ENVIRONMENTAL SCIENCE

1. 13e ENVIRONMENTALSCIENCE CHAPTER 3:Ecosystems: What Are They and How Do They Work?

2. Core Case Study: Tropical Rainforests Are Disappearing (1) • Found near the equator • 2% land surface • ~50% world’s known terrestrial plant and animal species • ≥50% destroyed or disturbed by humans • Cutting trees • Growing crops • Grazing cattle • Building settlements

3. Core Case Study: Tropical Rainforests Are Disappearing (2) • Consequences of disappearing tropical rainforests • Decreased biodiversity as species become extinct • Accelerated global warming: fewer trees to remove carbon dioxide from the atmosphere • Changes regional weather patterns: can lead to increase in tropical grasslands

4. Fig. 3-1, p. 39

5. 3-1 What Keeps Us and Other Organisms Alive? • Concept 3-1A The four major components of the earth’s life-support system are the atmosphere (air), the hydrosphere (water), the geosphere (rock, soil, sediment), and the biosphere (living things). • Concept 3-1B Life is sustained by the flow of energy from the sun through the biosphere, the cycling of nutrients within the biosphere, and gravity.

6. Earth Has Four Major Life-Support Components • Atmosphere • Hydrosphere • Geosphere • Biosphere

7. Fig. 3-2, p. 41

8. Vegetation and animals Atmosphere Biosphere Soil Rock Crust Lithosphere Mantle Biosphere (living organisms) Core Atmosphere (air) Mantle Crust (soil and rock) Geosphere (crust, mantle, core) Hydrosphere (water) Fig. 3-2, p. 41

9. Three Factors Sustain Life on Earth • One-way flow of high-quality energy from the sun • Cycling of matter or nutrients through parts of the biosphere • Gravity

10. Solar Energy Reaching the Earth • Electromagnetic waves • Visible light • UV radiation • Heat • Natural greenhouse effect • Energy in = energy out • Human-enhanced global warming

11. Fig. 3-3, p. 41

12. Solar radiation Reflected by atmosphere Radiated by atmosphere as heat UV radiation Lower Stratosphere (ozone layer) Most absorbed by ozone Visible light Troposphere Heat radiated by the earth Heat Greenhouse effect Absorbed by the earth Fig. 3-3, p. 41

13. 3-2 What Are the Major Components of an Ecosystem? • Concept 3-2 Some organisms produce the nutrients they need, others get the nutrients they need by consuming other organisms, and some recycle nutrients back to producers by decomposing the wastes and remains of organisms.

14. Ecology • How organisms interact with biotic and abiotic environment • Focuses on specific levels of matter: • Organisms • Populations • Communities • Ecosystems • Biosphere

15. Fig. 3-4, p. 42

16. Biosphere Parts of the earth's air,water, and soil where life is found Ecosystem A community of different species interacting with one another and with their nonliving environment of matter and energy Community Populations of different species living in a particular place, and potentially interacting with each other Population A group of individuals of the same species living in a particular place Organism An individual living being The fundamental structural and functional unit of life Cell Molecule Chemical combination of two or more atoms of the same or different elements Water Atom Smallest unit of a chemical element that exhibits its chemical properties Hydrogen Oxygen Fig. 3-4, p. 42

17. Biosphere Parts of the earth's air,water, and soil where life is found Ecosystem A community of different species interacting with one another and with their nonliving environment of matter and energy Community Populations of different species living in a particular place, and potentially interacting with each other Population A group of individuals of the same species living in a particular place Organism An individual living being The fundamental structural and functional unit of life Cell Molecule Chemical combination of two or more atoms of the same or different elements Atom Smallest unit of a chemical element that exhibits its chemical properties Stepped Art Fig. 3-4, p. 42

18. Living and Nonliving Components (1) • Abiotic • Water • Air • Nutrients • Solar energy • Rocks • Heat

19. Living and Nonliving Components (2) • Biotic • Plants • Animals • Microbes • Dead organisms • Waste products of dead organisms

20. Fig. 3-5, p. 43

21. Oxygen (O2) Precipitation Carbon dioxide (CO2) Producer Secondary consumer (fox) Primary consumer (rabbit) Producers Water Decomposers Soluble mineral nutrients Fig. 3-5, p. 43

22. Trophic Levels (1) • Producers – autotrophs • Photosynthesis • Consumers – heterotrophs • Primary - herbivores • Secondary - carnivores • Third-level • Omnivores

23. Trophic Levels (2) • Decomposers • Release nutrients from the dead bodies of plants and animals • Detrivores • Feed on the waste or dead bodies of organisms

24. Fig. 3-6, p. 44

25. Detritus feeders Decomposers Carpenter ant galleries Termite and carpenter ant work Bark beetle engraving Dry rot fungus Long-horned beetle holes Wood reduced to powder Mushroom Time progression Powder broken down by decomposers into plant nutrients in soil Fig. 3-6, p. 44

26. Production and Consumption of Energy • Photosynthesis • Carbon dioxide + water + solar energy glucose + oxygen • Aerobic respiration • Glucose + oxygen  carbon dioxide + water + energy

