1 / 52

Quantifying Communities

Quantifying Communities. Community structure is measured in different ways. Species Richness : The number of _______ species in the community Species Diversity : The number and _________of species in the community. Are All Ecosystems Equal?.

johnna
Télécharger la présentation

Quantifying Communities

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Quantifying Communities Community structure is measured in different ways. Species Richness: The number of _______ species in the community Species Diversity: The number and _________of species in the community

  2. Are All Ecosystems Equal? Different ecosystems have different amounts of biodiversity (and produce different amounts of _________)

  3. Diversity = Stability There is a direct relationship between biodiversity in an ecosystem and the stability of the ecosystem. Genetic Diversity Species Diversity Biome Diversity

  4. Ch 55: Ecosystems • Ecosystems, Energy, and Matter • An ecosystem consists of all the organisms living in a community (___________ factors) and all the abiotic factors with which they rely on

  5. The only constant is change Ecosystems are constantly changing. Disturbance: Anything that disrupts the homeostatic balance of an ecosystem.

  6. Tertiary consumers Microorganisms and other detritivores Secondary consumers Primary consumers Detritus Primary producers Heat Key Chemical cycling Sun Energy flow Figure 54.2 How does Energy and Chemical movement different through ecosystems?

  7. Trophic Efficiency  -Only __% of Sun’s energy reaches the earth -Most energy does ____ move up the food chain

  8. Tertiary consumers 10 J Secondary consumers 100 J Primary consumers 1,000 J Primary producers 10,000 J Figure 54.11 1,000,000 J of sunlight We measure Productivity with Pyramids! -Pyramid of Energy -Shows that within a food chain, only ~___% of energy at any trophic level will be passed on to the next trophic level.

  9. Dry weight (g/m2) Trophic level Tertiary consumers 1.5 Secondary consumers 11 37 Primary consumers Primary producers 809 (a) Most biomass pyramids show a sharp decrease in biomass at successively higher trophic levels, as illustrated by data froma bog at Silver Springs, Florida. Figure 54.12a Biomass also measures Productivity Energy is added in to a community by _______. Pyramids of Biomass show that ________ usually occupy the greatest biomass in the ecosystem.

  10. Trophic level Number of individual organisms Tertiary consumers 3 Secondary consumers 354,904 Primary consumers 708,624 Primary producers 5,842,424 Figure 54.13 Pyramids of Numbers • A pyramid of numbers represents the number of __________ in each trophic level

  11. Dry weight (g/m2) Trophic level 21 Primary consumers (zooplankton) Primary producers (phytoplankton) 4 (b) In some aquatic ecosystems, such as the English Channel, a small standing crop of primary producers (phytoplankton)supports a larger standing crop of primary consumers (zooplankton). Figire 54.12b • Certain aquatic ecosystems • Have inverted biomass pyramids

  12. Primary Productivity is the amount of light energy converted to chemical energy by autotrophs during a given time period Does all of the energy absorbed the sun go into the bodies (biomass) of producers?

  13. Productivity How is Gross primary productivity (GPP) different from net primary productivity (NPP)? NPP = GPP – (metabolism + lost energy)

  14. Are all ecosystems equally productive? Does productivity fluctuates seasonally, and with climate?

  15. 125 Open ocean 24.4 65.0 360 Continental shelf 5.2 5.6 1,500 Estuary 0.3 1.2 Algal beds and reefs 2,500 0.1 0.9 Upwelling zones 0.1 500 0.1 Extreme desert, rock, sand, ice 3.0 4.7 0.04 0.9 90 Desert and semidesert scrub 3.5 Tropical rain forest 2,200 22 3.3 2.9 Savanna 900 7.9 9.1 2.7 Cultivated land 600 Boreal forest (taiga) 9.6 2.4 800 1.8 Temperate grassland 600 5.4 Woodland and shrubland 700 1.7 3.5 Tundra 0.6 1.6 140 Tropical seasonal forest 1,600 7.1 1.5 Temperate deciduous forest 1,200 1.3 4.9 1,300 Temperate evergreen forest 1.0 3.8 0.4 Swamp and marsh 2,000 2.3 Lake and stream 0.4 250 0.3 0 10 20 30 40 50 60 0 500 1,000 1,500 2,000 2,500 0 5 10 15 20 25 Key Percentage of Earth’s net primary production Average net primary production (g/m2/yr) (a) (b) Percentage of Earth’s surface area Marine Terrestrial Figure 54.4a–c Freshwater (on continents) Different ecosystems vary in their net primary production • And in their contribution to the total NPP on Earth (c)

