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