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Ecosystem Ecology. Ecosystem ecology. Interaction among all communities and the abiotic and biotic factors Chemical cycling Use and reuse of chemical elements Energy flow Conversion of energy through the system Trophic levels Food web. Figure 48.3. Trophic Structure.
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Ecosystem ecology • Interaction among all communities and the abiotic and biotic factors • Chemical cycling • Use and reuse of chemical elements • Energy flow • Conversion of energy through the system • Trophic levels • Food web
Trophic Structure • Transfer of food energy through food web • Feeding relationships between organisms • Primary energy source is sunlight • Conversion of this energy source through trophic structure • Energy conversion is inefficient • Energy enters system as sunlight “lost” as heat • Food chain vs food web • Illustrates trophic interactions
Trophic Structure • Producer • autotrophic • Converts sunlight energy into chemical energy • Sun to sugars • Consumer • Primary consumer • Trophic level that feeds on producers • herbivores • Secondary consumer • Trophic level that feeds primarily on primary consumers • Typically smaller carnivores • Tertiary consumer • Trophic level that feeds primarily on secondary consumers • Quaternary Consumer • Trophic level that feeds primarily on teriary consumers
Food chain • Detritivore • Decomposers • Omnivores?
Trophic Structure • Detritivores • In soil • Feed on detritus (dead material) • Soil scavengers • Earthworms, soil nematodes • Decomposers • Recycle nutrients • Fungus, bacteria
Food web • Linkage based on trophic levels • Species can occupy more than 1 trophic level • Diagram complex relationships • Omnivores • Complexities
Limitations of Food Chain • 4-5 levels (9) • Energetic Hypothesis • Inefficiencey of E transfer • 10 % rule • Dynamic stability hypothesis • Long chains lack stability • Magnification of fluctuations in variable environments
Chemical Cycling • Chemical elements cycled through an ecosystem • Available resources vary across ecosystem types • Complex recycling system involves interactions of abiotic and biotic factors • Limiting resource in ecosystems • Biogeochemical cycles
Biogeochemical Cycles • Cycling of carbon, nitrogen, water • Abiotic reserves • “Sink” • Ex carbon primarily in atmosphere as CO2 • Biotic factors typically involved in harvesting or processing chemicals from sink into useable forms
Water Cycle • Reservoir in atmosphere & in oceans • Cycle driven through • Abiotic parameters • Solar energy, precipitation, evaporation, • Geological- runoff • Biotic parameters • Transpiration
Carbon Cycle • Reservoir in atmosphere • Cycle driven through • Abiotic parameters • Biotic parameters • Photosynthesis & cellular respiration • Decomposers & detritivores • bodies of living organisms
Nitrogen Cycle • Reservoir in atmosphere- N2 • Cycle driven through • Abiotic parameters • Biotic parameters • Soil bacteria- nitrogen fixers (ammonium) • Plants with symbiotic bacteria • Decomposers & detritivores
Phosphorus Cycle • Reservoir in rock & living organisms • Local recycling • Cycle driven through • Abiotic parameters • Precipitation- erosion • Geological- runoff • Biotic parameters • Plants • Decomposers & detritivores
Biomes • Major type of ecosystems • Ex desert • Sonoran desert • Mojave desert • Chihuahuan desert • Great Basin desert • Distinct distribution based on abiotic condition • Primarily driven by climate