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IB Biology Ecology Optional Topic C 2015

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IB Biology 2015 Curriculum

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IB Biology Ecology Optional Topic C 2015

  1. 1. Topic Eight: Ecology
  2. 2. Essential idea: The continued survival of living organisms including humans depends on sustainable communities. 4.1 Species, communities and ecosystems
  3. 3. The Earth as seen from Saturn's rings The Earth
  4. 4. Understandings Statement Guidance 4.1 U.1 Species are groups of organisms that can potentially interbreed to produce fertile offspring. 4.1 U.2 Members of a species may be reproductively isolated in separate populations. 4.1 U.3 Species have either an autotrophic or heterotrophic method of nutrition (a few species have both methods). 4.1 U.4 Consumers are heterotrophs that feed on living organisms by ingestion 4.1 U.5 Detritivores are heterotrophs that obtain organic nutrients from detritus by internal digestion. 4.1 U.6 Saprotrophs are heterotrophs that obtain organic nutrients from dead organisms by external digestion. 4.1 U.7 A community is formed by populations of different species living together and interacting with each other. 4.1 U.8 A community forms an ecosystem by its interactions with the abiotic environment. 4.1 U.9 Autotrophs obtain inorganic nutrients from the abiotic environment. 4.1 U.10 The supply of inorganic nutrients is maintained by nutrient cycling. 4.1 U.11 Ecosystems have the potential to be sustainable over long periods of time.
  5. 5. Applications and Skills Statement Guidance 4.1 S.1 Classifying species as autotrophs, consumers, detritivores or saprotrophs from a knowledge of their mode of nutrition. 4.1 S.2 Setting up sealed mesocosms to try to establish sustainability. (Practical 5) Mesocosms can be set up in open tanks, but sealed glass vessels are preferable because entry and exit of matter can be prevented but light can enter and heat can leave. Aquatic systems are likely to be more successful than terrestrial ones. 4.1 S.3 Testing for association between two species using the chi-squared test with data obtained by quadrat sampling To obtain data for the chi-squared test, an ecosystem should be chosen in which one or more factors affecting the distribution of the chosen species varies. Sampling should be based on random numbers. In each quadrat the presence or absence of the chosen species should be recorded. 4.1 S.4 Recognizing and interpreting statistical significance.
  6. 6. • BiosphereBiosphere • EcosystemEcosystem is a compilation of both biotic and abiotic factors, how organisms interact with their environment. • CommunityCommunity of different species in the same area which are interacting • PopulationPopulation group of organisms of the same species who live in the same area at the same time • Individuals speciesIndividuals species HabitatHabitat is the environment in which a species normally lives or the location of a living organism
  7. 7. Distinguish between autotroph and heterotroph. • Autotrophs are capable of making their own organic molecules from inorganic molecules as a food source (a.k.a. producers); Examples? • Heterotrophs – cannot make their own food and must obtain organic molecules from other organisms (a.k.a. consumers); Examples?
  8. 8. Consumers ingest organic matter which is living or recently killed food chains show the flow of energy through the trophic levels of a feeding relationship.
  9. 9. Decomposers Two Types • Detritivores (Ingest, then digest) ingests non-living organic matter • Saprotrophs (Digest first, then absorb) live in or on non- living matter, secreting digestive enzymes into it and absorbing digestive products SaprotrophsDetritivores
  10. 10. Trophic Levels of Feeding Groups • Ecologists divide the species in a community or ecosystem into trophic levels based on their main source of nutrition. • Primary producers- autotrophs- produce their own energy source. • Photoautotrophs- derive energy via photosynthesis- plants • Chemoautotrophs- use energy stored in chemical bonds- Sulfur
  11. 11. Trophic Levels Consumers- heterotrophs- derive energy from consuming other organisms • 1° consumer- eat producers • 2° consumer- eats herbivores- 1° consumer • 3° consumer- eats 2° and 1° consumers Decomposers- consume dead material- recycle nutrients back to the environment- Saprotroph
  12. 12. Trophic Levels
  13. 13. Overview of energy & nutrient dynamics
  14. 14. • Energy cannot be recycled  must be constantly supplied to an ecosystem (mostly by SUNSUN) • The autotrophs (“self feeders”) are the primary producers, and are usually photosynthetic (plants or algae). – They use light energy to synthesize sugars and other organic compounds. 4.2 U.2 Light energy is converted to chemical energy in carbon compounds by photosynthesis.
  15. 15. Heterotrophs are at trophic levels above the Primary producers and depend on their photosynthetic output. 4.2 U.3 Chemical energy in carbon compounds flows through food chains by means of feeding
  16. 16. Energy transfer between trophic levels is typically only 10% efficient • Production efficiency: only fraction of E stored in food • Energy used in respiration is lost as heat • Energy flows (not cycle!) within ecosystems 4.2 U.4 Energy released from carbon compounds by respiration is used in living organisms and converted to heat.
  17. 17. Trophic Levels Notice that only 10% is moved to the next level. Where does the rest go?
  18. 18. THE 10% RULE and ECOLOGICAL PYRAMID
  19. 19. Energy Flow Through Ecosystems
  20. 20. • Shows more complex interactions between species within a community/ ecosystem • More than one producer supporting a community • A consumer may have a number of different food sources on the same or different trophic levels Food webFood web
  21. 21. Soil Food webSoil Food web
  22. 22. Food webFood web
  23. 23. What are the factors that effect an ecosystem? • Abiotic (nutrients and energy) • Biotic individual organisms that live in that ecosystem
  24. 24. Factors controlling and ecosystem I. Nutrients (Closed System) II. Energy (Open System) III. Interactions between species
  25. 25. 4.3 Carbon cycling • Essential idea: Continued availability of carbon in ecosystems depends on carbon cycling.
  26. 26. Understandings Statement Guidance 4.3 U.1 Autotrophs convert carbon dioxide into carbohydrates and other carbon compounds. 4.3U.2 In aquatic ecosystems carbon is present as dissolved carbon dioxide and hydrogen carbonate ions. 4.3 U.3 Carbon dioxide diffuses from the atmosphere or water into autotrophs. 4.3 U.4 Carbon dioxide is produced by respiration and diffuses out of organisms into water or the atmosphere. 4.3 U.5 Methane is produced from organic matter in anaerobic conditions by methanogenic archaeans and some diffuses into the atmosphere or accumulates in the ground. 4.3 U.6 Methane is oxidized to carbon dioxide and water in the atmosphere. 4.3 U.7 Peat forms when organic matter is not fully decomposed because of acidic and/or anaerobic conditions in waterlogged soils. 4.3 U.8 Partially decomposed organic matter from past geological eras was converted either into coal or into oil and gas that accumulate in porous rocks. 4.3 U.9 Carbon dioxide is produced by the combustion of biomass and fossilized organic matter. 4.3 U.10 Animals such as reef-building corals and mollusca have hard parts that are composed of calcium carbonate and can become fossilized in limestone.
  27. 27. Applications and Skills Statement Guidance 4.3 A.1 Estimation of carbon fluxes due to processes in the carbon cycle. Carbon fluxes should be measured in gigatonnes. 4.3 A.2 Analysis of data from air monitoring stations to explain annual fluctuations. 4.3 S.1 Construct a diagram of the carbon cycle.
  28. 28. Essential idea: Soil cycles are subject to disruption. C.6 The nitrogen and phosphorus cycles (AHL) http://www.agricorner.com/wp-content/uploads/2013/09/urea-caf.jpg
  29. 29. Understandings, Applications and Skills Statement Guidance C.6 U.1 Nitrogen-fixing bacteria convert atmospheric nitrogen to ammonia. C.6 U.2 Rhizobium associates with roots in a mutualistic relationship. C.6 U.3 In the absence of oxygen denitrifying bacteria reduce nitrate in the soil. C.6 U.4 Phosphorus can be added to the phosphorus cycle by application of fertilizer or removed by the harvesting of agricultural crops. C.6 U.5 The rate of turnover in the phosphorus cycle is much lower than the nitrogen cycle. C.6 U.6 Availability of phosphate may become limiting to agriculture in the future. C.6 U.7 Leaching of mineral nutrients from agricultural land into rivers causes eutrophication and leads to increased biochemical oxygen demand. C.6 A.1 The impact of waterlogging on the nitrogen cycle. C.6 A.2 Insectivorous plants as an adaptation for low nitrogen availability in waterlogged soils. C.6 S.1 Drawing and labelling a diagram of the nitrogen cycle. C.6 S.2 Assess the nutrient content of a soil sample.
  30. 30. I. Nutrient Cycles ThroughI. Nutrient Cycles Through EcosystemsEcosystems Biogeochemical cyclesBiogeochemical cycles are cycles of matter between the abiotic and the biotic components of the environment • The carbon, nitrogen, and phosphorus cycles are central to life on Earth • Carbon and nitrogen cycles have atmospheric components, and cycle on a global scale • Phosphorus has no atmospheric component, and cycles on a local scale
  31. 31. Very few types of organism play a role in the cycling of nutrients Saprotrophic Bacteria cycle Nitrogen Fungi Cycle Carbon
  32. 32. 4.3 Carbon cycling • Essential idea: Continued availability of carbon in ecosystems depends on carbon cycling.
  33. 33. Carbon Cycle • Is exchanged of the element carbon among the biosphere. Or geosphere, hydrosphere, and atmosphere of the Earth. • Carbon interconnected by pathways of exchange with these reservoirs is mainly through plants .
  34. 34. Carbon Cycle 4.3 S.1 Construct a diagram of the carbon cycle. Carbon cycle diagrams vary greatly in the detail they contain. This one shows not only the sinks and the flows, but also estimates carbon storage and movement in gigatons/year.
