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Ecosystems: What Are They and How Do They Work?

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Title: Ecosystems: What Are They and How Do They Work?


1
Ecosystems What Are They and How Do They Work?
  • Chapter 3

2
Core Case Study Tropical Rain Forests Are
Disappearing
  • Cover about 2 of the earths land surface
  • Contain about 50 of the worlds 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
Cells Are the Basic Units of Life
  • Cell Theory
  • Eukaryotic cell
  • Prokaryotic cell

5
Species Make Up the Encyclopedia of Life
  • Species
  • 1.75 Million species identified
  • Insects make up most of the known species
  • Perhaps 1014 million species not yet identified

6
Ecologists Study Connections in Nature
  • Ecology
  • Ecology is the study of how organisms interact
    with one another and with their physical
    environment of matter and energy.
  • Levels of organization
  • Population
  • Genetic diversity
  • Community
  • Ecosystem
  • Biosphere

7
Stepped Art
Fig. 3-3, p. 52
8
Genetic Diversity in a Caribbean Snail Population
9
Importance of Insects
Displays of Evolution
Eat other insects
Pollinators
Loosen and renew soil
10
Importance of Insects
Fun!
Reproduce rapidly
Very resistant to extinction
11
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.

12
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

13
The Earths Life-Support System Has Four Major
Components
  • Atmosphere
  • Troposphere
  • (inner layer-contains most of what we breathe,
    also contains greenhouse gases)
  • Stratosphere
  • (outer layer-protects us from the suns UV, also
    contains the ozone)
  • Hydrosphere
  • consists of water on or near the earths surface
  • Geosphere
  • consists of earths core, mantle (thick-mainly
    rock), and crust (thin)
  • Biosphere
  • parts of the hydrosphere, geosphere, and
    atmosphere where life exists

14
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
15
Life Exists on Land and in Water
  • Biomes
  • Aquatic life zones
  • Freshwater life zones
  • Lakes and streams
  • Marine life zones
  • Coral reefs
  • Estuaries
  • Deep ocean

16
Major Biomes along the 39th Parallel in the U.S.
17
Three Factors Sustain Life on Earth
  • One-way flow of high-quality energy beginning
    with the sun
  • Cycling of matter or nutrients
  • Gravity

18
3-3 What Are the Major Components of an
Ecosystem?
  • Concept 3-3A Ecosystems contain living (biotic)
    and nonliving (abiotic) components.
  • Abiotic Biotic Water Living and once
    living Air Nutrients Rocks Heat Solar energy

19
Nutrient Cycling
  • Some organisms produce the nutrients they need
  • Plants (photosynthesis)
  • Bacteria (chemosynthesis)
  • Others get their nutrients by consuming other
    organisms
  • Consumers
  • Primary (plant eaters-herbivores)
  • Secondary, Tertiary, etc. (meat
    eaters-carnivores)
  • Some recycle nutrients back to producers by
    decomposing the wastes and remains of organisms
  • Decomposers and Detritivores

20
Oxygen (O2)
Precipitation
Carbon dioxide (CO2)
Producer
Secondary consumer (fox)
Primary consumer (rabbit)
Producers
Water
Decomposers
Soluble mineral nutrients
Fig. 3-9, p. 57
21
Detritivores and Decomposers on a Log
22
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.

23
  • Ecosystems differ in energy productionwhat are
    the most productive systems?
  • Do you see any problem with our choices in
    regards to these systems?

24
A Food Chain
25
Simplified Food Web in the Antarctic
26
Pyramid of Energy Flow
27
Several Abiotic Factors Can Limit Population
Growth
  • Limiting factor principle
  • 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 optimal
    range of tolerance

28
Range of Tolerance for a Population of Organisms
  • INSERT FIGURE 3-10 HERE

29
Producers and Consumers Are the Living Components
of Ecosystems (2)
  • Detritivores
  • Aerobic respiration
  • Anaerobic respiration, fermentation

30
Science Focus Many of the Worlds Most
Important Species Are Invisible to Us
  • Microorganisms
  • Bacteria
  • Protozoa
  • Fungi

31
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.

