Post on 27-Dec-2015
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Ecosystems and Human Ecosystems and Human InterferencesInterferences
Chapter 48Chapter 48
OutlineOutline Biotic ComponentsBiotic Components
AutotrophsAutotrophs HeterotrophsHeterotrophs
Energy FlowEnergy Flow Laws of ThermodynamicsLaws of Thermodynamics Ecological PyramidsEcological Pyramids
Biogeochemical CyclesBiogeochemical Cycles Hydrologic CycleHydrologic Cycle Carbon CycleCarbon Cycle Nitrogen CycleNitrogen Cycle Phosphorus CyclePhosphorus Cycle
Biotic ComponentsBiotic Components AutotrophsAutotrophs
Require only inorganic Require only inorganic nutrients (EX?) and an outside nutrients (EX?) and an outside energy source (EX?) to produce energy source (EX?) to produce organic nutrients.organic nutrients.
Examples of autotrophs?Examples of autotrophs?
HeterotrophsHeterotrophs
HeterotrophsHeterotrophs need a preformed need a preformed source of organic nutrients.source of organic nutrients. ConsumersConsumers
Herbivores EX?Herbivores EX?Carnivores EX?Carnivores EX?Omnivores EX?Omnivores EX?
DecomposersDecomposers EX? EX?
Biotic ComponentsBiotic Components
Abiotic Components: Abiotic Components: Energy And MatterEnergy And Matter
Energy---Flows Energy---Flows through through an an ecosystemecosystemWHY?WHY?
Matter—Cycles Matter—Cycles withinwithin an an ecosystemecosystemEXAMPLES?EXAMPLES?
DefinitionsDefinitions EnergyEnergy
PotentialPotential KineticKinetic ChemicalChemical Matter and energy are interconvertible.Matter and energy are interconvertible.
WorkWork Spontaneous change vs non-Spontaneous change vs non-
spontaneous changespontaneous change Do characteristics of life require work?Do characteristics of life require work?
Types of Energy in Biological Systems• Kinetic energy - energy of motion, work done
• Potential energy - stored energy, can be released to do work
• Archer draws bowstring back - used kinetic energy
• Tension now in bowstring represents potential energy
• Release of bowstring converts potential energy to kinetic energy
Energy (cont’d)Energy (cont’d)
ThermodynamicsThermodynamics a a system:system:
Some portion of the universe that you wish to studySome portion of the universe that you wish to study
The The surroundings:surroundings:The adjacent part of the universe outside the system, i.e. The adjacent part of the universe outside the system, i.e.
everything but the systemeverything but the system
NOTE: Changes in a system are associated NOTE: Changes in a system are associated with the transfer of energywith the transfer of energy
Natural systems tend toward states of minimum energyNatural systems tend toward states of minimum energy
1st Law of 1st Law of ThermodynamicsThermodynamics
Total Energy in Universe is Constant energy cannot be created or
destroyed Energy can be converted from one
form to another The pathway of conversion is irrelevant,
the energy change between identical initial and final states is equal
When it comes to energy-You can’t get ahead!
2nd Law of 2nd Law of Thermodynamics-You can’t Thermodynamics-You can’t
break even, either!break even, either! No conversion is 100% efficient. Total useful energy in a closed system
decreases as conversions occur. Closed systems go from complex to simple. Entropy
Measure of Disorder Closed systems tend to their highest state of
disorder Entropy of the universe increases with every
conversion
2nd Law of 2nd Law of ThermodynamicsThermodynamics
Randomness is spontaneous in a closed system
• Beaker on left has different colored marbles separated from each other
• Highly ordered system
• Low entropy
Examples of Entropy
low entropy high entropy
• Beaker on right has different colored marbles scattered amongst each other
• Highly disordered system
• High entropy Other examples?
SUMMARY-SUMMARY-THERMODYNAMICSTHERMODYNAMICS
First LawFirst Law: Energy cannot be : Energy cannot be created or destroyed, but it can be created or destroyed, but it can be changed from one form to another.changed from one form to another.
Second LawSecond Law: Energy cannot be : Energy cannot be changed from one form to another changed from one form to another without loss of usable energywithout loss of usable energy
ThermodynamicsThermodynamics The SystemThe System
OpenOpen ClosedClosed
System+Surroundings=UniverseSystem+Surroundings=Universe First Law—You Can’t WinFirst Law—You Can’t Win
Ways to State?Ways to State? Second Law—You Can’t Break Even Second Law—You Can’t Break Even
EitherEither Ways to State? Examples?Ways to State? Examples?