  35. 35. 4.3 S.1 Construct a diagram of the carbon cycle. You need to be able to produce a simplified carbon cycle. Use the following sinks and flows (processes) to build a carbon cycle: CO2 in the atmosphere and hydrosphere (oceans) Carbon compounds in fossil fuels Carbon compounds in producers (autotrophs) Carbon compounds in consumers Carbon compounds in dead organic matter Key: Sink Flux n.b. some of the fluxes will need to be used more than once. Cell respiration Photosynthesis Combustion FeedingEgestion Death Incomplete decomposition & fossilization
  36. 36. You need to be able to produce a simplified carbon cycle. Use the following sinks and flows (processes) to build a carbon cycle: CO2 in the atmosphere and hydrosphere (e.g. oceans) Carbon compounds in fossil fuels Carbon compounds in producers (autotrophs) Carbon compounds in consumers Carbon compounds in dead organic matter Key: Sink Flux Cell respiration Photosynthesis Combustion Feeding Egestion Death Incomplete decomposition & fossilisation Cellrespiration Combustion Cellrespiration Feeding Death Feeding
  37. 37. You need to be able to produce a simplified carbon cycle. Use the following sinks and flows (processes) to build a carbon cycle: CO2 in the atmosphere and hydrosphere (e.g. oceans) Carbon compounds in fossil fuels Carbon compounds in producers (autotrophs) Carbon compounds in consumers Carbon compounds in dead organic matter Key: Sink Flux Cell respiration Photosynthesis Combustion Feeding Egestion Death Incomplete decomposition & fossilisation Cellrespiration Combustion Cellrespiration Feeding Death Feeding Use the video to help practice your drawing skills* *this is a good resource, but there is one mistake in the video – carbon is egested, when not digested by an organism, not excreted.
  38. 38. Extend your understanding: 1.Between which sinks would you add a flux showing volcanoes and the weathering of rocks? 2.What additional sink would you add to show the role of corals and shellfish? What additional flux would be needed? 3.In some environments water is unable to drain out of soils so they become waterlogged and anaerobic. This prevents the decomposition of dead organic matter forming peat deposits [4.3.U7]. Peat can be dried and burnt as a fuel. Suggest how peat could be added to the carbon cycle. 4.Explain why fossil fuels are classified as non-renewable resources when the carbon cycle indicates they are renewed (hint: refer to the pictorial carbon cycle). 5.Diffusion is a flux that moves CO2 from the atmosphere to the hydrosphere and back again. Taken together these fluxes are largest in the cycle suggest why.
  39. 39. 4.3 U.1 Autotrophs convert carbon dioxide into carbohydrates and other carbon compounds. http://www.earthtimes.org/newsimage/photosynthesis-dream-renewable-energy_1_02842012.jpg n.b. Although most autotrophs fix carbon by photosynthesis. A few are Chemoautotrophs and fix carbon by utilising the energy in the bonds of inorganic compounds such as hydrogen sulfide. All autotrophs however convert carbon dioxide (from the atmosphere or dissolved in water) or into organic compounds. Plant initially synthesis sugars (e.g. glucose) which are then converted into other organic compounds such as: •complex carbohydrates e.g. starch, cellulose •lipids •amino acids
  40. 40. 4.3 U.2 In aquatic ecosystems carbon is present as dissolved carbon dioxide and hydrogen carbonate ions. CO2 + H2O → H2CO3 → H+ + HCO3 – Both dissolved carbon dioxide and hydrogen carbonate ions are absorbed by aquatic plants and other autotrophs that live in water. H+ ions explains how carbon dioxide reduces the pH of water. Some CO2 will directly dissolve in water, but most will combine with water to become carbonic acid. CO2 + H2O → H2CO3 → H+ + HCO3 –
  41. 41. 4.3 U.3 Carbon dioxide diffuses from the atmosphere or water into autotrophs http://www.kbg.fpv.ukf.sk/studium_materialy/morfologia_rastlin/webchap10epi/web10.3-6.jpg Transverse section of parsnip leaf (Pastinaca sativa) CO2 from outside the leaf diffuses down the concentration gradient into the leaf Photosynthesis uses CO2 keeping the concentration of CO2 inside the leaf low High CO2Concentration gradient CO2Concentration gradient Low CO2 moves through stomata openings in the leaves of land plants* atmosphere or water Inside the leaf atmosphere or water Plants must have a constant supply of carbon dioxide (CO2) to continually photosynthesize
  42. 42. 4.3 U.4 Carbon dioxide is produced by respiration and diffuses out of organisms into water or the atmosphere. In terms of the carbon cycle three main categories of organisms carry out respiration: •autotrophs, e.g. plants •heterotrophs, e.g. animals Organisms carry out respiration to release energy in the form of ATP. Carbon dioxide is a waste product of cell respiration http://ib.bioninja.com.au/_Media/cell_respiration_summary.jpeg
  43. 43. 4.3 U.7 Peat forms when organic matter is not fully decomposed because of acidic and/or anaerobic conditions in waterlogged soils. Partially decomposed organic matter can be compressed to form brown soil-like peat. Once dried peat burns easily and can be used as a fuel. Peat is a highly effective carbon sink, it is estimated that the world’s peat contains 550 Gt of carbon (International Mire Conservation Group, 2007-01-03) http://commons.wikimedia.org/wiki/File:Peat-bog-Ireland.jpg http://commons.wikimedia.org/wiki/File:Toppila_power_plant.JPG Toppila Peat-Fired Power Plant in Oulu, Finland
  44. 44. • In soils organic matter, e.g. dead leaves, are digested by saprotrophic bacteria and fungi. • Saprotrophs assimilate some carbon for growth and release as carbon dioxide during aerobic respiration (requiring O2). • Waterlogged soils are an anaerobic environment leaving these organisms unable to complete the process. • Large quantities of (partially decomposed) organic matter build up. The organic matter is compressed to form peat
  45. 45. 4.3.U7 Peat forms when organic matter is not fully decomposed because of acidic and/or anaerobic conditions in waterlogged soils. Saprotrophs assimilate some carbon for growth and release as carbon dioxide during aerobic respiration. Aerobic respiration requires oxygen Waterlogged soils are an anaerobic environment Partial decomposition causes acidic conditions saprotrophs and methanogens [4.3.U5] are inhibited Organic matter is only partially decomposed Large quantities of (partially decomposed) organic matter build up. The organic matter is compressed to form peat http://commons.wikimedia.org/wiki/File:Peat-bog-Ireland.jpg Organic matter
  46. 46. http://commons.wikimedia.org/wiki/File:Coal_lump.jpg Coal is formed when deposits of peat are buried under other sediments. The peat is compressed and heated over millions years eventually becoming coal.
  47. 47. http://commons.wikimedia.org/wiki/File:Coal_lump.jpg 4.3 U.8 Partially decomposed organic matter from past geological eras was converted either into coal or into oil and gas that accumulate in porous rocks. The cycle of sea-level changes that happened during the Carboniferous period caused costal swamps to be buried promoting the formation of coal.
  48. 48. Carboniferous • Extended from 359 million years ago, to the about 299. • A time of glaciation, low sea level and mountain building. With many beds of coal were laid down all over the world during this period.
  49. 49. Carboniferous period • The world’s large coal deposits occurred during this time period Two factors 1. The appearance of bark- bearing trees (containing bark fiber lignin). 2. Lower sea levels • Development of extensive lowland swamps and forests. • Large quantities of wood were buried during this period. • Animals and decomposing bacteria had not yet evolved that could effectively digest the new lignin.
  50. 50. Basidiomycetes (fungi) • Appear 290 million years ago. They can degrade it Lignin. The substance is insoluble, to heterogeneous because of specific enzymes, and toxic, they are one of the few organisms that can. http://andreas-und-angelika.de/galleries/andreas/2014- 05_Autumn_Colours/photos/aka-Autumn-Colours-2014-04- 19__D8X7633.jpg
  51. 51. 4.3 U.8 Partially decomposed organic matter from past geological eras was converted either into coal or into oil and gas that accumulate in porous rocks. http://commons.wikimedia.org/wiki/File:Oil_well.jpg http://www.agiweb.org/education/energy/images/oildrill.png Conditions are anaerobic and so decomposition is only partial. Methane forms the largest part of natural gas. The mixture of different types of oil and gas is the result of complex chemical changes. oil and gas formation occurred in ancient oceans
  52. 52. 4.3 U.10 Animals such as reef-building corals and Mollusca have hard parts that are composed of calcium carbonate and can become fossilized in limestone. http://commons.wikimedia.org/wiki/File:Fossils_in_a_beach_wall.J When the animals die the soft body parts decompose, but the calcium carbonate remains to form deposits on the ocean floor.
  53. 53. 4.3 U.10 Animals such as reef-building corals and Mollusca have hard parts that are composed of calcium carbonate and can become fossilized in limestone. • Some animals secrete calcium carbonate (CaCO3) structures to protect themselves:  Shells of mollusks  Hard corals exoskeletons • When the animals die the soft body parts decompose, but the calcium carbonate remains to form deposits on the ocean floor. • The deposits are buried and compressed and eventually form limestone rock • Imprints of the hard body parts remain in the rock as fossils. • Limestone rock is a huge carbon sink
  54. 54. Essential idea: Soil cycles are subject to disruption. Nitrogen cycle
  55. 55. C.6 U.1 Nitrogen-fixing bacteria convert atmospheric nitrogen to ammonia. Nitrogen gas Ammonia (NH3) Nitrites (NO2 - )nitrates (NO3 - ) Rhizobium & Azotobacter Nitrobacter* *Bacteria can be chemoautotrophs deriving energy (for carbon fixation) from the bonds in the compounds they convert. Nitrosomonas* The roles of bacteria in nitrogen fixation http://en.wikipedia.org/wiki/File:Azotobacter_cells.jpg Plants cannot directly absorb and assimilate nitrogen. It must be first converted to compounds such as nitrates and ammonia. http://on.be.net/1arnCUH nitrogen fixation Nitrification is the process of converting ammonia into nitrates
  56. 56. C.6 U.2 Rhizobium associates with roots in a mutualistic relationship. http://commons.wikimedia.org/wiki/File:French_bean_plant_from_lalbagh_2336.JPG • Mutualism describes relationships between organisms in which both organisms benefit. • The legume supplies carbohydrates to the bacteria. The bacteria use the carbohydrates for processes such as respiration. • The bacteria supply ammonia (fixed from atmospheric nitrogen) to the legume. • The legume requires ammonia for the synthesis of amino acids.
