1. Ecosystems: How They Work
Richard T. Wright
Environmental
Science
Tenth Edition
Chapter 3
Ecosystems: How They Work
Copyright © 2008 Pearson Prentice Hall, Inc.

2. Ecosystems: How They Work
Matter, energy, and life
Energy flow in ecosystems
The cycling of matter in ecosystems
Implications for human societies

3. Matter, Energy, and Life Matter in living and nonliving systems
Energy basics
Energy changes in organisms

4. The Four Spheres of Earth’s Environment

7. Elements of Life: A Summary
Of the 94 naturally occurring elements in the universe, only 24 are utilized by living organisms.
What elements would be considered harmful to living organisms?

8. Atmospheric Gases

9. Water and Its Three States

10. Minerals: Dense clusters of atoms of two or more elements held together by the attraction of positive and negative charges.
Na+ and Cl-

11. Interrelationships among
Air, Water, and Minerals

12. Organic Molecules

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. 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. Energy Conversions

17. 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!

18. Example of the Laws of Conservation of Matter and Thermodynamics
Global Warming
Acid Rain
Smog
Burning Coal = CO2 + SO + H2O + Ash +
(CxHxSxOx) Light + Noise + Heat

19. Entropy: Energy Changes in Organisms
Systems will go spontaneously in one direction only which is toward increasing entropy.

20. Entropy

21. First Principle of Ecosystem Sustainability
Ecosystems use sunlight as their source of energy.

22. How Ecosystems Use Sunlight As Their Source of Energy

23. Explain how it is possible to grow a plant in a sealed jar.
Photosynthesis
6 CO2 + 6 H2O
C6H12O6 + 6 O2
Respiration
C6H12O6 + 6 O2
6 CO2 + 6 H2O

24. 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

25. Food Assimilation in Consumers

26. 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.

27. Energy Flow in Ecosystems
Primary production
Energy flow and efficiency
Running on solar energy
Freely available
Nonpolluting
Everlasting

28. Productivity of Different Ecosystems

29. Energy Flow Through Trophic Levels
Third-order Consumer
Secondary Consumer
Primary Consumer
- 100x
- 10x
100 Kcal
10 Kcal
1 Kcal
Producer
10,000 Kcal

30. Energy Flow Through Trophic Levels

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

32. The Cycling of Matter in Ecosystems
The carbon cycle
The phosphorus cycle
The nitrogen cycle

33. 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?

35. 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?

37. 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?