ES2MT2studyguide

ES2MT2studyguide - Environmental Studies 2: Midterm 2 Study...

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Environmental Studies 2: Midterm 2 Study Guide Week 4: Ecosystems and Biogeography Fundamental characteristics of an Ecosystem o Ecosystem: an ecological community and its local, nonbiological community o Plants, soils, and consumers Minimum ecosystem components that can sustain life o It must include at least an autotroph, a decomposer, a liquid medium, a source and sink of energy, and all the chemical elements required by the autotroph and the decomposer Energy inputs o Energy, nutrients, water Primary Producers o Typically plants or other autotrophs o Photosynthesis and transpiration (O2-CO2 cycle) o Primary productivity and biomass production Balance of energy left over after a plant uses it for its own good Plant material left over after a year o Soil stabilization o Vegetative (ecosystem) structure, compositions, and biodiversity habitat Photosynthesis and respiration Trophic level o In an ecological community, all the organisms that are the same number of food-chain steps from the primary source of energy o For example: ina grassland the green grasses are on the same trophic level, grasshoppers on the second, birds that feed on grasshoppers are on the third, and so forth Net Primary Production Vegetative structure and composition o Vegetative structure Vegetation type Dominant growth forms (tree, shrub, epiphytes) Measured parameters Percent cover; density, basal area, veg. height, biomass Spatial distribution o Vegetative Composition Species composition Biodiversity indices (simpson’s diversity index) Consumers o Primary and secondary consumption (respiration and nutrient cycling) o Grazing and biomass removal o Competition, predator-prey relationships
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o Seed dispersal and ecosystem maintenance o Biodiversity Decomposers o Organisms that feed on dead organic matter o Biomass reduction and nutrient cycling Soil and water resources o Provides substrate for ecosystem development o Nutrient supply, biogeochemical cycling o Decomposers Soil Composition o Soil is composed of: Minerals: sand, clays, colloids Organic material: animal and plant matter Water: aqueous environment Soil Horizon o A layer in soil (A,B,C) that differs from another layer in chemical, physical, and biological properties Ecosystem services o Food and fiber production (agriculture, rangeland, fisheries, forest resources) o Soil stabilization and flood control o Water quality treatment and sediment trapping (wetlands) o Climate regulation and biogeochemical cycling o Biodiversity (medicines, industrial products, food) o Aesthetics and recreation Key Concepts o Ecological community o Food chain (web) o Habitat o Niche o Community effect o Keystone species o Energy and ecosystems Keystone Species o A species, such as the sea otter, that has a large effect on its community or ecosystem so that its removal or addition to the community leads to major changes in the abundances of many other species
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ES2MT2studyguide - Environmental Studies 2: Midterm 2 Study...

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