  57. 57. C.6 U.2 Rhizobium associates with roots in a mutualistic relationship. http://commons.wikimedia.org/wiki/File:Nitrogen-fixing_nodules_in_the_roots_of_legumes..JPG • Azotobacter are free-living in the soil whereas bacteria of the genus Rhizobium are often not free- living but live in a close symbiotic association in the roots of plants such as the legume family. • Legumes and the Rhizobium grow together to form nodules on the roots of the legume.
  58. 58. C.6 U.3 In the absence of oxygen denitrifying bacteria reduce nitrate in the soil. • Electron transport is a key process in cellular respiration • Oxygen or nitrate can be used as an electron acceptor in electron transport. • Though oxygen is preferred in oxygen poor conditions nitrate is used and the process releases nitrogen gas a product. Denitrification reduces the availability of nitrogen compounds to plants. Nitrate (NO3 - ) Nitrogen (N2) A chemical reduction process carried out by bacteria e.g. Pseudomonas sp. http://microbewiki.kenyon.edu/index.php/File:P._Cloroaphis.jpg
  59. 59. C.6 A.1 The impact of waterlogging on the nitrogen cycle. http://www.hampshirecam.co.uk/feb909_2.html
  60. 60. http://soer.justice.tas.gov.au/2009/image/1076/lan/id1076-p-SoilDegradationWaterlo-l.Jpg • Soil can become inundated by water, waterlogged, through flooding or irrigation with poor drainage. • Waterlogging reduces the oxygen availability in soils. • This encourages the process of denitrification by bacteria, e.g. Pseudomonas sp. • n.b. excess water in the soil also leads to greater leaching of nutrients, which leads to nutrient enrichment of rivers and lakes and therefore to eutrophication.
  61. 61. C.6 A.2 Insectivorous plants as an adaptation for low nitrogen availability in waterlogged soils. http://botany.org/Carnivorous_Plants/ Drosera sp. - the Sundews Find out more • Modified leaves have evolved to trap insects. • Enzymes are secreted to (extracellular) digest the animal. • The products of digestion are absorbed by the modified leaves. “Carnivorous plants have the most bizarre adaptations to low-nutrient environments. These plants obtain some nutrients by trapping and digesting various invertebrates, and occasionally even small frogs and mammals. Because insects are one of the most common prey items for most carnivorous plants, they are sometimes called insectivorous plants. It is not surprising that the most common habitat for these plants is in bogs and fens, where nutrient concentrations are low but water and sunshine seasonally abundant.”
  62. 62. http://i.telegraph.co.uk/multimedia/archive/01464/plant-5_1464520i.jpg Insectivorous plants cannot be truly considered carnivorous as only nitrogen compounds are absorbed. The plant still obtains it’s energy from light via photosynthesis.
  63. 63. C.6 S.1 Drawing and labelling a diagram of the nitrogen cycle. adapted from: http://commons.wikimedia.org/wiki/File:Nitrogen_Cycle.jpg#mediaviewer/File:Nitrogen_Cycle.svg On this diagram the pools (boxes) and fluxes (arrows) have been drawn on already. Add in the processes and state the bacteria related to the some of the processes. Rhizobium free-living nitrogen-fixing bacteria in the soil Azotobacter Mutualistic nitrogen-fixing bacteria in root nodules Nitrification (x2) Nitrosomonas Nitrobacter Uptake (by active transport) and assimilation by plants Natural nitrogen fixation by lightning Application of fertilizers containing nitrogen (fixed by the Haber process) Transfer by the food chain Denitrification Pseudomonas Death & decomposition Ammonification Excretion
  64. 64. C.6 S.1 Drawing and labelling a diagram of the nitrogen cycle. free-living nitrogen- fixing bacteria in the soil Azotobacter Mutualistic nitrogen-fixing bacteria in root nodules Nitrification Nitrobacter Uptake (by active transport) and assimilation by plants Natural nitrogen fixation by lightning Application of fertilizers containing nitrogen (fixed by the Haber process) Transfer by the food chain Denitrification Pseudomonas Death & decomposition Ammonification Excretion Nitrification Nitrosomonas Rhizobium
  65. 65. Essential idea: Soil cycles are subject to disruption. We consume phosphorus through food produced with fertilizers. The women above is spreading phosphorus by hand in her rice paddy to increase production.. Phosphorus cycles http://www.futureearth.org/blog/2014-oct-16/can-we-build-sustainable-phosphorus-governance
  66. 66. C.6 U.5 The rate of turnover in the phosphorus cycle is much lower than the nitrogen cycle. http://commons.wikimedia.org/wiki/File:Phosphorus_cycle.png
  67. 67. C.6 U.5 The rate of turnover in the phosphorus cycle is much lower than the nitrogen cycle. The phosphorous cycle shows the various different forms in which phosphorous can naturally be found. •Certain rocks, e.g. Phosphorite, contains high levels of phosphate minerals. Weathering of these rocks releases phosphates into the soil. Phosphates are a form of phosphorus that can is easily be absorbed by plants entering the food chains. •The rate of turnover is relatively slow, compared with Nitrogen, as phosphate is only slowly released to ecosystems by weathering. •Organisms have a variety of uses for phosphate  ATP  DNA and RNA  cell membranes  skeletons in vertebrates
  68. 68. C.6 U.4 Phosphorus can be added to the phosphorus cycle by application of fertilizer or removed by the harvesting of agricultural crops. • Phosphate is mined and converted to phosphate-based fertilizer – this increase the rate of turnover. • The fertilizer is then (transported great distances and) applied to crops . The processes remove phosphorus from the cycle in one location and adds it to another. http://commons.wikimedia.org/wiki/File:Agriculture_in_Volgograd_Oblas http://commons.wikimedia.org/wiki/File:Phosphate_Mine_Panorama.jpg
  69. 69. C.6 U.6 Availability of phosphate may become limiting to agriculture in the future. • The demand for artificial fertilizer in modern intensive farming is very high. • Consequently phosphate mining is being carried out at a much faster rate than the rocks can be naturally formed and hence replenished. Impacts to agriculture of reduced phosphate production are potentially great. • There are no sources of phosphate fertilizer other than mining minerals. • There is no synthetic way of creating phosphate fertilizers*, though this may change in the future. *Yields per unit of farmland would plummet without the *Unlike ammonia which can be created by the industrial conversion of plentiful supplies of atmospheric nitrogen. http://commons.wikimedia.org/wiki/File:Crop_spraying_near_ St_Mary_Bourne_-_geograph.org.uk_-_392462.jpg
  70. 70. http://commons.wikimedia.org/wiki/File:Phosphateproductionworldwide.svg The graph is based on US Geological Survey data and shows world phosphate production from mining. World production has varied greatly, but overall there have been smaller increases to production after than before 1980. As the reserves of phosphate rock are depleted the production of phosphorous is likely to peak and then decline. Though some sources the peak is likely to occur in in the next 30 years it is difficult to judge particularly due to the fact new phosphate mineral deposits are still being discovered. millions of Metric tons C.6 U.6 Availability of phosphate may become limiting to agriculture in the future.
  71. 71. http://commons.wikimedia.org/wiki/File:Potomac_green_water.JPG An increase in nutrients in aquatic ecosystems leads to eutrophication
  72. 72. C.6 U.7 Leaching of mineral nutrients from agricultural land into rivers causes eutrophication and leads to increased biochemical oxygen demand. http://nroc.mpls.k12.mn.us/Environm • Rainfall leaches water-soluble nutrients (e.g. phosphates, ammonia and nitrates) from the soil and carries them into rivers and lakes. • The nutrients can come either from artificial fertilizers, natural fertilizer such as manure or the urine of livestock. • Poorly drained, or waterlogged soils encourages leaching of these materials. • An increase in nutrients in aquatic ecosystems leads to eutrophication a negative environmental effect that could include hypoxia, the depletion of oxygen in the water, which may cause death to aquatic animals.
  73. 73. In summary: •Algal growth is normally limited by the availability of nutrients such as nitrates and phosphates •Rapid growth in the algal populations occurs, these increases are called ‘algal blooms’ also leading to an increase so naturally does the numbers of dead algae •the numbers of (saprotrophic) bacteria and microbes that feed on the dead algae also increase •an increase in biochemical oxygen demand (BOD) by the saprotrophic bacteria results in deoxygenation of the water supply (reduced dissolved O2) The consequences to organisms of low levels of dissolved oxygen: •death or emigration of oxygen sensitive organisms (e.g. fish) •proliferation of low dissolved O2 tolerant organisms •reduction of biodiversity •decrease in water transparency, i.e. an increase in turbidity stresses photosynthetic organisms … •… this in turn will affect the whole food chain •increased levels of toxins and greater numbers of pathogens means affected water is no longer suitable for bathing or drinking
  74. 74. C.6 U.7 Leaching of mineral nutrients from agricultural land into rivers causes eutrophication and leads to increased biochemical oxygen demand. Red tide on Long Island has lead to eutrophication.
