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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
All things come from earth and to earth they all
return
  • Menander (342-290 B.C)

3
How environmentally true is the previous
statement? Explain.

4
Main Questions of this chapter
  • What is ecology?
  • What is an ecosystem and its main components?
  • What happens to matter and energy in an ecosystem
    and how does that keep us alive?

5
(No Transcript)
6
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 of rain forest will have three major
    harmful effects
  • Reduce biodiversity
  • Accelerate global warming (burn, less absorption
    of greenhouse gases)
  • Change regional weather patterns

7
Natural Capital Degradation Satellite Image of
the Loss of Tropical Rain Forest
8
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.
  • Ecology is the study of connections in nature

9
Cells Are the Basic Units of Life
  • Cell Theory (all living things are composed of
    cells , the smallest and most fundamental unit of
    life)

Eukaryotic cells have membranes, nucleus and
organelles (internal specialized parts)
10
Prokaryotic cell Has membrane No distinct
nucleus No specialized internal parts All
bacteria consist of a single prokaryotic cell
Stepped Art
Fig. 3-2, p. 52
11
Animation Prokaryotic and eukaryotic cells
12
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

13
_________ of Glassfish in the Red Sea
14
__________ Diversity in a Caribbean Snail
Population
15
Ecologists Study Connections in Nature
  • Levels of organization
  • Population
  • Group of individuals that live in same place
  • Genetic diversity (variation in a population)
  • Habitat place where a population lives
  • Community
  • All populations that live in a particular place
  • Ecosystem
  • Describes the interaction of a community and
    their habitats
  • Biosphere
  • consists of parts of the earth where life is
    found, in effect the largest ecosystem

16
Stepped Art
Fig. 3-3, p. 52
17
Size of ecosystems
  • Range from a puddle of water to an ocean
  • Do not have clear boundaries
  • Not isolated from each other
  • Can be natural or man made

18
Think about the school in terms of how life can
be grouped
  • Populations
  • Communities
  • Ecosystems

19
Are insect populations important to the health of
human populations?
  • Which group needs the other more? Humans or
    insects?

20
Science Focus Have You Thanked the Insects
Today?
  • Pollinators
  • Eat other insects
  • Loosening and renewal of soil
  • Reproduce rapidly (food source)
  • Very resistant to extinction, fast evolutionary
    process

21
Do you think there is a useless population on
earth?
  • Explain your answer by defining the term
    useless first.

22
Active Figure Levels of organization
23
Section Check
  • Q1 Distinguish between a eukaryotic and a
    prokaryotic cell. Name an example of living
    organism that has them for each type.
  • Q3 What of all living species do we have
    information on? Which class of organism most
    likely has the greatest number of species?
  • Q4 What are the main differences between a
    population, a habitat and a ecosystem? Name an
    example of each.

24
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.

25
What are the 4 majors parts (spheres) of the
earth life support system?
26
The Earths Life-Support System Has Four Major
Components
  • Atmosphere
  • Troposphere closest, weather, warmth, air
  • Stratosphere - farther away from surface, ozone
  • Hydrosphere
  • Geosphere- includes interior, minerals, oil, soil
  • Biosphere- all living things in all other spheres

27
Vegetation and animals
Atmosphere
Biosphere
Soil
Rock
Crust
Natural Capital
Lithosphere
Mantle
Biosphere (living organisms)
Atmosphere (air)
Core
Crust (soil and rock)
Mantle
Hydrosphere (water)
Geosphere (crust, mantle, core)
Fig. 3-6, p. 55
28
What is a Biome?
29
Life Exists on Land and in Water
  • Biomes (land)
  • regions of earth with one dominant type of
    environment (Deserts, plains, deciduous
    forests)
  • Aquatic life zones
  • Freshwater life zones
  • Lakes and streams
  • Marine life zones
  • Coral reefs
  • Estuaries
  • Deep ocean

30
Major biomes along 39th parallel in US
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
31
Three Factors Sustain Life on Earth
  • One-way flow of high-quality energy beginning
    with the sun
  • From sun through food cycle to environment
    exiting back into space
  • Dictated by 2nd law of Thermo, high to low
    quality energy
  • Cycling of matter or nutrients
  • Earth is basically closed in terms of matter
  • Nutrients must be recycled, in seconds or in
    centuries
  • Gravity (law of gravity)
  • How does gravity help sustain life on Earth?

32
How does gravity help?
  • Allows earth to hold on to an atmosphere
  • Allows movement of materials, life on earth

33
How do you think the troposphere stays warm?
34
  • The name of the effect is ______________
  • How do you think this effects works?
  • Is this effect natural or man-made?

