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APES Fall 2006 Chapter 3 Question Set Answers Due: October 6, 2006 1. Identify the five major “levels of organization of matter” which the field of ecology focuses on: Organism, population, community, ecosystem and biosphere 2. Distinguish between the following: population, community, and ecosystem. Population consists of a group of interacting organisms of the same species that occupy a specific area at the same time. Communities are populations of different species occupying a particular place. Ecosystems are communities of different species interacting with one another and their nonliving environment. Biospher 3. Describe each of the following: a) lithosphere – the earth’s crust and upper mantle e b) hydrosphere – the earth’s liquid water, ice, and water vapor c) atmosphere – the air around the planet d) ecosphere/biosphere – all the living organisms and the parts they interact with 4. Describe what abiotic ecosystem components are; include 3 examples. Abiotic components are all the nonliving physical and chemical factors that influence living organisms in an ecosystem. Examples are sunlight, temperature, precipitation, wind, latitude, altitude, soil, water current, light penetration, nutrients, salinity, etc. 5. How does the optimum range relate to the range of tolerance? (For a given species and a specific abiotic factor, such as a Golden Trout and water temperature.) The optimum range is the narrow band in which a species may do best at within the range of tolerance. 6. What does the Limiting Factor Principle state? The limiting factor principle states that too much or too little of any abiotic factor can limit or prevent growth of a population even if all other factors are at or near the optimum range of tolerance. 7. Write the chemical equation for photosynthesis. 6CO2 + 6H2O + solar energy = C6H12O6 + 6O2 8. Write the chemical equation for cellular respiration. C6H12O6 + 6O2 = 6CO2 + 6H2O + energy 9. What other category of producers exist besides the photosynthetic producers? Identify 2 locations/environments where you might find such non-photosynthetic producers. Chemosynthetic producers – they are found in hydrothermal vents in the ocean’s depths, and in areas deep within the earth’s crust 10. Identify and distinguish between six types of consumers. 1) Herbivores – plant eaters 2) Carnivores – meat eaters 3) Omnivores – plant and meat eaters 4) Scavengers – feed on dead organisms 5) Detritus feeders - feed on decomposing organic matter 6) Decomposers – break down organic matter and release it back to the nutrient cycle 11. Approximately what percent of the kilocalories found in the “preceding” or lower trophic level actually become incorporated into the tissues of organisms in the trophic level directly above it? 10% 12. From the above question, what happens to the remainder of the kilocalories (those that do not make it in to the biomass of the consumer organisms feeding on the trophic level below them? It is converted into heat. 13. If there are 1,000,000 kilocalories in the producer level of an energy pyramid, how many kilocalories will be incorporated into the bodies of the: a) primary consumers? 100,000 kcal b) secondary consumers? 10,000 kcal c) tertiary consumers? 1,000 kcal 14. Briefly describe the seven main processes involved in the hydrologic cycle: 1) evaporation – conversion of water into water vapor APES Fall 2006 2) transpiration – evaporation from leaves of water extracted from soil by roots and transported throughout the plant 3) condensation – conversion of water vapor into droplets of liquid water 4) precipitation – rain, sleet, hail or snow 5) infiltration – movement of water into soil 6) percolation – downward flow of water through soil and permeable rock to groundwater storage areas 7) runoff – downslope surface movement back to the sea 15. Name the two driving forces behind the water cycle: Sun and gravity. 16. Why is it necessary that biogeochemical cycles exist? Explain: Biogeochemical cycles bring the necessary nutrient that organisms need to live, grow and reproduce. 17. Relate the following terms: groundwater, aquifer, and water table. Groundwater is the name of water found underground. It is stored in permeable rocks called aquifers. The top of the groundwater is called the water table. 18. Describe three significant anthropogenic interventions in the hydrological cycle. 1) Withdrawing large quantities of fresh water 2) clearing vegetation 3) modifying water quality. 