Ecosystems: What Are They and How Do They Work?

1. Ecosystems: What Are They and How Do They Work? Chapter 3 Dr. Wesam Al Madhoun

2. Core Case Study: Tropical Rain Forests Are Disappearing • Cover about 2% of the earth’s land surface • Contain about 50% of the world’s known plant and animal species • Disruption will have three major harmful effects • Reduce biodiversity • Accelerate global warming • Change regional weather patterns

3. Natural Capital Degradation: Satellite Image of the Loss of Tropical Rain Forest

4. 3-1 What Is Ecology? • Concept 3-1 Ecology is the study of how organisms interact with one another and with their physical environment of matter and energy.

5. Cells Are the Basic Units of Life • Cell Theory: all living things composed of cells. • Eukaryotic cell: surrounded by membrane and has a distinct nucleus (a membrane bounded structure contain DNA) • Prokaryotic cell: surrounded by membrane but no distinct nucleus.

6. Structure of a Eukaryotic Call and a Prokaryotic Cell

7. Species Make Up the Encyclopedia of Life • Species: a set of individuals that can mate and introduce fertile offspring. • 1.75 Million species identified • Insects make up most of the known species • Perhaps 10–14 million species not yet identified

8. Ecologists Study Connections in Nature • Ecology : study of how organism interact with their living environment of other organism and with their non living (a biotic) environment of soil, water and energy. • Levels of organization • Population: a group of individual of the same species living in the same place, same time. • Genetic diversity: genetic variation in a population. • Community: all the population of different species that live in a particular place. • Ecosystem: a community of different species interacting with each other and with nonliving environment. • Biosphere: consist of the parts of the earths, air water and soil where life is found.

9. Parts of the earth's air, water, and soil where life is found Biosphere A community of different species interacting with one another and with their nonliving environment of matter and energy Ecosystem Populations of different species living in a particular place, and potentially interacting with each other Community Population A group of individuals of the same species living in a particular place An individual living being Organism The fundamental structural and functional unit of life Cell Chemical combination of two or more atoms of the same or different elements Molecule Smallest unit of a chemical element that exhibits its chemical properties Atom Stepped Art Fig. 3-3, p. 52

10. Population of Glassfish in the Red Sea

11. Genetic Diversity in a Caribbean Snail Population

12. Science Focus: Have You Thanked the Insects Today? • Pollinators • Eat other insects • Loosen and renew soil • Reproduce rapidly • Very resistant to extinction

13. Importance of Insects

14. 3-2 What Keeps Us and Other Organisms Alive? • Concept 3-2 Life is sustained by the flow of energy from the sun through the biosphere, the cycling of nutrients within the biosphere, and gravity.

15. The Earth’s Life-Support System Has Four Major Components • Atmosphere • Troposphere: 17 km above sea level at tropic, and 7 km at north and south poles “contain majority of the air that we breath”. • Stratosphere: 17-50 km above earth surface. • Hydrosphere: consist of all the water on and near the earth surface. • Geosphere: consist of the earth’s intensely hot core, a thick mantle of rock, thin outer crust. • Biosphere: occupies atmosphere, hydrosphere and geosphere where life exist.

16. Vegetation and animals Atmosphere Biosphere Soil Rock Crust Lithosphere Mantle Biosphere (living organisms) Atmosphere (air) Core Crust (soil and rock) Mantle Hydrosphere (water) Geosphere (crust, mantle, core) Fig. 3-6, p. 55

17. Life Exists on Land and in Water • Biomes : large regions (forest, desert, grasslands) with distinct climate and certain species. • Aquatic life zones • Freshwater life zones • Lakes and streams • Marine life zones • Coral reefs • Estuaries • Deep ocean

18. Major Biomes along the 39th Parallel Average annual precipitation 100–125 cm (40–50 in.) 75–100 cm (30–40 in.) 50–75 cm (20–30 in.) 25–50 cm (10–20 in.) below 25 cm (0–10 in.) Denver Baltimore San Francisco St. Louis Coastal mountain ranges Sierra Nevada Great American Desert Rocky Mountains Great Plains Mississippi River Valley Appalachian Mountains Coastal chaparral and scrub Coniferous forest Desert Coniferous forest Prairie grassland Deciduous forest Fig. 3-7, p. 55

