Chapter 19 “Ecosystem Essentials”
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Transcript of Chapter 19 “Ecosystem Essentials”
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Chapter 19
Ecosystem Essentials
Geosystems 6eAn Introduction to Physical Geography
Robert W. ChristophersonCharles E. Thomsen
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Ecology
Study of relationships between organisms and their abiotic environment
Can be studies at several levels:PopulationCommunityEcosystemBiosphereFig 1.8
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CommunitiesFig. 19.3
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Community TermsHabitatType of environment where an organism residesNicheFunction of a life form within a community
In stable community, no niche is left unfilled
Competitive Exclusion Principle applies:No two species occupy same niche at same time
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Interactions in communitiesCompetitionNegative for both species (/)
Symbiotic/Mutualistic (+/+)Both species benefitlichen (fungi and algae)
Predation (+/)One benefits, one loses
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EcosystemFigure 19.2
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Plants (Vegetation)Critical biotic link between solar energy and the biosphereBase of vast majority of food websAbout 20 species of plants provide 90% of the human food supplyWheat, corn (maize), and rice are halfConvert carbon dioxide to oxygenTranspiration elevates atmospheric humidity
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Photosynthesis and RespirationFigure 19.5
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Distribution of VegetationFive major factors:Climate (temperature and precipitation)Topography (elevation, slope)Soils (nutrients, minerals)Biotic Influences (dispersal mechanisms)Disturbance (natural or anthropogenic)
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ClimateFigure 19.8
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Life ZonesFigure 19.9
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Carbon and Oxygen Cycle
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Climate ChangeFigure 19.23
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Whats limiting these distributions?Figure 19.12
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Soils nutrients, mineralshttp://www.cfr.washington.edu/Classes.esc.520B/ImagesNorthFork/Serpentine6SM.jpghttp://www.krisweb.com/krisnavarro/krisdb/ac/dscn2166_sm.jpghttp://nrs.ucdavis.edu/mclaughlin/images/plants/Seep.jpgSerpentine
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Dispersal Mechanisms Fruit and Seedhttp://www.cas.vanderbilt.edu/bioimages/pages/fruit-seed-dispersal.htm
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What about this fruit?Osage orange (Hedge apple)These huge fruits ooze sticky, white latex when bruised. They are large and hard - what would want, or be able to eat them? Probably were once dispersed by extinct megafauna (large mammals) that died out soon after humans arrived in North America. http://www.cas.vanderbilt.edu/bioimages/pages/fruit-seed-dispersal.htm
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Extinct Megafaunahttp://sscl.berkeley.edu/~anth122/mammoth.gifhttp://www.intersurf.com/~chalcedony/gomp.jpghttp://mishilo.image.pbase.com/u36/zidar/upload/23675731.pbtooth1.jpgMammothGomphothereTooth
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Disturbance
NaturalWater, wind, volcano, fireAnthropogenic (human-caused)Deforestation, fire, development
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SuccessionEcological succession when newer communities replace older communities of plants and animalsPrimary succession an area of bare rock or disturbed site with no previous communitySecondary succession some aspects pf a previously functioning community are present
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Succession
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End Chapter 19Geosystems 6eAn Introduction to Physical Geography
Robert W. ChristophersonCharles E. Thomsen