ENVIRONMENTAL SCIENCE

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

2. Rainforest • http://www.youtube.com/watch?v=Ws6m46AAbQQ

3. Core Case StudyIn class assignment • Tropical Rainforests are Disappearing • Where are tropical rainforests found? • How much of the earth’s land surface do they cover? Studies indicate they contain up to ______ of the world’s known terrestrial plant and animal species • Define ecosystems • About ________ of these forests have been destroyed by humans

4. Core Case Study: Tropical Rainforests Are Disappearing (2) • Consequences of disappearing tropical rainforests • __________ as species become extinct • ______________: fewer trees to remove carbon dioxide from the atmosphere • _______________: can lead to increase in tropical grasslands

5. Define Ecological Tipping Point- • What is the ecological tipping point for this case study?

6. Satellite image of the loss of tropical rain forest near the Bolivian City of Santa Cruz. Why is this an example of Natural Capital degradation? June 1975 May 2003 Fig. 3-1, p. 39

7. 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.

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

9. 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

10. Three Factors Sustain Life on Earth 1) One-way flow of high-quality energy from the sun 2) Cycling of matter or nutrients through parts of the biosphere 3) Gravity

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

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. Greenhouse Effect Animation • http://www.youtube.com/watch?v=CxUK2TizQ4g&feature=related

14. 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.

15. Ecology • How organisms interact with biotic (pertaining to life) and abiotic environment (non-living) • Focuses on specific levels of matter: • Organisms • Populations • Communities • Ecosystems • Biosphere

16. Which 5 levels does ecology focus on? 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

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

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

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

20. Trophic Levels (feeding levels)(1) • Producers– autotrophs • Photosynthesis • Consumers – heterotrophs • Primary - herbivores • Secondary - carnivores • Third-level (tertiary) • quartenary • Omnivores

21. Trophic Levels (2) • Decomposers (ex. bacteria and fungi) • Release nutrients from the dead bodies of plants and animals • Detrivores(ex. earthworms, some insects, vultures) • Feed on the waste or dead bodies of organisms

22. 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

23. Production and Consumption of Energy • Photosynthesis • Carbon dioxide + water + solar energy glucose + oxygen 6CO2 + 6H2O + solar E C6H12O6 + 6O2 • Aerobic respiration (opposite) • Glucose + oxygen  carbon dioxide + water + energy

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

25. Main components of an ecosystem 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

26. 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.

27. 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

28. Food chain 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

29. Humans Antarctic Food Web 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

30. 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

31. 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) What happens to amount of usable energy as you go up each level? Fig. 3-10, p. 47

32. Two Kinds of Primary Productivity • Gross primary productivity (GPP): the rate at which an ecosystems producers convert solar E into chemical E in the form of biomass found in their tissues • Net primary productivity (NPP)- rate at which producer’s use photosynthesis to produce and store chemical E minus the rate at which they use some of this stored E thru aerobic respiration • 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

33. 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

34. 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.

35. Biogeochemical Cycles • Nutrient cycles • Reservoirs- temporary storage sites for nutrients • Connect all organisms through time

36. 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, most of water reaching the atmosphere comes from transpiration

37. 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

38. 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

39. Science Focus: Water’s Unique Properties (2) • Dissolves a variety of compounds • Filters out UV light from the sun • Adheres to a solid surface – allows capillary action in plants • Expands as it freezes

40. Carbon Cycle • Based on carbon dioxide (CO2) • CO2 makes up 0.038% of atmosphere volume • Major cycle processes • Aerobic respiration • Photosynthesis • Fossil fuel combustion and deforestation • Fossil fuels add CO2 to the atmosphere and contribute to global warming

41. Carbon dioxide in atmosphere Respiration Photosynthesis Burning fossil fuels Forest fires Animals (consumers) Diffusion Deforestation Plants (producers) Carbon in plants (producers) Respiration Transportation Carbon in animals (consumers) Carbon dioxide dissolved in ocean Decomposition Carbon in fossil fuels Marine food webs Producers, consumers, decomposers Carbon in limestone or dolomite sediments Compaction Processes Reservoir Pathway affected by humans Natural pathway Fig. 3-13, p. 51

42. Nitrogen Cycle • Multicellular plants and animals cannot utilize atmospheric nitrogen (N2) • Nitrogen fixation • Nitrification • Ammonification • Denitrification

43. Processes Reservoir Pathway affected by humans Natural pathway Nitrogen in atmosphere Denitrification by bacteria Electrical storms Nitrogen in animals (consumers) Nitrogen oxides from burning fuel Volcanic activity Nitrification by bacteria Nitrogen in plants (producers) Nitrates from fertilizer runoff and decomposition Decomposition Uptake by plants Nitrate in soil Nitrogen loss to deep ocean sediments Nitrogen in ocean sediments Bacteria Ammonia in soil Fig. 3-14, p. 52

44. Phosphorus Cycle • Does not cycle through the atmosphere • Obtained from terrestrial rock formations • Limiting factor on land and in freshwater ecosystems • Biologically important for producers and consumers

45. Processes Reservoir Pathway affected by humans Natural pathway Phosphates in sewage Phosphates in fertilizer Plate tectonics Phosphates in mining waste Runoff Runoff Sea birds Runoff Phosphate in rock (fossil bones, guano) Erosion Ocean food chain Animals (consumers) Phosphate dissolved in water Phosphate in shallow ocean sediments Phosphate in deep ocean sediments Plants (producers) Bacteria Fig. 3-15, p. 53

46. Sulfur Cycle • Most sulfur stored in rocks and minerals • Enters atmosphere through: • Volcanic eruptions and processes • Anaerobic decomposition in swamps, bogs, and tidal flats • Sea spray • Dust storms • Forest fires

47. Sulfur dioxide in atmosphere Sulfuric acid and Sulfate deposited as acid rain Burning coal Refining fossil fuels Smelting Sulfur in animals (consumers) Dimethyl sulfide a bacteria byproduct Sulfur in plants (producers) Mining and extraction Uptake by plants Decay Sulfur in ocean sediments Decay Processes Sulfur in soil, rock and fossil fuels Reservoir Pathway affected by humans Natural pathway Fig. 3-16, p. 54

48. 3-5 How Do Scientists Study Ecosystems? • Concept 3-5 Scientists use field research, laboratory research, and mathematical and other models to learn about ecosystems.

49. Field Research • Collecting data in the field by scientists • Remote sensing devices • Geographic information systems (GIS)

50. Laboratory Research • Simplified model ecosystems • Culture tubes • Bottles • Aquariums • Greenhouses • Chambers with controllable abiotic factors • How well do lab experiments correspond with the greater complexity of real ecosystems?