra-terrestrial habitats can be setup and maintained. http://upload.wikimedia.org/wikipedia/commons/1/13/Biosphere_2_-_1998_a.jpg
  41. 41. C.2.A2 Consideration of one example of how humans interfere with nutrient cycling. Humans practices can accelerate the the flow of matter into and out of ecosystems. This by implication (and often design) alters the nutrient cycling in ecosystems. Phosphate mined and converted to fertiliser. Nitrate fertiliser produced from atmospheric Nitrogen (by the Haber process) Agriculture Harvesting of crops Water run-off (leaching) from agricultural fields results in build- up of phosphates and nitrates in waterways and leads to eutrophication.
  42. 42. Bibliography / Acknowledgments Jason de Nys

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