19. What Happens to Solar Energy Reaching the Earth? • UV, visible, and IR energy • Radiation • Absorbed by ozone • Absorbed by the earth • Reflected by the earth • Radiated by the atmosphere as heat • Natural greenhouse effect

20. Solar radiation Reflected by atmosphere Radiated by atmosphere as heat UV radiation Lower Stratosphere (ozone layer) Most absorbed by ozone Troposphere Visible light Heat radiated by the earth Heat Absorbed by the earth Greenhouse effect Fig. 3-8, p. 56

21. 3-3 What Are the Major Components of an Ecosystem? • Concept 3-3A Ecosystems contain living (biotic) and nonliving (abiotic) components. • Concept 3-3B Autotrophs (self feeding, Heterotrophs (other feeders), Detritovores (feed on waste or dead bodies).

22. Ecosystems Have Living and Nonliving Components • Abiotic • Water • Air • Nutrients • Rocks • Heat • Solar energy • Biotic • Living and once living

23. Major Biotic and Abiotic Components of an Ecosystem

24. Oxygen (O2) Precipitation Carbon dioxide (CO2) Producer Secondary consumer (fox) Primary consumer (rabbit) Producers Water Decomposers Soluble mineral nutrients Fig. 3-9, p. 57

25. Several Abiotic Factors Can Limit Population Growth • Limiting factor principle • Too much or too little of any a biotic factor can limit or prevent growth of a population, even if all other factors are at or near the optimal range of tolerance.

26. Range of Tolerance for a Population of Organisms INSERT FIGURE 3-10 HERE

27. Producers and Consumers Are the Living Components of Ecosystems (1) • Producers, autotrophs • Photosynthesis: the way, energy enter most ecosystem • Chemosynthesis: producers (bacteria) convert inorganic compound to more complex nutrient without sun light. • Consumers, heterotrophs • Primary (plant eaters such as rabbits) • Secondary (meat eater, birds , frogs) • Third and higher level (tigers ,wolves) • Decomposers

28. Producers and Consumers Are the Living Components of Ecosystems (2) • Detritivores : feed on waste and dead bodies such as some insects and earth worms. • Aerobic respiration: use of oxygen to convert glucose (C6H12O6) back into carbon dioxide and water • Anaerobic respiration, fermentation: some decomposers get the energy they need by breaking down glucose in the absence of oxygen.

29. Science Focus: Many of the World’s Most Important Species Are Invisible to Us • Microorganisms • Bacteria • Protozoa • Fungi

30. 3-4 What Happens to Energy in an Ecosystem? • Concept 3-4A Energy flows through ecosystems in food chains and webs. • Concept 3-4B As energy flows through ecosystems in food chains and webs, the amount of chemical energy available to organisms at each succeeding feeding level decreases.

31. Energy Flows Through Ecosystems in Food Chains and Food Webs • Food chain: a sequence of organism, each of which serves as a source of food or energy for the next. • Food web: a complex network of interconnected food chains.

32. 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. 3-13, p. 62

33. Usable Energy Decreases with Each Link in a Food Chain or Web • Biomass: the dry weight of all organic matter contained in its organisms. • Ecological efficiency: the % of useable chemical energy transferred as biomass from one trophic level to the next • Pyramid of energy flow: cumulative energy loss.

34. 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) Fig. 3-15, p. 63

35. Some Ecosystems Produce Plant Matter Faster Than Others Do • Gross primary productivity (GPP): is the rate at which ecosystem producers (plants) convert solar energy into chemical energy as biomass found in their tissues. • Net primary productivity (NPP): NPP = GPP – R. where R is energy used in respiration. • Ecosystems and life zones differ in their NPP

36. Terrestrial Ecosystems Swamps and marshes Tropical rain forest Temperate forest Northern coniferous forest 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. 3-16, p. 64

37. 3-5 What Happens to Matter in an Ecosystem? • Concept 3-5 Matter, in the form of nutrients, cycles within and among ecosystems and the biosphere, and human activities are altering these chemical cycles.