19. Provide three specific ways in which carbon is essential for biota to function: 1) It is a building block for carbs, fats, proteins, DNA 2) It is a key component in the earth’s thermostat (as CO2) 3) It is used in photosynthesis 20. Identify the two processes, which have the greatest influence on tropospheric concentrations of carbon dioxide on a monthly or yearly basis. Explain: 1) Diffusion of CO2 in the atmosphere into the ocean because it is readily soluble in water and is removed by photosynthesizing producers 2) Burning of fossil fuels because we are taking a resource/reservoir that took millions of years to form and adding it to the atmosphere in a couple of hundred years. 21. Name the two largest sinks (storage areas) for carbon; briefly explain how these areas have become such substantial carbon sinks. Ocean sediments and continental rocks because the carbon from these areas are cycled very slowly so they are allowed to build up over time. 22. Describe the two major human interventions in the carbon cycle. 1) Burning of fossil fuels 2) Deforestation and vegetation removal. 23. Why is the nitrogen cycle significant to biota? Organisms need nitrogen to make many organic compounds (proteins, DNA, and RNA) 24. Identify the two major ways that nitrogen is fixed; 1) By cyanobacteria in soil and water 2) Rhizobium bacteria living in small nodules on the root systems of certain plants 25. Describe what takes place in each of the following processes or steps of the N-cycle a. Nitrogen fixation – specialized bacteria convert gaseous nitrogen to ammonia (NH3) that can be used by plants. b. Nitrification – the ammonia in soil is converted by specialized aerobic bacteria to nitrite ions (NO2-), which are toxic to plants and nitrate ions (NO3-), which are easily taken up by the plants c. Assimilation – plant roots absorb inorganic ammonia, ammonium ions, and nitrate ions and use these ions to make nitrogen-containing organic compounds (DNA, proteins) d. Ammonification – specialized decomposer bacteria convert the nitrogen-rich organic wastes into ammonia (NH3) and ammonium ions (NH4+) e. Denitrification – specialized bacteria convert the ammonia and ammonium ions back into nitrite and nitrate ions and then into nitrogen gas and nitrous oxide (N2O) 26. Identify the major sinks for nitrogen. 1) the atmosphere (78% N2), and 2) in continental rocks 27. Describe seven anthropogenic interventions in the nitrogen cycle. APES Fall 2006 1) Adding large amounts of nitric oxide (NO) into the atmosphere when we burn fuel 2) Adding nitrous oxide (N2O) to the atmosphere through the action of anaerobic bacteria on livestock wastes and fertilizers 3) Removing nitrogen from topsoil 4) Adding nitrogen compounds to aquatic systems 5) Accelerating the deposition of acidic nitrogen compounds from the atmosphere onto terrestrial ecosystems 28. How is phosphorous important to biota? It is an essential nutrient of both plants and animals (DNA, ATP, certain fats, and bones, teeth and shells) 29. Explain why phosphorous does not circulate in the troposphere to a great extent: There are no common gaseous forms of phosphorous, and is only found in the atmosphere as particles of dust. 30. Identify the largest sinks for phosphorous: 1) Terrestrial rocks, 2) ocean sediments, and 3) water 31. Comment on how human activities have influenced the phosphorous cycle regarding each of the following: a. Mining phosphate rock – adds phosphates to water systems in the form of runoff b. Deforestation – reduces the amount of phosphates in the soil c. Animal wastes from livestock feedlots – increase the amount of phosphate in the soil and the local fresh water d. Commercial phosphate fertilizers in agricultural areas - increase the amount of phosphate in the soil and the local fresh water e. Discharge of municipal sewage/wastewater treatment facilities - increase the amount of phosphate in the soil and the local fresh water 32. How is sulfur significant to biota? In the atmosphere, sulfur can be converted into sulfuric acid which is harmful to plants and animals. 33. Identify the two largest storage areas for sulfur: 1) Terrestrial rocks and 2) ocean sediments 34. Identify the major natural sources of each of the following sulfur compounds: a) H2S – active volcanoes b) SO2 - volcanoes c) SO42- - sea spray d)CH3SCH3 (dimethyl sulfide, or DMS) – certain marine algae 35. Explain the chemical transformations (reactions) which occur when SO2 reacts with O2 and H2O in the troposphere to eventually become sulfuric acid: Sulfur dioxide reacts with oxygen to form sulfur trioxide gas (SO3). Some of this sulfur trioxide gas reacts with water vapor to produce tiny droplet of sulfuric acid (H2SO4). 36. Identify the three major human activities influencing the sulfur cycle: 1) Burning sulfur-containing coal and oil to produce electric power 2) Refining sulfur-containing petroleum to make gasoline and heating oil 3) using smelting to convert sulfur compounds of metallic minerals into free metals such as copper, lead, and zinc.