  16. North Pole 60N 30N Equator 30S 60S South Pole 120W 180 0 60E 120E 180 60W Figure 54.5 • Overall, terrestrial ecosystems contribute about two-thirds of global NPP and marine ecosystems about one-third

  17. Matter Cycles Matter cycles between abiotic and ________ reservoirs in an ecosystem

  18. Producers & Decomposers Producers move matter from ______ sources (sun, soil) to biotic sources. Decomposers move matter from biotic sources to abiotic sources.

  19. Figure 54.3 Nutrients cycle through ecosystems • Decomposers or detritivores (mainly bacteria and fungi) recycle essential elements by decomposing organic material and returning elements to inorganic reservoirs

  20. RESULTS Phytoplankton abundance parallels the abundance of phosphorus in the water (a). Nitrogen, however, is immediately taken up by algae, and no free nitrogen is measured in the coastal waters. The addition of ammonium (NH4) caused heavy phytoplankton growth in bay water, but the addition of phosphate (PO43) did not induce algal growth (b). Ammonium enriched Phytoplankton 30 8 8 Phosphate enriched 7 7 Unenriched control Inorganic phosphorus 24 6 6 Phytoplankton (millions of cells/mL) Inorganic phosphorus (g atoms/L) 5 5 18 4 4 Phytoplankton (millions of cells per mL) 3 3 12 2 2 1 1 6 0 0 2 4 5 11 30 15 19 21 0 Station number Starting algal density 2 4 5 11 30 15 19 21 Great South Bay Moriches Bay Shinnecock Bay Station number (a) Phytoplankton biomass and phosphorus concentration (b) Phytoplankton response to nutrient enrichment Since adding phosphorus, which was already in rich supply, had no effect on Nannochloris growth, whereas adding nitrogen increased algal density dramatically, researchers concluded that nitrogen was the nutrient limiting phytoplankton growth in this ecosystem. CONCLUSION Figure 54.6 What are the Limiting Factors in Marine Ecosystems?

  21. Table 54.1 • Experiments in another ocean region • Showed that iron limited primary production

  22. Figure 54.7 What happens when you have too many nutrients? • Eutrophication of lakes (algae on top prevent light from reaching bottom, dead algae add to biomass and all decrease Oxygen which kills fish, etc

  23. Trophic level Secondary consumers Primary consumers Primary producers • Worldwide agriculture could successfully feed many more people • If humans all fed more efficiently, eating only ________ Figure 54.14

  24. Reservoir a Reservoir b Organic materials available as nutrients Organic materials unavailable as nutrients Fossilization Living organisms, detritus Coal, oil, peat Respiration, decomposition, excretion Assimilation, photosynthesis Burning of fossil fuels Reservoir d Reservoir c Inorganic materials unavailable as nutrients Inorganic materials available as nutrients Weathering, erosion Atmosphere, soil, water Minerals in rocks Formation of sedimentary rock Figure 54.16 • A general model of nutrient cycling • Includes the main reservoirs of elements and the processes that transfer elements between reservoirs

  25. THE CARBON CYCLE THE WATER CYCLE CO2 in atmosphere Transport over land Photosynthesis Solar energy Cellular respiration Net movement of water vapor by wind Precipitation over land Precipitation over ocean Evaporation from ocean Burning of fossil fuels and wood Evapotranspiration from land Higher-level consumers Primary consumers Percolation through soil Carbon compounds in water Detritus Runoff and groundwater Decomposition Figure 54.17 Biogeochemical Cycles • What drives the water cycle versus the Carbon cycle?

  26. How does Nitrogen enter and leave ecosystems?

  27. Consumers Producers Decomposers Nutrients available to producers Abiotic reservoir Geologic processes Figure 54.18 Decomposition and Nutrient Cycling Rates • Decomposers (detritivores) play a key role • In the general pattern of chemical cycling

  28. Why is Phosphorus considered more of a Local nutrient?

  29. 80.0 Deforested 60.0 40.0 20.0 Nitrate concentration in runoff (mg/L) Completion of tree cutting 4.0 Control 3.0 2.0 1.0 0 1967 1965 1966 1968 (c) The concentration of nitrate in runoff from the deforested watershed was 60 times greater than in a control (unlogged) watershed. Figure 54.19c • How does human activityaffect ecosystems?