38. Nutrients Cycle in the Biosphere • Biogeochemical cycles, nutrient cycles • Hydrologic • Carbon • Nitrogen • Phosphorus • Sulfur • Connect past, present , and future forms of life

39. Global warming Condensation Ice and snow Condensation Evaporation from land Evaporation from ocean Precipitation to land Transpiration from plants 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 Groundwater movement (slow) Ocean Aquifer depletion from overpumping Processes Processes affected by humans Reservoir Pathway affected by humans Natural pathway Fig. 3-17, p. 66

40. Science Focus: Water’s Unique Properties • Properties of water due to hydrogen bonds between water molecules: • Exists as a liquid over a large range of temperature • Changes temperature slowly • High boiling point: 100˚C • Expands as it freezes • Filters out harmful UV

41. Carbon Cycle Depends on Photosynthesis and Respiration • Link between photosynthesis in producers and respiration in producers, consumers, and decomposers • Additional CO2 added to the atmosphere • Tree clearing • Burning of fossil fuels

42. Carbon dioxide in atmosphere Respiration Photosynthesis Burning fossil fuels Forest fires Animals (consumers) Diffusion Deforestation Plants (producers) Carbon in plants (producers) Transportation Respiration Carbon in animals (consumers) Carbon dioxide dissolved in ocean Carbon in fossil fuels Decomposition Marine food webs Producers, consumers, decomposers Carbon in limestone or dolomite sediments Compaction Processes Reservoir Pathway affected by humans Natural pathway Fig. 3-18, p. 68

43. Nitrogen Cycles through the Biosphere: Bacteria in Action (1) • Nitrogen fixed – N 2 converted to nutrient by: • Lightning : electrical discharge in the atmosphere. • Nitrogen-fixing bacteria: in soil or plan roots. • Nitrification :is the biological oxidation of ammonia with oxygen into nitrite followed by the oxidation of these nitrites into nitrates • Denitrification: is a microbially facilitated process of nitrate reduction that may ultimately produce molecular nitrogen (N2) through a series of intermediate gaseous nitrogen oxide products.

44. Nitrogen Cycles through the Biosphere: Bacteria in Action (2) • Human intervention in the nitrogen cycle • Additional NO and N2O • Destruction of forest, grasslands, and wetlands • Add excess nitrates to bodies of water • Remove nitrogen from topsoil

45. Processes Nitrogen in atmosphere Reservoir Pathway affected by humans Natural pathway Denitrification by bacteria Electrical storms Nitrogen oxides from burning fuel and using inorganic fertilizers Nitrogen in animals (consumers) 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. 3-19, p. 69

46. 300 Projected human input 250 200 Total human input 150 Nitrogen input (teragrams per year) Fertilizer and industrial use 100 50 Nitrogen fixation in agroecosystems Fossil fuels 0 1900 1920 1940 1960 1980 2000 2050 Year Fig. 3-20, p. 70

47. 3-6 How Do Scientists Study Ecosystems? • Concept 3-6 Scientists use field research, laboratory research, and mathematical and other models to learn about ecosystems.

48. Some Scientists Study Nature Directly • Field research: “muddy-boots biology” • New technologies available • Remote sensors • Geographic information system (GIS) software • Digital satellite imaging • 2005, Global Earth Observation System of Systems (GEOSS) – integrate sensors, gauges and satellite that monitor earth, atmosphere and oceans

49. Some Scientists Study Ecosystems in the Laboratory • Simplified systems carried out in • Culture tubes and bottles • Aquaria tanks • Greenhouses • Indoor and outdoor chambers • Supported by field research

50. Some Scientists Use Models to Simulate Ecosystems • Computer simulations and projections • Field and laboratory research needed for baseline data