ch 55 ecosystems
DESCRIPTION
Ecosystems ppt based on Ch 55 in 8th edition of Biology, by Campbell and ReeceTRANSCRIPT
- Ch 55 Ecosystems Jeff Jewett ACS June 2010 Ver 1
- Ecosystem
- Sum of all organisms in an area AND all the abiotic factors with which they interact
- Communities PLUS abiotic factors
- Boundaries are rarely clear-cut, may depend on scale of question
- Ch 55 Key Topics
- Conservation of Energy/Mass
- GPP/NPP and limitations
- Energy Transfer pyramids of energy/biomass
- Biogeochemical Cycles (C, N, H 2 0)
- Human impact on biogeo. Cycles
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- Global warming, eutrophication, biomagnification, acid rain, ozone hole
- Energy Flows, Matter Cycles
- Energy enters (usually as sunlight)
- Converted to biomass (chemical energy) by autotrophs
- Passed to heterotrophs (incl. decomposers)
- Dissipated as heat
- Energy Flows, Matter Cycles (2)
- Chemical elements (C, N, P) are cycled between abiotic and biotic parts of ecosystem (Law of Conservation of Mass)
- Matter continuously cycles (not created or destroyed)
- 2 nd law of Thermodynamics:
- Energy conversions are never 100% efficient, therefore some is always lost as heat
- Ecosystems require constant input of energy
- Trophic Levels
- Autotrophs = primary producers (redundant)
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- Photoautotrophs rely on light for energy (by FAR the most common)
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- Chemoautotrophs oxidize naturally occuring inorganic compounds as fuel (common in hot springs, deep-sea volcanic vents)
- All of the ecosystem depends on autotrophs!
- Trophic Levels (2)
- Heterotrophs
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- depend directly or indirectly on autotrophs
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- eat things that are alive or were alive
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- Consumers & decomposers (detritivores)
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- Detritivores fungus, bacteria, insects (FBI) eat detritus (non-living organic material such as feces, dead critters, fallen leaves, wood)
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- Consumers primary, secondary, tertiary, quarternary (higher levels rare)
- http://image.tutorvista.com/content/ecosystem/food-web-terrestrial-aquatic-ecosystem.jpeg
- 55.2 Energy GPP
- Gross Primary Production (GPP) = Amount of light energy converted to chemical energy (sugars) per time (rate of photosynthesis)
- Some of this energy is used by the plant for life (cellular respiration)
- Some is converted into biomass, such as starch storage or structural components (new growth)
- NPP a very important ecological statistic!
- Net Primary Productivity amount of sugars left over after respiration, per unit time (rate of new biomass production)
- NPP = GPP R
- Value of NPP gives the size of the base of the food chain (how much total food is there for consumers?)
- NPP highest where it is warm/wet
- (tropical rainforest)
- Global NPP, 2008 NASA Earth Observatory: http://earthobservatory.nasa.gov/IOTD/view.php?id=38889
- June NPP http://www.uwsp.edu/geo/faculty/lemke/geog101/images/14c_npp_junemap_nasa.jpg
- December NPP http://www.uwsp.edu/geo/faculty/lemke/geog101/images/14e_npp_decmap_nasa.jpg
- Human Appropriation of NPP
- SKIP THIS SLIDE
- Aquatic NPP Limitation
- Light -