  30. Figure 54.20 Agriculture and Nitrogen Cycling • Agriculture constantly removes nutrients from ecosystems • That would ordinarily be cycled back into the soil

  31. Nitrogen is the main nutrient lost through agriculture • Thus, agriculture has a great impact on the nitrogen cycle • Industrially produced fertilizer is typically used to replace lost nitrogen • But the effects on an ecosystem can be harmful

  32. Contamination of Aquatic Ecosystems • The critical load for a nutrient • Is the amount of that nutrient that can be absorbed by plants in an ecosystem without damaging it

  33. When excess nutrients are added to an ecosystem, the critical load is exceeded • And the remaining nutrients can contaminate groundwater and freshwater and marine ecosystems

  34. Sewage runoff contaminates freshwater ecosystems • Causing cultural eutrophication, excessive algal growth, which can cause significant harm to these ecosystems

  35. Acid Precipitation • Combustion of fossil fuels • Is the main cause of acid precipitation

  36. 4.6 4.3 4.6 4.3 4.6 4.1 4.3 4.6 Europe Figure 54.21 North America • North American and European ecosystems downwind from industrial regions • Have been damaged by rain and snow containing nitric and sulfuric acid

  37. Field pH 5.3 5.2–5.3 5.1–5.2 5.0–5.1 4.9–5.0 4.8–4.9 4.7–4.8 4.6–4.7 4.5–4.6 4.4–4.5 4.3–4.4 Figure 54.22 4.3 • By the year 2000 • The entire contiguous United States was affected by acid precipitation

  38. Environmental regulations and new industrial technologies • Have allowed many developed countries to reduce sulfur dioxide emissions in the past 30 years

  39. Toxins in the Environment • Humans release an immense variety of toxic chemicals • Including thousands of synthetics previously unknown to nature • One of the reasons such toxins are so harmful • Is that they become more concentrated in successive trophic levels of a food web

  40. Herring gull eggs 124 ppm Lake trout 4.83 ppm Concentration of PCBs Smelt 1.04 ppm Zooplankton 0.123 ppm Phytoplankton 0.025 ppm Figure 54.23 • In biological magnification • Toxins concentrate at higher trophic levels because at these levels biomass tends to be lower

  41. In some cases, harmful substances • Persist for long periods of time in an ecosystem and continue to cause harm

  42. Atmospheric Carbon Dioxide • One pressing problem caused by human activities • Is the rising level of atmospheric carbon dioxide

  43. 1.05 390 0.90 380 0.75 370 Temperature 0.60 360 0.45 350 CO2 concentration (ppm) Temperature variation (C) 0.30 340 CO2 0.15 330 0 320 0.15 310  0.30  0.45 300 1975 1980 1985 1990 1995 2000 2005 1960 1965 1970 Year Figure 54.24 Rising Atmospheric CO2 • Due to the increased burning of fossil fuels and other human activities • The concentration of atmospheric CO2 has been steadily increasing

  44. Figure 54.25 How Elevated CO2 Affects Forest Ecology: The FACTS-I Experiment • The FACTS-I experiment is testing how elevated CO2 • Influences tree growth, carbon concentration in soils, and other factors over a ten-year period

  45. The Greenhouse Effect and Global Warming • The greenhouse effect is caused by atmospheric CO2 • But is necessary to keep the surface of the Earth at a habitable temperature

  46. Increased levels of atmospheric CO2 are magnifying the greenhouse effect • Which could cause global warming and significant climatic change

  47. Depletion of Atmospheric Ozone • Life on Earth is protected from the damaging effects of UV radiation • By a protective layer or ozone molecules present in the atmosphere

  48. 350 300 250 Ozone layer thickness (Dobson units) 200 150 100 50 0 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year (Average for the month of October) Figure 54.26 • Satellite studies of the atmosphere • Suggest that the ozone layer has been gradually thinning since 1975

More Related