27. Energy Flow and Nutrient Recycling • Ecosystems sustained through: • One-way energy flow from the sun • Nutrient recycling

28. Fig. 3-7, p. 45

29. Solar energy Abiotic chemicals (carbon dioxide, oxygen, nitrogen, minerals) Heat Heat Heat Producers (plants) Decomposers (bacteria, fungi) Consumers (herbivores, carnivores) Heat Heat Fig. 3-7, p. 45

30. Science Focus: Invisible Organisms (1) • Microorganisms/Microbes • Bacteria • Protozoa • Fungi • Phytoplankton

31. Science Focus: Invisible Organisms (2) • Microbes can cause disease • Malaria • Athlete’s foot • Microbes are also beneficial • Intestinal flora • Purify water • Phytoplankton remove carbon dioxide from the atmosphere

32. 3-3 What Happens to Energy in an Ecosystem? • Concept 3-3 As energy flows through ecosystems in food chains and webs, the amount of chemical energy available to organisms at each succeeding feeding level decreases.

33. Energy Flow in Ecosystems • Trophic levels • Food chain • Sequence of organisms, each of which serves as a source of food for the next • Food web • Network of interconnected food chains • More complex than a food chain

34. Fig. 3-8, p. 46

35. First Trophic Level Second Trophic Level Third Trophic Level Fourth Trophic Level Producers (plants) Primary consumers (herbivores) Secondary consumers (carnivores) Tertiary consumers (top carnivores) Heat Heat Heat Heat Solar energy Heat Heat Heat Decomposers and detritus feeders Fig. 3-8, p. 46

36. Fig. 3-9, p. 46

37. Humans Sperm whale Blue whale Elephant seal Crabeater seal Killer whale Leopard seal Adelie penguin Emperor penguin Squid Petrel Fish Carnivorous plankton Herbivorous zooplankton Krill Phytoplankton Fig. 3-9, p. 46

38. Usable Energy by Trophic Level • Energy flow follows the second law of thermodynamics – energy lost as heat • Biomass decreases with increasing trophic level • Ecological efficiency – typically 10% • Pyramid of energy flow

39. Fig. 3-10, p. 47

40. Usable energy available at each trophic level (in kilocalories) Heat Tertiary consumers (human) 10 Heat Secondary consumers (perch) 100 Heat Heat Decomposers Primary consumers (zooplankton) 1,000 Heat 10,000 Producers (phytoplankton) Fig. 3-10, p. 47

41. Usable energy available at each trophic level (in kilocalories) Heat Tertiary consumers (human) 10 Heat Secondary consumers (perch) 100 Heat Decomposers Heat Primary consumers (zooplankton) 1,000 Heat 10,000 Producers (phytoplankton) Stepped Art Fig. 3-10, p. 47

42. Two Kinds of Primary Productivity • Gross primary productivity (GPP) • Net primary productivity (NPP) • Planet’s NPP limits number of consumers • Humans use, waste, or destroy 10-55% of earth’s total potential NPP • Human population is less than 1% of total biomass of earth’s consumers

43. Fig. 3-11, p. 48

44. Terrestrial Ecosystems Swamps and marshes Tropical rain forest Temperate forest Northern coniferous forest (taiga) Savanna Agricultural land Woodland and shrubland Temperate grassland Tundra (arctic and alpine) Desert scrub Extreme desert Aquatic Ecosystems Estuaries Lakes and streams Continental shelf Open ocean 800 1,600 2,400 3,200 4,000 4,800 5,600 6,400 7,200 8,000 8,800 9,600 Average net primary productivity (kcal/m2/yr) Fig. 3-11, p. 48

45. 3-4 What Happens to Matter in an Ecosystem? • Concept 3-4 Matter, in the form of nutrients, cycles within and among ecosystems and in the biosphere, and human activities are altering these chemical cycles.

46. Biogeochemical Cycles • Nutrient cycles • Reservoirs • Connect all organisms through time

47. Hydrologic Cycle • Water cycle is powered by the sun • Evaporation • Precipitation • Transpiration - evaporates from plant surfaces • Water vapor in the atmosphere comes from the oceans – 84% • Over land, ~90% of water reaching the atmosphere comes from transpiration

48. Fig. 3-12, p. 49

49. Climate change Condensation Ice and snow Condensation Precipitation to land Transpiration from plants Evaporation from land Evaporation from ocean Surface runoff Increased flooding from wetland destruction Precipitation to ocean Runoff Lakes and reservoirs Reduced recharge of aquifers and flooding from covering land with crops and buildings Point source pollution Infiltration and percolation into aquifer Surface runoff Ocean Groundwater movement (slow) Aquifer depletion from overpumping Processes Processes affected by humans Reservoir Pathway affected by humans Natural pathway Fig. 3-12, p. 49

50. Science Focus: Water’s Unique Properties (1) • Holds water molecules together – hydrogen bonding • Liquid over a wide temperature range • Changes temperature slowly • Requires large amounts of energy to evaporate