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512064026670Subtopics:4.1 Species, Communities & Ecosystems4.2 Energy Flow4.3 Carbon Cycling2.8 Cellular Respiration2.9 Photosynthesis4.4 Climate Change00Subtopics:4.1 Species, Communities & Ecosystems4.2 Energy Flow4.3 Carbon Cycling2.8 Cellular Respiration2.9 Photosynthesis4.4 Climate Change-1841515240Unit 4: Ecology & Cellular Energy00Unit 4: Ecology & Cellular EnergyEQs & TOK: The precautionary principle is meant to guide decision-making in conditions where a lack of certainty exists. Is certainty ever possible in the natural sciences? Evolutionary history is an especially challenging area of science because experiments cannot be performed to establish past events or their causes. There are nonetheless scientific methods of establishing beyond reasonable doubt what happened in some cases. How do these methods compare to those used by historians to reconstruct the past?Major Understandings, Applications & Skills (Study Guide):Species, Communities & Ecosystems (4.1)Proficient:Species are groups of organisms that can potentially interbreed to produce fertile offspring.Members of a species may be reproductively isolated in separate populations.Species have either an autotrophic or heterotrophic method of nutrition (a few species have both methods).Consumers are heterotrophs that feed on living organisms by ingestion.Detritivores are heterotrophs that obtain organic nutrients from detritus by internal digestion.Saprotrophs are heterotrophs that obtain organic nutrients from dead organisms by external digestion.A community is formed by populations of different species living together and interacting with each other.A community forms an ecosystem by its interactions with the abiotic environment.Autotrophs obtain inorganic nutrients from the abiotic environment.Exceeds:The supply of inorganic nutrients is maintained by nutrient cycling.Ecosystems have the potential to be sustainable over long periods of time.Skill: Classifying species as autotrophs, consumers, detritivores or or saprotrophs from a knowledge of their mode of nutrition.Skill: Setting up sealed mesocosms between two species to try to establish sustainability (Practical 5)Skill: Testing for association between two species using the using the chi-squared test with data obtained by quadrat sampling.Skill: Recognizing and interpreting statistical significance.Energy Flow (4.2)Proficient:Most ecosystems rely on a supply of energy from sunlight.Light energy is converted to chemical energy in carbon compounds by photosynthesis.Chemical energy is carbon compounds flows through food chains by means of feeding.Energy released from carbon compounds by respiration is used in living organisms and converted to heat.Living organisms cannot convert heat to other forms of energy.Heat is lost from ecosystems.Exceeds:Energy losses between trophic levels restrict the length of food chains and the biomass of higher trophic levels.Skill: Quantitative representations of energy flow using pyramids of energy.Carbon Cycling (4.3)Proficient:Autotrophs convert carbon dioxide into carbohydrates and other carbon compounds.In aquatic ecosystems carbon is present as dissolved carbon dioxide and hydrogen carbonate ions.Carbon dioxide diffuses from the atmosphere or water into autotrophs.Carbon dioxide is produced by respiration and diffuses out of organisms into water or the atmosphere.Methane is produced from organic matter in anaerobic conditions by methanogenic archaeans and some diffuses into the atmosphere or accumulates in the ground.Methane is oxidized to carbon dioxide and water in the atmosphere.Peat forms when organic matter is not fully decomposed because of acidic and/or anaerobic conditions in waterlogged soils.Partially decomposed organic matter from past geological eras was converted either into oil and gas that accumulate in porous rocks.Carbon dioxide is produced by the combustion of biomass and fossilized organic matter.Animals such as reef-building corals and mollusca have hard parts that are composed of calcium carbonate and can become fossilized limestone.Exceeds:Application: Estimation of carbon fluxes due to processes in the in the carbon cycle.Application: Analysis of data from air monitoring stations to explain annual fluctuations.Skill: Construct a diagram of the carbon cycle.Cell Respiration (2.8)Proficient:Cell respiration is the controlled release of energy from organic compounds to produce ATPATP from cell respiration is immediately