  75. 75. C.6 S.2 Assess the nutrient content of a soil sample. Guidance on proper use of tests and limitations of simple home test kits: http://www.ext.colostate.edu/mg/ga Garden supply companies commonly sell soil quality assessment kits. The kits involve adding a chemical to a sample of soil that reacts with the nutrient in question, if present. A colour is produced that can be visually compared to a key. An example kit from Urban Farmer: http://www.ufseeds.com/Premium-Soil-Test-Kit.item
  76. 76. Essential idea: Ecosystems require a continuous supply of energy to fuel life processes and to replace energy lost as heat. 4.2 Energy flow
  77. 77. Understandings Statement Guidance 4.2 U.1 Most ecosystems rely on a supply of energy from sunlight. 4.2 U.2 Light energy is converted to chemical energy in carbon compounds by photosynthesis. 4.2 U.3 Chemical energy in carbon compounds flows through food chains by means of feeding The distinction between energy flow in ecosystems and cycling of inorganic nutrients should be stressed. Students should understand that there is a continuous but variable supply of energy in the form of sunlight but that the supply of nutrients in an ecosystem is finite and limited. 4.2 U.4 Energy released from carbon compounds by respiration is used in living organisms and converted to heat. 4.2 U.5 Living organisms cannot convert heat to other forms of energy. 4.2 U.6 Heat is lost from ecosystems. 4.2 U.7 Energy losses between trophic levels restrict the length of food chains and the biomass of higher trophic levels. Pyramids of number and biomass are not required. Students should be clear that biomass in terrestrial ecosystems diminishes with energy along food chains due to loss of carbon dioxide, water and other waste products, such as urea.
  78. 78. Applications and Skills Statement Guidance 4.2 S.1 Quantitative representations of energy flow using pyramids of energy. Pyramids of energy should be drawn to scale and should be stepped, not triangular. The terms producer, first consumer and second consumer and so on should be used, rather than first trophic level, second trophic level and so on.
  79. 79. C.2 Communities and Ecosystems Essential idea: Changes in community structure affect and are affected by organisms.
  80. 80. Understandings Statement Guidance C.2 U.1 Most species occupy different trophic levels in multiple food chains. C.2 U.2 A food web shows all the possible food chains in a community. C.2 U.3 The percentage of ingested energy converted to biomass is dependent on the respiration rate. C.2 U.4 The type of stable ecosystem that will emerge in an area is predictable based on climate. C.2 U.5 In closed ecosystems energy but not matter is exchanged with the surroundings. C.2 U.6 Disturbance influences the structure and rate of change within ecosystems.
  81. 81. Applications and Skills Statement Guidance C.2 A.1 Conversion ratio in sustainable food production practices. C.2 A.2 Consideration of one example of how humans interfere with nutrient cycling. C.2 S.1 Comparison of pyramids of energy from different ecosystems. C.2 S.2 Analysis of a climograph showing the relationship between temperature, rainfall and the type of ecosystem. C.2 S.3 Construction of Gersmehl diagrams to show the inter-relationships between nutrient stores and flows between taiga, desert and tropical rainforest. C.2 S.4 Analysis of data showing primary succession. C.2 S.5 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.
  82. 82. II. Energy (Open system on Earth)
  83. 83. Sunlight is the initial energy source for almost all communities • Energy flows through the food chain, being lost at each stage due to respiration.
  84. 84. Pyramids of energy • Show the flow of energy between trophic levels • Measured in units of energy per unit area per unit time. KJ m-2 y-1 • The transfer of energy is never 100% efficient
  85. 85. Energy Flow through the Ecosystem
  86. 86. • The conversion of light energy into energy stored in chemical bonds within plant tissue. Primary production results in the addition of new plant biomass to the system. • Two types • Net Primary Production • Gross Primary Production. Primary ProductionPrimary Production
  87. 87. Primary Productivity •The most productive terrestrial areas are tropical rain forests; least productive are deserts
  88. 88. NPP = GPP - R • Gross Primary Production (GPP)Gross Primary Production (GPP) is the amount of light energy that is converted to chemical energy by photosynthesis per unit time. • Net Primary Production (NPP)Net Primary Production (NPP) is equal to gross primary production minus the energy used by the primary producers for respiration (R). Which will be the total energy available to all the other living things in that ecosystem
  89. 89. Biomass • Biomass is the total dry mass of organic matter in the organisms or ecosystem. • By measuring biomass of an ecosystem we can see how productive it is and compare this to other ecosystems of past data
  90. 90. Pyramids of BiomassPyramids of Biomass
  91. 91. C.2 A.1 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. 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. It is calculated by:
  92. 92. 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 minimizing 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) •Optimizing 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? C.2 A.1 Conversion ratio in sustainable food production practices.
  93. 93. C.2 S.1 Comparison of pyramids of energy from different ecosystems.
  94. 94. C.2 S.1 Comparison of pyramids of energy from different ecosystems.
  95. 95. C.2 S.1 Comparison of pyramids of energy from different ecosystems.
  96. 96. C.2 S.1 Comparison of pyramids of energy from different ecosystems.
  97. 97. C.2 S.1 Comparison of pyramids of energy from different ecosystems.
  98. 98. C.2 S.1 Comparison of pyramids of energy from different ecosystems.
  99. 99. C.2 S.1 Comparison of pyramids of energy from different ecosystems.
  100. 100. C.2 S.1 Comparison of pyramids of energy from different ecosystems.
  101. 101. C.2 S.1 Comparison of pyramids of energy from different ecosystems.
  102. 102. source of data: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/N/NetProductivity.html To understand why analyze the energy pyramids of the different ecosystems. Net productivity of different ecosystems varies greatly C.2 S.1 Comparison of pyramids of energy from different ecosystems.
  103. 103. 1. High primary productivity (by producers) means more energy is available to the ecosystem. 3. Higher the primary productivity and greater the efficiency 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) C.2 S.1 Comparison of pyramids of energy from different ecosystems.
  104. 104. 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 C.2 S.3 Construction of Gersmehl diagrams to show the inter-relationships between nutrient stores and flows between taiga, desert and tropical rainforest.
  105. 105. 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 C.2 S.3 Construction of Gersmehl diagrams to show the inter-relationships between nutrient stores and flows between taiga, desert and tropical rainforest.
  106. 106. C.2 S.3 Construction of Gersmehl diagrams to show the inter-relationships between nutrient stores and flows between taiga, desert and tropical rainforest. When used to analyze 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 *
  107. 107. C.2 S.3 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.
  108. 108. C.2.U3 The percentage of ingested energy converted to biomass is dependent on the respiration rate.
  109. 109. Ecosystems are not fixed, but constantly change with time. This change is called succession. Imagine a lifeless area of bare rock. There are two types of succession Primary and Secondary C.2 S.4 Analysis of data showing primary succession.
  110. 110. C.2 S.4 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/libra Use the examples to analyze data showing primary succession http://wps.pearsoncustom.com/wps/media/objects/2128/2179441/28_03.html
  111. 111. Secondary successionSecondary succession •Starts with soil, but no (or only a few) species, such as in a forest clearing, following a forest fire, or when soil is deposited by a meandering river After a forest fireAfter a forest fire One year laterOne year later Five years laterFive years later C.2 U.6 Disturbance influences the structure and rate of change within ecosystems.
  112. 112. C.2 S.5 Investigation into the effect of an environmental disturbance on an ecosystem. http://en.wikipedia.org/wiki/File:NASAburningbrazil.jpg
  113. 113. C.2 S.5 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
  114. 114. 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
  115. 115. C.2 U.4 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
  116. 116. C.2 U.4 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 You don’t have to remember the individual biomes …
  117. 117. 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). … but, you do have to be able to analyse a climatograph
  118. 118. 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).
  119. 119. 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
  120. 120. C.2 A.2 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. Biomass (including phosphates and nitrates) removed from the agricultural ecosystem Phosphates and nitrates removed from the agricultural ecosystem and added to adjacent aquatic ecosystems phosphates added to the agricultural ecosystem phosphates added to the agricultural ecosystem 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.
  121. 121. C.1 Species and Communities Essential idea: Community structure is an emergent property of an ecosystem.
  122. 122. Understandings Statement Guidance C.1 U.1 The distribution of species is affected by limiting factors. C.1 U.2 Community structure can be strongly affected by keystone species. C.1 U.3 Each species plays a unique role within a community because of the unique combination of its spatial habitat and interactions with other species. C.1 U.4 Interactions between species in a community can be classified according to their effect. C.1 U.5 Two species cannot survive indefinitely in the same habitat if their niches are identical.
  123. 123. Applications and Skills Statement Guidance C.1 A.1 Distribution of one animal and one plant species to illustrate limits of tolerance and zones of stress. C.1 A.2 Local examples to illustrate the range of ways in which species can interact within a community. C.1 A.3 The symbiotic relationship between Zooxanthellae and reef-building coral reef species. C.1 S.1 Analysis of a data set that illustrates the distinction between fundamental and realized niche. C.1 S.2 Use of a transect to correlate the distribution of plant or animal species with an abiotic variable.
  124. 124. III. Interactions between species
  125. 125. G 1.2a Explain the factors that affect the distribution of animal species, including temperature, water, breeding sites, food supply and territory.