35
What Happens to Solar Energy Reaching the Earth?
  • UV, visible, and IR energy (forms of
    electromagnetic radiation (waves))
  • Radiation
  • Is absorbed by ozone
  • Is absorbed by the earth
  • Is reflected by the earth, as heat
  • Some is trapped in troposphere
  • The raising heat moves the air , creating wind

36
Energy flow to/from Earth
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
37
Natural Greenhouse Effect
  • Energy from sun is reflected back towards space
    as infrared radiation (felt as heat)
  • Encounter greenhouse gases (CO2, CH4, No3- and
    O3)
  • Causes gas molecules to vibrate more
  • More vibration ? greater KE and Heat
  • Warmer atmosphere and surface

38
1) What if there was no greenhouse effect?
  • 2) What would happen if the greenhouse effect is
    increased?

39
Too cold, or too hot
40
Active Figure Energy flow from the Sun to Earth
41
Section Check
  • Q5 How do the stratosphere and the troposphere
    differ? What are the main benefits humans
    derive from each?
  • Q8 How are Biomes and Aquatic Life Zones
    similar?
  • Q9 What are the 3 factors that sustain life on
    Earth? What the laws that relate to the factor?

42
Section Check Green House Gasses
  • Q6 What are greenhouse gases and how do they
    affect life on the planet?
  • Q10 What is the benefit of the ozone in the
    troposphere? What would be the result if it were
    removed?
  • Q11 How is wind generated by solar energy?
  • Q12 How do greenhouse gases keep the earth warm?

43
3-3 What Are the Major Components of an
Ecosystem?
  • Concept 3-3A Ecosystems contain living (biotic)
    and nonliving (abiotic) components.
  • Concept 3-3B Some organisms produce the
    nutrients they need, others get their nutrients
    by consuming other organisms, and some recycle
    nutrients back to producers by decomposing the
    wastes and remains of organisms.

44
Ecosystems Have Living and Nonliving Components
  • Abiotic Non-living components
  • Water
  • Air
  • Nutrients
  • Rocks
  • Heat
  • Solar energy
  • Biotic
  • Living and once living

45
Precipitation
Oxygen (O2)
Carbon dioxide (CO2)
Major Biotic and Abiotic components of an
Ecosystem
Producer
Secondary consumer (fox)
Primary consumer (rabbit)
Producers
Decomposers
Water
Soluble mineral nutrients
Fig. 3-9, p. 57
46
Identify the autotrophs and heterotrophs (all
levels, groups)
47
List of groups
  • Autotrophs
  • Primary consumers
  • Secondary consumers
  • Tertiary (and higher) consumers
  • Omnivores
  • Decomposers
  • Detritivores

48
Active Figure Roles of organisms in an ecosystem
49
Range of Tolerance
Higher limit of tolerance
Lower limit of tolerance
No organisms
Few organisms
Few organisms
No organisms
Abundance of organisms
Population size
Zone of intolerance
Zone of physiological stress
Optimum range
Zone of physiological stress
Zone of intolerance
Temperature
Low
High
Fig. 3-10, p. 58
50
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
  • Principle of sustainability connection
    population control

51
Producers and Consumers Are the Living Components
of Ecosystems (1)
  • Producers, autotrophs
  • Photosynthesis sunlight-sugar
  • Chemosynthesis no sunlight- not sugar
  • Consumers, heterotrophs
  • Primary- feed off of plants
  • Secondary- feed off of herbivores
  • Third and higher level

52
What type of consumers are they
Insect B
Insect C
Insect A
53
Producers and Consumers Are the Living Components
of Ecosystems (2)
  • Decomposers
  • release nutrients from dead bodies
  • Mushrooms, Bacteria
  • Detritivores-
  • feed off of wastes and the dead
  • Worms and Vultures

54
Producers and Consumers Are the Living Components
of Ecosystems (2)
  • Aerobic respiration
  • uses oxygen to convert sugar (glucose) to CO2
    H2O energy
  • Anaerobic respiration, fermentation
  • does not use oxygen to convert sugar to energy

55
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. 3-11, p. 60
56
The Main Structural Components of an Ecosystem
57
Active Figure Matter recycling and energy flow
58
Animation Energy flow in Silver Springs
59
Who are these guys?
60
Science Focus Many of the Worlds Most
Important Species Are Invisible to Us
  • Microorganisms (Microbes)
  • Bacteria
  • Protozoa
  • Fungi
  • Some Benefits
  • Break down food in our stomachs
  • Protect lungs
  • Purify water
  • Produce foods (bread, cheese, yogurt)
  • Decomposers
  • Phytoplankton take up CO2

61
Questions on 3-3
  • Q13 Distinguish between the abiotic and biotic
    components of an ecosystem.
  • Q19 What is the difference between photosynthesis
    and chemosynthesis? Where does chemosynthesis
    occur on earth?
  • Q15 List an example of a specific organism for
    each of the following categories decomposer,
    secondary consumers, omnivores, producer and
    primary consumers.