32
Nutrients Cycle in the Biosphere
  • Biogeochemical cycles, nutrient cycles
  • Hydrologic
  • Carbon
  • Nitrogen
  • Phosphorus
  • Sulfur
  • Connect past, present , and future forms of life

33
Water Cycles through the Biosphere
  • Natural renewal of water quality three major
    processes
  • Evaporation
  • Precipitation
  • Transpiration
  • Alteration of the hydrologic cycle by humans
  • Withdrawal of large amounts of freshwater at
    rates faster than nature can replace it
  • Clearing vegetation
  • Increased flooding when wetlands are drained

34
Hydrologic Cycle Including Harmful Impacts of
Human Activities
35
Global warming
Condensation
Condensation
Ice and snow
Evaporation from land
Evaporation from ocean
Transpiration from plants
Precipitation to land
Surface runoff
Increased flooding from wetland destruction
Precipitation to ocean
Runoff
Reduced recharge of aquifers and flooding from
covering land with crops and buildings
Lakes and reservoirs
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
36
Science Focus Waters 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 100C
  • Adhesion and cohesion
  • Expands as it freezes
  • Solvent
  • Filters out harmful UV

37
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

38
Natural Capital Carbon Cycle with Major Harmful
Impacts of Human Activities
39
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
40
Nitrogen Cycles through the Biosphere Bacteria
in Action (1)
  • Nitrogen fixed
  • Lightning
  • Nitrogen-fixing bacteria
  • Nitrification
  • Denitrification

41
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

42
Nitrogen Cycle in a Terrestrial Ecosystem with
Major Harmful Human Impacts
43
Processes
Nitrogen in atmosphere
Reservoir
Pathway affected by humans
Natural pathway
Denitrification by bacteria
Electrical storms
Nitrogen in animals (consumers)
Nitrogen oxides from burning fuel and using
inorganic fertilizers
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
44
Annual Increase in Atmospheric N2 Due to Human
Activities
45
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
2050
2000
1980
1960
1940
1920
1900
Year
Fig. 3-20, p. 70
46
Phosphorus Cycles through the Biosphere
  • Cycles through water, the earths crust, and
    living organisms
  • May be limiting factor for plant growth
  • Impact of human activities
  • Clearing forests
  • Removing large amounts of phosphate from the
    earth to make fertilizers

47
Phosphorus Cycle with Major Harmful Human Impacts
48
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 webs
Animals (consumers)
Phosphate dissolved in water
Phosphate in shallow ocean sediments
Phosphate in deep ocean sediments
Plants (producers)
Bacteria
Fig. 3-21, p. 71
49
Sulfur Cycles through the Biosphere
  • Sulfur found in organisms, ocean sediments, soil,
    rocks, and fossil fuels
  • SO2 in the atmosphere
  • H2SO4 and SO4-
  • Human activities affect the sulfur cycle
  • Burn sulfur-containing coal and oil
  • Refine sulfur-containing petroleum
  • Convert sulfur-containing metallic mineral ores

50
Natural Capital Sulfur Cycle with Major Harmful
Impacts of Human Activities
51
Sulfur dioxide in atmosphere
Sulfuric acid and Sulfate deposited as acid rain
Smelting
Burning coal
Refining fossil fuels
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. 3-22, p. 72
52
Active Figure Carbon cycle
53
Active Figure Hydrologic cycle
54
Animation Linked processes
55
Active Figure Nitrogen cycle
56
Animation Phosphorus cycle
57
Active Figure Sulfur cycle
58
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.

59
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)

60
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

61
Some Scientists Use Models to Simulate Ecosystems
  • Computer simulations and projections
  • Field and laboratory research needed for baseline
    data

62
We Need to Learn More about the Health of the
Worlds Ecosystems
  • Determine condition of the worlds ecosystems
  • More baseline data needed
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