  126. 126. C.1 U.1 The distribution of species is affected by limiting factors. Example: Territory availability and distribution of animals •Tigers are solitary animals that require large territories, the size of which is determined mostly by the availability of prey. •A tiger’s territory consists of forest, to shelter their prey, and access to water. •Although individuals do not patrol their territories, they visit over a period of days or weeks and mark their territory with urine and feces. http://upload.wikimedia.org/wikipedia/commons/1/16/Indian_Tiger.jpg
  127. 127. Example factors affecting the distribution of species Oak and Maple trees synthesize ‘antifreeze proteins’ which prevents the formation of ice crystals inside cells. This enables these species to survive in temperatures as low as -40 o C. http://upload.wikimedia.org/wikipedia/commons/thumb/f/f7/BrockenSnowedTrees.jpg/1024px-BrockenSnowedTrees.jpg
  128. 128. Migration for food supply in animals “Southern right whales migrate from their Antarctic feeding areas to temperate breeding areas along the costs of Chile and Argentina, southern Africa, and Australia and New Zealand, covering 2,500 km each way. http://www.nature.com/scitable/knowledge/library/animal-migration-13259533 http://upload.wikimedia.org/wikipedia/commons/c/c2/Southern_right_whale6.jpg
  129. 129. G 1.1a Outline the factors that affect the distribution of plant species, including temperature, water, light, soil pH, salinity and mineral nutrients.
  130. 130. G 1.2b Explain the factors that affect the distribution of animal species, including temperature, water, breeding sites, food supply and territory.
  131. 131. G 1.2c Explain the factors that affect the distribution of animal species, including temperature, water, breeding sites, food supply and territory.
  132. 132. G 1.2c Explain the factors that affect the distribution of animal species, including temperature, water, breeding sites, food supply and territory.
  133. 133. C.1 U.1 The distribution of species is affected by limiting factors. Temperature - plant can only survive in a range of temperatures to which they are adapted •Metabolic pathways are controlled by enzymes, which have optimal temperatures, too high and the enzymes will denature •High temperatures increase the rate of evaporation (and hence transpiration) Water availability limits plant growth in most terrestrial ecosystems •Needed to maintain cell turgor •Needed for photosynthesis and respiration to occur •Xerophytes, e.g. Cacti are adapted to low water conditions, hydrophytes, e.g. rice, are adapted to waterlogged soils Light (intensity/wavelength) limits the plants ability to carryout photosynthesis. •Plants that grow in shade (lower light intensity) contain more chlorophyll, they have darker green leaves •Plants, e.g. Kelp (algae), appear brown, not green, and have pigments that are adapted to absorbing the blue wavelengths as red wavelengths do not easily penetrate water Detail on how the factors affecting the distribution of Plant species: n.b. Although it is unlikely you will need to learn all of these details understanding the concepts will enable you to better communicate your examples.
  134. 134. C.1 U.1 The distribution of species is affected by limiting factors. Most plants only tolerate a narrow Soil pH range •pH affects the availability of mineral nutrients, e.g. minerals can either be bound more strongly in the soil or leeched from the soil more easily at different pHs. •pH may affect the decomposition of organic matter, and hence the rate at which nutrients are (re-)cycled and made available to plants Most plants have a low Soil salinity tolerance or can only tolerate a narrow range of salinity •High salinity either makes uptake of water (osmosis) by plants more difficult, or in extremes causes water loss •Halophytes, e.g. Mangrove trees, are adapted to high salinity soils Minerals nutrient availability affects plant fertility, different plants need minerals (e.g. Nitrogen, Phosphorus and Potassium) in different quantities. •Waterlogged soils encourage denitrifying bacteria and lower the nitrogen availability to plants •Weathering of rocks often increases the availability of nutrients in the soil Detail on how the factors affecting the distribution of Plant species: n.b. Although it is unlikely you will need to learn all of these details understanding the concepts will enable you to better communicate your examples.
  135. 135. C.1 U.1 The distribution of species is affected by limiting factors. Temperature must be within a viable range (based on adaptations) for survival – few animals can survive extreme temperature conditions •Body size (specifically SA:Vol ratio) will determine an animal's ability to conserve heat – a large SA:Vol ratio means that heat is easily lost to /gained from the environment •Homeotherms (organisms that maintain a stable internal body temperature) can colonize a wider range of habitats than poikilotherms (internal temperature varies considerably) Water must be available in quantities sufficient for the particular species concerned. •Apart from drinking to maintain cells’ osmotic balance water can be required as a habitat, transport medium, a place to lay eggs, a source of dissolved oxygen, food maybe filtered from water (e.g. corals), and as a coolant. [See 2.2 Water for details] Breeding sites are required for the maintenance of the species. •Breeding sites need to provide protection for eggs, juveniles, and nesting adults. •Sites are often rich in food or other resources necessary for juveniles, and breeding adults •Juveniles may have specialized environmental requirements different from the adults, e.g. dragonfly nymphs live underwater. Detail on how the factors affecting the distribution of animal species: n.b. Although it is unlikely you will need to learn all of these details understanding the concepts will enable you to better communicate your examples.
  136. 136. Food availability is critical in determining the maximum population size. •Animals maybe specialized so that they will only consume a particular species of animal or plant, e.g. the caterpillars of the Small Tortoiseshell butterfly eat only nettle plants. •Seasonal or geographical variation in food directly affects abundance of the population. Territory – not all animals are territorial, but those that may do so to attracting mates, rearing young, forage for food or to avoid predators. •Animals may mark territories, e.g. by urinating or marking trees •Territories can be established by individuals, breeding pairs or groups •Territories maybe temporary (e.g. just for the duration of breeding cycle) or permanent •Establishment of territories can lead to intra-specific (within species) or inter-specific (between species) competition Detail on how the factors affecting the distribution of animal species: n.b. Although it is unlikely you will need to learn all of these details understanding the concepts will enable you to better communicate your examples. C.1 U.1 The distribution of species is affected by limiting factors.
  137. 137. C.1 A.1 Distribution of one animal and one plant species to illustrate limits of tolerance and zones of stress. Black mangrove (Avicennia germinans) is a very widespread mangrove tree. It can survive and grow in a wide range of salinity levels from 0 to 96 part per thousand (ppt). Greatest growth rates occur at salinity levels of 24 and 48 ppt, the optimal zone, outside of this range the Black Mangrove trees experience the zones of stress. http://commons.wikimedia.org/wiki/File:Avicennia_germinans.jpg
  138. 138. Interactions Between SpeciesInteractions Between Species • CompetitionCompetition is when two species need the same resource such as a breeding site or food. It will result in the removal of one of the species. There are two major types of competition
  139. 139. I. Intraspecific competition • A form of competition in which individuals of the same species compete for the same resource in an ecosystem. This tends to have a stabilizing influence on population size. If the population gets too big, intraspecific population increases, so the population falls again.
  140. 140. II. Interspecific competition • A form of competition in which individuals of different species compete for the same resource in an ecosystem.
  141. 141. Types of Species Interactions • An ecological community is a group of actually or potentially interacting species, living in the same place • A community is bound together by the network of influences that species have on one another. • There are four main classes of two-way interactions, and many possible pathways of indirect interaction.
  142. 142. Type of interaction Sign Effects mutualism +/+ both species benefit commensalism +/0 one species benefits, one is unaffected competition-/- each is neg. affected predation +/- each is pos. affected (includes herbivory, parasitism) Types of Species Interactions
  143. 143. • A. Predation is the relation between the predator, which is usually bigger, and the prey, which is usually smaller. An example would be a fox and a rabbit Anteater Ant
  144. 144. • B. Parasitism is the relation between the host and the parasite. The parasite causes harm to the host to get food and other resources. Examples of parasites are some viruses, fungi, worms, bacteria, and protazoa. Bass Lamprey
  145. 145. C. MutualismMutualism is where two members of different species benefit and neither suffers. Examples include rumen termite/protazoa that digest cellulose
  146. 146. D. Herbivory • Primary Consumers that feed only on plant material. Considered predators of plants. Ladybug and a caterpillar are examples of herbivories
  147. 147. Niche ConceptNiche Concept • A population’s niche refers to its role in its ecosystem. • This usually means its feeding role in the food chain. • A description of a niche should really include many different aspects such as its food, its habitat, its reproduction method and the organisms it interacts with. • Identifying the different niches in an ecosystem helps us to understand the interactions between populations. Members of the same population always have the same niche, and will be well-adapted to that niche.
  148. 148. Competitive Exclusion • No two species in a community can occupy the same niche Species A niche Species B niche
  149. 149. Principle of Competitive ExclusionPrinciple of Competitive Exclusion • Where two species need the same resources and will compete until one species is removed. • One would be more capable of gathering more resources or reproducing more rapidly until the other was run out of existence. • Experiments with paramecium populations in the lab of Ecologist G.F. Gause demonstrated this concept scientifically.
  150. 150. The niche concept was investigated in some classic experiments in the 1930s by Gause. He used flasks of different species of the protozoan Paramecium, which eats bacteria and yeast. • Conclusion: These two species of Paramecium share the same niche, so they compete. P. aurelia is faster-growing, so it out-competes P. caudatum. Experiment 1
  151. 151. P. aureliaP. aurelia P. caudatumP. caudatum
  152. 152. • In the second experiment he took P. caudatum and had it compete with a second type of Paramecia. It is important to understand the distribution in experiment 2. • P. caudatum lives in the upper part of the flask because only it is adapted to that niche and it has no competition. In the lower part of the flask both species could survive, but only P. bursaria is found because it out-competes P. caudatum. Experiment 2Experiment 2
  153. 153. Experiment 2 • Conclusion: These two species of Paramecium have slightly different niches, so they don't compete and can coexist.