available as a source of energy in the cellAnaerobic cell respiration gives a small yield of ATP from glucoseAerobic cell respiration requires oxygen and give a lard yield of ATP from glucoseExceeds:Application: Use of Anaerobic cell respiration in yeasts to produce ethanol and carbon dioxide in baking.Application: Lactate production in humans when anaerobic respiration is used to maximize the power of muscle contractions.Skill: Analysis of results from experiments involving measurement of respiration rates in germinating seeds or invertebrates using respirometer.Photosynthesis (2.9)Proficient:Photosynthesis is the production of carbon compounds in cells using light energyVisible light has a range of wavelengths with violet the shortest wavelength and red the longestChlorophyll absorbs red and blue light most effectively and reflects green light more than other colorsOxygen is produced in photosynthesis from the photolysis of waterEnergy is needed to produce carbohydrates and other carbon compounds from carbon dioxideTemperature, light intensity and carbon dioxide concentration are possible limiting factors on the rate of photosynthesisExceeds:Application: Change’s to the Earth’s atmosphere, oceans and rock deposition due to photosynthesis.Skill: Drawing an absorption spectrum for chlorophyll and an action spectrum for photosynthesis.Skill: Design of experiments to investigate the effect of limiting factors on photosynthesis.Skill: Separation of photosynthetic pigments by chromatography (Practical 4)Climate Change (4.4)Proficient:Carbon dioxide and water vapor are the most significant greenhouse gases.Other gases including methane and nitrogen oxides have less impact.The impact of a gas depends on its ability to absorb long wave radiation as well as on its concentration in the atmosphere.The warmed Earth emits longer wavelength radiation (heat).Global temperatures and climate patterns are influenced by concentrations of greenhouse gases.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.Recent increases in atmospheric carbon dioxide are largely due to increases in the combustion of fossilized organic matter.Exceeds:Application: Threats to coral reefs from increasing concentrations of dissolved carbon dioxide.Application: Correlations between global temperatures and carbon dioxide concentrations on Earth.Application: Evaluating claims that human activities are not causing climate change.Lab: Greenhouse Gas EffectKey TermsSpeciesHabitatPopulationCommunityEcosystemBioticAbioticProducerConsumerDetritivoreSaprophyteEcologyAutotrophHeterotrophFood chainFood webTrophic levelsCarbon cyclePhotosynthesisCellular respirationFossilizationGreenhouse effectPrecautionary principleGlucoseGlycolysisATPAerobicAnaerobicFermentationKrebs cyclePyruvateElectron Transport ChainAbsorption spectrumAction SpectrumChlorophyllChloroplastLight EnergyPhoto activationPhotolysisStromaStromaLumenGranumRubiscoSpecies, Communities, and Ecosystems, you should be able to….Define the following terms: species, population, community and ecosystem. Make sure you understand the relationship between these terms!Distinguish between autotrophs and heterotrophs. How do they differ in the ways that they obtain nutrition?Answer Data based Question on pg. 204Describe what is meant by consumer, detritivore and saprotroph and provide a specific example for each one.Describe how you would perform random sampling of a meadow using the quadrat method.Answer Data Based Question on pg. 209Use the chi-squared test to determine if there is an association between the two species in the table below. This data was recorded in a sample of 100 quadrats positioned randomly in an open meadow in the alpine tundra:SpeciesFrequencySalix arctica only10Ledum groenlandicum only8Both species60Neither species 25Explain what is meant when results are described as “statistically significant”. Be sure to discuss the null hypothesis, alternative hypothesis, critical region and significance level.In general, describe how nutrients move through an ecosystem. How is this different than the movement of energy through an ecosystem?Identify the three requirements for sustainability in an ecosystem. Energy Flow, you should be able to….Identify the initial source of energy for most ecosystems and the type of organisms that capture it.Answer Data Based Question on pg. 214Describe how light energy is converted to chemical energy in carbon compounds in most ecosystems.Define food chain and provide 2 examples with at least 3 linkages