1. Chapter 3
Ecosystems and Energy

2. What is Ecology? Ecology –
study of the interactions among organisms and between organisms (biotic) and their abiotic environment.

3. What is Ecology?
Levels of Biological Organization

4. What is Ecology?
Ecological Levels of Organization:
Population

5. What is Ecology?
Ecological Levels of Organization:
Community

6. What is Ecology?
Ecological Levels of Organization:
CO2
Ecosystem

7. What is Ecology? Landscape –
encompasses larger area and several ecosystems
Biosphere –
the area where all life exists

8. The Energy of Life
Potential vs. Kinetic Energy

9. The Energy of Life
Thermodynamics –

10. The Energy of Life 1st Law of Thermodynamics –
energy can change forms, but is not created or destroyed
2nd Law of Thermodynamics –
“Entropy Rules!”
amount of usable energy decreases as energy changes forms
1st Law deals with quantity of energy,
2nd Law with quality of energy.

11. The Energy of Life Photosynthesis 6 CO2 + 12 H2O + radiant energy
C6H12O6 + 6 H2O + 6 O2

12. The Energy of Life Cellular Respiration C6H12O6 + 6 O2
6 CO2 + 6 H2O + energy

13. The Energy of Life
Case-in-Point: Life Without the Sun

14. The Flow of Energy Through Ecosystems
Producers, Consumers, and Decomposers

15. The Path of Energy Flow
Food Chains –

16. Food Webs –

17. The Path of Energy Flow
Case-in-Point: How Humans Have Affected the Antarctic Food Web
Baleen whales
What would happen if you eliminated krill?
Krill
Squid
Fishes
Toothed whales
Penguins
Seals

18. The Path of Energy Flow Ecological Pyramids Pyramid of Biomass
Pyramid of Numbers

19. The Path of Energy Flow
Ecological Pyramids
Pyramid of Energy

20. The Path of Energy Flow Example: Thermodynamics in Action
Temperate forest: Primary producers = 1,500 g / m2
Desert: Primary producers = 100 g / m2
Food webs very complex, more tertiary consumers, some quaternary.
Food webs very simple, very few tertiary consumers

21. The Path of Energy Flow Desert Biomass Pyramid such as . . .
13.5 kg coyote must range ~12 ha to subsist (30 acres).
Desert Biomass Pyramid
Tertiary consumers = 0.1 g / m2
Tertiary consumers must range over large areas to obtain enough energy to subsist.
Secondary consumers = 1.0 g / m2
Primary consumers = 10 g / m2
Primary producers = 100 g / m2

22. The Path of Energy Flow Temperate Forest Biomass Pyramid
13.5 kg coyote only needs ~1 ha to subsist (2.5 acres).
Temperate Forest Biomass Pyramid
NOTE: just relative examples, not accurate
Tertiary consumers = 1.5 g / m2
Secondary consumers = 15 g / m2
Primary consumers = 150 g / m2
Primary producers = 1,500 g / m2
Also, possibility of quaternary consumers, like bears.

23. The Path of Energy Flow Ecosystem Productivity =
Net Primary Productivity
Gross Primary Productivity
Plant cellular respiration =

24. The Path of Energy Flow
Ecosystem Productivity