  154. 154. Fundamental vs. Realized Niche • Fundamental Niche: the potential mode of existence, given the adaptation of the species • Realized Niche: the actual mode of existence, which results from its adaptations and competition with other species Competition II Competition I Com petiti on III Realized Niche
  155. 155. Keystone Species Concept •In ecological communities there are little players and big players. The biggest players of all are referred to as keystone species. •A keystone species may be defined as one whose presence/ absence, or increase/decrease in abundance, strongly affects other species in the community. •Evidence usually comes from addition or removal experiments. Example: Kelp forests • Can grow two feet per day • Require cool water • Host many species – high biodiversity • Fight beach erosion Kelp forests threatened by • Sea urchins • Pollution • Rising ocean temperatures Removal of the keystone in the arch will cause the structure to collapse. C.1 U.2 Community structure can be strongly affected by keystone species.
  156. 156. Southern Sea Otter Keystone Species
  157. 157. Kelp forests
  158. 158. sea urchins
  159. 159. Endangered Southern Sea Otter Keystone species: plays a role affecting many other organisms in ecosystem specifically sea otters eat sea urchins that would otherwise destroy kelp forests • Kelp forests provide essential habitat for entire ecosystem •~16,000 around 1900 •Hunted for fur and because considered competition for abalone and shellfish •1938-2008: increase from 50 to ~2760 •1977: declared an endangered species
  160. 160. C.1 U.2 Community structure can be strongly affected by keystone species. Sea star (Pisaster orchraceus) is a keystone species in the rocky intertidal habitat along the California. They have a profound impact on mussel bed population, thereby reducing the health of the intertidal environment https://sfmsi.files.wordpress.com/2014/03/2010-040.jpg
  161. 161. C.1 U.2 Community structure can be strongly affected by keystone species. Keystone modifier species, such as the North American beaver (Casor candensis), determine the prevalence and activities of many other species by dramatically altering the environment. http://www.joshnagel.com/wp-content/uploads/2012/11/beaver-.jpg
  162. 162. C.1 U.2 Community structure can be strongly affected by keystone species. Species like the Saguaro cactus (Carnegiea gigantea) in desert environments and palm and fig trees in tropical forests are called keystone host species because they provide habitat for a variety of other species. Keystone prey are species that can maintain their numbers despite being preyed upon, therefore controlling the density of a predator. http://www.nature.com/scitable/knowledge/library/keystone-species-15786127 http://commons.wikimedia.org/wiki/File:Carnegiea_gigantea_Saguaro_NP_1.jpg
  163. 163. C.5 Population ecology (AHL) Essential idea: Dynamic biological processes impact population density and population growth. Fish populations, such as the schooling Anchovies (right) being hunted by the Dolphin (left) are an excellent example of how dynamic populations are. http://i.dailymail.co.uk/i/pix/2015/03/28/15/2711793A00000578-0-image-m-103_1427557828184.jpg
  164. 164. Understandings, Applications and Skills Statement Guidance C.5 U.1 Sampling techniques are used to estimate population size.   C.5 U.2 The exponential growth pattern occurs in an ideal, unlimited environment.   C.5 U.3 Population growth slows as a population reaches the carrying capacity of the environment.   C.5 U.4 The phases shown in the sigmoid curve can be explained by relative rates of natality, mortality, immigration and emigration.   C.5 U.5 Limiting factors can be top down or bottom up.   C.5 A.1 Evaluating the methods used to estimate the size of commercial stock of marine resources.   C.5 A.2 Use of the capture-mark-release-recapture method to estimate the population size of an animal species.   C.5 A.3 Discussion of the effect of natality, mortality, immigration and emigration on population size.   C.5 A.4 Analysis of the effect of population size, age and reproductive status on sustainable fishing practices.   C.5 A.5 Bottom-up control of algal blooms by shortage of nutrients and top-down control by herbivory.   C.5 S.1 Modelling the growth curve using a simple organism such as yeast or species of Lemna.  
  165. 165. Populations • The total number of individuals of a species in a given area. Populations are affected by four main factors
  166. 166. Four Factors Influence the Size of a Population: Natality: Birth Rate (offspring produced and added to population)
  167. 167. Mortality:  Death Rate (individuals that die)
  168. 168. Immigration:Immigration: Movement of membersMovement of members of the species into the areaof the species into the area
  169. 169. Emigration:Emigration: Movement of members of the species outMovement of members of the species out of area to live elsewhere.of area to live elsewhere.
  170. 170. Population Changes
  171. 171. 3 Phases: 1. Exponential growth Phase 2. Transitional Phase 3. Plateau Phase Limited Growth Sigmoid (S-Shaped)Sigmoid (S-Shaped)
  172. 172. 1. Exponential Growth Phase • Population increases exponentially. • Resources are abundant. • Predators and disease are rare.
  173. 173. 2. Transitional Phase • As a result of intra-specific competition for food, shelter, nesting space, etc., and the build up of waste. • The growth rate slows down. Birth rates decline and death rate increases
  174. 174. 3. Plateau Phase • Natality and mortality are equal so population size is constant. • When the number of individuals in the population have reached the maximum which can be supported by the environment. The number is called the CARRYING CAPACITY
  175. 175. Population size oscillates around the carrying capacity (K) Time N K overshoot oscillations
  176. 176. • Density Dependent Limits  Food  Water  Shelter  Disease • Density Independent Limits  Natural Disasters  Humans (logging, mining, farming) Water and shelter are critical limiting factors in the desert. Fire is an example of a Density independent Limiting factor. Limits on Population Growth
  177. 177. C.5 U.2 The exponential growth pattern occurs in an ideal, unlimited environment. This graph shows the explosion of human population over the last 10,000 years along with some relevant historical events.
  178. 178. How has the human population grown so quickly? • When I graduated high school in 1975 there were 4 billion people. • Today there are almost 7 billion people
  179. 179. If we look back, to about 5 million years ago. We were hunter-gathers, with about 1 million humans
  180. 180. Neolithic Period (6000 B.C.) No longer living in a natural settingNo longer living in a natural setting. We moved to an agrarian society, increased food availability. 100 million people
  181. 181. Common area 2000 years ago 300 million people
  182. 182. 1800-2000? • From 1 billion to 6 billion? How???
  183. 183. Steam engineSteam engine 1800’s the population increases to 1 billion people Humans take over the carbon cycle (burning fossil fuel), leading to an increase in population
  184. 184. London between 1800 to 1880 • 1800 pop. 1 million • 1880 pop. 4.5 million • Improvements in medicine and public health
  185. 185. Life Expectance • Neolithic it was 20 • 1900 it was 30 • 1950 it was 47 • Current world average is 70
  186. 186. 1908 News flash! Humans have taken control of the Nitrogen Cycle • Up until 1908 farms were dependent on organic sources for nitrogen (manure) • Haber figured out how to convert N2 into NH3 and then into NH4 + of NO3 - Commercial fertilizers are Born! Human population grows! Fritz Haber
  187. 187. 1944 Plant Breeding • Improves yields • Disease resistance improvements • Less day-length sensitive • Improve sharing of ideas on plant breeding Human population grows!
  188. 188. C.5 U.2 The exponential growth pattern occurs in an ideal, unlimited environment. Examples of exponential population growth http://www.nature.com/scitable/knowledge/library/an-introduction-to-population-growth-84225544 Throughout the 1800's, hunters decimated the American Plains bison populations, and by 1889, only about one thousand bison remained. The US government, along with private landowners, established protected herds in the late 1800's and early 1900's. The herds started small, but with plentiful resources and few predators, they grew quickly. The bison population in northern Yellowstone National Park increased from 21 bison in 1902 to 250 in only 13 years.
  189. 189. C.5 U.4 The phases shown in the sigmoid curve can be explained by relative rates of natality, mortality, immigration and emigration. Limiting factors are environmental factors that controls the maximum rate at which a process, e.g. population growth, can occur. • build-up of toxic by products of metabolism • Injury • Senescence (death from age related illness)
  190. 190. All examples of competition for resources • Injury • Senescence (death from age related illness) • build-up of toxic by products of metabolism
  191. 191. • build-up of toxic by products of metabolism The effect of these limiting factors increases as the population increases. These factors are described as being density dependent limiting factors. • Injury • Senescence (death from age related illness)
  192. 192. • build-up of toxic by products of metabolism The this limiting factor does not increases as the population increases. This factor is described as being a density independent limiting factor. • Injury • Senescence (death from age related illness) Examples include: •Climate / weather •Availability of light (for plants) •Natural disasters such as volcanic eruptions and fire
  193. 193. C.5 U.5 Limiting factors can be top down or bottom up. A limiting factor is an environmental selection pressure that limits population growth. There are two categories of limiting factor: Top-down factors are pressures applied by other organisms at higher trophic levels. Bottom-up factors are those that involve resources or lower tropic levels. A keystone species exerts top-down influence on its community by preventing species at lower trophic levels from monopolizing critical resources, such as competition for space or food sources. http://commons.wikimedia.org/wiki/File:Tierpark_Sababurg_Wolf.jpg http://commons.wikimedia.org/wiki/File:Green_Sea_Turtle_grazing_seagrass.jpg
  194. 194. C.5 A.5 Bottom-up control of algal blooms by shortage of nutrients and top-down control by herbivory. An algal bloom is a rapid increase or accumulation in the population of algae (typically microscopic) in a water system. http://commons.wikimedia.org/wiki/File:Mar%C3%A9_vermelha.JPG
  195. 195. C.5 A.5 Bottom-up control of algal blooms by shortage of nutrients and top-down control by herbivory. •The water around coral-reef ecosystems is generally nutrient-poor. •Essential nutrients in these areas are e.g. magnesium is needed to make chlorophyll are in short supply •Algae depend on photosynthesis for nutrition and photosynthesis depends on proteins. Proteins such as chlorophyll in short supply the rate of photosynthesis is limited. Nutrients are therefore a bottom-up limiting factor to growth. •Free-living algae blooms can disrupt coral reef communities by blocking sunlight and preventing photosynthesis in the symbiotic zooxanthellae. With Nutrient enrichment through human activity (fish farming, fertilizer or sewage outflows directly or from nearby rivers) can cause known as eutrophication – algal populations increase rapidly (blooms) due to the removal of nutrients as a limiting factor. https://pointreyesscience.files.wordpres s.com/2011/09/thumbnail-for-web.jpg
  196. 196. C.5 A.5 Bottom-up control of algal blooms by shortage of nutrients and top-down control by herbivory. • Parrotfish are herbivores that graze on free-living algae at a lower trophic level. This is an example of top-down control of algae. • Fishing practices which remove herbivorous fish from coral reefs can lessen the predation of algae. • If herbivorous fish numbers decline this can lead to algal blooms http://upload.wikimedia.org/wikipedia/commons/f/f3/Stoplight-parrotfish.jpg
  197. 197. C.5 S.1 Modelling the growth curve using a simple organism such as yeast or species of Lemna. http://commons.wikimedia.org/wiki/File:Lemna_minor_Prague_2012_1.jpg Duckweed (Lemna sp.) is a good model organism for measuring sigmoidal population growth
  198. 198. • Place a small number of plants in a container, e.g. a plastic cup • Count the number of fronds (leaves) every day until the surface of the container is covered, i.e. the population has ceased to increase. • Plot your results – you should obtain a sigmoidal curve • Your investigation can be extended by considering different independent variables e.g. nutrient availability and the surface area of the container. In the absent of equipment using one or more of the following resources to model population growth: • Yeast Population Growth lab and simulation by i-Biology ( http://www.slideshare.net/gurustip/population-growth-9457952) • Bunny population growth by PhET ( http://phet.colorado.edu/files/activities/3896/04.02 - CW - bunny simulation - 2014-07-30 - ) C.5 S.1 Modelling the growth curve using a simple organism such as yeast or species of Lemna.
