Chapter 3Chapter 3
Ecosystems: How They WorkEcosystems: How They Work
MatterMatter
Anything that hasAnything that has Made of atoms of elements Made of atoms of elements →→ molecules molecules
and compoundsand compounds ______ molecules have carbon-carbon ______ molecules have carbon-carbon
bonds or carbon-hydrogen bonds (can be bonds or carbon-hydrogen bonds (can be synthesized)synthesized)
______ molecules are not from living ______ molecules are not from living thingsthings
Matter (cont)Matter (cont)
Law or Conservation of Mass:Law or Conservation of Mass:
EnergyEnergy
The ability to move matterThe ability to move matter Kinds:Kinds:
____: Energy of motion or action____: Energy of motion or action ____: Stored energy____: Stored energy ____: stored energy in the form of chemicals & fuels____: stored energy in the form of chemicals & fuels
Measured: Measured: ____ (c) – heat required to raise 1 gram of water one ____ (c) – heat required to raise 1 gram of water one
degree Celsiusdegree Celsius ____ (C): food calories____ (C): food calories
Forms of EnergyForms of Energy
Energy LawsEnergy Laws
11stst Law of Thermodynamics (law of conservation Law of Thermodynamics (law of conservation of energy):of energy):
22ndnd Law of Thermodynamics: In any energy Law of Thermodynamics: In any energy conversion, some of the usable energy is always conversion, some of the usable energy is always lost: lost: Example: Chemical reaction of RespirationExample: Chemical reaction of Respiration
Matter and Energy Changes in Matter and Energy Changes in Organisms and EcosystemsOrganisms and Ecosystems
Producers: Producers: Kinetic energy of light is converted to high Kinetic energy of light is converted to high
potential energy in the form of carbon bonds.potential energy in the form of carbon bonds. The original energy is always there (sun) to drive The original energy is always there (sun) to drive
this mechanism.this mechanism.
Matter and Energy (cont)Matter and Energy (cont)
ConsumersConsumers Respiration releases high potential energy of Respiration releases high potential energy of
glucose bonds into low potential energy of CO2 glucose bonds into low potential energy of CO2 and energy loss by body heat.and energy loss by body heat.
Fate of FoodFate of Food ____% is oxidized for energy.____% is oxidized for energy. ____% is converted to the body tissues of the ____% is converted to the body tissues of the
consumer.consumer. Some of the ____% is passed through-fecal waste.Some of the ____% is passed through-fecal waste.
Detritus Feeders and DecomposersDetritus Feeders and Decomposers
Digest ____ and use as energy sourceDigest ____ and use as energy source Sometimes respiration occurs in the absence of Sometimes respiration occurs in the absence of
oxygen: _______oxygen: _______
Principles of Ecosystem FunctionPrinciples of Ecosystem Function
Energy Flow: Energy Flow: Most energy is from the sun for producers. Most energy is from the sun for producers.
The actual production of crops at any one time The actual production of crops at any one time on Earth is know as the standing crop biomass.on Earth is know as the standing crop biomass.
Productivity of different ecosystems depends Productivity of different ecosystems depends on different biotic and abiotic factors (see p on different biotic and abiotic factors (see p 67).67).
Energy moves through the trophic levels.Energy moves through the trophic levels.
Energy Flow (cont)Energy Flow (cont)
Energy EfficiencyEnergy Efficiency Only a small fraction of energy flows from one Only a small fraction of energy flows from one
trophic level to the next.trophic level to the next. Often the majority of energy ends up and flows Often the majority of energy ends up and flows
through the detritus food web.through the detritus food web. Ecosystems do not use energy at a rate that is Ecosystems do not use energy at a rate that is
faster than that which is available from the sun.faster than that which is available from the sun. Humans are consuming fossil fuels at a rate Humans are consuming fossil fuels at a rate
faster than they can be produced.faster than they can be produced.
Energy Flows, Nutrients CycleEnergy Flows, Nutrients Cycle
Nutrient CyclesNutrient Cycles
Keeping in mind the law of Conservation of Keeping in mind the law of Conservation of Matter: the molecules in an organism can Matter: the molecules in an organism can eventually be found in another.eventually be found in another.
Carbon CycleCarbon Cycle
Changing the location of this element is the primary issue in global warming, from fossil fuels to the atmosphere.
Phosphorus CyclePhosphorus Cycle
Changing the location of this element is one of Changing the location of this element is one of the primary reasons for the increased nutrient the primary reasons for the increased nutrient load in aquatic ecosystems, from concentrated load in aquatic ecosystems, from concentrated waste and deposits in soil to its release in waste and deposits in soil to its release in water.water.
Nitrogen CycleNitrogen Cycle
Changing the location of this element also Changing the location of this element also increases the nutrient load in aquatic increases the nutrient load in aquatic ecosystems.ecosystems.
Sulfur CycleSulfur Cycle
2 Principles of Ecosystem 2 Principles of Ecosystem SustainabilitySustainability
1. Ecosystems 1. Ecosystems
2. Ecosystems 2. Ecosystems
Implications for HumansImplications for Humans
____ are excellent models for Humans____ are excellent models for Humans Non-sustainable actions by humans affect the Non-sustainable actions by humans affect the
nutrient cycles:nutrient cycles: NN HH EE CC FF