Key Concepts

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

2. 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 flowof energy • Cycling ofmatter 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. 4-10 p. 71

11. Principles of Ecological Factors • Law of tolerance • Abiotic factors • Limiting factors • Biotic factors Fig. 4-14 p. 73; Refer to Fig. 4-13 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) • Aerobicrespiration • Decomposers Fig. 4-16 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. 4-18 p. 77; Refer to Fig. 4-19 p. 78

17. Ecological Pyramids • Pyramid ofenergy flow Fig. 4-20 p. 79 • Ecologicalefficiency • Pyramid ofbiomass • Pyramid ofnumbers

18. Primary Productivity of Ecosystems • Gross primary productivity (GPP) • Net primary productivity (NPP) Fig. 4-25 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. 4-27 p. 83

21. The Carbon Cycle (Terrestrial) Fig. 4-28 p. 84-85

22. The Carbon Cycle (Aquatic) Fig. 4-28 p. 84-85

23. The Nitrogen Cycle Fig. 4-29 p. 86

24. The Phosphorus Cycle Fig. 4-30 p. 88

25. The Sulfur Cycle Fig. 4-31 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. 4-32 p. 91 Fig. 4-33 p. 91

28. Ecosystem Servicesand Sustainability Fig. 4-34 p. 92