  199. 199. Why monitor populationsWhy monitor populations?? • Determine current status of a population • Determine habitat requirements of a species • Evaluate effects of management *Complete “census” of natural populations is often very difficult! Population Sampling C.5 U.1 Sampling techniques are used to estimate population size.
  200. 200. Population vs.Population vs. SampleSample SampleTrue Population
  201. 201. RANDOM SAMPLING • A sampling procedure that assures that each element in the population has an equal chance of being selected • Sampled population should be representative of target population
  202. 202. Sample Methods • Quadrat • Mark-Recapture • There are MANY more…
  203. 203. Quadrat Sampling • A square frame is placed in a habitat • All the individuals in the quadrat are counted • The process is repeated until the sample size is large enough
  204. 204. • Useful for small organisms or for organisms that do not move
  205. 205. Converting a population study into a graph
  206. 206. MARK-RECAPTURE (Lincoln Index) • Capture and mark known number of individuals • 2nd round of captures soon after Time for mixing, but not mortality • Fraction of marked individuals in recapture sample is estimate of the proportion of population marked in first capture
  207. 207. Marking methods • Paint or dye • Color band  birds • Unique markings  Large mammals; keep photo record • Toe clipping  Reptiles, amphibians, rodents • Radio Collars • Micro chips (NPS 2000)
  208. 208. Lincoln Index • Using mark-recapture sampling to estimate animal populations Population Size P =(# initially marked) x (total 2nd catch) (# of marked recaptures) Or N1 x N2 N3
  209. 209. Mark Recapture Lincoln Index N1 = 4 N2 = 5 N3 = 2 N1 = first capture N2 = second capture N3 = #’s of marked in           second capture
  210. 210. Survey 1: N1= 12 Survey 2: N2 = 15 N3 = 4
  211. 211. • You capture and mark 150 fish in a lake. (This must be a random, representative sample.) • You release them back into the lake, allowing enough time for them to remix with the population. • You trap another 220 fish, of which 25 are recaptures (i.e., marked from the initial trapping. • What is your estimate of the total population of fish in the lake? Example:
  212. 212. • N1 = 150 • N2 = 220 • N3 = 25 • P = [(220)(150)] / 25 = 1320 FISH Example:
  213. 213. Example: • Use the Lincoln Index to monitor this mountain gorilla population over time
  214. 214. Human Effect on the World Fish PopulationHuman Effect on the World Fish Population • Overexploitation of species affects the loss of genetic diversity and the loss in the relative species abundance of both individual and/or groups of interacting species. Overexploitation may include over fishing and over harvesting • Historically, humans have fished the oceans, which never seemed to pose a problem due to their abundant resources. Gear (fish trap, gill nets, electro- fishing) and vessel efficiency modifications have caused a significant decrease in fish populations.
  215. 215. A case study: The Peruvian Anchovy (Engraulis ringens) Universidad de La Serena
  216. 216. The Peruvian Anchovy • This is a small (12-20cm), short-lived species maturing in 1 year • Anchovy live in the surface waters in large shoals off the coast of Peru and northern Chile • Here there are cold currents up-welling from the sea bed bringing nutrients for phytoplankton • Plankton is at the base of the food chain.
  217. 217. The Peruvian Anchovy • The harvest of this fish doubled every year from 1955 to 1961 • Experts estimated the maximum harvestable yield (MSY) at 10 to 11 million tonnes per year • Through the 1960s the harvest was about this level • The biggest fishing harvest in the world • Some of the anchovy were used for human food • But a lot was ground into fishmeal for animal feed
  218. 218. The collapse of the anchovy fishery • In 1972 there was an El Niño event that brought warm tropical water into the area • The up-welling stopped, • the phytoplankton growth decreased • the anchovy numbers fell and concentrated further south • The concentrated shoals of anchovy were easy targets for fishing boat eager to recuperate their harvest • The political will was not there to impose reduced quotas • Larger catches were made • No young fish were entering the population (no recruitment) • No reproduction was taking place • The fish stocks collapsed and did not recover
  219. 219. Population dynamics of fisheries • A fishery is an area with an associated fish population which is harvested for its commercial or recreational value. Fisheries can be wild or farmed. • Population dynamics describes the ways in which a given population grows and shrinks over time, as controlled by birth, death, and emigration or immigration. It is the basis for understanding changing fishery patterns and issues such as habitat destruction, predation and optimal harvesting rates. • The population dynamics of fisheries is used by fisheries scientists to determine sustainable yields
  220. 220. Sampling method Situation in which the method is used Usage and limitations Random sampling Not used. Ineffective as fish are too mobile. Capture-mark- release-recapture Fish are temporarily  stunned with electric  shocks and then  counted Used in lakes and rivers, but  recapture numbers are too small  to be useful in open waters such  as oceans. Echo sounders Can be used to  estimate the size of  fish shoals Only useful for schooling fish  species Fish catches Age structure of  landed fish can be  used to estimate  population size. Violators of fishing regulations  designed to control the age of fish  landed often do not report what  they land or they dump the  restricted fish causing a bias in  the estimates. Estimating Fish populations
  221. 221. Sampling method Situation in which the method is used Usage and limitations Random sampling Not used. Ineffective as fish are too mobile. Capture-mark- release-recapture Fish are temporarily  stunned with electric  shocks and then  counted Used in lakes and rivers, but  recapture numbers are too small  to be useful in open waters such  as oceans. Echo sounders Can be used to  estimate the size of  fish shoals Only useful for schooling fish  species Fish catches Age structure of  landed fish can be  used to estimate  population size. Violators of fishing regulations  designed to control the age of fish  landed often do not report what  they land or they dump the  restricted fish causing a bias in  the estimates. Estimating Fish populations C.5.A1 Evaluating the methods used to estimate the size of commercial stock of marine resources. • Fish are very mobile – they pursue what is frequently a mobile food supply. • They often school so are unevenly distributed. … so how can we count/estimate their numbers? If we know how big fish population are we can fish sustainably, but ….
  222. 222. Maximum Sustainable Yield (MSY) Based upon: 1. the harvest rate 2. the recruitment rate of new (young) fish into the population • a population can be harvested at the point in their population growth rate where it is highest (the exponential phase) • Harvesting (output) balances recruitment (input) • Fixed fishing quotas will produce a constant harvesting rate (i.e. a constant number of individuals fished in a given period of time) C.5 A.4 Analysis of the effect of population size, age and reproductive status on sustainable fishing practices.
  223. 223. Maximum Sustainable Yield (MSY)
  224. 224. Maximum Sustainable Yield • The Largest possible catch without adversely affecting the ability of the population to recover.
  225. 225. Problems with MSY Age structure: If all the age groups are harvested recruitment of young fish into the reproductive group will be reduced. The answer is to use a net with a big enough mesh size that lets the young fish escape Age and sustainable fishing • If a population is growing, then the relative number of younger fish will be higher (there are many potential breeding fish for the future). • If a population is in decline, then the proportion of older fish will be higher (older fish have a higher mortality and are unlikely to be as productive in breeding).
  226. 226. Problems with MSY Limiting factors: If the limiting factors in the environment change so does the population growth rate • Limiting factors set the carrying capacity (K) of an environment • Increasing limiting factors will cause K to drop • Fixed quotas cannot cope with this • Data: For MSY to work accurate data in fish populations is needed (population size, age structure, recruitment rates) • Usually these are not well known
  227. 227. What is required? • Nets with bigger mesh size • Regulated fishing methods • More data on fish populations (e.g. by fish tagging investigations – mark and recapture) • Constant monitoring to observe changes in environmental factors (e.g.El Niño events • Policing of fishing industry – respect of quotas • International agreements • Greater exploitation of fish farming • But this is not without its own problems (space, diseases and pollution are all associated with intensive fish culture)
  228. 228. C.1 A.1 Distribution of one animal and one plant species to illustrate limits of tolerance and zones of stress. Shelford's law of tolerance is a useful tool to understand the relative abundance of a species and hence predict community structure. It plots the range of a biotic or abiotic factor that is tolerated by a species,. Because their is variability but within a population the limits of tolerance and where the zones of stress start is not always easy to measure. http://www.anselm.edu/homepage/bpenney/teaching/BI320/elements/Krohne_Shelfords.jpg
  229. 229. 4.4 Climate change Essential idea: Essential idea: Concentrations of gases in the atmosphere affect climates experienced at the Earth’s surface.
