1. Key Concepts
Basic ecological principles
Major components of ecosystems
Matter cycles and energy flow
Ecosystem studies
Ecological services

2. Ecosystem organization
The Nature of Ecology
Ecosystem organization
Organisms
Populations
Communities
Ecosystems
Biosphere
Fig. 4-2 p. 66

3. Ecology
A. Ecology: study of interactions among organisms and their abiotic
environments
1) organism: any form of life
2) species: group of organisms with similar appearance (?) and ability
to reproduce among themselves
a) estimated 5 to 100 million species (1.75 million known)
3) population: group of individuals of a certain species in a given area
4) habitat: where a population lives
5) community: all populations in a given area
6) ecosystem: all species and abiotic environment and their interactions
7) biosphere: all ecosystems on earth
8) ecotone: transition between ecosystems
a) edge effect:: an ecotone often has more biodiversity and higher
population density
9) climate: long term weather
10) biomes: all ecosystems of a certain type

5. The Earth’s Life-Support Systems
Troposphere
Stratosphere
Hydrosphere
Lithosphere
Biosphere
Fig. 4-6 p. 68

6. Sustaining Life of Earth
One-way flow of energy
Cycling of matter
Fig. 4-7 p. 69

7. The Source of Energy
Fig. 4-8 p. 69

8. The Sun
1) fusion (H = 72%; He = 28%)
2) 93,000,000 miles, 8 minutes
3) 4.2 million tons converted to energy every second
4) of all incoming solar radiation (100%),
- 34% is reflected back by clouds, dust, oceans, land
- 66% heats air, land, evaporates water
- .023% is used in photosynthesis
5) most of the 72% leaves earth as IR (heat)
- process of heat loss is slowed by natural greenhouse effect (H2O, CO2, CH4 etc)
- without natural geenhouse effect life could not exist on earth
6) Geenhouse effect*
If bond vibrational frequency is “in phase” with IR ,
bond absorbs energy, speeds up vibration
and releases energy in all directions,
some of which go back to surface.

9. Ecosystem Concepts and Components
Biomes
Role of climate
Aquatic life zones
Fig. 4-9 p. 70

10. Ecosystem Boundaries: Ecotones
Fig p. 71

11. Principles of Ecological Factors
Abiotic factors
Law of tolerance
Biotic factors
Limiting factors
Fig p. 73; Refer to Fig p. 73

12. Tolerance Limits range of tolerance a) tolerance limits dam
b) organisms may acclimate to changing
conditions but once they cross over the
threshold (tolerance limit), they may suddenly die
c) limiting factor: one factor that is more important
than others in limiting population

13. The Biotic Components of Ecosystems
Producers (autotrophs)
Photosynthesis
Consumers (heterotrophs)
Aerobic respiration
Decomposers
Fig p. 75

14. Trophic Levels Primary consumer (herbivore)
Secondary consumer (carnivore)
Tertiary consumer
Omnivore
Detritivores and scavengers
Decomposers

15. Biodiversity Genetic diversity Species diversity Ecological diversity
Functional diversity

16. Connections: Food Webs and Energy Flow in Ecosystems
Food chains
Food webs
Fig p. 77; Refer to Fig p. 78

17. Ecological Pyramids Pyramid of energy flow Ecological efficiency
Fig p. 79
Ecological efficiency
Pyramid of biomass
Pyramid of numbers

18. Primary Productivity of Ecosystems
Gross primary productivity (GPP)
Net primary productivity (NPP)
Fig p. 81

19. Connections: Matter Cycling in Ecosystems
Biogeochemical cycles
Hydrologic cycle (H2O)
Atmospheric cycles (C, N)
Sedimentary cycles (P, S)

20. Hydrologic (Water) Cycle
Fig p. 83

21. The Carbon Cycle (Terrestrial)
Fig p

22. The Carbon Cycle (Aquatic)
Fig p

23. The Nitrogen Cycle
Fig p. 86

24. The Phosphorus Cycle
Fig p. 88

25. The Sulfur Cycle
Fig p. 89

26. How Do Ecologists Learn About Ecosystems?
Field research
Remote sensing
Geographic information systems (GIS)
Laboratory research
Systems analysis

27. GIS and Systems Analysis
Fig p. 91
Fig p. 91

28. Ecosystem Services and Sustainability
Fig p. 92