Chapter 4 Ecosystems: What Are They and How Do They Work?

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<ul><li>Slide 1</li></ul> <p>Chapter 4 Ecosystems: What Are They and How Do They Work? Slide 2 ECOLOGY Ecology is the study of the connection between organisms and their living and non-living environments. The average number of organisms that can be sustained in an ecosystem is known as carrying capacity. Food, water, and shelter are known as limiting factors. Slide 3 Biosphere Ecosystems Communities Populations Organisms L E V E L S of O R G A N I Z A T I O N F O C U S E D on in E C O L O G Y Slide 4 Species is the lowest on this hierarchy and Biosphere is the largest Species is the lowest on this hierarchy and Biosphere is the largest. Slide 5 Slide 6 Slide 7 Vegetation and animals Soil Rock Biosphere Crust core Mantle Lithosphere (crust, top of upper mantle) Hydrosphere (water) Atmosphere (troposphere, stratosphere) (air) Biosphere (Living and dead organisms) Crust (soil and rock) Oceanic crust Continental crust Lithosphere Upper mantle Asthenosphere Lower mantle Slide 8 Solar radiation Energy in = Energy out Reflected by atmosphere (34%) UV radiation Absorbed by ozone Absorbed by the earth Visible light Lower stratosphere (ozone layer) Troposphere Heat Greenhouse effect Radiated by atmosphere as heat (66%) Earth Heat radiated by the earth Solar Capital Slide 9 ECOLOGY Abiotic All of the non-living elements in an ecosystem like air, water, and temperature. Biotic All of the living elements in an ecosystem. Slide 10 Biotic Factors in an Aquatic Ecosystem Slide 11 Sunlight Temperature Precipitation Wind Latitude (distance from equator) Altitude (distance above sea level) Fire frequency Soil Light penetration Water currents Dissolved nutrient concentrations (especially N and P) Suspended solids Salinity Abiotic Factors in Terrestrial and Aquatic Ecosystems Slide 12 Ecotones: Ecosystem Boundaries Slide 13 Tolerance Range of Tolerance: range of chemical and physical conditions that must be maintained for populations of a particular species to stay alive and grow, develop, and function normally. Law of Tolerance: the existence, abundance, and distribution of a species in an ecosystem are determined by whether the levels of one or more physical or chemical factors fall within the range tolerated by the species. Slide 14 Population Size LowHighTemperature Zone of intolerance Zone of physiological stress Optimum range Zone of physiological stress Zone of intolerance No organisms Few organisms Lower limit of tolerance Abundance of organisms Few organisms No organisms Upper limit of tolerance Range of tolerance for a population of organisms, such as fish, to an abiotic environmental factorin this case, temperature. Slide 15 Ecology Biodiversity is the number and variety of organisms found within a certain region. Extinction is when a species is no longer in existence. Endangered means a species is in danger of extinction throughout all of a significant portion of its range. Slide 16 ECOLOGY Food Chain A chain illustrating the organisms and their food source. Grass grasshopper bird Slide 17 A food chain illustrates the transfer of energy from one trophic level to the next. Slide 18 Slide 19 ECOLOGY Food Web multiple chains assembled into one large web. Slide 20 ECOLOGY Ecological Pyramid A food chain that shows the relationship between the organisms in each trophic level. Slide 21 The figures represent number of individuals counted at each trophic level. Ecological Pyramid of Numbers Slide 22 The total dry weight of organisms in a particular trophic level is referenced as biomass. Ecological Pyramid of Biomass BIOMASS = # of organisms x the weight of an average individual Slide 23 Ecological Pyramid of Energy Energy in ecosystems flows from producers to consumers. Energy is depicted in kilocalories. Ecological efficiency: % of usable energy transferred from one trophic level to the next. (Average is about 10%.) Slide 24 Ecological Pyramid of Energy Slide 25 Slide 26 Nutrient Cycles Cycling of materials between the environment and organisms. Chemical and biological processes. Examples: Water cycle Carbon cycle Nitrogen cycle Phosphorus cycle Sulfur cycle Oxygen cycle Slide 27 Precipitation to ocean Evaporation From ocean Surface runoff (rapid) Ocean storage Condensation Transpiration Rain clouds Infiltration and percolation Transpiration from plants Groundwater movement (slow) Runoff Surface runoff (rapid) Precipitation Water (Hydrologic) Cycle Slide 28 Carbon Cycle Slide 29 Nitrogen Cycle Slide 30 Nitrogen Fixation: bacteria convert nitrogen to ammonia Nitrification: bacteria convert ammonia to nitrite and nitrate, which are used by plants Assimilation: plant roots absorb ammonia and nitrate Ammonification: decomposers convert dead organisms and waste to simpler compounds Denitrification: bacteria convert ammonia back into nitrite and nitrate, which are released into the air (cycle begins again) Slide 31 Phosphorus Cycle Phosphate Mining Fertilizer containing phosphates Animal waste Phosphate Rock Dissolved Phosphates Animal Excretion Erosion Uplifting into rocks Slide 32 The Sulfur Cycle </p>