  230. 230. Understandings, Applications and Skills Statement Guidance 4.4 U.1 Carbon dioxide and water vapour are the most significant greenhouse gases. 4.4 U.2 Other gases including methane and nitrogen oxides have less impact. The harmful consequences of ozone depletion do not need to be discussed and it should be made clear that ozone depletion is not the cause of the enhanced greenhouse effect. 4.4 U.3 The impact of a gas depends on its ability to absorb long wave radiation as well as on its concentration in the atmosphere. Carbon dioxide, methane and water vapour should be included in discussions. 4.4 U.4 The warmed Earth emits longer wavelength radiation (heat). 4.4 U.5 Longer wave radiation is absorbed by greenhouse gases that retain the heat in the atmosphere. 4.4 U.6 Global temperatures and climate patterns are influenced by concentrations of greenhouse gases. 4.4 U.7 There is a correlation between rising atmospheric concentrations of carbon dioxide since the start of the industrial revolution 200 years ago and average global temperatures. 4.4 U.8 Recent increases in atmospheric carbon dioxide are largely due to increases in the combustion of fossilized organic matter. 4.4 A.1 Threats to coral reefs from increasing concentrations of dissolved carbon dioxide. 4.4 A.2 Correlations between global temperatures and carbon dioxide concentrations on Earth. 4.4 A.3 Evaluating claims that human activities are not causing climate change.
  231. 231. C.3 Impacts of humans on ecosystems Essential idea: Human activities impact on ecosystem function. Rhododendrons are beautiful eye catching shrubs that grow in many gardens throughout the world. Rhododendrons are native to alpine regions in Asia. Since their introduction to non-native regions they become an invasive species causing major disruptions to ecosystems, e.g. in Western Europe they have out-competed local woodland plants causing major reductions in local biodiversity. http://www.gardeningknowhow.com/wp-content/uploads/2012/07/rhododendron1.jpg By Chris Paine https://bioknowledgy.weebly.com/ 
  232. 232. Understandings, Applications and Skills Statement Guidance C.3 U.1 Introduced alien species can escape into local ecosystems and become invasive. C.3 U.2 Competitive exclusion and the absence of predators can lead to reduction in the numbers of endemic species when alien species become invasive. C.3 U.3 Pollutants become concentrated in the tissues of organisms at higher trophic levels by biomagnification. C.3 U.4 Macroplastic and microplastic debris has accumulated in marine environments. C.3 A.1 Study of the introduction of cane toads in Australia and one other local example of the introduction of an alien species. C.3 A.2 Discussion of the trade-off between control of the malarial parasite and DDT pollution. C.3 A.3 Case study of the impact of marine plastic debris on Laysan albatrosses and one other named species. C.3 S.1 Analysis of data illustrating the causes and consequences of biomagnification. C.3 S.2 Evaluation of eradication programs and biological control as measures to reduce the impact of alien species.
  233. 233. C.4 Conservation of biodiversity Essential idea: Entire communities need to be conserved in order to preserve biodiversity. The tremendous biodiversity of the amazon rainforest can only be conserved in situ it is simply too complex to recreate or conserve in part. Many species rely on a complex web of interactions with other species that they share the environment with, if the balance is disturbed then species will be lost and the community will become less diverse. http://3.bp.blogspot.com/-p19vnPIw5WY/Tla1Xp07zQI/AAAAAAAAAkE/Ot-Lo1ZwKOQ/s1600/amazon.png By Chris Paine https://bioknowledgy.weebly.com/
  234. 234. Understandings, Applications and Skills Statement Guidance C.4 U.1 An indicator species is an organism used to assess a specific environmental condition. C.4 U.2 Relative numbers of indicator species can be used to calculate the value of a biotic index. C.4 U.3 In situ conservation may require active management of nature reserves or national parks. C.4 U.4 Ex situ conservation is the preservation of species outside their natural habitats. C.4 U.5 Biogeographic factors affect species diversity. C.4 U.6 Richness and evenness are components of biodiversity. C.4 A.1 Case study of the captive breeding and reintroduction of an endangered animal species. C.4 A.2 Analysis of the impact of biogeographic factors on diversity limited to island size and edge effects. C.4 S.1 Analysis of the biodiversity of two local communities using Simpson's reciprocal index of diversity. The formula for Simpson’s reciprocal index should be known by students.
  235. 235. 4 Serious Environmental Issues 1. Reduction in Biodiversity 2. Biomagnification 3. Plastics 4. Climate Change
  236. 236. 1. Reduction in Biodiversity1. Reduction in Biodiversity
  237. 237. Simpson diversity indexSimpson diversity index The index of diversity is used as a measure of the range and numbers of species in an area. It usually takes into account the number of species present and the number of individuals of each species. It can be calculated by the following formulae: D = N(N-1) ∑n(n-1) D= Diversity index n = number of individuals of a each species found in an area. N = total # of organisms of all species found in an area. The Simpson diversity index is a measure of species richness. A high value of D suggests a stable and ancient site.
  238. 238. Example: Crested newt 8 Stickleback 20 Leech 15 Great pond snail 20 Dragon fly larva 2 Stonefly larva 10 Water boatman 6 Caddisfly larva 30 N = 111 N(N-1) = 111(111-1) = 12,210 ∑n(n-1) = (8x7) + (20x19) + (20x19) + (15x14) + (20x19) + (2x1) + (10x9) + (6x5) + ( 30x29) = 2018 D = 12,210 =6.05
  239. 239. Example: In another pond there were: Crested newt 45 Stickleback 4 Leech 18 Great pond snail 10 N=77 D = 2.6 Comparing both indices, 6.05 is an indicator of greater diversity.  The higher number indicates greater diversity
  240. 240. Abiotic factors for Biodiversity In extreme environmentsIn extreme environments the diversity of organisms is usually low (has a low index number). This may result in an unstable ecosystem in which populations are usually dominated by abiotic factors. The abiotic factor(s) are extreme and few species have adaptations allowing them to survive. Therefore food webs are relatively simple, with few food chains, or connections between them – because few producers survive.
  241. 241. In less hostile environmentsIn less hostile environments The diversity of organisms is usually high (high index number). This may result in a stable ecosystem in are usually dominated by biotic factors, and abiotic factors are not extreme. Many species have adaptations that allow them to survive, including many plants/producers. Therefore food webs are complex, with many inter-connected food chains. Abiotic factors for Biodiversity
  242. 242. The use of biotic indicator for monitoring environmental change • Are a good indicator of change • Highly sensitive to environmental changes • Highly sensitive to population increases or decreases. • The numbers of organisms in the indicator species populations, can be measured directly so they are easy to keep track of larger changes that maybe occurring.
  243. 243. American DipperAmerican Dipper •Feeds on aquatic insects and their larvae, including dragonfly, nymphs and caddisfly larvae. It may also take tiny fish. •The presence of this indicator speciesindicator species shows good water quality; it has vanished from some locations due to pollutionpollution or increased silt load in streams
  244. 244. Lichens (Air pollution) •Lichens are formed from a symbiotic relationship between a fungus and an alga. •They often grow on exposed rocks and trees, and need to be efficient at absorbing water. •Air pollutants dissolved in rainwater, especially sulphur dioxide, can damage lichens and prevent them from growing. •By looking at the species present in a particular area, scientists can assess the level of air pollution.
  245. 245. Humans Contribute to Declining Biological Diversity Introduction of exotic species harms native species due to competition, predation, or interbreeding • The zebra mussel native to Russia, introduced into the American Great Lakes by tanker ships. These mussels not only cause billions of dollars of damage but have displaced the native clams and mussels Invasive of Alien Species
  246. 246. REMEMBER GAUSE… Competitive exclusion principle: Two species cannot occupy the same niche in a community, as there will be competition for the same resources. When one species has even the slightest advantage or edge over another then the one with the advantage will dominate. Advantages can come in different forms, 5 examples of advantages between species occupying similar niches are: 1.High reproductive rate 2.Larger size / more aggressive 3.Faster / more efficient forager 4.Absence of predator Invasive species often lack a predator, due to being in a foreign environment. In the case of invasive plants this can mean an absence of suitable herbivores. C.3 U.2 Competitive exclusion and the absence of predators can lead to reduction in the numbers of endemic species when alien species become invasive.
  247. 247. Asian long-horned beetleAsian long-horned beetle • Discovered in the US in 1996 on several hardwood trees (destroying the hardwood tree) in Brooklyn, NY. The wood-boring beetle is believed to have been introduced on wood pallets and wood packing material in cargo shipments from Asia. The infestation quickly spread to Long Island, Manhattan and Queens
  248. 248. Phragmites • A wetland plant species found in every U.S. state (crowding out the native species). • It can grow up to 6 meters high in dense stands and is long lived. The species is invasive particularly in the eastern states along the Atlantic Coast and increasingly across much of the Midwest and in parts of the Pacific Northwest.
  249. 249. Biological ControlBiological Control • The use of an organism (introduced) to control another organism • Risks: introduced organism may not behave as expected (Cane Toads) • Benefits: introduced organism may be the only control mechanism flexible enough to be effective against another invasive with no predators Examples • Purple loosestrife (invasive in US and Canada) – controlled by 2 species of beetles (Gallerucella)

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