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Ch 55 Ecosystems Jeff Jewett ACS June 2010 Ver 1
Ch 55 ecosystems
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Ecosystems ppt based on Ch 55 in 8th edition of Biology, by Campbell and Reece
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- 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
- Energy Transfer pyramids of energy/biomass
- Biogeochemical Cycles (C, N, H 2 0)
- Human impact on biogeo. Cycles
-
- 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)
- 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)
-
- Photoautotrophs rely on light for energy (by FAR the most
common)
-
- 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)
-
- depend directly or indirectly on autotrophs
-
- eat things that are alive or were alive
-
- Consumers & decomposers (detritivores)
-
- Detritivores fungus, bacteria, insects (FBI) eat detritus
(non-living organic material such as feces, dead critters, fallen
leaves, wood)
-
- 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)
- 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
- 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
http://sedac.ciesin.columbia.edu/es/hanpp.html
http://earthobservatory.nasa.gov/Features/HANPP/hanpp.php
- Aquatic NPP Limitation