62
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.

63
Energy Flows Through Ecosystems in Food Chains
and Food Webs
  • Food chain
  • Food web
  • Difference?

64
A Food Chain
65
Simplified Food Web in the Antarctic
66
Animation Prairie food web
67
Active Figure Rainforest food web
68
Animation Diet of a red fox
69
Animation Prairie trophic levels
70
Usable Energy Decreases with Each Link in a Food
Chain or Web
  • Biomass
  • dry weight of all organic matter on a certain
    level
  • Ecological efficiency
  • of useable energy transferred from one level to
    next.
  • 2-40, 10 average
  • Where does 90 go?
  • Pyramid of energy flow

71
Stepped Art
Fig. 3-15, p. 63
72
Some Ecosystems Produce Plant Matter Faster Than
Others Do
  • Gross primary productivity (GPP)
  • Rate producers solar energy into bio-mass with
    chemical energy
  • Net primary productivity (NPP)
  • GPP energy needed by producers
  • Ecosystems and life zones differ in their NPP
  • Faster rate, more energy available to consumers

73
Understanding the difference between (GPP) and
(NPP)
  • Lab

74
Estimated Annual Average NPP in Major Life Zones
and Ecosystems
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
75
Questions on 3-4
  • Q22 Why cant there be 16 trophic levels in a
    food chain or in food web?
  • Q23 Why is a vegetarian diet more energy
    efficient than a meat based diet?
  • Q25 Why are tigers few in number and the species
    vulnerable to premature extinction because of
    human activites?
  • Q26 Why are there so many insects in the
    world?

76
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.

77
Nutrients Cycle in the Biosphere
  • Biogeochemical cycles, nutrient cycles
  • Hydrologic
  • Carbon
  • Nitrogen
  • Phosphorus
  • Sulfur
  • Connect past, present, and future forms of life

78
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

79
Hydrologic Cycle Including Harmful Impacts of
Human Activities
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
80
Active Figure Hydrologic cycle
81
Water cycle Lab
82
Biogeochemical Cycles lab
83
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

84
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

85
Carbon dioxide in atmosphere
Carbon Cycle
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
86
Active Figure Carbon cycle
87
Nitrogen Cycles through the Biosphere Bacteria
in Action (1)
  • Nitrogen fixation
  • Lightning (ionizes the nitrogen in air)
  • Nitrogen-fixing bacteria and blue green
    algae(combine gas N2 and H to make ammonia)
  • Nitrification
  • converted to ammonia ions- bacteria
  • Then converted to proteins, nucleic acids,
    vitamins, amino acids- plants
  • Products used by animals
  • Denitrification reverse process

88
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

89
Nitrogen in atmosphere
Denitrification by bacteria
Electrical storms
Nitrogen in animals (consumers)
Nitrogen oxides from burning fuel and using
inorganic fertilizers
Nitrogen cycle
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
90
Active Figure Nitrogen cycle
91
Annual Increase in Atmospheric N2 Due to Human
Activities
92
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

93
Processes
Phosphorous Cycle
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
94
Animation Phosphorus cycle
95
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

96
Sulfur Cycle
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
97
Active Figure Sulfur cycle
98
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.

99
Some Scientists Study Nature Directly
  • Field research muddy-boots biology
  • New technologies available
  • Remote sensors
  • Geographic information system (GIS) software
  • Digital satellite imaging

100
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

101
Some Scientists Use Models to Simulate Ecosystems
  • Computer simulations and projections
  • Field and laboratory research needed for baseline
    data

102
We Need to Learn More about the Health of the
Worlds Ecosystems
  • Determine condition of the worlds ecosystems
  • More baseline data needed

103
Your Questions?
  • Connected to the information presented in this
    chapter

104
UN Project Questions
  • What are the main foods for the middle class and
    poor in your country? On what trophic level are
    the most common foods of the poor and middle
    class come from?
  • List the main Biomes type that exist in your
    country. Using your textbook, determine the NPP
    for the major biomes.
  • Describe some producers, herbivores, carnivores,
    decomposers and scavengers that are native to
    your country
  • What are some of the human based effects on the
    major nutrient cycle?
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