Ecosystems: What Are They and How Do They Work?

1. Ecosystems: What Are They and How Do They Work? Chapter 4 APES Ms. Miller

2. Key Concepts • Basic ecological principles • Major components of ecosystems • Matter cycles and energy flow • Ecosystem studies • Principles of Sustainability

3. The Nature of Ecology • Ecosystem organization • Organisms—any form of life • Populations—group of interacting individuals of same species in a specific area • Communities—all populations of species interacting in an area • Ecosystems—a community interacting with abiotic factors • Biosphere—all earth’s ecosystems together Fig. 4-2 p. 57

4. The Earth’s Life-Support Systems • Troposphere-sea level to 11 mi above; most of Earth’s air • Stratosphere-11-30 miles above; contains ozone layer • Hydrosphere-all the Earth’s water • Lithosphere-earth’s crust and upper mantle • Biosphere-where all organisms live and interact Fig. 4-7 p. 60

5. Natural Capital: Sustaining Life of Earth • One-way flowof energy from Sun • Cycling ofCrucial Elements • Gravity Fig. 4-8 p.60

6. Solar Capital: Flow of Energy to and from the Earth Fig. 4-9 p. 61

7. Natural Capital: Major Biomes • Biomes • Role of climate • Aquatic life zones Fig. 4-10 p. 62

8. Ecosystem Factors • Range of tolerance • Abiotic factors • Limiting factors • Biotic factors Fig. 4-13 p. 64

9. Tolerance and Limiting Factors Law of Tolerance—states “the existence, abundance and distribution of a species in an ecosystem are determined by whether the levels of one or more physical or chemical factors fall within the range tolerated by that species”

10. Limiting Factor Principle—states “too much or too little of any abiotic factor can limit or prevent growth of a population, even if all other factors are at or near the optimum range of tolerance”

12. Components of Ecosystems • Abiotic chemicals Fig. 4-17 p. 67

13. Aerobic respiration

14. Photosynthesis

15. Producers (autotrophs)

16. Consumers(heterotrophs)

17. Decomposers

18. Biodiversity • Genetic diversity-the variety of genetic material within a species or a population

19. Species diversity-the number of species present in different habitats

20. Ecological diversity-the variety of terrestrial and aquatic ecosystems in an area or on earth

21. Functional diversity-biologicaland chemical processes such as energy flow and matter cycling needed for survival of species, communities and ecosystems

22. Connections: Energy Flow in Ecosystems • Food chains-movement of energy and nutrients from one organism to the next • Trophic Levels-a feeding level in an ecosystem dependent on whether it is a producer or consumer • Food webs-complex network of interconnected food chains

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

24. Connections: Food Chains and Energy Flow in Ecosystems Fig. 4-18 p. 68

25. Ecological Pyramids • Pyramid ofenergy flow • Ecologicalefficiency • Pyramid ofbiomass • Pyramid ofnumbers Fig. 4-21 p. 70

26. Primary Productivity of Ecosystems • Gross primary productivity (GPP)-rate at which solar energy converted to chemical energy • Net primary productivity (NPP)- GPP-rate at which producer uses stored energy Fig. 4-24 p. 72

27. Soils Origins—mixture of eroded rock, mineral nutrients, decaying organic material, water, air, and billions of living organisms Importance—provides most of the nutrients needed for plant growth and helps purify water Maturity and Horizons—mature soils have a series of horizontal layers called horizons (O horizon—surface litter layer; A horizon—topsoil; B horizon—subsoil; C horizon—bedrock) Variations with Climate and Biomes—five major types of soil 1) desert; 2) grassland; 3) tropical rain forest; 4) deciduous forest; 5) coniferous forest Variations in Texture and Porosity—size of particles and space between particles Clay—very fine particles Silt—fine particles Sand—medium-sized particles Gravel—coarse particles

28. Soil Profiles in Different Biomes Fig. 4-27, p. 75

29. Connections: Matter Cycling in Ecosystems • Biogeochemical cycles • Hydrologic cycle (H2O) • Carbon cycle • Nitrogen cycle • Phosphorus cycle • Sulfur cycle

30. Hydrologic (Water) Cycle Fig. 4-28 p. 76

31. The Carbon Cycle (Marine) Fig. 4-29, p. 78

32. The Carbon Cycle (Terrestrial) Fig. 4-29, p. 78

33. The Nitrogen Cycle Fig. 4-31 p. 80

34. The Phosphorus Cycle Fig. 4-33 p. 82

35. The Sulfur Cycle Fig. 4-34 p. 83

36. How Do Ecologists Learn About Ecosystems? • Field research—going into nature and observing and measuring structure of ecosystem and what happens in them • Remote sensing—field data collecting via aircraft and satellites • Geographic information systems (GIS) Information gathered from broad geographic regions and stored in computer databases • Laboratory research—model ecosystem situations tested under laboratory conditions • Systems analysis—mathematical and other models that simulate ecosystems

37. Geographic Information System (GIS) Fig. 4-35 p. 84

38. Systems Analysis Fig. 4-36 p. 85