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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
  • Dr. Wesam Al Madhoun

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
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 1014 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
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 Earths 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 earths 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
100125 cm (4050 in.) 75100 cm (3040
in.) 5075 cm (2030 in.) 2550 cm (1020
in.) below 25 cm (010 in.)
Denver
Baltimore
San Francisco
St. Louis
Appalachian Mountains
Coastal mountain ranges
Sierra Nevada
Great American Desert
Rocky Mountains
Great Plains
Mississippi River Valley
Deciduous forest
Coastal chaparral and scrub
Coniferous forest
Desert
Coniferous forest
Prairie grassland
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 Worlds 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
Tertiary consumers (top carnivores)
Producers (plants)
Primary consumers (herbivores)
Secondary consumers (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
Heat
Decomposers
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
4,000
9,600
8,800
800
1,600
2,400
8,000
7,200
3,200
6,400
5,600
4,800
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
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
40
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
  • 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 ammo
    nia 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 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
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
2050
2000
1980
1960
1940
1920
1900
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
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