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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5 Principles of Sustainability to Learn from
Natural Ecosystems

• (Almost) all ecosystems use sunlight as the
  primary energy source
• Ecosystems dispose of waste and replenish
  nutrients by recycling all elements
• The size of consumer populations are controlled
  such that overgrazing and other overuse does not
  occur
• Ecosystems are resilient to disturbances and
  pollutants
• Ecosystems require biodiversity to function
  indefinitely

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Ecological Principles DICE
Diversity Interrelationships Cycles Energy
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Biosphere II

• Purpose recreate conditions of Earth (Biosphere
  I)
• to understand our world better
• space travel
• 5 acres in Arizona, 4000 species,
• 10 humans
• problem 02 CO2
• were absorbed by concrete
• ants and cockroaches took over

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Recycle or Die is the take home message

• This means that we have a limited supply of raw
  materials (formation of the earth)
• All matter is recycled through the lithosphere,
  hydrosphere, and atmosphere.
• Nothing is created nothing is destroyed
• All stable ecosystems recycle matter and get
  energy from the sun

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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 Top 8 elements
in the earths crust (in order) O, Si, Al, Fe
(iron), Ca, Na (sodium), P, Mg Only silly apes in
college study past midnight.
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Atmospheric Gases in Troposphere
78 Nitrogen
21 Oxygen
lt0.04 Carbon Dioxide
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Organic Compounds

• C-C bonds and/or C-H bonds
• They can be natural or synthetic
• Natural compounds that make up living systems
• Synthetic man-made compounds

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Elements of Life
Organic carbon based molecules Example
C6H12O6, CH4 Inorganic molecules without
carbon-carbon nor carbon-hydrogen
bonds Example NaCl, NH4, H2SO4
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Match the Elements (Left) With Molecules (Right)

• Nitrogen
• Carbon
• Hydrogen
• Oxygen
• Phosphorus
• Sulfur

• Glucose
• Proteins
• Starch
• Fats
• Nucleic acids
• All of the above

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Building blocks of living things

• Fats/Lipids
• Phospholipids
• Steroids
• Proteins
• Chains of amino acids
• Muscles
• Enzymes

• Nucleic acids
• Chain of nucleotides
• Deoxyribonucleic acid
• Ribonucleic acid

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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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Physics

• Energy is measured in calories
• Calorie amount of heat needed to raise 1 gram
  of water 1 degree Celsius.
• Kilocalorie 1,000 calories
• 1st law of thermodynamics
• Energy cannot be created nor destroyed, only
  change forms (light to chemical)
• 2nd law of thermodynamics
• Energy transformation increases disorder
  (entropy) of the universe.
• Heat is the lowest grade of energy.

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Matter and Energy

• Energy anything that has the ability to move
  matter, has no mass and does not occupy space.
• 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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Entropy

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

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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.

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Elements of Life
Photosynthesis 6 CO2 6 H20
C6H12O6 6 O2
Respiration C6H12O6 6 O2
6 CO2 6 H20
Which process uses and which produces
energy? Which process occur in plants and which
in animals?
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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?
• How is the role of autotrophs and heterotrophs
  different and the same?
• What are the human impacts on the cycle?

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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?

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Phosphorus cycle

• No gas phase, only solid and liquid
• Man-made fertilizers contain organic phosphates
• Because P is a limiting factor in aquatic
  systems, it leads to eutrophication
• The rain forest is very good at recycling P,
  except when we cut it down

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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?

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Nitrogen cycle

• Main reserve in the atmosphere
• Living things must get N from ammonium (NH4) or
  nitrate (NO3)
• N from the atmo must be fixed
• Change N2 into ammonium or nitrate
• Rhizobium (bacteria living in roots of legumes)
  fig 3-10
• Industrial
• Lightning
• Burning fossil fuels

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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