each. Each example should have NAMED organisms (for example, use “sea lettuce” instead of “plant” or “tree”) in a real ecosystem.Describe how energy flows through a food chain. Answer Data Based Question on pg. 216Define biomass. Biomass usually decreases in successive trophic levels in an ecosystem. Explain THREE reasons for the loss of biomass in successive trophic levels.Explain why food chains rarely go past 4 or 5 trophic levels.Construct a scaled pyramid of energy for the following ecosystem and explain reasons for the same of the pyramid of energy. Trophic levelEnergy fixed in biomass (kJ m-2 yr-1)Producers150,000Primary consumers2,500Secondary consumers200Carbon Cycling, you should be able to….Identify ways in which carbon dioxide is:a. Removed from the atmosphereb. Added to the atmospherec. Removed from bodies of water (ocean, etc)d. Added to bodies of waterConstruct a diagram of the carbon cycle. Make sure to include both terrestrial and aquatic ecosystems. Pools should be clearly identified with text boxes and fluxes should be labeled arrows. Answer Data Based Question on pg. 2224. Describe the process of methanogenesis (How is methane produced from organic matter? What types of organisms are involved and what do they do?)5. Explain why atmospheric methane levels are typically very low (Hint- what happens to methane in the stratosphere?)6. Explain how the following form:PeatCoalOil and natural gasLimestone 7. Explain how the combustion of organic matter occurs and identify the products of complete combustion. 8. Explain why global atmospheric carbon dioxide levels fluctuate throughout the year. Cellular Respiration, you should be able to….Define cellular respiration and write the equation for aerobic cellular respiration.Describe how energy can be stored and released from ATP (this may be best represented as a labeled diagram!).Describe the process of anaerobic cellular respiration. Make sure to include:The conditions under which it occursThe reactantsThe products Describe the industrial uses of anaerobic cellular respiration in yeast to produce ethanol and carbon dioxide (alcohol, bioethanol, baking, etc).Describe the purpose of anaerobic cellular respiration in human muscle cells.Describe the process of aerobic cellular respiration. Make sure to include:The conditions under which it occursThe reactantsThe productsThe organelles involved in eukaryotic cellsExplain how a respirometer can be used to measure the rate of cellular respiration.Photosynthesis, you should be able to….Define photosynthesis and write the equation for photosynthesis.Identify the most and least effective wavelengths of visible light for photosynthesis.Describe the role of chlorophyll and accessory pigments in photosynthesis.Sketch and label an absorption spectrum for chlorophyll and an action spectrum for photosynthesis.Identify the source of oxygen in photosynthesis. What process produces oxygen in photosynthesis?Describe how photosynthesis has changed the Earth’s atmosphere, oceans and rock deposition.Explain how photosynthesis involves the conversion of energy from one form to another.Explain what is meant by a limiting factor in photosynthesis.Sketch graphs to show how each of the following factors affect photosynthesis and explain the reasons for their shapes:TemperatureLight intensityCarbon dioxide concentrationClimate Change, you should be able to….1. Define greenhouse gas and identify 4 examples of greenhouse gases.2. Identify the 2 greenhouse gases that have the largest warming effect and 2 greenhouse gases that haveless of a warming effect.3. Describe the two factors that determine the impact of a particular greenhouse gas.4. Explain the greenhouse effect. Include the roles of short wave radiation, long wave radiation andgreenhouse gases.5. Describe the correlation between atmospheric carbon dioxide concentrations and global temperatures(you should go back about 800,000 years).6. Describe the effects of increased global temperatures on climate patterns.7. Describe the relationship between atmospheric carbon dioxide levels since industrialization and averageglobal temperatures.8. Define the precautionary principle (look at the pink TOK box on p. 235). What does the precautionaryprinciple say about how we should address climate change?9. Identify three reasons why there is opposition to climate change.10. Describe the threats to coral reefs from increased dissolved carbon dioxide. ................
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