1. Environmental Science: Toward A Sustainable Future Chapter 3
Ecosystems: How They Work

2. 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.

3. 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

4. Ecological Principles: DICE
Diversity
Interrelationships
Cycles
Energy

5. 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

6. 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

7. Elements of Life Top 8 elements in the earths crust (in order)
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.

8. Atmospheric Gases in Troposphere
78% Nitrogen
21% Oxygen
<0.04% Carbon Dioxide

9. 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

10. Elements of Life Organic = carbon based molecules
Example: C6H12O6, CH4
Inorganic = molecules without carbon-carbon
nor carbon-hydrogen bonds
Example: NaCl, NH4, H2SO4

11. Match the Elements (Left) With Molecules (Right)
Nitrogen
Carbon
Hydrogen
Oxygen
Phosphorus
Sulfur
Glucose
Proteins
Starch
Fats
Nucleic acids
All of the above

12. 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

13. 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.

14. Physics Energy is measured in calories 1st law of thermodynamics
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.

15. 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.

16. 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!

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

18. Example of the Laws of Conservation of Matter and Thermodynamics
Global Warming
Acid Rain
Smog
Burning Coal = CO2 + SOx + H20 + Ash
(CxHxSxOx) Light + Noise + Heat

19. First Principles of Ecosystem Sustainability
Ecosystems use sunlight as their source of energy.

20. Elements of Life 6 CO2 + 6 H20 C6H12O6 + 6 O2 Respiration
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?

21. The First Principle of Ecosystem Sustainability At Work

22. 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

23. 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

24. The Second Principle of Ecosystem Sustainability
Ecosystems dispose of wastes and replenish nutrients by recycling all elements.

25. 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?

27. 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?

29. 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…

30. 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?

32. 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

33. The Human System

34. The Human System

35. 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.

36. 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.

37. Ecosystem Services and Functions
Gas, climate and water regulation
Water supply
Erosion control
Soil formation
Pollination
Biological control

38. Ecosystem Services and Functions
Food production
Recreation
Raw materials
Nutrient cycling
Waste treatment