Energy Balances and Energy Balances and ThermoodynamicsThermoodynamics
Energy FlowEnergy Flow
Food WebFood Web - Interconnecting paths of - Interconnecting paths of energy flow describing trophic energy flow describing trophic relationships.relationships.
Ecological PyramidsEcological Pyramids
A A trophic leveltrophic level is composed of all is composed of all the organisms that feed at a the organisms that feed at a particular link in a food chain.particular link in a food chain.
Pyramid of BiomassPyramid of Biomass Pyramid of NumbersPyramid of Numbers Pyramid of EnergyPyramid of Energy
10% Rule10% Rule
Ecological PyramidEcological Pyramid
Chemical CyclingChemical Cycling
Chemicals cycle as organic Chemicals cycle as organic nutrients are returned to the nutrients are returned to the producers.producers. ExcretionExcretion DeathDeath Cellular RespirationCellular Respiration
Global Biogeochemical Global Biogeochemical CyclesCycles
Chemical cycling may involve:ReservoirExchange Pool Biotic Community
When exploring chemical cycles, evaluate the human impact on that cycle
Hydrologic CycleHydrologic Cycle
Fresh water evaporates from bodies Fresh water evaporates from bodies of water.of water.
Precipitation on land enters the Precipitation on land enters the ground, surface waters, or aquifers.ground, surface waters, or aquifers.
Water eventually returns to the Water eventually returns to the oceans.oceans.
Hydrologic CycleHydrologic Cycle
Carbon CycleCarbon Cycle
Exchange pool?Exchange pool? Reservoir?Reservoir? Biotic community: How Biotic community: How
does carbon enter the does carbon enter the biotic community?biotic community?
Circle of LifeCircle of Life
Carbon compounds, O2
CO2, H2O
Respiration
Photosynthesis
Energy
Energy
Carbon CycleCarbon Cycle
Greenhouse EffectGreenhouse Effect
Greenhouse gasesGreenhouse gases allow solar radiation allow solar radiation to pass through atmosphere but trap to pass through atmosphere but trap heat (infrared radiation) from escaping.heat (infrared radiation) from escaping. Carbon dioxide, nitrous oxide, methane, HCarbon dioxide, nitrous oxide, methane, H22OO If Earth’s temperature rises, more water will If Earth’s temperature rises, more water will
evaporate, forming more clouds and setting evaporate, forming more clouds and setting up a potential positive feedback loop.up a potential positive feedback loop.
Earth’s Radiation BalancesEarth’s Radiation Balances
Nitrogen CycleNitrogen Cycle
Atmospheric nitrogen is fixed by Atmospheric nitrogen is fixed by bacteria in order to make it available bacteria in order to make it available to plants.to plants. Nodules on legume roots Nodules on legume roots
(Rhizobium/legume symbiosis).(Rhizobium/legume symbiosis). NitrificationNitrification - Production of nitrates. - Production of nitrates. DenitrificationDenitrification - Conversion of nitrate - Conversion of nitrate
to nitrous oxide and nitrogen gas.to nitrous oxide and nitrogen gas. Balances nitrogen fixation.Balances nitrogen fixation.
The Nitrogen CycleThe Nitrogen Cycle
Nitrogen and Air PollutionNitrogen and Air Pollution
Acid DepositionAcid Deposition Nitrogen oxides and sulfur dioxide are Nitrogen oxides and sulfur dioxide are
converted to acids when they combine converted to acids when they combine with water vapor.with water vapor.
Thermal InversionThermal Inversion
Phosphorus CyclePhosphorus Cycle
Phosphorus does not enter the Phosphorus does not enter the atmosphere.atmosphere. Sedimentary cycle.Sedimentary cycle.
Phosphate taken up by producers Phosphate taken up by producers incorporated into a variety of organic incorporated into a variety of organic molecules.molecules.
Can lead to water eutrophication.Can lead to water eutrophication. BiomagnificationBiomagnification
Phosphorus CyclePhosphorus Cycle
Sources of Water PollutionSources of Water Pollution
ReviewReview Biotic ComponentsBiotic Components
AutotrophsAutotrophs HeterotrophsHeterotrophs
Energy FlowEnergy Flow Ecological PyramidsEcological Pyramids
Biogeochemical CyclesBiogeochemical Cycles Hydrologic CycleHydrologic Cycle Carbon CycleCarbon Cycle Nitrogen CycleNitrogen Cycle Phosphorus CyclePhosphorus Cycle
Energy BalancesEnergy Balances