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Ecosystems: Natures Answer to a Perpetual Motion Machine Could this ecosphere be considered an ecosystem? Slide 2 I.Characteristics of an Ecosystem A. It is the basic unit of Ecology B. Includes all the interactions of abiotic and biotic factors C. Must be self-perpetuating and self- maintaining D. All have similar structures due to the 4 unbreakable laws of physics Slide 3 II. The 2 Energy Laws A. Law of Conservation of Energy Fire Steam Turbine Transformation (Chemical Energy) (Heat Energy) (Mechanical Energy) Implication: All ecosystems form transformable energy relationships. Energy can not be created nor destroyed but can be transformed into different forms Slide 4 Captures unusable energy from inorganic sources and transforms energy into useable organic form Main Energy Transformers Useable chemical energy (organic chemical bonds) passed from one organism to another Processing Methods Food Chain 1. Photosynthesis 99% 2. Chemosynthesis 1% Unusable Energy Usable Energy Useable Energy Slide 5 Fire Steam Turbine Transformation (Chemical Energy) (Heat Energy) (Mechanical Energy) B. 2nd Law of Thermodynamics In every energy transformation there is a loss of usable energy Energy Loss (heat) Energy Lost (heat) Implication: 1. As energy is passed through an ecosystem, energy is lost. 2. Ecosystem must have a constant unlimited energy source to perpetuate Slide 6 This Law Explains why: 1.Measured energy flow through an ecosystem forms an energy pyramid 2. Food chains tend to be only 4-5 trophic levels Pyramid of Numbers Pyramid of Biomass May not be the most accurate Why? Slide 7 Where does the energy go? How much energy is transferred from one level to the next? Important Concepts: 1.Gross Primary Production: The amount of energy the producers convert to food by photosynthesis. This can be measured in terms of : a) amount of CO 2 taken from the atmosphere b) amount of C 6 H 12 O 6 made c) amount of O 2 produced Pyramid of Net Production 10% 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 What parts of the world contribute most to primary productivity? Slide 19 Slide 8 2. Net Primary Production: The total amount of carbon made available to the consumers. Net Primary Production = Gross Primary Production Plant Respiration 3. Secondary Production: The amount of energy converted to actual biomass by a consumer Gross Primary Production Net Primary Production Secondary Production Abiotic or biotic conditions that restrict productivity in an ecosystem. 4. Limiting Factors: (influence of) Where on the earth does most of the Net Primary Production take place? Slide 20 Temperature, moisture, soil composition, nitrates and phosphates Slide 17 Slide 9 III. 2 Matter Laws A. All matter is made of atoms Implication: All living things require the same basic atoms NCHOPS > 98% Ca, K, Na, Fe, Cl, < 2% B. Matter can not be created nor destroyed Implication: All living things must compete for atoms. The limited amount of atoms must recycle through an ecosystem if the ecosystem is self perpetuating The Major Biogeochemical Cycles: Water, Carbon/Oxygen, Nitrogen, Phosphorus Slide 10 Biogeochemical Cycles Biological Interactions Geochemical Interactions Consumers Producers Detritivores Nutrients available to producers Abiotic reservoir Geologic processes Slide 11 The Water Cycle: Required to make clean water available for all living things Evaporation Precipitation Condensation Transpiration Evaporation Precipitation Percolation Ground Water Runoff Condensation PrecipitationEvaporation Percolation Transpiration RunoffGround Water Human Impact 1. Air Pollutants a. Nitrates b. Sulfates Acid Rain a. Nitric Acid b. Sulfuric Acid Slide 12 The Carbon/Oxygen Cycle: Required for Carbon Building Blocks and Energy Combustion CO 2 in Atmosphere Cellular Respiration Photosynthesis Primary Consumers Secondary Consumers Detritivores Detritus Human Impact 1. Global Warming (Green House Effect) 2. Deforestation Anaerobic Decomposition Fossil Fuels CO 2 + H 2 O C 6 H 12 O 6 + O 2 C 6 H 12 O 6 + O 2 CO 2 + H 2 O CO2 in Atmosphere Food Chains O 2 in Atmosphere Photosynthesis Decomposition Carbon compounds in water Plant Primary Producers Phytoplankton Primary Producers Waste / Death Slide 13 The Nitrogen Cycle: Nitrogen Required for Making Proteins Human Impact: 1. Fertilizers 2. Sewage Eutrophication: Overgrowth in lakes Nitrogen in atmosphere (N 2 ) Plants Assimilation Nitrates (NO3) Denitrifying Bacteria Decomposers (bacteria and fungi) Ammonification Death Waste Nitrification Nitrifying Bacteria Nitrites (NO 2 ) Ammonium (NH 4 +) Bacteria soil Nitrogen Fixing Nitrogen-Fixing bacteria in root nodules of legumes Animals Nitrifying Bacteria Denitrification Lightning (N2) Food Chains Ammonifying Bacteria Ammonia (NH 3 ) Slide 14 Phosphorus Cycle: Phosphates Required to Make DNA, ATP, Cell Membranes Animals Plants Decomposers Phosphate in soil Leaching Dissolved Phosphate Chemical Precipitation Waste Death Sedimentation = new rocks Geological uplifting Weathering of phosphate from rocks Runoff Organic Phosphate Inorganic Phosphate Food Chains Human Impact: 1. Fertilizers 2. Sewage Eutrophication: Overgrowth in lakes Assimilation Algae Plants Decomposition Slide 15 Summary of Ecosystems As Matter flows through an Ecosystem, Matter is: _________________ What are the minimal steps required to have a functional Ecosystem? As Energy flows through an Ecosystem, energy is: _________________ Lost Recycled 1. Producers: For energy transformation 2. Detritivores/Decomposers: For recycling (Red Arrows) (Blue arrows) Slide 16 The 5 Laws of Ecology (according to Dr. Barry Commoner) 1.Everything is connected to everything else 2.Everything has to go somewhere 3.There is no such thing as a free lunch 4.Nature know best 5.The whole is greater then the sum of its parts Which laws are being ignored with each of the following issues? 1.Ozone depletion 2.Biomagnification of DDT 3.Cultural Eutrophication 4.Acid rain 5.Global warming 6.Smog in cities 7.Polluted Drinking water 8.Human Malnutrition 9.Over Use of Resources Slide 17 Nutrient Addition Experiments in a Hudson Bay Salt Marsh What are the limiting factors in this Ecosystem? Slide 18 Slide 18 Effect of Limiting Factors in Aquatic Ecosystems Collection Data Points (in vitro) What is the Limiting Factor in this this Ecosystem? Slide 8 Slide 19 Different Ecosystems have Different Productivity Capabilities 1. Which ecosystem is the most productive (g/m /yr) ? 2 #2 #1 2. Which Ecosystem provides the earth with the most primary production? #1 #2 Primary Production of Ecosystems Slide 7 Slide 20 Regional Annual Net Primary Production For the Earth Lower Higher Which Biomes are the Most Productive? Slide 8