Environmental Science: Toward A Sustainable Future Chapter 3

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Environmental Science Toward A Sustainable
Future Chapter 3

• Ecosystems How They Work

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This Lesson Is About How Ecosystems Function
Transfer Energy and Nutrients

• Capture of sun energy transfer through different
  trophic levels.
• Capture of essential elements of life and
  transfer through different trophic levels.
• Nutrient cycles.
• Human impacts on ecosystem function.

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Ecological Principles DICE
Diversity Interrelationships Cycles Energy
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Elements of Life
92 naturally occurring elements Elements Found
in Living Organisms N CHOPS (macronutrients) C
HOPKINS Ca Fe Mg B Mn Cu Cl Mo Zn
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Atmospheric Gases
78 Nitrogen
21 Oxygen
lt0.04 Carbon Dioxide
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Elements of Life
Organic carbon based molecules produced by
living organisms Example C6H12O6,
CH4 Inorganic molecules without carbon-carbon
nor carbon-hydrogen bonds Example NaCl, NH4,
H2SO4
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Matter and Energy

• Matter anything that occupies space and has
  mass.
• Cannot be created or destroyed.
• Can be changed from one form into another.
• Can be recycled.
• Can be measured where gravity is present.

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Matter and Energy

• Energy anything that has the ability to move
  matter, has no mass and does not occupy space.
  Ability to do work!
• Cannot be created or destroyed.
• Can be changed from one form to another.
• Cannot be recycled.
• Can be measured.

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Laws of Thermodynamics
First Law (CHANGE) Energy is neither created
nor destroyed but may be converted from one
form to another. NO FREE LUNCHES! Second Law
(LOSS) In any energy conversion, you will end up
with less usable energy than you started with.
YOU CAN T BREAK EVEN!
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Laws of Thermodynamics
Second Law Energy is lost in the energy
conversion process, as heat. The energy value of
work performed will always be less than the fuel
it consumes.
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Entropy

• Systems will go spontaneously in one direction
  only which is toward increasing entropy.(disorder)

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Example of the Laws of Conservation of Matter and
Thermodynamics
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First Principles of Ecosystem Sustainability

• Ecosystems use sunlight as their source of
  energy.
• The source of all energy is the sun.
• All elements are recycled

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Elements of Life
Produces energy in plants Produces glucose
(sugar) oxygen
Photosynthesis 6 CO2 6 H20
C6H12O6 6 O2
Cell Respiration C6H12O6 6 O2
Uses energy in animals
6 CO2 6 H20
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Photosynthesis

• Natural process
• Converts atmospheric inorganic carbon
• To organic forms of carbon found in living
  systems
• Happens in plants
• Sunlight is the source of all energy
• For plants
• For other living organisms

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The First Principle of Ecosystem Sustainability
At Work
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Match Outcomes (Left) With Process (Right)

• Releases O2
• Stores energy
• Releases CO2
• Uses CO2
• Releases energy
• Produces sugar
• Uses sugar
• Uses O2

• Photosynthesis
• Cell respiration
• Both
• Neither

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Match Outcomes (Left) With Organisms (Right)

• Releases O2
• Stores energy
• Releases CO2
• Uses CO2
• Releases energy
• Produces sugar
• Uses sugar
• Uses O2

• Plants
• Animals
• Both
• Neither

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The Second Principle of Ecosystem Sustainability

• Ecosystems dispose of wastes and replenish
  nutrients by recycling all elements.

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The Carbon Cycle

• How and in what form does carbon enter and leave
  the cycle?
• What are the human impacts on the cycle?
• Fossil fuel burning is an anthropogenic cause of
  return of carbon to the atmosphere

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The Phosphorus Cycle

• How and in what form(s) does phosphorus enter and
  leave the cycle?
• How is the role of autotrophs and heterotrophs
  different and the same?
• What are the human impacts on the cycle?
• Inadvertent fertilization of waterways
• Accumulation of phosphorus rich pollutants in the
  atmosphere
• Depletion of soil supplies by overharvesting and
  erosion

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The Nitrogen Cycle

• How and in what form(s) does nitrogen enter and
  leave the cycle?
• How is the role of autotrophs and heterotrophs
  different and the same?
• What are the human impacts on the cycle?
• The addition of fertilizer to soil contributes to
  the nitrogen cycle
• Farmers plant legumes (soybeans) to enrich the
  soil with nitrogen.
• Nitrogen fixation is the process by which
  microbes work with the legume to produce the
  nitrogen
• Converting the nitrogen gas to a chemical form
  the plant can use

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Nitrogen fixation
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The Human System
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The Human System
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Violations of the First Principle of Ecosystem
Sustainability

• Excessive use of fossil fuels.
• Feeding largely on the third trophic level.
• Use of coal or nuclear power.
• Use of agricultural land to produce meats.

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Violations of the Second Principle of Ecosystem
Sustainability

• Lack of recycling.
• Excessive use of fertilizers.
• Destruction of tropical rain forests.
• Nutrient overcharge into aquatic ecosystems.
• Production and use of nonbiodegradable compounds.

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Ecosystem Services and Functions
Gas, climate and water regulation Water
supply Erosion control Soil formation Pollination
Biological control
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Ecosystem Services and Functions
Food production Recreation Raw materials Nutrient
cycling Waste treatment
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Solar Energy

• Drives the following cycles
• Carbon
• Water
• Nitrogen
• Phosophorus